The Australian Primary Standard of Air Kerma for
60Co Radiation (the Carbon Cavity Chamber)
by
Christopher P Oliver, John F Boas, Neville J Hargrave,
Robert B Huntley, Lew H Kotler and Keith N Wise
Technical Report 155 619 Lower Plenty Road
ISSN 0157-1400 Yallambie Vic 3085
April 2011 Telephone: +61 3 9433 2211
Fax: + 61 3 9432 1835
Notice
Commonwealth of Australia 2011
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ABSTRACT
The Australian primary standard of air kerma for 60Co radiation is a carbon
(graphite) cavity chamber maintained by ARPANSA. It is a thick walled double
pancake chamber similar to the international reference standard held at the Bureau
International des Poids et Mesures (BIPM). The realisation of the reference air kerma
rate relies on the calculation of a number of correction factors and physical constants.
These fall into two categories, the first of which relate to calculating the dose to the
gas inside the chamber and are experimentally determined. The second relate to
converting the dose to the gas in the chamber to the air kerma rate at that point in
space in the absence of the chamber. The method of evaluation and values for all
parameters is presented. Monte Carlo methods have been recently used to replace a
number of correction factors. As a result, changes to the standard are presented. A
new 60Co source was installed at ARPANSA in February 2010. This report will finalise
all work done with the previous 60Co source and air kerma primary standard.
Appendix 3 gives preliminary details of a comparison with the BIPM in 2010 using
the new ARPANSA 60Co source.
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Table of Contents
ABSTRACT ................................................................................................................. II
1. INTRODUCTION ................................................................................................... 1
2. BASIC DOSIMETRY THEORY ............................................................................. 2
3. DESCRIPTION OF THE ARPANSA CARBON CAVITY CHAMBER ................... 3
4. THE DETERMINATION OF THE AIR KERMA RATE .......................................... 5
5. DETERMINATION OF THE CHAMBER PARAMETERS AND THE
PHYSICAL CONSTANTS AS AT 2001 ................................................................ 6
5.1 Determination of the chamber volume ........................................................... 6
5.2 Ratio of the mean mass energy absorption coefficients ................................. 6
5.3 Mean energy required to produce an ion pair ................................................ 6
5.4 Stopping power ratio ....................................................................................... 6
5.5 Uncertainties in the product (W/e).sc,a............................................................7
5.6 Density of air ....................................................................................................7
5.7 Fraction of energy dissipated outside the cavity ............................................ 8
5.8 Other physical parameters relevant to the ARPANSA graphite cavity
chamber ........................................................................................................... 8
6. THE CORRECTION FACTORS AND THEIR DETERMINATION AS AT 2001 .... 9
6.1 Correction factors and uncertainties applied to the measurement of the
current ............................................................................................................. 9
6.2 Correction factors related to the physical and structural characteristics
of the chamber ................................................................................................ 11
7. MONTE-CARLO CALCULATIONS OF THE CORRECTION FACTORS BY
K N WISE IN 2001 .............................................................................................. 17
7.1 History and reasons for moving to Monte Carlo methods ............................ 17
8. MONTE CARLO MODELLING IN 2009 BY C P OLIVER. ................................. 19
8.1 Primary standard chamber modelling .......................................................... 20
8.2 kwall ................................................................................................................. 22
8.3 kan................................................................................................................... 22
8.4 ............................................................................................................... 23
8.5 .............................................................................................................. 23
8.6 ............................................................................................................ 23
8.7 krn in 2009 ..................................................................................................... 24
8.8 Changes to the Standard using new Monte Carlo values ............................. 25
8.9 Monte Carlo Uncertainties ............................................................................ 26
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9. MEASUREMENTS OF THE AIR KERMA RATE AND ITS UNCERTAINTY
BASED ON THE ARPANSA GRAPHITE CAVITY CHAMBER .......................... 30
10. REFERENCES .................................................................................................... 31
APPENDIX 1: Comparisons with the BIPM and the continuity of the
Australian standard of air kerma .............................................. 34
A1.1 The 1988 comparison between ARL and BIPM ................................................. 34
A1.2 The 1997 comparison between ARPANSA and BIPM........................................ 34
A1.3 90Sr check source results ..................................................................................... 35
A1.4 Uncertainties ...................................................................................................... 35
A1.5 Continuity of the Australian standards of air kerma........................................ 35
APPENDIX 2: Indirect comparisons of air kerma standards ......................... 37
A2.1 Equipment and Radiation Sources .....................................................................37
A2.2 Transfer Chamber Measurements ..................................................................... 38
A2.3 Uncertainties ...................................................................................................... 40
APPENDIX 3: 2010 intercomparison of air kerma primary standards for
Co-60 with the BIPM................................................................... 42
APPENDIX 4: 2009 Monte carlo input files ...................................................... 47
A4.1 Co-60 spectrum .................................................................................................. 47
A4.2 kwall – The following file was input to cavrznrc to calculate the kwall
correction. ............................................................................................................ 51
A4.3 kan – The following two files were used to calculate kan. File 1 uses a
parallel beam and File 2 uses the non-parallel beam ........................................57
A4.4 - The following input file was used with sprrznrc to calculate the
stopping power ratio. ......................................................................................... 69
A4.5 - The following input file was used with g to calculate the correction
for bremsstrahlung loss ......................................................................................75
A4.6 The following two files were used with dosrznrc to calculate the
mass energy transfer coefficients ...................................................................... 76
A4.7 krn – The following radial profile of the Co-60 beam produced using
beamdp was used for the Monte Carlo determination of krn. ........................... 87
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1. INTRODUCTION
The Australian primary standard of exposure or air kerma for 60Co radiation is a
thick-walled pancake graphite cavity chamber similar in design to that described by
Boutillon and Niatel (1973). It was designed and tested during the period 1982-1988
and was indirectly compared with the BIPM standard of exposure for 60Co gamma
radiation in 1988 (Perroche and Hargrave 1989), 1997 (Allisy-Roberts et al. 1989)
and 2010 (Allisy-Roberts et al. To be published). As well as the comparisons with the
BIPM, Australian standards of air kerma have been compared with a number of other
National standards e.g. those held by NRL (New Zealand), NPL (UK), NRCC Canada)
and INER (Taiwan).
This report describes the present status of the Australian primary standard of air
kerma for 60Co radiation and of the correction factors as applied to the standard as at
01/01/2011.
This report has the following aims:
To document the present status of the physical constants, correction factors and
their uncertainties as of January 1, 2011, as used in the determination of the air
kerma rate at ARPANSA.
To indicate where these differ from the values used previously, particularly those
used in the 1988 and 1997 comparisons of air kerma standards with the BIPM.
To outline the means by which the correction factors were calculated by one of us
(NJH) during the period 1982-1988 and the results of a re-evaluation carried out
during 1997-2000, and a further re-evaluation in 2009.
To indicate the implications on the standard for the correction factors evaluated
using Monte Carlo methods in 2009.
It has been argued that the earlier correction factor calculations based on the work of
Boutillon and Niatel (1973) are not sufficiently rigorous in an era of Monte Carlo
calculations. The Monte Carlo calculations of 2009 result in an increase of 0.56% in
the air kerma rate which decreases the difference between the ARPANSA primary
standard and most other international primary standards.
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2. BASIC DOSIMETRY THEORY
For a cavity chamber, the quantity of air kerma, K, is evaluated at ARPANSA by the
expression
Q W 1 sc ( en / ) a
K ( )( )
V e (1 g ) s a ( en / ) c
k i (1)
where:
Q is the charge produced in the volume of dry air V with density ρ
W is the average energy required to produce an ion pair in dry air
e is the electronic charge
g is the fraction of energy which is dissipated outside the cavity through
bremsstrahlung radiation produced in the cavity.
sc and sa are the mass stopping powers of graphite and air
(μen/ρ)a and (μen/ρ)c are the mass-energy absorption coefficients of air and
graphite respectively
Πki is the product of all the correction factors described below in Section 6.
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3. DESCRIPTION OF THE ARPANSA CARBON CAVITY
CHAMBER
The ARPANSA carbon cavity chamber was machined from homogeneous graphite
and consists of an annular ring and two end plates, forming a right circular cylinder
enclosing a cylindrical graphite disc. The disc acts as the central electrode and is
supported by aluminium rods, anchored through Teflon to the annular ring. The
electrical connection also acts as a support and passes through an insulating bush
inside an aluminium stem attached to the outside of the annular ring.
The dimensions of the components of the chamber were measured with certified
depth gauges and measuring blocks traceable to Australian measurement standards.
The results are shown in Table 1, with the dimensions of the similar chamber at
BIPM, (Boutillon and Niatel 1973) also shown for comparison. The calculations of the
chamber volume were re-examined in 1997, giving the result in Table 1, which is
0.11% higher than that used for the 1988 comparison with BIPM. A re-calculation in
2001 gave a result comparable to that of 1997 when rounding-off errors are
considered. The volume corrections for the ARPANSA chamber are estimates
accounting for the volume of the cavity taken up by the support structures of the
central electrode and the stem. A re-evaluation in 2010 resulted in an increase in the
volume of 0.13% (see Appendix 3).
Figure 1: Front radiograph, side radiograph and photo of the carbon cavity chamber
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Table 1: Dimensions and physical properties of the ARPANSA and BIPM
graphite cavity chambers. Values for the ARPANSA chamber
given in parentheses are the results of the re-calculation in 2001
BIPM (1973) ARPANSA (1997)
Graphite density (g/cm3) 1.84 1.726
Annulus wall thickness (mm) 2.75 2.721
Mean front and rear wall thickness (mm) 2.829 2.821
Internal diameter (mm) 41.999 45.023
Internal depth (mm) 5.130 5.150 1
Collecting electrode diameter (mm) 40.982 41.013 2
Collecting electrode thickness (mm) 1.019 5 1.002
Collecting electrode volume (mm3) 1344.82 1324.95 (1323.75)
Volume corrections (mm3) -28.49
Chamber volume (mm3) 6811.6 6845.7 (6847.0)
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4. THE DETERMINATION OF THE AIR KERMA RATE
The air kerma rate on the beam axis at the central plane of the chamber is given by
Equation 1 with Q replaced by Im. Im is the mean of the currents measured with
voltages of positive and negative polarity applied to the chamber , and the other
symbols have the meanings as described in Section 2. The correction factors and their
uncertainties are discussed in detail in Section 6.
The air kerma rate at ARPANSA is determined under the following conditions:
the reference distance between the effective centre of the source and the
geometric centre of the graphite cavity chamber is 993 mm
the field size in air at the reference distance is a square, approximately 10 cm × 10
cm
the photon fluence rate at the centre of each side of the square is approximately
50% of the photon fluence rate at the centre of the square
the polarising voltage applied to the chamber is 120 V and the current is taken as
the mean of the currents obtained when the central electrode is positive and
negative with respect to the chamber wall
one of the flat walls is identified as the front wall and the chamber is always
aligned so that this wall faces the source
the measured current is converted to the conditions of 20°C, 101.325 kPa and
50% relative humidity by the computer associated with the ARPANSA current
integrator. The humidity correction factor is then applied to convert the current
to that at the standard reference conditions for air kerma of 20°C, 101.325 kPa
and dry air (ie 0% RH). The uncertainties in Table 3 include those arising from
both steps
the chamber stem is evacuated to less than 1 kPa with a rotary backing pump
the K value is the mean of all sets of measurements made with the graphite cavity
chamber since the installation of the 60Co source in March 1995 and corrected to
the reference date of the comparison. The half life of 60Co was taken as 1925.5 d,
σ = 0.5 d (IAEA 1991).
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5. DETERMINATION OF THE CHAMBER PARAMETERS AND THE
PHYSICAL CONSTANTS AS AT 2001
The physical constants and chamber parameters applicable to the ARPANSA graphite
cavity chamber are listed in Table 2 and are discussed together with their
uncertainties in the following sections.1
5.1 Determination of the chamber volume
This was evaluated as described in Section 3.
5.2 Ratio of the mean mass energy absorption coefficients
(en/ρ)a,c is the ratio of the mean mass energy absorption coefficients of air and
graphite and was obtained by the convolution of the photon energy fluence spectrum
from the 60Co source at a distance of 1 metre, obtained by a Monte Carlo simulation
(Kotler 1993) with the mass-energy absorption coefficients of Higgins et al. (1993).
The value obtained of 0.9993 is that used in the 1997 comparison of the air kerma
standards of ARPANSA and BIPM (Allisy-Roberts et al 1989) and is slightly higher
than the value of 0.9987 used earlier (Perroche and Hargrave 1989). The latter was
calculated for photon beams of energy 1.25 MeV with no scattered radiation. It should
be noted that the calculations show that approximately 25% of the photon flux at a
distance of 1 metre from the source arise from scattered radiation. The scattered
radiation component is larger than the 14 % reported for the BIPM beam.
The uncertainty in the ratio arises from two components, with the Type A uncertainty
being obtained from the statistical uncertainty in the calculation and the Type B
uncertainty being estimated from the uncertainties in the coefficients themselves.
The estimate of the Type B uncertainty is obtained as follows. The uncertainty of the
ratio may range from zero if the uncertainties of the coefficients are completely
correlated to about 0.5% if they are not (Higgins et al. 1993). Since all values between
0 and 0.5% may be equally probable, we treat the distribution as rectangular which
gives an uncertainty of 0.14%.
5.3 Mean energy required to produce an ion pair
W is the average energy spent by an electron of charge e to produce an ion pair in dry
air. The value of W/e recommended by the CCEMRI(I) is 33.97 J/C (BIPM 1985).
