Text by liuhongmeiyes


									I. Introduction (Prisca)

Since the first Homestake NUSL studies seven years ago, an on-site low background
facility for screening and production/storage of radiopure materials has been identified as
a priority. The design of the facility was explored in the NUSL White paper [1] and was
mapped into the infrastructure matrix [2] during the DUSEL Solicitation 1 process, with
its own technical chapter of the Deep Science Report [3]. Its importance was reaffirmed
during the November 2007 Town Meeting by the B1 Crosscutting Group on Low
Background (attended by ~40 physicists representing the full range of underground
science disciplines). At that time we agreed to submit a single S4 proposal to articulate
an integrated program to define necessary technologies and capabilities which must be
available when DUSEL starts operations, as well as the R&D program needed to develop
technologies providing enhanced sensitivities. The clear consensus was that DUSEL
must have world class facilities capable of providing assay and ultra-clean materials
support for the initial suite of science experiments, as well as integration tools to share
data, exchange equipment, train personnel, optimize screening throughput (both on-site
and off-site), foster new collaborations in areas of geology, biology and homeland
security, and identify new users in other research fields.

The breadth of this vision is only possible if it is approached in the context of a cost-
effective, shared facility which can satisfy the collective needs of all the relevant
experiments, rather than duplicating installations and treating the data as proprietary. It
includes a commitment to free exchange of information and makes use of international
ties to strengthen collaborations and share expertise. Any such facility will require a
trained local staff. The expectation would be that this staff would provide state-of-the-
art assay and materials preparation and eventually would also help lead and direct future
R&D efforts to develop enhanced sensitivities.

This S4 proposal starts the transition from the current loosely organized community into
a cohesive DUSEL-focused group. This process can be achieved using a model similar
to the European ILIAS JRA-1 organization, which joins institutions and facilities
interested in low-level counting and ultra-clean materials in a cooperative manner. It is
clear that the S4 process is the ideal route to provide resources to help unite and
coordinate the separate groups and institutions as the community develops an integrated
program. It is expected that as part of the early S4 efforts, an open database will be
developed which provides Web-based access to information on material radiopurities
already assayed, as well as current assay capabilities at other facilities (both above and
below ground). This will define the landscape in which DUSEL will reside and help
prioritize and schedule the development of the DUSEL facility. Since the low
background facility should be one of the earliest modules at DUSEL, we plan to work
closely with the Sanford Lab to leverage existing resources (EPSCoR, State funds, and a
possible MRE) such that expertise and screening can be part of the early implementation
plan, with capacity ramping up fast enough to keep up with the needs as the first suite of
experiments are constructed. We will bridge the gap between the early S4 efforts and
the final DUSEL installation by forming an integrated training and re-allocation plan,
whereby distributed sites which are already serving the community (e.g. Kimballton,
Soudan, WIPP, Oroville, etc.) act as training centers for the distribution of the craft.

Common technical capabilities identified as needed by the initial suite of DUSEL
experiments include:

Gamma screening - HPGe detectors of varying sensitivity and segmentation. Includes
systems at the surface or 300’ level for pre-screening as well as sensitive systems located
at moderate depth.

Alpha, Beta, and Rn counting - Both commercial pre-screeners and more sensitive new
technology that is currently being developed. Radon emanation chambers and systems.

Access to Mass spectrometry – The means to obtain sensitivities at the sub-microBq/kg
level, employing exisiting mass spec facilities or dedicated on-site machines. Requires
ultra-clean reagents and wet-lab facilities.

NAA and RNAA screening - The ability to facilitate and conduct neutron activation and
radiochemistry NAA measurements. The RNAA measurements require wet lab
capabilities. They both require dedicated HPGe detectors with moderate sensitivity.

Underground storage of ultra-pure materials - Storage of clean materials such as
cryogens, water, noble liquids and gases, copper, lead and germanium.

Underground ultra-pure material production facilities - Expected materials include
electroformed copper, Kr removal, and potentially Ge crystal growth. Also includes
access to a clean machine shop, and special fabrication tools such as EDM machines and
laser welders.

Ultra-sensitive whole body counter - A later large-scale immersion facility (possibly
liquid scintillator) to provide whole body counting capabilities for large samples or
materials. This is the only element that should be located at the 4850 level or deeper.

These elements do not exist on their own. In order to fully utilize the capabilities
outlined above, there need to be organizational structures which allow for the
prioritization of samples, programs and R&D, exchange of technologies and expert
personnel, expansion of the user base, and the smooth running of the facility. These have
been identified as

Materials Database – web-accessible open database of all materials screened, their
contamination levels, production details, and expected use.