5.4 Stopping power ratio
sc,a is the ratio of the mean stopping powers of graphite and air. It was obtained by
interpolation from Rogers et al. (1985, 1986) to the density of the graphite in the
ARPANSA cavity chamber of 1.726 g/cm3. This value, 1.0004, was used in the 1988
1 The uncertainties in this comparison are expressed as relative standard uncertainties where si;(vi)
represents the type A relative uncertainty uA(xi )/ x i assessed by statistical means and with the
number of degrees of freedom in parentheses and ui represents the Type B relative standard
uncertainty uB(xi )/ x i assessed by other means.
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(Perroche and Hargrave 1989) and 1997 (Allisy-Roberts et al. 1989) comparisons
ofthe air kerma standards of ARPANSA and BIPM. The calculations of Rogers et al.
(1985, 1986) used the stopping power ratios of Berger and Seltzer (1982).
Table 2: Physical constants and other parameters applicable to the
ARPANSA graphite cavity chamber and their relative standard
uncertainties used in the 1997 BIPM comparison
Relative standard
ARPANSA uncertainty
Parameter
value
100 si ; (vi ) 100 ui
V / cm3 6.8470 0.02: (64) 0.05
ρa / kg.m-3 1.2930(1) ----- 0.01
( / )
( en / ) a ,c en air
0.9993 0.05 0.14
( / )
en graphite
s graphite
s c, a 1.0004 ------ 0.11(2)
S air
W/e (J/C) 33.97
1-g 0.9968 ----- 0.02
Quadratic sum 0.05
.19
Combined uncertainty 0.20
(1) For 0°C, 101.325 kPa and no compressibility correction. For 20°C, 101.325 kPa and including the
compressibility correction, the value is 1.20447 (Davis 1992)
(2) Uncertainty in the product (W/e).sc,a , see below.
5.5 Uncertainties in the product (W/e).sc,a
The uncertainties of W/e and sc,a are expressed as the uncertainty of the product,
(W/e).sc,a, where the combined uncertainty of the product is less than the
uncertainties of the components. This arises because the components are not derived
by completely independent means (Boutillon and Perroche 1985, Niatel et al. 1985,
Rogers 1995a). The value given here of 0.11% is that proposed by the CCRI(I) at its
1999 meeting (Allisy-Roberts et al. 1999) for use by all National Metrology Institutes
(NMIs) for the purpose of analysing key comparison data.
5.6 Density of air
The quantity air kerma has very largely replaced exposure. It is defined as the kinetic
energy released per unit mass of dry air for particular reference conditions of
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temperature and pressure, not limited to STP. Previously the Australian primary
standard of air kerma was realised as being that at 0 ºC and 101.325 kPa using the
density of air given by BIPM for these conditions, namely 1.2930 kg/m3. However, we
have now suggested that it be realised for a temperature of 20 ºC and a pressure of
101.325 kPa, where the density of dry air is evaluated (Davis 1992) as 1.20447 kg/m3.
This expression includes the air compressibility correction factor.
This factor has previously been included as an explicit correction term in the
expression for the determination of air kerma. If the previous density of dry air is
used together with Boyle‟s and Charles‟ laws, but no air compressibility correction
factor, a dry air density of 1.20479 kg/m3 is obtained for 20 ºC, 101.325 kPa. The new
value of 1.20447 kg/m3 leads to an increase in the air kerma rate of 0.026%.
5.7 Fraction of energy dissipated outside the cavity
The factor g is the fraction of the energy deposited in the air cavity which is converted
to bremsstrahlung and thus dissipated outside the air cavity. The value recommended
by the CCEMRI(I) for 60Co is 0.003 2 (Boutillon 1985) Although this value was
promulgated in 1985, a more recent calculation by Borg et al. (Borg et al. 2000) gives
the same value, namely 0.0032 with an uncertainty of 5% i.e. a correction factor of
0.9968 with a relative standard uncertainty of 0.02%.
5.8 Other physical parameters relevant to the ARPANSA graphite
cavity chamber
The following physical parameters do not explicitly appear in equation 1 but are
required for the estimation of the correction factors.
The linear attenuation coefficient was determined experimentally from the
measurement of the chamber current as graphite discs were progressively placed in
the beam at the end of the lead collimator attached to the source housing. A non-
linear, least squares fit to the equation
x
I a e (2)
gave = 0.010391 mm-1 with an asymptotic standard error of 0.48%. The effect of the
difference between this value and that of 0.010381 mm-1 used previously is not
significant.
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6. THE CORRECTION FACTORS AND THEIR DETERMINATION
AS AT 2001
Πki is the product of the correction factors related to the physical characteristics of
the chamber and to the measurement of the current. It is given by
k k k k k k k k k k k k k k
i s T P RH d t blb st an rn cep sc at
(3)
These correction factors and their relative standard uncertainties are discussed below
and are listed in Tables 3 and 5.
6.1 Correction factors and uncertainties applied to the measurement of
the current
6.1.1 Correction for incomplete charge recombination
The saturation correction factor ks is applied to the measured ionisation current to
correct for the incomplete collection of charge due to recombination. For the
continuous radiation case applicable to 60Co beams, we use the initial recombination
model (Kara-Michaelova and Lea 1940) where ks is given by
k I I
s
s 1 a
V
m (4)
where Is is the current at saturation i.e. at infinite collecting potential and Im is the
measured current at the voltage applied to the chamber, V. The usual polarising
voltage applied to the chamber is ±120V.
6.1.2 Temperature correction factor
The temperature correction factor kT, corrects the measured chamber current for
changes in the mass of air enclosed in the chamber which arise from ambient
temperature changes. At ARPANSA all measured currents are automatically
corrected to the reference condition of 293.15 K (20o Celsius) by the computer
associated with the current integrator. For an ideal gas, the temperature correction
factor is given by
k T (273 .15 T )
293 .15 (5)
where T is the measured temperature in degree Celsius. The correction is made using
Boyle‟s Law, without allowing for air compressibility. Since the temperature in the
ARPANSA laboratory is usually maintained at 22 ± 1 ºC, the additional uncertainty
introduced by neglect of this correction factor is less than 0.01%.
The ambient temperature is measured with linearised thermistors calibrated
regularly against either certified mercury in glass thermometers or a platinum
resistance thermometer. Both are traceable to the standards maintained at the
National Measurement Laboratory (NML).
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6.1.3 Pressure correction factor
The pressure correction factor kP corrects the ionisation chamber current for the
changes in the mass of air enclosed by the chamber as a result of ambient pressure
changes. All measurements at ARPANSA are corrected to standard atmospheric
pressure, namely 101.325 kPa, where the pressure correction is given by
k 101.35 P
p
a (6)
where Pa is the measured ambient pressure in kPa. It is assumed that the gas is ideal
and Charles‟ law is followed. The uncertainty introduced by neglect of air
compressibility is assumed to be less than 0.01%.
The value of the ambient pressure used by the computer associated with the
ARPANSA current integrator is measured by a capacitance manometer which is
regularly calibrated by a Kew pattern mercury barometer traceable to national
standards maintained at NML. The correction of the current to that at a pressure of
101.325 kPa is automatically applied by the ARPANSA computer controlled current
integrator.
6.1.4 Humidity correction factor
The factor kRH is for the relative humidity correction. This corrects the ionisation
chamber current for the effect of the variation in water content of the air. A correction
to 50% relative humidity is automatically applied during the internal processing of
the ionisation current measurements (for both the carbon cavity primary standard
chamber and the transfer standard chambers) by the ARPANSA computer controlled
current integrator. Thus the output of this device is the ionisation current corrected
to 50% relative humidity. To convert this to dry air a further correction factor of
0.9971 is applied to the carbon cavity chamber current for 60Co radiation. The
correction factor for a given measured relative humidity is obtained from an
empirical formula derived by Hargrave (1981). A more recent evaluation of the
humidity correction (Rogers and Ross 1988) also obtains a correction factor of
0.9971.
The relative humidity is measured by means of either dial hygrometers or an
electronic humidity sensor. All hygrometers are checked on a regular basis against an
aspirated wet and dry bulb hygrometer.
6.1.5 Background, leakage and bias current correction factor
Background, leakage effects and bias currents at ARPANSA have been found to be
approximately 1 fA for both the primary standard graphite chamber and for
ionisation chambers when the ARPANSA current integrator is used. The correction
factor for these effects, kblb is taken as 1.0000 with a relative standard uncertainty of
0.01%. BIPM includes a multiplicative correction factor to account for leakage
currents observed in the absence of applied voltage.
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6.1.6 The correction factor for air compressibility
The air compressibility correction factor kz arises from the deviation of air from ideal
gas behaviour. It is included in the calculation of the air density and is mentioned
here only for completeness.
Table 3: Correction factors applied to the measurement of the current
from the ARPANSA graphite cavity chamber and their relative
standard uncertainties in the 1997 BIPM comparison
100 si;
Factor Value 100 ui
(vi)
ks (recombination) 1.0012 ------- 0.030
kT ambient to 20°C --------- ------ 0.017
20°C to 0°C 1.0732
kP (ambient pressure to 101.325 kPa) -------- ------ 0.020
kRH ambient to 50% RH --------- ---------- 0.010
50% RH to dry air) 0.9971 ---------- 0.010
kd (distance to ref. Dist.) 993.00 mm ------ 0.030
kt (source decay) 0.010
kblb (background, leakage and bias 1.0000 0.010
current)
current measurement Calibration 0.007
Repeatability 0.053:5
Quadratic sum 0.053 0.053
Combined uncertainty 0.075
6.2 Correction factors related to the physical and structural
characteristics of the chamber
The derivation of these correction factors closely follows the treatment of Boutillon
and Niatel (1973), for the BIPM chamber in which the numerical values of the factors
are obtained by a combination of experiment and calculation. Some factors could be
wholly or partially determined by experiments with the ARPANSA carbon cavity
chamber similar to those described by Boutillon and Niatel (1973). Some of the terms
in the expressions for the correction factors could be calculated using the parameters
appropriate to the ARPANSA chamber, such as dimensions and graphite density
whilst for others it was necessary to use the original values (Boutillon and Niatel
1973) for the BIPM chamber. There are also a number of common terms in the
expressions for the correction factors and these are discussed under the correction
factors where they first appear.
6.2.1 The stem scatter correction factor
The stem scatter correction factor, kst, was determined experimentally (Boutillon and
Niatel 1973) by attaching a dummy stem to the annular ring in a position
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diametrically opposite to the actual stem. The mean current from the cavity chamber
with the dummy stem in place was 9.3625 nA (12 measurements; sd = 0.25%) and
with the dummy stem removed was 9.3492 nA (10 measurements; sd = 0.17%).
Assuming that the stems have no influence on each other, the scatter from a single
stem may be estimated to make a contribution of 0.142% to the measured current.
Thus the correction factor may be estimated as 0.9986, with a relative standard
uncertainty of 0.09% based on an assumed rectangular distribution. The value of kst
for the BIPM chamber was 1.0000, with a relative standard uncertainty of 0.01%.
6.2.2 The wall attenuation correction
The wall attenuation correction kat was evaluated following the earlier procedure
(Boutillon and Niatel 1973). The expression for kat is reproduced below.
Ap Ap
k at (1 )[ e ( z1m z1 ) e / 2 (1 )e ( z1m z1 ) ] e ( z2 z1 ) / 2
Ac Ac (7)
In this equation, Ap and Ac are the cross-section areas of the collecting plate (central
electrode) and cavity respectively, is the linear attenuation coefficient of the wall
material, e is the thickness of the collecting plate, z is the abscissa on the beam axis of
a plane perpendicular to Oz (better understood as the distance from the source (O) to
the point z on the beam axis) and z1, z1m, zm and z2 are the distances from O to the
incident face of the front wall, the exit face of the front wall, the geometric centre of
the cavity (assumed to be the same as the mid-point of the electrode) and the exit face
of the rear wall. The only term in this equation unable to be evaluated independently
of the earlier work (Boutillon and Niatel 1973) is , the fraction of the total ionisation
current due to electrons originating in the side wall of the chamber. Their estimated
value of = 0.14 gives kat = 1.0389 for the BIPM chamber, with an uncertainty of
0.12%. More recently, BIPM have used kat = 1.0402 with an uncertainty of about
0.04%. (Allisy-Roberts et al 1989).
Experiments in which increasing thicknesses of side wall material were progressively
added to a chamber with an original side wall thickness of 0.5 mm could not be
performed. Figure 4 (Boutillon and Niatel 1973) shows the relative ionisation current
as a function of wall thickness, from which a value of = 0.14 was estimated by
extrapolation to zero thickness. It should be noted that a major objection to the use of
the experimental/analytical determinations of the correction factors is the doubt
about the validity of the extrapolation procedure.
If we use = 0.14 and all other terms in the equation are calculated using the
chamber dimensions and linear attenuation coefficient for the ARPANSA chamber,
we obtain kat = 1.0374. This value of kat was used in the 1997 comparison with BIPM
and is slightly less than the value of 1.0377 used in 1988. Since the ARPANSA and
BIPM chambers have almost identical dimensions and wall thicknesses but slightly
different graphite densities, it may be argued that the change in is proportional to
the change in graphite density. If so, a change in to 0.13 or 0.15 only gives a change
in kat of about 0.02%. Thus there would seem to be no basis at present for making a
change in the value of kat.
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The uncertainty was estimated as 0.15% for the 1988 and 1997 comparisons. The
major contributor to the uncertainty is the uncertainty in arising from the
extrapolation to zero wall thickness. A change in from 0.1 to 0.2 gives a change in
kat of 0.23%. From examining Figure 4 (Boutillon and Niatel 1973) a range in of this
magnitude would seem to be reasonable. If we then take the range as covering 6
standard deviations (99% confidence level), we can then estimate that one standard
deviation is 0.04%. This is close to the present BIPM estimate, although the means by
which BIPM derived this estimate is unknown. An alternative, more valid approach is
to assume a rectangular distribution of within the range 0.1 to 0.2, an assumption
which is more consistent with the extrapolation procedure. An estimate of the
standard deviation is then approximately 0.07%.
6.2.3 The correction factor for scattering from the chamber walls
This correction factor ksc takes account of the contribution to the ionisation current
from the radiation scattered by the chamber walls and was evaluated experimentally
following the procedure of Boutillon and Niatel (1973) who used the method
suggested by Allisy (Allisy 1967). The procedure involves the measurement of the
ionisation current as a function of wall thickness, the removal of the contribution due
to attenuation in the wall and the extrapolation to zero thickness. For the front wall, a
quadratic function best fitted the data, whereas a linear fit was best for the back and
side walls. The contributions of the various components to the correction are given in
Table 4.
An estimate of the uncertainties may be made from the range of possible fits to the
experimental results. If we again assume a rectangular distribution, we obtain a total
uncertainty of 0.013%.
Thus the value of ksc is 0.9702, which is not significantly different from the value of
0.9703 used in 1988 and 1997 when rounding off errors are considered. The BIPM
value (Boutillon and Niatel 1973) is 0.9735, although the result arising from the
values of their components as given in Table 4 is 0.9740. The value given by BIPM in
1997 was 0.9716, with a Type A uncertainty of 0.01% and a Type B uncertainty of
0.07%. If we take our uncertainty calculated above as a Type A uncertainty, then
ARPANSA and BIPM are in agreement as to the magnitude of this component. It is
difficult to estimate the magnitude of the Type B uncertainties. The 1988 ARPANSA
estimate was 0.10% and it would appear reasonable to retain this for the total
uncertainty.
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Table 4: The components of the scattering correction factor
ARPANSA BIPM
Component Correction Fitting Uncertainty Correction
Range (%)
(%) Procedure (%)
Front Plate 2.25 Quadratic 0.0002 0.007 1.85
Back Plate 0.14 Linear 0.00002 #MUST NOT not put tabs after any character inputs,
#including delimeters.
#equal signs must have no space on the left and
#at least one space on the right.
###################
:start I/O control: #This is a start delimeter, see matching stop below
IWATCH= off #off,interactions,steps,deposited,graph;
#debug output with increasing detail,
#graph outputs .gph file for EGS_Windows
#if not "off" use very few histories
STORE INITIAL RANDOM NUMBERS= no #no,last,all deposited,all;
#last: store initial random numbers for last
# history in .egsrns
#all deposited: store initial random numbers
# for each history that deposits energy
# in the cavity
#all: store initial random numbers for each
# history
IRESTART= restart #first,restart,make,analyze,for graphics,parallel;
#first: first run
#restart: restart of old run (requires .egsdat file)
#make: just create an input file and exit
#analyze: read in data from .egsdat file and
# do statistical analysis and output results
# to .egslst
#for graphics: read starting random numbers from
# .egsrns--eg for output to graphics package
#parallel: read .egsdat files from parallel jobs
# (named inputfile_w*), do statistical
# analysis and output to .egslst
STORE DATA ARRAYS= yes #yes,no;
#yes: output .egsdat file for restarts, parallel
# post-processing, etc
OUTPUT OPTIONS= short #short,cavity details;
#short: output cavity summary + dose grid
#cavity details: above plus details for every zone
# in cavity
:stop I/O control:
##################
##########################
:start Monte Carlo inputs:
NUMBER OF HISTORIES= 100000000 #splits into $STAT statistical batches
#must be >=$STAT**2 if IWATCH= Off
#can have less than this if IWATCH set to
#another option
INITIAL RANDOM NO. SEEDS= 1, 3 #With ranmar: these must be between 1 and
# 30081 (default to 9373)
#With ranlux: 1st is luxury level 0->4 allowed
# but should not be 0
# 2nd is seed 1 -> 1073741824
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MAX CPU HOURS ALLOWED= 90.000 #Will shut down cleanly prior to
#exceeding this limit, as long as one
#batch has completed.
IFULL= Aatt and Ascat #dose and stoppers,Aatt and Ascat,Ap,Afl and g/w;
#dose and stoppers: output total dose plus that due
# to stoppers and discards
#Aatt and Ascat: above plus Aatt, Ascat
#Ap: above plus Ap
#Afl and g/w: above plus Afl and stopping power
# ratio gas/water
STATISTICAL ACCURACY SOUGHT= 0.0000 #If 0, goes until number of histories
# or CPU limit exceeded. If not zero
# goes until this uncertainty (in %)
# is achieved in the peak dose region
PHOTON REGENERATION= no #no,yes,no electrons from wall;
#no: normal calculation
#yes: regenerate parent photon after interaction
# (used for FANO calculations)
#no electrons from wall: photons not regenerated
# secondary electrons from cavity wall are
# eliminated
:stop Monte Carlo inputs:
#########################
##########################
:start geometrical inputs:
METHOD OF INPUT= groups #groups,individual,cavity information:
#group: input groups of slabs of equal thickness
#individual: input Z of bottom of every slab
#cavity information: generate simple geometry
# from cavity info input in section below.
# If you use this, there are no more inputs
# in this section
Z OF FRONT FACE= 0 #Beginning of first slab
NSLAB= 1, 1, 1, 1, 1, 1 #Define a group of 10 slabs with thickness
1 cm
SLAB THICKNESS= 0.2821, 0.2074, 0.1002, 0.2074, 0.2821, 2 #followed by 50
slabs with thickness 2 cm
#Example with METHOD OF INPUT= individual:
#DEPTH BOUNDARIES= 0.3,0.5,0.8
RADII= 2.0507, 2.2512, 2.5233, 5 #Radii of cylinders
######## Material Input
MEDIA= 1726C, AIR521ICRU #the media in the problem
#These must match exactly, including case, one
#of the media names in the pegs4 data set being
#used in the problem.
#The maximum length of name is 24 characters
#They are automatically left justified on input.
#Next we specify which media are in
#which geometric regions
#note that by default all regions contain
#medium 1 and which medium to input as 1 should
#be selected with this in mind.
DESCRIPTION BY= planes #planes,regions;
#planes: use slab and cylinder no.'s to
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# define what medium goes where
#regions: use region numbers to define this
(region numbers start at 2 and
number from top to bottom of
geometry and innermost radius to
outermost radius)
MEDNUM= 1, 2, 2, 1, 1, 2, 1, 2, 1, 1, 2 #This puts water everywhere
and then
START ZSLAB= 1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 6 #inserts a small column of
air on the central
STOP ZSLAB= 1, 6, 2, 2, 3, 3, 3, 4, 4, 5, 6 #axis with radius 1cm and
going from Z=10cm
START RING= 1, 4, 1, 3, 1, 2, 3, 1, 3, 1, 1 #to Z=12cm
STOP RING= 3, 4, 2, 3, 1, 2, 3, 2, 3, 3, 3
#Example with DESCRIPTION BY= regions to do the same as above
# MEDNUM= 2
# START REGION= 3
# STOP REGION= 3
:stop geometrical inputs:
#########################
#####################
:start cavity inputs:
NUMBER OF CAVITY REGIONS= 5 #this defines the small cylinder of
REGION NUMBERS OF THE CAVITY= 3, 5, 9, 10, 11 #air in the geometry to be the
cavity
#If METHOD OF INPUTS= cavity information:
# WALL THICKNESS= 0.5 #thickness of chamber wall in cm (defaults to
#0.273)
# CAVITY RADIUS= 1.0 #outer radius of the cavity in cm
# CAVITY LENGTH= 2.0 #in cm (defaults to 0.2)
# ELECTRODE RADIUS= 0.01 #in cm (defaults to 0)
# WALL MATERIAL= H2O521ICRU
# ELECTRODE MATERIAL= AL521ICRU #only if ELECTRODE RADIUS > 0
:stop cavity inputs:
#####################
:start source inputs:
# INCIDENT PARTICLE= photon #electron,photon,positron,all,charged;
#all & charged: only for phase space sources
# SOURCE NUMBER= 1 #0,1,2,3,4,10,11,12,13,14,20,21
#1: point source incident from the front
#for details, see srcrz.mortran
# SOURCE OPTIONS= 100., 1.3, 0, 0 #for source 1: SSD of beam, radius of
# beam on front surface
# INCIDENT ENERGY= monoenergetic #monoenergetic, spectrum;
# INCIDENT KINETIC ENERGY(MEV)= 1.25 #only use for "monoenergetic"
#If INCIDENT ENERGY= spectrum:
# SPEC FILENAME= full name of file containing energy spectrum
# SPEC IOUTSP= include #none,include;
#none: no spectrum data in .egslst file
#include: output spectrum data to .egslst file
#Example with SOURCE NUMBER= 21 (phase space source):
INCIDENT PARTICLE= all
SOURCE NUMBER= 21
SOURCE OPTIONS= 0., 0., 0., 0. #only active input is 1st one
#mode =0 => 7 variables/record
#mode = 1 => 8 variables/record
FILSPC= /home/chriso/egsnrc_mp/BEAM_Co-60/Co-60_40rr_987604.egsphsp1
:stop source inputs:
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#########################
#########################
:Start MC Transport Parameter:
Global ECUT= 0.521 #Electron cutoff for transport
Global PCUT= 0.001 #Photon cutoff for transport
Global SMAX= 1e10 #Maximum step size in cm (not needed
#unless old PRESTA algorithm used)
#ECUT, PCUT and SMAX can also be set on a
#region-by-region basis.
#
#Set XXXX= f_value1, f_value2, ...
#Set XXXX start region= i_value1, i_value2, ...
#Set XXXX stop region= j_value1, j_value2, ...
#
#where XXXX is ECUT, PCUT or SMAX ,
#f_value1, f_value2,... are the desired values for XXXX
#and i_value_i and j_value_i are the start and
#stop regions.
ESTEPE= 0.25 #Max fractional continuous energy loss
#per step. Use 0.25 unless using
#PRESTA-I
XIMAX= 0.5 #Max first elastic scattering moment
#per step. Using default.
Boundary crossing algorithm= exact #exact,PRESTA-I;
#exact: cross boundaries in single scattering
# mode (distance at which to go into
# single scattering mode determined by
# "Skin depth for BCA"
#PRESTA-I: cross boundaries with lateral
# correlations off and force multiple
# scattering mode
Skin depth for BCA= 3 #Distance from a boundary (in elastic
#MFP) at which the algorithm will go
#into single scattering mode (using
#default here)
Electron-step algorithm= PRESTA-II #PRESTA-II,PRESTA-I;
#Determines the algorithm used to take
#into account lateral and longitudinal
#correlations in a condensed history
#step
Spin effects= On #Off (default),On;
#Turns off/on spin effects for electron
#elastic scattering. Spin On is
#ABSOLUTELY necessary for good
#backscattering calculations. Will
#make a difference even in `well
#conditioned' situations (e.g. depth
#dose curves).
Brems angular sampling= KM #Simple,KM (default);
#Simple: leading term of Koch-Motz
# dist'n used to determine angle
# of bremsstrahlung photons
#KM: Koch-Motz distribution used to
# determine angle
Brems cross sections= BH #BH (default),NIST;
#BH: Bethe-Heitler cross-sections used
#NIST: NIST cross-sections used
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Bound Compton scattering= Off #Off (default),On;
#Off: Klein-Nishina used for compton
# scattering
#On: Impulse approximation used for
# scattering
#It has not been established that the
#the scoring routines work with this
#option ON.
Pair angular sampling= Simple #Off, Simple (default),KM);
#Simple: use leading term of K-M
# dist'n
#KM: use complete Koch and Motz dist'n
#Off: angle of pairs is m/E--like old EGS4
Photoelectron angular sampling= Off #Off (default),On;
#Off: Photoelectrons get direction of
# photon that creates them
#On: Sauter's formula is used
Rayleigh scattering= Off #Off (default),On;
#Off: no coherent scattering
#On: simulates coherent scattering
Atomic relaxations= Off #Off (default),On;
#Note, it has not been verified that
#AUSGAB works with this option ON
#On: use correct cross section
# for p.e. events and shell vacancies
# for Compton & p.e. events are relaxed
# via emission of fluorescent X-Rays,
# Auger and Koster-Cronig electrons
# electrons
#The following allow for adjustment
#of ECUT, PCUT and SMAX in
#individual regions
#The following are not needed but
#prevent extra warnings
Set ECUT= 0.0 #this is off for this example
Set ECUT start region= 1 #region 1 is outside the geometry
Set ECUT stop region= 1
Set PCUT= 0.0 #this is off for this example
Set PCUT start region= 1 #region 1 is outside the geometry
Set PCUT stop region= 1
Set SMAX= 0.0 #this is off for this example
Set SMAX start region= 1 #region 1 is outside the geometry
Set SMAX stop region= 1
# Atomic relaxations, Rayleigh scattering, Photoelectron angular sampling and
# Bound compton scattering can be turned on/off on a region by region basis.
# Instead of simply "On" or "Off" for these cases put:
# Atomic relaxations= On (or Off) in Regions
# Relaxations start region= 1, 40 #turns relaxations on in regions 1-10 and
# Relaxations stop region= 10, 99 #40-99
#
# Rayleigh scattering= On (or Off) in Regions
# Rayleigh start region= 1, 40
# Rayleigh stop region= 10, 99
#
# Photoelectron angular sampling= On (or Off) in Regions
# PE sampling start region= 1, 40
# PE sampling stop region= 10, 99
#
# Bound Compton scattering= On (or Off) in Regions
# Bound Compton start region= 1, 40
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# Bound Compton stop region= 10, 99
:Stop MC Transport Parameter:
########################
:Start Variance Reduction:
ELECTRON RANGE REJECTION= Off #Off,On;
#On: if charged particle energy is below ESAVEIN
# and it cannot get out of current region
# with energy > ECUT, the particle is
# terminated
#also terminates all electrons which cannot
#reach the cavity under conservative
#assumptions.