Assay Capabilities – web-accessible scheduling tools with the sensitivities and
characteristics of all machines and processes available to the user, including techniques
only available offsite (Mass Spec, Irradiation for NAA, chemical assay)
Code repository - updated and maintained software for the operation and interpretation of
screening data, cosmogenic activation and shower production, nuclear cross sections, etc.

Integrative activities – workshops and networking activities to foster continued research
into new low background techniques, international and cross-cutting collaboration, and
extension into other research areas.

II. Elements of a Low Radiation Facility

Introduction to Assay of Materials

The common thread in the search for rare events or weakly interacting particles is their
need for an environment free of background from cosmic rays and natural radioactivity.
Every component which goes into these experiments must be radiopure to such a high
degree that even the best screening facilities available in shielded sites at the earth’s
surface are insufficiently sensitive. Therefore it is absolutely essential that space be
reserved underground for shielded screening of components. These ultra-sensitive
screening detectors can also be used by geology, microbiology, environmental science,
and national security applications to identify radioisotopes, date samples, and measure
tracers introduced into hydrological or biological systems.

Although the background is reduced significantly by moving screening detectors
underground, it is not possible to exploit extreme depths, since backgrounds internal to
the detectors themselves become the limiting factor beyond an overburden of 1500 mwe.
In figure 1, this is explicitly shown for a sample of operating high purity germanium
detectors at several sites. Moreover, for many practical applications, the counting time
itself would become prohibitively long. Thus, except for an ultra-low background,
whole body counting facility an underground screening facility does not have to be
deeper than roughly 2000 mwe, even accounting for improvements in the purification of
germanium crystals and new shielding materials. Some applications, such as neutron
activation, can be on the surface, and others might do quite well at the 300’ level.
However, in the interest of creating the most efficient facility, there is a desire to keep
most of the screeners in the same, mid-level location.
     Figure 1. Integral background counting rates of HPGe detectors (from 40 to 2700 keV)
     divided by the mass of the Ge-crystal as a function of the operating depth of different
     underground laboratories. The solid line shows the muon fluence rate in arbitrary units
     normalised to the background counting rate above ground. The IAEA-MEL detector
     includes active shielding. [22]

In determining the size and throughput required for the LBCF, it is important to quantify
the number and type of samples which current and proposed experiments intend to
process and compare projected needs to the availability of such infrastructure. Surveys of
experimental needs were completed several years ago in the context of Solicitation 1, but
must be updated over the design period in order to make a reasonable assessment of
needs. This will be one of the projects which we expect this S4 to support. Even early
projections ( see figure??) indicate that the total number of samples requiring some sort
of screening for current and next generation dark matter, solar neutrino, and double beta
decay experiments far exceed what presently exists and also that they are needed before
DUSEL comes online. This argues for early implementation of elements of the low
background facility at SUSEL and use of existing sites for initial screening and training
of personnel. Purchase and installation of new screening detectors at existing sites, with
a DUSEL relocation plan which is matched to experimental schedules and infrastructure
completion, would create the throughput needed early, and provide for a smooth
transition to a more centralized location later.

Once we have the final survey of experimental low background needs, we will be
dividing the applications into modalities (e.g. counting or mass spec or chemical) and
into sensitivity regimes (as was done in figure ??). We fully expect that we will need a
range of sensitivities, including conventional radiometric materials screening (alpha, beta,
gamma for solids, liquids, and gases) for all major DUSEL experiments, as well as the
research applications demanded by bio and geosciences. Since there is clean fabrication
and electroforming capability in the same location, it can provide materials and controls
1000-fold lower than a surface facility and an order of magnitude lower in contamination.
The purpose of a production measurement facility is to provide the throughput necessary
for sensitive applications, not to push the limits of sensitivity.

Gamma Counting

Low background gamma ray spectroscopy using germanium semiconductor detectors is a
well-developed and mature technology which has served as the prime tool for material
selection. Sensitivities down to a few hundred ppt of U and Th are routinely achieved
using commercially available detectors [11]. The outstanding energy resolution gives
these HPGe detectors high diagnostic power. This makes them an excellent choice for
counting applications where radioisotope identification is important. All current
generation solar neutrino, dark matter and double beta decay experiments have been
relying heavily on this detection technique.

High sample through-put (equivalent to the availability of multiple counting stations) and
good diagnostic power are needed to fulfill this task. There should be at least 8 well-
shielded HPGe stations of varying sensitivities and configurations. Along with the usual
planar detectors, there should be at least 2 well-type HPGes, one of which should be
segmented for coincidence counting, to handle small samples (electronic components or
tracer analyses for microbial samples or cosmogenic and nucleogenic isotope dating).
These can be assembled from discrete crystals, such as the coincidence counter at Lower
Monumental Dam or the more ambitious SEGA and MEGA [12]. The CLOVER detector
(Canberra Eurysis) is a commercially available 4 to 16-fold segmented well counter that
also would be well-suited to this application. With appropriate choice of low background
cryostat and shielding (OFHC copper can be obtained with <100 Bq/kg U/Th
contamination [13]), such coincidence detectors can reach ~10-11 g/g. precision counting
precision for 238U and 232Th. [14]. This can be improved to ~10 μBq/kg or 10-12 g/g by
fully implementing segmentation and pulse shape discrimination for gamma-ray tracking.