ESAVEIN= 2.0 #total energy below which range rejection is
#considered
RUSSIAN ROULETTE DEPTH= 0.0000 #play Russian Roulette with photons once they
#cross this Z plane
RUSSIAN ROULETTE FRACTION= 0.0000 #probability of photon survival--if this
#and #RUSSIAN ROULETTE DEPTH both 0, then
#photon Russian Roulette is not played
#exponential pathlength biasing can be
#used. See Rogers&Bielajew 1990 review for
#discussion. C pathlength shortening
# >0 => pathlength stretching
# along z axis both cases
EXPONENTIAL TRANSFORM C= 0.0000
PHOTON FORCING= Off #Off (default),On;
#On: force photons to interact according to
# START FORCING and STOP FORCING AFTER inputs
START FORCING= 1 #Start forcing at this interaction number
STOP FORCING AFTER= 1 #Number of photon interactions after which
#to stop forcing photon interactions
PHOTON SPLITTING= 1 #no. of times to split a photon
#if normal transport
#overrides PHOTON FORCING if >= 2
#can only be >= 2 if IFULL= dose and stoppers
# or if IFULL= Aatt and Ascat
#CAVRZnrc allows for having the photon cross
#section scaled to enhance interactions.
# If this input is missing or set to 1, the
# effect is dramatic: all other user input
# concerning photon forcing, splitting, exp.
# transform, etc., is ignored. In addition,
# the calculation result corresponds ALWAYS
# to 'Aatt and Ascat', no matter what the
# user requested (but only Awall is calculated,
# not the individual Ascat and Aatt).
# The algorithm employed is implemented via
# $RAYLEIGH-CORRECTION and appropriate calls to
# AUSGAB. For more detail see the manual and the
# header of cavrznrc.mortran
CS ENHANCEMENT FACTOR= 1.0 #Photon cross section scaling factors
:Stop Variance Reduction:
#########################
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A4.3 kan – The following two files were used to calculate kan. File 1 uses a
parallel beam and File 2 uses the non-parallel beam
File 1
TITLE= cavrznrc_template: 1.25 MeV on graphite pancake chamber
#File to explain input to CAVRZnrc
#all options for a given quantity are shown, separated
#by commas and ending with a ;
#NB====> #MUST NOT not put tabs after any character inputs,
#including delimeters.
#equal signs must have no space on the left and
#at least one space on the right.
###################
:start I/O control: #This is a start delimeter, see matching stop below
IWATCH= off #off,interactions,steps,deposited,graph;
#debug output with increasing detail,
#graph outputs .gph file for EGS_Windows
#if not "off" use very few histories
STORE INITIAL RANDOM NUMBERS= no #no,last,all deposited,all;
#last: store initial random numbers for last
# history in .egsrns
#all deposited: store initial random numbers
# for each history that deposits energy
# in the cavity
#all: store initial random numbers for each
# history
IRESTART= first #first,restart,make,analyze,for graphics,parallel;
#first: first run
#restart: restart of old run (requires .egsdat file)
#make: just create an input file and exit
#analyze: read in data from .egsdat file and
# do statistical analysis and output results
# to .egslst
#for graphics: read starting random numbers from
# .egsrns--eg for output to graphics package
#parallel: read .egsdat files from parallel jobs
# (named inputfile_w*), do statistical
# analysis and output to .egslst
STORE DATA ARRAYS= yes #yes,no;
#yes: output .egsdat file for restarts, parallel
# post-processing, etc
OUTPUT OPTIONS= short #short,cavity details;
#short: output cavity summary + dose grid
#cavity details: above plus details for every zone
# in cavity
:stop I/O control:
##################
##########################
:start Monte Carlo inputs:
NUMBER OF HISTORIES= 500000000 #splits into $STAT statistical batches
#must be >=$STAT**2 if IWATCH= Off
#can have less than this if IWATCH set to
#another option
INITIAL RANDOM NO. SEEDS= 1, 3 #With ranmar: these must be between 1 and
# 30081 (default to 9373)
#With ranlux: 1st is luxury level 0->4 allowed
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# but should not be 0
# 2nd is seed 1 -> 1073741824
MAX CPU HOURS ALLOWED= 90.000 #Will shut down cleanly prior to
#exceeding this limit, as long as one
#batch has completed.
IFULL= Aatt and Ascat #dose and stoppers,Aatt and Ascat,Ap,Afl and g/w;
#dose and stoppers: output total dose plus that due
# to stoppers and discards
#Aatt and Ascat: above plus Aatt, Ascat
#Ap: above plus Ap
#Afl and g/w: above plus Afl and stopping power
# ratio gas/water
STATISTICAL ACCURACY SOUGHT= 0.0000 #If 0, goes until number of histories
# or CPU limit exceeded. If not zero
# goes until this uncertainty (in %)
# is achieved in the peak dose region
PHOTON REGENERATION= no #no,yes,no electrons from wall;
#no: normal calculation
#yes: regenerate parent photon after interaction
# (used for FANO calculations)
#no electrons from wall: photons not regenerated
# secondary electrons from cavity wall are
# eliminated
:stop Monte Carlo inputs:
#########################
##########################
:start geometrical inputs:
METHOD OF INPUT= groups #groups,individual,cavity information:
#group: input groups of slabs of equal thickness
#individual: input Z of bottom of every slab
#cavity information: generate simple geometry
# from cavity info input in section below.
# If you use this, there are no more inputs
# in this section
Z OF FRONT FACE= 0. #Beginning of first slab
NSLAB= 1, 1, 1, 1, 1, 1 #Define a group of 10 slabs with thickness
1 cm
SLAB THICKNESS= 0.2821, 0.2074, 0.1002, 0.2074, 0.2821, 0 #followed by 50 slabs
with thickness 2 cm
#Example with METHOD OF INPUT= individual:
# DEPTH BOUNDARIES= 0.3,0.5,0.8
RADII= 2.0507, 2.2512, 2.5233, 2.5233 #Radii of cylinders
######## Material Input
MEDIA= AIR521ICRU, 1726C #the media in the problem
#These must match exactly, including case, one
#of the media names in the pegs4 data set being
#used in the problem.
#The maximum length of name is 24 characters
#They are automatically left justified on input.
#Next we specify which media are in
#which geometric regions
#note that by default all regions contain
#medium 1 and which medium to input as 1 should
#be selected with this in mind.
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DESCRIPTION BY= planes #planes,regions;
#planes: use slab and cylinder no.'s to
# define what medium goes where
#regions: use region numbers to define this
(region numbers start at 2 and
number from top to bottom of
geometry and innermost radius to
outermost radius)
MEDNUM= 2, 1, 1, 2, 2, 1, 2, 1, 2, 2, 1 #This puts water
everywhere and then
START ZSLAB= 1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 6 #inserts a small column
of air on the central
STOP ZSLAB= 1, 6, 2, 2, 3, 3, 3, 4, 4, 5, 6 #axis with radius 1cm and
going from Z=10cm
START RING= 1, 4, 1, 3, 1, 2, 3, 1, 3, 1, 1 #to Z=12cm
STOP RING= 3, 4, 2, 3, 1, 2, 3, 2, 3, 3, 3
#Example with DESCRIPTION BY= regions to do the same as above
# MEDNUM= 2
# START REGION= 3
# STOP REGION= 3
:stop geometrical inputs:
#########################
#####################
:start cavity inputs:
NUMBER OF CAVITY REGIONS= 5 #this defines the small cylinder of
REGION NUMBERS OF THE CAVITY= 3, 5, 9, 10, 11 #air in the geometry to be the
cavity
#If METHOD OF INPUTS= cavity information:
# WALL THICKNESS= 0.5 #thickness of chamber wall in cm (defaults to
#0.273)
# CAVITY RADIUS= 1.0 #outer radius of the cavity in cm
# CAVITY LENGTH= 2.0 #in cm (defaults to 0.2)
# ELECTRODE RADIUS= 0.01 #in cm (defaults to 0)
# WALL MATERIAL= H2O521ICRU
# ELECTRODE MATERIAL= AL521ICRU #only if ELECTRODE RADIUS > 0
:stop cavity inputs:
#####################
:start source inputs:
INCIDENT PARTICLE= photon #electron,photon,positron,all,charged;
#all & charged: only for phase space sources
SOURCE NUMBER= 0 #0,1,2,3,4,10,11,12,13,14,20,21
#1: point source incident from the front
#for details, see srcrz.mortran
SOURCE OPTIONS= 5.0, 0.0, 0.0, 1.0 #for source 1: SSD of beam, radius of
# beam on front surface
INCIDENT ENERGY= spectrum #monoenergetic, spectrum;
# INCIDENT KINETIC ENERGY(MEV)= 1.25 #only use for "monoenergetic"
#If INCIDENT ENERGY= spectrum:
SPEC FILENAME= /home/chriso/HEN_HOUSE/spectra/co60CPO8.spectrum
SPEC IOUTSP= include #none,include;
#none: no spectrum data in .egslst file
#include: output spectrum data to .egslst file
#Example with SOURCE NUMBER= 21 (phase space source):
# INCIDENT PARTICLE= all
# SOURCE NUMBER= 21
# SOURCE OPTIONS= 0., 0., 0., 0. #only active input is 1st one
#mode =0 => 7 variables/record
#mode = 1 => 8 variables/record
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# FILSPC= /usr/people/dave/egs4/BEAM_slabs2/new.50MV.8cm.5.egs4phsp1
:stop source inputs:
#########################
#########################
:Start MC Transport Parameter:
Global ECUT= 0.521 #Electron cutoff for transport
Global PCUT= 0.001 #Photon cutoff for transport
Global SMAX= 1e10 #Maximum step size in cm (not needed
#unless old PRESTA algorithm used)
#ECUT, PCUT and SMAX can also be set on a
#region-by-region basis.
#
#Set XXXX= f_value1, f_value2, ...
#Set XXXX start region= i_value1, i_value2, ...
#Set XXXX stop region= j_value1, j_value2, ...
#
#where XXXX is ECUT, PCUT or SMAX ,
#f_value1, f_value2,... are the desired values for XXXX
#and i_value_i and j_value_i are the start and
#stop regions.
ESTEPE= 0.25 #Max fractional continuous energy loss
#per step. Use 0.25 unless using
#PRESTA-I
XIMAX= 0.5 #Max first elastic scattering moment
#per step. Using default.
Boundary crossing algorithm= exact #exact,PRESTA-I;
#exact: cross boundaries in single scattering
# mode (distance at which to go into
# single scattering mode determined by
# "Skin depth for BCA"
#PRESTA-I: cross boundaries with lateral
# correlations off and force multiple
# scattering mode
Skin depth for BCA= 3 #Distance from a boundary (in elastic
#MFP) at which the algorithm will go
#into single scattering mode (using
#default here)
Electron-step algorithm= PRESTA-II #PRESTA-II,PRESTA-I;
#Determines the algorithm used to take
#into account lateral and longitudinal
#correlations in a condensed history
#step
Spin effects= On #Off (default),On;
#Turns off/on spin effects for electron
#elastic scattering. Spin On is
#ABSOLUTELY necessary for good
#backscattering calculations. Will
#make a difference even in `well
#conditioned' situations (e.g. depth
#dose curves).
Brems angular sampling= KM #Simple,KM (default);
#Simple: leading term of Koch-Motz
# dist'n used to determine angle
# of bremsstrahlung photons
#KM: Koch-Motz distribution used to
# determine angle
Brems cross sections= BH #BH (default),NIST;
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#BH: Bethe-Heitler cross-sections used
#NIST: NIST cross-sections used
Bound Compton scattering= Off #Off (default),On;
#Off: Klein-Nishina used for compton
# scattering
#On: Impulse approximation used for
# scattering
#It has not been established that the
#the scoring routines work with this
#option ON.
Pair angular sampling= Simple #Off, Simple (default),KM);
#Simple: use leading term of K-M
# dist'n
#KM: use complete Koch and Motz dist'n
#Off: angle of pairs is m/E--like old EGS4
Photoelectron angular sampling= Off #Off (default),On;
#Off: Photoelectrons get direction of
# photon that creates them
#On: Sauter's formula is used
Rayleigh scattering= Off #Off (default),On;
#Off: no coherent scattering
#On: simulates coherent scattering
Atomic relaxations= Off #Off (default),On;
#Note, it has not been verified that
#AUSGAB works with this option ON
#On: use correct cross section
# for p.e. events and shell vacancies
# for Compton & p.e. events are relaxed
# via emission of fluorescent X-Rays,
# Auger and Koster-Cronig electrons
# electrons
#The following allow for adjustment
#of ECUT, PCUT and SMAX in
#individual regions
#The following are not needed but
#prevent extra warnings
Set ECUT= 0.0 #this is off for this example
Set ECUT start region= 1 #region 1 is outside the geometry
Set ECUT stop region= 1
Set PCUT= 0.0 #this is off for this example
Set PCUT start region= 1 #region 1 is outside the geometry
Set PCUT stop region= 1
Set SMAX= 0.0 #this is off for this example
Set SMAX start region= 1 #region 1 is outside the geometry
Set SMAX stop region= 1
# Atomic relaxations, Rayleigh scattering, Photoelectron angular sampling and
# Bound compton scattering can be turned on/off on a region by region basis.
# Instead of simply "On" or "Off" for these cases put:
# Atomic relaxations= On (or Off) in Regions
# Relaxations start region= 1, 40 #turns relaxations on in regions 1-10 and
# Relaxations stop region= 10, 99 #40-99
#
# Rayleigh scattering= On (or Off) in Regions
# Rayleigh start region= 1, 40
# Rayleigh stop region= 10, 99
#
# Photoelectron angular sampling= On (or Off) in Regions
# PE sampling start region= 1, 40
# PE sampling stop region= 10, 99
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#
# Bound Compton scattering= On (or Off) in Regions
# Bound Compton start region= 1, 40
# Bound Compton stop region= 10, 99
:Stop MC Transport Parameter:
########################
:Start Variance Reduction:
ELECTRON RANGE REJECTION= Off #Off,On;
#On: if charged particle energy is below ESAVEIN
# and it cannot get out of current region
# with energy > ECUT, the particle is
# terminated
#also terminates all electrons which cannot
#reach the cavity under conservative
#assumptions.
ESAVEIN= 2.0 #total energy below which range rejection is
#considered
RUSSIAN ROULETTE DEPTH= 0.0000 #play Russian Roulette with photons once they
#cross this Z plane
RUSSIAN ROULETTE FRACTION= 0.0000 #probability of photon survival--if this
#and #RUSSIAN ROULETTE DEPTH both 0, then
#photon Russian Roulette is not played
#exponential pathlength biasing can be
#used. See Rogers&Bielajew 1990 review for
#discussion. C pathlength shortening
# >0 => pathlength stretching
# along z axis both cases
EXPONENTIAL TRANSFORM C= 0.0000
PHOTON FORCING= Off #Off (default),On;
#On: force photons to interact according to
# START FORCING and STOP FORCING AFTER inputs
START FORCING= 1 #Start forcing at this interaction number
STOP FORCING AFTER= 1 #Number of photon interactions after which
#to stop forcing photon interactions
PHOTON SPLITTING= 1 #no. of times to split a photon
#if normal transport
#overrides PHOTON FORCING if >= 2
#can only be >= 2 if IFULL= dose and stoppers
# or if IFULL= Aatt and Ascat
#CAVRZnrc allows for having the photon cross
#section scaled to enhance interactions.
# If this input is missing or set to 1, the
# effect is dramatic: all other user input
# concerning photon forcing, splitting, exp.
# transform, etc., is ignored. In addition,
# the calculation result corresponds ALWAYS
# to 'Aatt and Ascat', no matter what the
# user requested (but only Awall is calculated,
# not the individual Ascat and Aatt).
# The algorithm employed is implemented via
# $RAYLEIGH-CORRECTION and appropriate calls to
# AUSGAB. For more detail see the manual and the
# header of cavrznrc.mortran
CS ENHANCEMENT FACTOR= 1.0 #Photon cross section scaling factors
:Stop Variance Reduction:
#########################
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File 2
TITLE= cavrznrc_template: 1.25 MeV on graphite pancake chamber
#File to explain input to CAVRZnrc
#all options for a given quantity are shown, separated
#by commas and ending with a ;
#NB====> #MUST NOT not put tabs after any character inputs,
#including delimeters.
#equal signs must have no space on the left and
#at least one space on the right.
###################
:start I/O control: #This is a start delimeter, see matching stop below
IWATCH= off #off,interactions,steps,deposited,graph;
#debug output with increasing detail,
#graph outputs .gph file for EGS_Windows
#if not "off" use very few histories
STORE INITIAL RANDOM NUMBERS= no #no,last,all deposited,all;
#last: store initial random numbers for last
# history in .egsrns
#all deposited: store initial random numbers
# for each history that deposits energy
# in the cavity
#all: store initial random numbers for each
# history
IRESTART= first #first,restart,make,analyze,for graphics,parallel;
#first: first run
#restart: restart of old run (requires .egsdat file)
#make: just create an input file and exit
#analyze: read in data from .egsdat file and
# do statistical analysis and output results
# to .egslst
#for graphics: read starting random numbers from
# .egsrns--eg for output to graphics package
#parallel: read .egsdat files from parallel jobs
# (named inputfile_w*), do statistical
# analysis and output to .egslst
STORE DATA ARRAYS= yes #yes,no;
#yes: output .egsdat file for restarts, parallel
# post-processing, etc
OUTPUT OPTIONS= short #short,cavity details;
#short: output cavity summary + dose grid
#cavity details: above plus details for every zone
# in cavity
:stop I/O control:
##################
##########################
:start Monte Carlo inputs:
NUMBER OF HISTORIES= 500000000 #splits into $STAT statistical batches
#must be >=$STAT**2 if IWATCH= Off
#can have less than this if IWATCH set to
#another option
INITIAL RANDOM NO. SEEDS= 1, 3 #With ranmar: these must be between 1 and
# 30081 (default to 9373)
#With ranlux: 1st is luxury level 0->4 allowed
# but should not be 0
# 2nd is seed 1 -> 1073741824
MAX CPU HOURS ALLOWED= 90.000 #Will shut down cleanly prior to
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#exceeding this limit, as long as one
#batch has completed.
IFULL= Aatt and Ascat #dose and stoppers,Aatt and Ascat,Ap,Afl and g/w;
#dose and stoppers: output total dose plus that due
# to stoppers and discards
#Aatt and Ascat: above plus Aatt, Ascat
#Ap: above plus Ap
#Afl and g/w: above plus Afl and stopping power
# ratio gas/water
STATISTICAL ACCURACY SOUGHT= 0.0000 #If 0, goes until number of histories
# or CPU limit exceeded. If not zero
# goes until this uncertainty (in %)
# is achieved in the peak dose region
PHOTON REGENERATION= no #no,yes,no electrons from wall;
#no: normal calculation
#yes: regenerate parent photon after interaction
# (used for FANO calculations)
#no electrons from wall: photons not regenerated
# secondary electrons from cavity wall are
# eliminated
:stop Monte Carlo inputs:
#########################
##########################
:start geometrical inputs:
METHOD OF INPUT= groups #groups,individual,cavity information:
#group: input groups of slabs of equal thickness
#individual: input Z of bottom of every slab
#cavity information: generate simple geometry
# from cavity info input in section below.
# If you use this, there are no more inputs
# in this section
Z OF FRONT FACE= 0. #Beginning of first slab
NSLAB= 1, 1, 1, 1, 1, 1 #Define a group of 10 slabs with thickness
1 cm
SLAB THICKNESS= 0.2821, 0.2074, 0.1002, 0.2074, 0.2821, 0 #followed by 50 slabs
with thickness 2 cm
#Example with METHOD OF INPUT= individual:
# DEPTH BOUNDARIES= 0.3,0.5,0.8
RADII= 2.0507, 2.2512, 2.5233, 2.5233 #Radii of cylinders
######## Material Input
MEDIA= AIR521ICRU, 1726C #the media in the problem
#These must match exactly, including case, one
#of the media names in the pegs4 data set being
#used in the problem.
#The maximum length of name is 24 characters
#They are automatically left justified on input.
#Next we specify which media are in
#which geometric regions
#note that by default all regions contain
#medium 1 and which medium to input as 1 should
#be selected with this in mind.
DESCRIPTION BY= planes #planes,regions;
#planes: use slab and cylinder no.'s to
# define what medium goes where
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#regions: use region numbers to define this
(region numbers start at 2 and
number from top to bottom of
geometry and innermost radius to
outermost radius)
MEDNUM= 2, 1, 1, 2, 2, 1, 2, 1, 2, 2, 1 #This puts water
everywhere and then
START ZSLAB= 1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 6 #inserts a small column
of air on the central
STOP ZSLAB= 1, 6, 2, 2, 3, 3, 3, 4, 4, 5, 6 #axis with radius 1cm and
going from Z=10cm
START RING= 1, 4, 1, 3, 1, 2, 3, 1, 3, 1, 1 #to Z=12cm
STOP RING= 3, 4, 2, 3, 1, 2, 3, 2, 3, 3, 3
#Example with DESCRIPTION BY= regions to do the same as above
# MEDNUM= 2
# START REGION= 3
# STOP REGION= 3
:stop geometrical inputs:
#########################
#####################
:start cavity inputs:
NUMBER OF CAVITY REGIONS= 5 #this defines the small cylinder of
REGION NUMBERS OF THE CAVITY= 3, 5, 9, 10, 11 #air in the geometry to be the
cavity
#If METHOD OF INPUTS= cavity information:
# WALL THICKNESS= 0.5 #thickness of chamber wall in cm (defaults to
#0.273)
# CAVITY RADIUS= 1.0 #outer radius of the cavity in cm
# CAVITY LENGTH= 2.0 #in cm (defaults to 0.2)
# ELECTRODE RADIUS= 0.01 #in cm (defaults to 0)
# WALL MATERIAL= H2O521ICRU
# ELECTRODE MATERIAL= AL521ICRU #only if ELECTRODE RADIUS > 0
:stop cavity inputs:
#####################
:start source inputs:
INCIDENT PARTICLE= photon #electron,photon,positron,all,charged;
#all & charged: only for phase space sources
SOURCE NUMBER= 16 #0,1,2,3,4,10,11,12,13,14,20,21
#1: point source incident from the front
#for details, see srcrz.mortran
SOURCE OPTIONS= 99.3, 0, 0.6, 0 #for source 1: SSD of beam, radius of
# beam on front surface
INCIDENT ENERGY= spectrum #monoenergetic, spectrum;
# INCIDENT KINETIC ENERGY(MEV)= 1.25 #only use for "monoenergetic"
#If INCIDENT ENERGY= spectrum:
SPEC FILENAME= /home/chriso/HEN_HOUSE/spectra/co60CPO8.spectrum
SPEC IOUTSP= include #none,include;
#none: no spectrum data in .egslst file
#include: output spectrum data to .egslst file
#Example with SOURCE NUMBER= 21 (phase space source):
# INCIDENT PARTICLE= all
# SOURCE NUMBER= 21
# SOURCE OPTIONS= 0., 0., 0., 0. #only active input is 1st one
#mode =0 => 7 variables/record
#mode = 1 => 8 variables/record
# FILSPC= /usr/people/dave/egs4/BEAM_slabs2/new.50MV.8cm.5.egs4phsp1
:stop source inputs:
#########################
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#########################
:Start MC Transport Parameter:
Global ECUT= 0.521 #Electron cutoff for transport
Global PCUT= 0.001 #Photon cutoff for transport
Global SMAX= 1e10 #Maximum step size in cm (not needed
#unless old PRESTA algorithm used)
#ECUT, PCUT and SMAX can also be set on a
#region-by-region basis.
#
#Set XXXX= f_value1, f_value2, ...
#Set XXXX start region= i_value1, i_value2, ...
#Set XXXX stop region= j_value1, j_value2, ...
#
#where XXXX is ECUT, PCUT or SMAX ,
#f_value1, f_value2,... are the desired values for XXXX
#and i_value_i and j_value_i are the start and
#stop regions.
ESTEPE= 0.25 #Max fractional continuous energy loss
#per step. Use 0.25 unless using
#PRESTA-I
XIMAX= 0.5 #Max first elastic scattering moment
#per step. Using default.
Boundary crossing algorithm= exact #exact,PRESTA-I;
#exact: cross boundaries in single scattering
# mode (distance at which to go into
# single scattering mode determined by
# "Skin depth for BCA"
#PRESTA-I: cross boundaries with lateral
# correlations off and force multiple
# scattering mode
Skin depth for BCA= 3 #Distance from a boundary (in elastic
#MFP) at which the algorithm will go
#into single scattering mode (using
#default here)
Electron-step algorithm= PRESTA-II #PRESTA-II,PRESTA-I;
#Determines the algorithm used to take
#into account lateral and longitudinal
#correlations in a condensed history
#step
Spin effects= On #Off (default),On;
#Turns off/on spin effects for electron
#elastic scattering. Spin On is
#ABSOLUTELY necessary for good
#backscattering calculations. Will
#make a difference even in `well
#conditioned' situations (e.g. depth
#dose curves).
Brems angular sampling= KM #Simple,KM (default);
#Simple: leading term of Koch-Motz
# dist'n used to determine angle
# of bremsstrahlung photons
#KM: Koch-Motz distribution used to
# determine angle
Brems cross sections= BH #BH (default),NIST;
#BH: Bethe-Heitler cross-sections used
#NIST: NIST cross-sections used
Bound Compton scattering= Off #Off (default),On;
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#Off: Klein-Nishina used for compton
# scattering
#On: Impulse approximation used for
# scattering
#It has not been established that the
#the scoring routines work with this
#option ON.
Pair angular sampling= Simple #Off, Simple (default),KM);
#Simple: use leading term of K-M
# dist'n
#KM: use complete Koch and Motz dist'n
#Off: angle of pairs is m/E--like old EGS4
Photoelectron angular sampling= Off #Off (default),On;
#Off: Photoelectrons get direction of
# photon that creates them
#On: Sauter's formula is used
Rayleigh scattering= Off #Off (default),On;
#Off: no coherent scattering
#On: simulates coherent scattering
Atomic relaxations= Off #Off (default),On;
#Note, it has not been verified that
#AUSGAB works with this option ON
#On: use correct cross section
# for p.e. events and shell vacancies
# for Compton & p.e. events are relaxed
# via emission of fluorescent X-Rays,
# Auger and Koster-Cronig electrons
# electrons
#The following allow for adjustment
#of ECUT, PCUT and SMAX in
#individual regions
#The following are not needed but
#prevent extra warnings
Set ECUT= 0.0 #this is off for this example
Set ECUT start region= 1 #region 1 is outside the geometry
Set ECUT stop region= 1
Set PCUT= 0.0 #this is off for this example
Set PCUT start region= 1 #region 1 is outside the geometry
Set PCUT stop region= 1
Set SMAX= 0.0 #this is off for this example
Set SMAX start region= 1 #region 1 is outside the geometry
Set SMAX stop region= 1
# Atomic relaxations, Rayleigh scattering, Photoelectron angular sampling and
# Bound compton scattering can be turned on/off on a region by region basis.
# Instead of simply "On" or "Off" for these cases put:
# Atomic relaxations= On (or Off) in Regions
# Relaxations start region= 1, 40 #turns relaxations on in regions 1-10 and
# Relaxations stop region= 10, 99 #40-99
#
# Rayleigh scattering= On (or Off) in Regions
# Rayleigh start region= 1, 40
# Rayleigh stop region= 10, 99
#
# Photoelectron angular sampling= On (or Off) in Regions
# PE sampling start region= 1, 40
# PE sampling stop region= 10, 99
#
# Bound Compton scattering= On (or Off) in Regions
# Bound Compton start region= 1, 40
# Bound Compton stop region= 10, 99
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:Stop MC Transport Parameter:
########################
:Start Variance Reduction:
ELECTRON RANGE REJECTION= Off #Off,On;
#On: if charged particle energy is below ESAVEIN
# and it cannot get out of current region
# with energy > ECUT, the particle is
# terminated
#also terminates all electrons which cannot
#reach the cavity under conservative
#assumptions.
ESAVEIN= 2.0 #total energy below which range rejection is
#considered
RUSSIAN ROULETTE DEPTH= 0.0000 #play Russian Roulette with photons once they
#cross this Z plane
RUSSIAN ROULETTE FRACTION= 0.0000 #probability of photon survival--if this
#and #RUSSIAN ROULETTE DEPTH both 0, then
#photon Russian Roulette is not played
#exponential pathlength biasing can be
#used. See Rogers&Bielajew 1990 review for
#discussion. C pathlength shortening
# >0 => pathlength stretching
# along z axis both cases
EXPONENTIAL TRANSFORM C= 0.0000
PHOTON FORCING= Off #Off (default),On;
#On: force photons to interact according to
# START FORCING and STOP FORCING AFTER inputs
START FORCING= 1 #Start forcing at this interaction number
STOP FORCING AFTER= 1 #Number of photon interactions after which
#to stop forcing photon interactions
PHOTON SPLITTING= 1 #no. of times to split a photon
#if normal transport
#overrides PHOTON FORCING if >= 2
#can only be >= 2 if IFULL= dose and stoppers
# or if IFULL= Aatt and Ascat
#CAVRZnrc allows for having the photon cross
#section scaled to enhance interactions.
# If this input is missing or set to 1, the
# effect is dramatic: all other user input
# concerning photon forcing, splitting, exp.
# transform, etc., is ignored. In addition,
# the calculation result corresponds ALWAYS
# to 'Aatt and Ascat', no matter what the
# user requested (but only Awall is calculated,
# not the individual Ascat and Aatt).
# The algorithm employed is implemented via
# $RAYLEIGH-CORRECTION and appropriate calls to
# AUSGAB. For more detail see the manual and the
# header of cavrznrc.mortran
CS ENHANCEMENT FACTOR= 1.0 #Photon cross section scaling factors
:Stop Variance Reduction:
#########################
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A4.4 - The following input file was used with sprrznrc to calculate
the stopping power ratio.
TITLE= sprrznrc_template
#File to explain input to SPRRZnrc
#all options for a given quantity are shown, separated
#by commas and ending with a ;
#NB====> #MUST NOT not put tabs after any character inputs,
#including delimeters.
#equal signs must have no space on the left and
#at least one space on the right.
###################
:start I/O control: #This is a start delimeter, see matching stop below
IWATCH= off #off,interactions,steps,deposited,graph;
#debug output with increasing detail,
#graph outputs .gph file for EGS_Windows
#if not "off" use very few histories
STORE INITIAL RANDOM NUMBERS= no #no,last,all;
#last: store initial random numbers for last
# history in .egsrns
#all: store initial random numbers for each
# history
IRESTART= first #first,restart,make,analyze,start-RNS;
#first: first run
#restart: restart of old run (requires .egsdat file)
#make: just create an input file and exit
#analyze: read in data from .egsdat file and
# do statistical analysis and output results
# to .egslst
#start-RNS: read starting random numbers from
# .egsrns
STORE DATA ARRAYS= yes #yes,no;
#yes: output .egsdat file for restarts, parallel
# post-processing, etc
SPR OUTPUT= slabs/cylinders #regions,slabs/cylinders;
#regions: if RANGE REJECTION= Off (see below),
# output stopping power ratios for
# all regions to .egslst file.
# if RANGE REJECTION= On,
# output stopping power ratios only in
# user-specified regions. Range
# rejection will be turned off in these
# regions.
#slabs/cylinders: if RANGE REJECTION= Off,
# output stopping power ratios for
# all regions to .egslst file and
# output stopping-power ratios for
# user-specified vertical cylinders
# and/or horizontal slabs to .plotdat
# file for plotting.
# If RANGE REJECTION= On,
# Output stopping-power ratios only in
# user-specified cylinders/slabs to
# .egslst and .plotdat files. Range
# rejection will be turned off in these
# cylinders/slabs.
SPR IN CYLINDER IX= 1,2 #If RANGE REJECTION= On, will output
#stopping-power ratios for cylinders 1 and 2 to
#the .egslst file (range rejection will be
#turned off in these cylinders).
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#If RANGE REJECTION= Off, will output
#stopping-power ratios for all regions to .egslst
#file. In both cases, will output
#stopping-power ratio vs depth data for cylinders
#1 and 2 to .plotdat file for plotting.
SPR IN SLAB IZ= 0 #Don't output stopping-power ratio vs radius
#data for any slabs to the .plotdat file
#Example with SPR OUTPUT= regions
# SPR START REGION= 2, 42
# SPR STOP REGION= 21, 61
#If RANGE REJECTION= On, will output stopping-power ratios for 1st and 3rd
#vertical cylinders to .egslst file (range rejection will be turned off
#in these regions). If RANGE REJECTION= Off, stopping power
#ratios will be output for all regions regardless of this input, but input
#must still be supplied. In both cases, no .plotdat file will be output.
:stop I/O control:
##################
##########################
:start Monte Carlo inputs:
NUMBER OF HISTORIES= 1000000 #splits into $STAT statistical batches
#must be >=$STAT**2 if IWATCH= Off
#can have less than this if IWATCH set to
#another option
INITIAL RANDOM NO. SEEDS= 1, 3 #With ranmar: these must be between 1 and
# 30081 (default to 9373)
#With ranlux: 1st is luxury level 0->4 allowed
# but should not be 0
# 2nd is seed 1 -> 1073741824
MAX CPU HOURS ALLOWED= 90.000 #Will shut down cleanly prior to
#exceeding this limit, as long as one
#batch has completed.
PHOTON REGENERATION= yes #no,yes;
#no: normal calculation
#yes: primary photons regenerated, scattered
# photons eliminated
# (used for ion chambers in air)
:stop Monte Carlo inputs:
#########################
##########################
:start geometrical inputs:
METHOD OF INPUT= groups #groups,individual,cavity information:
#group: input groups of slabs of equal thickness
#individual: input Z of bottom of every slab
#cavity information: generate simple geometry
# from cavity info input in section below.
# If you use this, there are no more inputs
# in this section
Z OF FRONT FACE= 0. #Beginning of first slab
NSLAB= 1, 1, 1, 1, 1 #Define a group of 10 slabs with thickness 1
cm
SLAB THICKNESS= 0.2821, 0.2074, 0.1002, 0.2074, 0.2821 #followed by 50 slabs
with thickness 2 cm
#Example with METHOD OF INPUT= individual:
#DEPTH BOUNDARIES= 0.3,0.5,0.8
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RADII= 2.0507, 2.2512, 2.5233 #Radii of cylinders
######## Material Input
MEDIA= 1726C, AIR521ICRU #the media in the problem
#These must match exactly, including case, one
#of the media names in the pegs4 data set being
#used in the problem.
#The maximum length of name is 24 characters
#They are automatically left justified on input.
#Next we specify which media are in
#which geometric regions
#note that by default all regions contain
#medium 1 and which medium to input as 1 should
#be selected with this in mind.
DESCRIPTION BY= planes #planes,regions;
#planes: use slab and cylinder no.'s to
# define what medium goes where
#regions: use region numbers to define this
(region numbers start at 2 and
number from top to bottom of
geometry and innermost radius to
outermost radius)
MEDNUM= 1, 1, 1, 1, 1, 1, 1 #This puts water everywhere and then
# RHOR= 1.726, 1.726, 1.726, 1.726, 1.726, 1.726,1.726
START ZSLAB= 1, 2, 2, 3, 3, 4, 5 #inserts a small column of air on the
central
STOP ZSLAB= 1, 2, 4, 3, 4, 4, 5 #axis with radius 1cm and going from
Z=10cm
START RING= 1, 1, 3, 1, 2, 1, 1 #to Z=12cm
STOP RING= 3, 2, 3, 1, 2, 1, 3
#Example with DESCRIPTION BY= regions to do the same as above
# MEDNUM= 2
# START REGION= 3
# STOP REGION= 3
:stop geometrical inputs:
#########################
#####################
:start source inputs:
INCIDENT PARTICLE= photon #electron,photon,positron,all;
#all: only used for phase space sources
SOURCE NUMBER= 0 #0,1,2,3,4,10,11,12,13,14,20,21
#0: parallel beam incident from front
SOURCE OPTIONS= 5.0, 0, 0, 1, #for source 0: radius of beam, incident
# X,Y,Z direction cosines
INCIDENT ENERGY= spectrum #monoenergetic, spectrum;
# INCIDENT KINETIC ENERGY(MEV)= 1.25 #only use for "monoenergetic"
#If INCIDENT ENERGY= spectrum:
SPEC FILENAME= /home/chriso/HEN_HOUSE/spectra/co60CPO8.spectrum
SPEC IOUTSP= include #none,include;
#none: no spectrum data in .egslst file
#include: output spectrum data to .egslst file
#Example with SOURCE NUMBER= 21 (phase space source):
# INCIDENT PARTICLE= all
# SOURCE NUMBER= 21
# SOURCE OPTIONS= 0., 0., 0., 0.
# FILSPC= /home/chriso/egsnrc_mp/BEAM_Co-60/Co-60_40rr_70.egsphsp1
:stop source inputs:
#########################
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#########################
:Start MC Transport Parameter:
Global ECUT= 0.521 #Electron cutoff for transport
Global PCUT= 0.01 #Photon cutoff for transport
Global SMAX= 1e10 #Maximum step size in cm (not needed
#unless old PRESTA algorithm used)
#ECUT, PCUT and SMAX can also be set on a
#region-by-region basis.
#
#Set XXXX= f_value1, f_value2, ...
#Set XXXX start region= i_value1, i_value2, ...
#Set XXXX stop region= j_value1, j_value2, ...
#
#where XXXX is ECUT, PCUT or SMAX ,
#f_value1, f_value2,... are the desired values for XXXX
#and i_value_i and j_value_i are the start and
#stop regions.
ESTEPE= 0.25 #Max fractional continuous energy loss
#per step. Use 0.25 unless using
#PRESTA-I
XIMAX= 0.5 #Max first elastic scattering moment
#per step. Using default.
Boundary crossing algorithm= exact #exact,PRESTA-I;
#exact: cross boundaries in single scattering
# mode (distance at which to go into
# single scattering mode determined by
# "Skin depth for BCA"
#PRESTA-I: cross boundaries with lateral
# correlations off and force multiple
# scattering mode
Skin depth for BCA= 3 #Distance from a boundary (in elastic
#MFP) at which the algorithm will go
#into single scattering mode (using
#default here)
Electron-step algorithm= PRESTA-II #PRESTA-II,PRESTA-I;
#Determines the algorithm used to take
#into account lateral and longitudinal
#correlations in a condensed history
#step
Spin effects= On #Off (default),On;
#Turns off/on spin effects for electron
#elastic scattering. Spin On is
#ABSOLUTELY necessary for good
#backscattering calculations. Will
#make a difference even in `well
#conditioned' situations (e.g. depth
#dose curves).
Brems angular sampling= KM #Simple,KM (default);
#Simple: leading term of Koch-Motz
# dist'n used to determine angle
# of bremsstrahlung photons
#KM: Koch-Motz distribution used to
# determine angle
Brems cross sections= BH #BH (default),NIST;
#BH: Bethe-Heitler cross-sections used
#NIST: NIST cross-sections used
Bound Compton scattering= Off #Off (default),On;
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#Off: Klein-Nishina used for compton
# scattering
#On: Impuls approximation used for
# scattering
#note: SPRRZ has not be adjusted to work with bound compton
Pair angular sampling= Simple #Off, Simple (default),KM;
#Simple: use leading term of K-M
# dist'n
#KM: use complete Koch and Motz dist'n
#Off: angle of pairs is m/E--like old EGS4
Photoelectron angular sampling= Off #Off (default),On;
#Off: Photoelectrons get direction of
# photon that creates them
#On: Sauter's formula is used
Rayleigh scattering= Off #Off (default),On;
#Off: no coherent scattering
#On: simulates coherent scattering
Atomic relaxations= Off #Off (default),On;
#On: use correct cross section
# for p.e. events and shell vacancies
# for Compton & p.e. events are relaxed
# via emission of fluorescent X-Rays,
# Auger and Koster-Cronig electrons
# electrons
#The following allow for adjustment
#of ECUT, PCUT and SMAX in
#individual regions
Set ECUT= 0.0 #this is off for this example
Set ECUT start region= 1 #region 1 is outside the geometry
Set ECUT stop region= 1
Set PCUT= 0.0 #this is off for this example
Set PCUT start region= 1 #region 1 is outside the geometry
Set PCUT stop region= 1
Set SMAX= 0.0 #this is off for this example
Set SMAX start region= 1 #region 1 is outside the geometry
Set SMAX stop region= 1
# Atomic relaxations, Rayleigh scattering, Photoelectron angular sampling and
# Bound compton scattering can be turned on/off on a region by region basis.
# Instead of simply "On" or "Off" for these cases put:
# Atomic relaxations= On (or Off) in Regions
# Relaxations start region= 1, 40 #turns relaxations on in regions 1-10 and
# Relaxations stop region= 10, 99 #40-99
#
# Rayleigh scattering= On (or Off) in Regions
# Rayleigh start region= 1, 40
# Rayleigh stop region= 10, 99
#
# Photoelectron angular sampling= On (or Off) in Regions
# PE sampling start region= 1, 40
# PE sampling stop region= 10, 99
#
# Bound Compton scattering= On (or Off) in Regions
# Bound Compton start region= 1, 40
# Bound Compton stop region= 10, 99
:Stop MC Transport Parameter:
########################
:Start Variance Reduction:
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RUSSIAN ROULETTE DEPTH= 0.0000 #play Russian Roulette with photons once they
#cross this Z plane
RUSSIAN ROULETTE FRACTION= 0.0000 #probability of photon survival--if this
#and #RUSSIAN ROULETTE DEPTH both 0, then
#photon Russian Roulette is not played
#exponential pathlength biasing can be
#used. See Rogers&Bielajew 1990 review for
#discussion. C pathlength shortening
# >0 => pathlength stretching
# along z axis both cases
EXPONENTIAL TRANSFORM C= 0.0000
PHOTON FORCING= Off #Off,Default,On;
#Default: force photons to interact
# if IFULL= dose and stoppers:
# force initial interaction only
# for other settings of IFULL:
# force 2 interactions
#On: force photons to interact according to
# START FORCING and STOP FORCING AFTER inputs
START FORCING= 1 #Start forcing at this interaction number
STOP FORCING AFTER= 1 #Number of photon interactions after which
#to stop forcing photon interactions
ELECTRON RANGE REJECTION= Off #Off,On:
#Off: no electron range rejection
#On: charged particles which cannot reach
# region boundaries with energy > Global
# ECUT (see above) are terminated and their
# energy deposited in the current region.
# Range rejection is only considered for
# particles with energy #MUST NOT not put tabs after any character inputs,
#including delimeters.
#equal signs must have no space on the left and
#at least one space on the right.
###################
:start I/O control: #This is a start delimeter, see matching stop below
#DOSRZnrc scores data only in region specified. This is
#to save space on listing files if there are many
#regions in a calculation. It saves very little time
#to use a restricted scoring region..
#Best to have all regions.
DOSE ZBOUND MIN= 1 #Min plane number defining dose region
DOSE ZBOUND MAX= 61 #Max plane number defining dose region
DOSE RBOUND MIN= 0 #Min cylinder defining dose region
#(could also start at 1)
DOSE RBOUND MAX= 60 #Max cylinder defining dose region
IWATCH= off #off,interactions,steps,deposited,graph;
#debug output with increasing detail,
#graph outputs .gph file for EGS_Windows
#if not "off" use very few histories
STORE INITIAL RANDOM NUMBERS= no #no,last,all;
#can store initial random numbers for
#last history or each history in .egsrns
#(useful for debugging)
IRESTART= first #first,restart,make,analyze,start-RNS,parallel;
#first: first run
#restart: restart of old run (requires .egsdat file)
#make: just create an input file and exit
#analyze: read in data from .egsdat file and
# do statistical analysis and output results
# to .egslst
#start-RNS: read initial random numbers from a file
#parallel: read .egsdat files from parallel jobs
# (named inputfile_w*), do statistical
# analysis and output to .egslst
OUTPUT OPTIONS= long #short,dose summary,material summary,
#material and dose summary, long;
#short => just a dose grid output (DG)
#dose summary=> just doses, no grid -useful for later
# processing
#material summary=> material grid(MG) +DG
#material and dose summar=>MG + DS
#long=> MG + DG + DS
STORE DATA ARRAYS= yes #yes,no;
#yes: output .egsdat file for restarts, parallel
# post-processing, etc
ELECTRON TRANSPORT= normal #normal, no interactions;
#normal: normal e- transport
#no interactions: use with special PEGS4
# data sets to do CSDA calculation
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:stop I/O control:
##################
##########################
:start Monte Carlo inputs:
NUMBER OF HISTORIES= 10000000 #splits into $STAT statistical batches
#must be >=$STAT**2 if IWATCH= Off
#can have less than this if IWATCH set to
#another option
INITIAL RANDOM NO. SEEDS= 1, 3 #With ranmar: these must be between 1 and
# 30081 (default to 9373)
#With ranlux: must be between 0 and
# 1073741824, although first
# number (the luxury level)
# should not be 0
MAX CPU HOURS ALLOWED= 90.000 #Will shut down cleanly prior to
#exceeding this limit, as long as one
#batch has completed.
IFULL= dose and stoppers #dose and stoppers,entrance regions,
#pulse height distribution, scatter fraction;
#determines what doses are output
STATISTICAL ACCURACY SOUGHT= 0.0000 #If 0, goes until number of histories
# or CPU limit exceeded. If not zero
# goes until this uncertainty (in %)
# is achieved in the peak dose region
SCORE KERMA= yes #no,yes;
#yes: score kerma wherever dose scored and estimate
# ratio of dose/kerma (only makes sense for photon
# beams)
:stop Monte Carlo inputs:
#########################
##########################
:start geometrical inputs:
METHOD OF INPUT= groups #groups,individual:
#group: input groups of slabs of equal thickness
#individual: input Z of bottom of every slab
Z OF FRONT FACE= 0. #Beginning of first slab
NSLAB= 1 #Define a group of 10 slabs with thickness 1 cm
SLAB THICKNESS= 0.0002 #followed by 50 slabs with thickness 2 cm
#Example with METHOD OF INPUT= individual:
# DEPTH BOUNDARIES= 1.0, 1.5, 1.5, 1.0, 0.5, 0.5, 1.0, 1.5, 2.0, 2.0, 50.0
RADII= 1000 #Radii of cylinders
######## Material Input
MEDIA= AIR521ICRU #the media in the problem
#These must match exactly, including case, one
#of the media names in the pegs4 data set being
#used in the problem.
#The maximum length of name is 24 characters
#They are automatically left justified on input.
#Next we specify which media are in
#which geometric regions
#note that by default all regions contain
#medium 1 and which medium to input as 1 should
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#be selected with this in mind.
DESCRIPTION BY= planes #planes,regions;
#planes: use slab and cylinder no.'s to
# define what medium goes where
#regions: use region numbers to define this
(region numbers start at 2 and
number from top to bottom of
geometry and innermost radius to
outermost radius)
MEDNUM= 1 #This puts water everywhere and then
START ZSLAB= 1 #inserts a small column of air on the central
STOP ZSLAB= 1 #axis with radius 1cm and going from Z=10cm
START RING= 1 #to Z=12cm
STOP RING= 1
#Example with DESCRIPTION BY= regions to do the same as above
# MEDNUM= 1,2
# START REGION= 2, 12
# STOP REGION= 301, 12
:stop geometrical inputs:
#########################
#####################
:start source inputs:
INCIDENT PARTICLE= photon #electron,photon,positron,all;
#all: only used for phase space sources
SOURCE NUMBER= 0 #0,1,2,3,4,10,11,12,13,14,20,21
#0: parallel beam incident from front
SOURCE OPTIONS= 5.0, 0, 0, 1, #for source 0: radius of beam, incident
# X,Y,Z direction cosines
INCIDENT ENERGY= spectrum #monoenergetic, spectrum;
# INCIDENT KINETIC ENERGY(MEV)= 1.25 #only use for "monoenergetic"
#If INCIDENT ENERGY= spectrum:
SPEC FILENAME= /home/chriso/HEN_HOUSE/spectra/co60CPO8.spectrum
SPEC IOUTSP= include #none,include;
#none: no spectrum data in .egslst file
#include: output spectrum data to .egslst file
#Example with SOURCE NUMBER= 21 (phase space source):
# INCIDENT PARTICLE= all
# SOURCE NUMBER= 21
# SOURCE OPTIONS= 0., 0., 0., 0.
# FILSPC= /usr/people/dave/egs4/BEAM_slabs2/new.50MV.8cm.5.egs4phsp1
:stop source inputs:
#########################
#########################
:Start MC Transport Parameter:
Global ECUT= 2 #Electron cutoff for transport
Global PCUT= 0.001 #Photon cutoff for transport
Global SMAX= 1e10 #Maximum step size in cm (not needed
#unless old PRESTA algorithm used)
#ECUT, PCUT and SMAX can also be set on a
#region-by-region basis.
#
#Set XXXX= f_value1, f_value2, ...
#Set XXXX start region= i_value1, i_value2, ...
#Set XXXX stop region= j_value1, j_value2, ...
#
#where XXXX is ECUT, PCUT or SMAX ,
#f_value1, f_value2,... are the desired values for XXXX
#and i_value_i and j_value_i are the start and
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#stop regions.
ESTEPE= 0.25 #Max fractional continuous energy loss
#per step. Use 0.25 unless using
#PRESTA-I
XIMAX= 0.5 #Max first elastic scattering moment
#per step. Using default.
Boundary crossing algorithm= exact #exact,PRESTA-I;
#exact: cross boundaries in single scattering
# mode (distance at which to go into
# single scattering mode determined by
# "Skin depth for BCA"
#PRESTA-I: cross boundaries with lateral
# correlations off and force multiple
# scattering mode
Skin depth for BCA= 3 #Distance from a boundary (in elastic
#MFP) at which the algorithm will go
#into single scattering mode (using
#default here)
Electron-step algorithm= PRESTA-II #PRESTA-II,PRESTA-I;
#Determines the algorithm used to take
#into account lateral and longitudinal
#correlations in a condensed history
#step
Spin effects= On #Off (default),On;
#Turns off/on spin effects for electron
#elastic scattering. Spin On is
#ABSOLUTELY necessary for good
#backscattering calculations. Will
#make a difference even in `well
#conditioned' situations (e.g. depth
#dose curves).
Brems angular sampling= KM #Simple,KM (default);
#Simple: leading term of Koch-Motz
# dist'n used to determine angle
# of bremsstrahlung photons
#KM: Koch-Motz distribution used to
# determine angle
Brems cross sections= BH #BH (default),NIST;
#BH: Bethe-Heitler cross-sections used
#NIST: NIST cross-sections used
Bound Compton scattering= Off #Off (default),On;
#Off: Klein-Nishina used for compton
# scattering
#On: Impuls approximation used for
# scattering
Pair angular sampling= Simple #Off, Simple (default),KM);
#Simple: use leading term of K-M
# dist'n
#KM: use complete Koch and Motz dist'n
#Off: angle of pairs is m/E--like old EGS4
Photoelectron angular sampling= Off #Off (default),On;
#Off: Photoelectrons get direction of
# photon that creates them
#On: Sauter's formula is used
Rayleigh scattering= Off #Off (default),On;
#Off: no coherent scattering
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#On: simulates coherent scattering
Atomic relaxations= On #Off (default),On;
#On: use correct cross section
# for p.e. events and shell vacancies
# for Compton & p.e. events are relaxed
# via emission of fluorescent X-Rays,
# Auger and Koster-Cronig electrons
# electrons
# Atomic relaxations, Rayleigh scattering, Photoelectron angular sampling and
# Bound compton scattering can be turned on/off on a region by region basis.
# Instead of simply "On" or "Off" for these cases put:
# Atomic relaxations= On (or Off) in Regions
# Relaxations start region= 1, 40 #turns relaxations on in regions 1-10 and
# Relaxations stop region= 10, 99 #40-99
#
# Rayleigh scattering= On (or Off) in Regions
# Rayleigh start region= 1, 40
# Rayleigh stop region= 10, 99
#
# Photoelectron angular sampling= On (or Off) in Regions
# PE sampling start region= 1, 40
# PE sampling stop region= 10, 99
#
# Bound Compton scattering= On (or Off) in Regions
# Bound Compton start region= 1, 40
# Bound Compton stop region= 10, 99
:Stop MC Transport Parameter:
########################
:Start Variance Reduction:
BREM SPLITTING= Off #Off, On;
NUMBER OF BREMS PER EVENT= 1 #Used to set nbr_split. Only used if BREM
#SPLITTING= On
CHARGED PARTICLE RUSSIAN ROULETTE= Off #Off, On;
#On: use Russian Roulette to eliminate
# secondary charged particles with
# probability of survival=1/nbr_split
ELECTRON RANGE REJECTION= off #Off,On;
#On: if charged particle energy is below ESAVEIN
# and it cannot get out of current region
# with energy > ECUT, the particle is
# terminated
ESAVEIN= 0.0 #Energy below which range rejection is
#considered
RUSSIAN ROULETTE DEPTH= 0.0000 #play Russian Roulette with photons once they
#cross this Z plane
RUSSIAN ROULETTE FRACTION= 0.0000 #probability of photon survival--if this and
#RUSSIAN ROULETTE DEPTH both 0, then no
#photon Russian Roulette is played
#exponential pathlength biasing can be
#used. See Rogers&Bielajew 1990 review for
#discussion. C pathlength shortening
# >0 => pathlength stretching
# along z axis both cases
EXPONENTIAL TRANSFORM C= 0.0000
PHOTON FORCING= On #Off (default),On;
#On: force photons to interact in geometry
START FORCING= 1 #Start forcing at this interaction number
STOP FORCING AFTER= 1 #Number of photon interactions after which
#to stop forcing photon interactions
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#DOSRZnrc allows for having the photon cross
#section scaled to enhance interactions in
#or near a region of interest.
CS ENHANCEMENT FACTOR= 1.0 #Photon cross section scaling factors
CS ENHANCEMENT START REGION= 1 #Regions in which to start applying above
#enhancement factors
CS ENHANCEMENT STOP REGION= 1 #Regions in which to stop applying above
#enhancement factors
#Region 1 is outside geometry-->no enhancement
#will take place here
:Stop Variance Reduction:
#########################
:start plot control:
PLOTTING= on #Off,On;
#On: create plots
LINE PRINTER OUTPUT= Off #Off,On;
#On: plot in .egslst file
EXTERNAL PLOTTER OUTPUT= On #Off,On;
#On: create .plotdat file for xmgr
EXTERNAL PLOT TYPE= Histogram #Point,Histogram,Both;
#Point: output point plots in .plotdat file
#Histogram: output histogram plots in .plotdat
#Both: output both types in .plotdat
PLOT RADIAL REGION IX= 1,2 #Indices of cylinders for which to plot depth-
#dose data (0 for no depth-dose plots)
PLOT PLANAR REGION IZ=10 #Indices of slabs for which to plot dose vs
#radius data (0 for no dose vs radius plots)
:stop plot control:
########################
File 2 – Graphite
TITLE= dosrznrc_template--depth dose in H2O due to Cobalt beam
#File to explain input to DOSRZnrc
#all options for a given quantity are shown, separated
#by commas and ending with a ;
#NB====> #MUST NOT not put tabs after any character inputs,
#including delimeters.
#equal signs must have no space on the left and
#at least one space on the right.
###################
:start I/O control: #This is a start delimeter, see matching stop below
#DOSRZnrc scores data only in region specified. This is
#to save space on listing files if there are many
#regions in a calculation. It saves very little time
#to use a restricted scoring region..
#Best to have all regions.
DOSE ZBOUND MIN= 1 #Min plane number defining dose region
DOSE ZBOUND MAX= 61 #Max plane number defining dose region
DOSE RBOUND MIN= 0 #Min cylinder defining dose region
#(could also start at 1)
DOSE RBOUND MAX= 60 #Max cylinder defining dose region
IWATCH= off #off,interactions,steps,deposited,graph;
#debug output with increasing detail,
#graph outputs .gph file for EGS_Windows
#if not "off" use very few histories
STORE INITIAL RANDOM NUMBERS= no #no,last,all;
#can store initial random numbers for
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#last history or each history in .egsrns
#(useful for debugging)
IRESTART= first #first,restart,make,analyze,start-RNS,parallel;
#first: first run
#restart: restart of old run (requires .egsdat file)
#make: just create an input file and exit
#analyze: read in data from .egsdat file and
# do statistical analysis and output results
# to .egslst
#start-RNS: read initial random numbers from a file
#parallel: read .egsdat files from parallel jobs
# (named inputfile_w*), do statistical
# analysis and output to .egslst
OUTPUT OPTIONS= long #short,dose summary,material summary,
#material and dose summary, long;
#short => just a dose grid output (DG)
#dose summary=> just doses, no grid -useful for later
# processing
#material summary=> material grid(MG) +DG
#material and dose summar=>MG + DS
#long=> MG + DG + DS
STORE DATA ARRAYS= yes #yes,no;
#yes: output .egsdat file for restarts, parallel
# post-processing, etc
ELECTRON TRANSPORT= normal #normal, no interactions;
#normal: normal e- transport
#no interactions: use with special PEGS4
# data sets to do CSDA calculation
:stop I/O control:
##################
##########################
:start Monte Carlo inputs:
NUMBER OF HISTORIES= 10000000 #splits into $STAT statistical batches
#must be >=$STAT**2 if IWATCH= Off
#can have less than this if IWATCH set to
#another option
INITIAL RANDOM NO. SEEDS= 1, 3 #With ranmar: these must be between 1 and
# 30081 (default to 9373)
#With ranlux: must be between 0 and
# 1073741824, although first
# number (the luxury level)
# should not be 0
MAX CPU HOURS ALLOWED= 90.000 #Will shut down cleanly prior to
#exceeding this limit, as long as one
#batch has completed.
IFULL= dose and stoppers #dose and stoppers,entrance regions,
#pulse height distribution, scatter fraction;
#determines what doses are output
STATISTICAL ACCURACY SOUGHT= 0.0000 #If 0, goes until number of histories
# or CPU limit exceeded. If not zero
# goes until this uncertainty (in %)
# is achieved in the peak dose region
SCORE KERMA= yes #no,yes;
#yes: score kerma wherever dose scored and estimate
# ratio of dose/kerma (only makes sense for photon
# beams)
:stop Monte Carlo inputs:
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#########################
##########################
:start geometrical inputs:
METHOD OF INPUT= groups #groups,individual:
#group: input groups of slabs of equal thickness
#individual: input Z of bottom of every slab
Z OF FRONT FACE= 0. #Beginning of first slab
NSLAB= 1 #Define a group of 10 slabs with thickness 1 cm
SLAB THICKNESS= 0.0002 #followed by 50 slabs with thickness 2 cm
#Example with METHOD OF INPUT= individual:
# DEPTH BOUNDARIES= 1.0, 1.5, 1.5, 1.0, 0.5, 0.5, 1.0, 1.5, 2.0, 2.0, 50.0
RADII= 1000 #Radii of cylinders
######## Material Input
MEDIA= 1726C #the media in the problem
#These must match exactly, including case, one
#of the media names in the pegs4 data set being
#used in the problem.
#The maximum length of name is 24 characters
#They are automatically left justified on input.
#Next we specify which media are in
#which geometric regions
#note that by default all regions contain
#medium 1 and which medium to input as 1 should
#be selected with this in mind.
DESCRIPTION BY= planes #planes,regions;
#planes: use slab and cylinder no.'s to
# define what medium goes where
#regions: use region numbers to define this
(region numbers start at 2 and
number from top to bottom of
geometry and innermost radius to
outermost radius)
MEDNUM= 1 #This puts water everywhere and then
START ZSLAB= 1 #inserts a small column of air on the central
STOP ZSLAB= 1 #axis with radius 1cm and going from Z=10cm
START RING= 1 #to Z=12cm
STOP RING= 1
#Example with DESCRIPTION BY= regions to do the same as above
# MEDNUM= 1,2
# START REGION= 2, 12
# STOP REGION= 301, 12
:stop geometrical inputs:
#########################
#####################
:start source inputs:
INCIDENT PARTICLE= photon #electron,photon,positron,all;
#all: only used for phase space sources
SOURCE NUMBER= 0 #0,1,2,3,4,10,11,12,13,14,20,21
#0: parallel beam incident from front
SOURCE OPTIONS= 5.0, 0, 0, 1, #for source 0: radius of beam, incident
# X,Y,Z direction cosines
INCIDENT ENERGY= spectrum #monoenergetic, spectrum;
# INCIDENT KINETIC ENERGY(MEV)= 1.25 #only use for "monoenergetic"
#If INCIDENT ENERGY= spectrum:
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SPEC FILENAME= /home/chriso/HEN_HOUSE/spectra/co60CPO8.spectrum
SPEC IOUTSP= include #none,include;
#none: no spectrum data in .egslst file
#include: output spectrum data to .egslst file
#Example with SOURCE NUMBER= 21 (phase space source):
# INCIDENT PARTICLE= all
# SOURCE NUMBER= 21
# SOURCE OPTIONS= 0., 0., 0., 0.
# FILSPC= /usr/people/dave/egs4/BEAM_slabs2/new.50MV.8cm.5.egs4phsp1
:stop source inputs:
#########################
#########################
:Start MC Transport Parameter:
Global ECUT= 2 #Electron cutoff for transport
Global PCUT= 0.001 #Photon cutoff for transport
Global SMAX= 1e10 #Maximum step size in cm (not needed
#unless old PRESTA algorithm used)
#ECUT, PCUT and SMAX can also be set on a
#region-by-region basis.
#
#Set XXXX= f_value1, f_value2, ...
#Set XXXX start region= i_value1, i_value2, ...
#Set XXXX stop region= j_value1, j_value2, ...
#
#where XXXX is ECUT, PCUT or SMAX ,
#f_value1, f_value2,... are the desired values for XXXX
#and i_value_i and j_value_i are the start and
#stop regions.
ESTEPE= 0.25 #Max fractional continuous energy loss
#per step. Use 0.25 unless using
#PRESTA-I
XIMAX= 0.5 #Max first elastic scattering moment
#per step. Using default.
Boundary crossing algorithm= exact #exact,PRESTA-I;
#exact: cross boundaries in single scattering
# mode (distance at which to go into
# single scattering mode determined by
# "Skin depth for BCA"
#PRESTA-I: cross boundaries with lateral
# correlations off and force multiple
# scattering mode
Skin depth for BCA= 3 #Distance from a boundary (in elastic
#MFP) at which the algorithm will go
#into single scattering mode (using
#default here)
Electron-step algorithm= PRESTA-II #PRESTA-II,PRESTA-I;
#Determines the algorithm used to take
#into account lateral and longitudinal
#correlations in a condensed history
#step
Spin effects= On #Off (default),On;
#Turns off/on spin effects for electron
#elastic scattering. Spin On is
#ABSOLUTELY necessary for good
#backscattering calculations. Will
#make a difference even in `well
#conditioned' situations (e.g. depth
#dose curves).
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Brems angular sampling= KM #Simple,KM (default);
#Simple: leading term of Koch-Motz
# dist'n used to determine angle
# of bremsstrahlung photons
#KM: Koch-Motz distribution used to
# determine angle
Brems cross sections= BH #BH (default),NIST;
#BH: Bethe-Heitler cross-sections used
#NIST: NIST cross-sections used
Bound Compton scattering= Off #Off (default),On;
#Off: Klein-Nishina used for compton
# scattering
#On: Impuls approximation used for
# scattering
Pair angular sampling= Simple #Off, Simple (default),KM);
#Simple: use leading term of K-M
# dist'n
#KM: use complete Koch and Motz dist'n
#Off: angle of pairs is m/E--like old EGS4
Photoelectron angular sampling= Off #Off (default),On;
#Off: Photoelectrons get direction of
# photon that creates them
#On: Sauter's formula is used
Rayleigh scattering= Off #Off (default),On;
#Off: no coherent scattering
#On: simulates coherent scattering
Atomic relaxations= On #Off (default),On;
#On: use correct cross section
# for p.e. events and shell vacancies
# for Compton & p.e. events are relaxed
# via emission of fluorescent X-Rays,
# Auger and Koster-Cronig electrons
# electrons
# Atomic relaxations, Rayleigh scattering, Photoelectron angular sampling and
# Bound compton scattering can be turned on/off on a region by region basis.
# Instead of simply "On" or "Off" for these cases put:
# Atomic relaxations= On (or Off) in Regions
# Relaxations start region= 1, 40 #turns relaxations on in regions 1-10 and
# Relaxations stop region= 10, 99 #40-99
#
# Rayleigh scattering= On (or Off) in Regions
# Rayleigh start region= 1, 40
# Rayleigh stop region= 10, 99
#
# Photoelectron angular sampling= On (or Off) in Regions
# PE sampling start region= 1, 40
# PE sampling stop region= 10, 99
#
# Bound Compton scattering= On (or Off) in Regions
# Bound Compton start region= 1, 40
# Bound Compton stop region= 10, 99
:Stop MC Transport Parameter:
########################
:Start Variance Reduction:
BREM SPLITTING= Off #Off, On;
NUMBER OF BREMS PER EVENT= 1 #Used to set nbr_split. Only used if BREM
#SPLITTING= On
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CHARGED PARTICLE RUSSIAN ROULETTE= Off #Off, On;
#On: use Russian Roulette to eliminate
# secondary charged particles with
# probability of survival=1/nbr_split
ELECTRON RANGE REJECTION= off #Off,On;
#On: if charged particle energy is below ESAVEIN
# and it cannot get out of current region
# with energy > ECUT, the particle is
# terminated
ESAVEIN= 0.0 #Energy below which range rejection is
#considered
RUSSIAN ROULETTE DEPTH= 0.0000 #play Russian Roulette with photons once they
#cross this Z plane
RUSSIAN ROULETTE FRACTION= 0.0000 #probability of photon survival--if this and
#RUSSIAN ROULETTE DEPTH both 0, then no
#photon Russian Roulette is played
#exponential pathlength biasing can be
#used. See Rogers&Bielajew 1990 review for
#discussion. C pathlength shortening
# >0 => pathlength stretching
# along z axis both cases
EXPONENTIAL TRANSFORM C= 0.0000
PHOTON FORCING= On #Off (default),On;
#On: force photons to interact in geometry
START FORCING= 1 #Start forcing at this interaction number
STOP FORCING AFTER= 1 #Number of photon interactions after which
#to stop forcing photon interactions
#DOSRZnrc allows for having the photon cross
#section scaled to enhance interactions in
#or near a region of interest.
CS ENHANCEMENT FACTOR= 1.0 #Photon cross section scaling factors
CS ENHANCEMENT START REGION= 1 #Regions in which to start applying above
#enhancement factors
CS ENHANCEMENT STOP REGION= 1 #Regions in which to stop applying above
#enhancement factors
#Region 1 is outside geometry-->no enhancement
#will take place here
:Stop Variance Reduction:
#########################
:start plot control:
PLOTTING= on #Off,On;
#On: create plots
LINE PRINTER OUTPUT= Off #Off,On;
#On: plot in .egslst file
EXTERNAL PLOTTER OUTPUT= On #Off,On;
#On: create .plotdat file for xmgr
EXTERNAL PLOT TYPE= Histogram #Point,Histogram,Both;
#Point: output point plots in .plotdat file
#Histogram: output histogram plots in .plotdat
#Both: output both types in .plotdat
PLOT RADIAL REGION IX= 1,2 #Indices of cylinders for which to plot depth-
#dose data (0 for no depth-dose plots)
PLOT PLANAR REGION IZ=10 #Indices of slabs for which to plot dose vs
#radius data (0 for no dose vs radius plots)
:stop plot control:
########################
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A4.7 krn – The following radial profile of the 60Co beam produced using
beamdp was used for the Monte Carlo determination of krn.
Radial profile of Co-60 beam
9.00E-06
8.00E-06
7.00E-06
6.00E-06
Intensity
5.00E-06
4.00E-06
3.00E-06
2.00E-06
1.00E-06
0.00E+00
0 1 2 3 4 5 6
Radius (cm)
Figure A4.2: Radial profile of 60Co beam produced using beamdp from the phase space file
of the source at the plane coincident with the front face of the primary
standard.
For krn calculation the profile was fitted with a fifth degree polynomial which had the
form
where y is the intensity and x is the radius.
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