(Mei’s contribution, edited by Prisca)
Along with conventional HPGe screening, we should invest in higher-sensitivity, large
(~3.3 kg) HPGe detectors, which have recently become commercially available. Internal
materials require at least one order of magnitude lower radioactivity than shielding
materials for most of the incoming DUSEL experiments. Special care has to be taken in
making ultra-low background germanium detectors that will be built at the 4850-ft level
to satisfy the needs of screening internal materials. In particular, the next generation
neutrinoless double-beta decay experiments strictly demand a radioactivity level of about
0.03 ppt for 232Th and 0.01 ppt for 238U for internal materials. Therefore, Neutron
Activation Analysis (NAA), ICPMS, and other techniques must be used in order to
measure such low activity in the materials.
An ultra-low background counting facility (ULBCoF) will include the development of
background rejection techniques, active and passive shielding, veto systems, atmosphere
control systems to reduce radon levels, pulse shape discrimination techniques, and low-
background detectors. The deliverables of this research activity will be a worldwide
valued and coordinated system of US facilities for ultra-low background measurement
applications in rare event physics and in other fields such as environmental physics and
geophysics. Figures 1-1 to 1-3 show a conceptual design of the ultra-low background
facility and a possible location for it at the 4850-ft level underground.

Fig.1-1. Conceptual Design of the ULBCoF. The configuration in this plot can be used
for both material screening and double-beta decay to excited states experiments.
Fig. 1-2. Conceptual Design of the ULBCoF. Shown configuration is used for screening

Fig. 1-3. Conceptual Design of the ULBCoF. The plot shows a possible ULBCoF
location plan (elevation view) for the DUSEL/Homestake Early Implementation
A conceptual picture of the counting facility is given in Figures 1-1 to Figure 1-3. A few
essential requirements determine the main features of the concept: simple assembly and
quick establishment; use of existing technology and commercially available materials;
easy access to underground; and capable of screening any type of material.

The counting facility will be installed in a controlled clean room, which will be a
standard low-background laboratory (3.5 m x 4 m). The design and materials for this
clean room are commercially available.

The two low-background detectors are made by Canberra [4]. The detector is about 10
cm in diameter and 8 cm in length. The detector has high-resolution, cold-FET energy
readouts. The pulse shape discrimination has been well studied at Los Alamos National
Laboratory as shown in Fig. 3-1 [5].

The inner shielding is 10 cm oxygen-free high conductivity (OFHC) copper with 99.99%
purity. The contamination of 238U and 232Th in this material is less than 100 μBq/kg [6].
We also suggest that Canberra use such highly pure copper to make the cryostat for the
two low-background detectors. Outside the copper shielding, a 5 cm layer of 30% borated
polyethylene is used to absorb the low-energy neutrons produced in the lead by muons.
After the borated polyethylene layer, a 30 cm layer of lead is utilized to stop the
environmental gamma-rays from entering the detector. The outmost shielding is a 50 cm
layer of pure polyethylene bricks to stop the neutrons produced from the surrounding
rock. The muon veto detectors are placed outside the outer shielding, providing coverage
of 4π.

The state of South Dakota is committed to re-fabricate the Ray-Davis cavity at the 4850-
ft level and to make it a modern underground laboratory named Sanford Underground
Science and Engineering Laboratory (SUSEL). SUSEL will be ready to accommodate
experiments a few years ahead of DUSEL. Our strategy is to build two commercially
available gamma-ray counting stations at the 800-ft level in 2010 to meet the needs of the
early implementation experiments. Two more gamma-ray counting stations with
electroforming copper as the cryostat will be built at the 4850-ft level in 2012 before
DUSEL starts. We will work together with the existing facility at Soudan Mine,
Kamilton, and WIPP to build a counting network in the US to ensure the best quality of
low-background counting for all planned low-background experiments. This network will
be used to train new workers and share the resources and screening materials. From this,
a coherent library of the database will be developed for users of the different counting
laboratories, which will be necessary for the design of the underground experiments.
Existing information will be collected, coordinated, and analyzed for future comparison.

A low-background gamma-ray counting facility is essential to the success of all incoming
DUSEL experiments. We plan to have a total of 10 gamma-rays stations described above
to meet the needs of the incoming experiments. Among the 10 stations, 6 of them are
commercially available low-background germanium detectors that will serve as the
counting facility for external materials. The other 4 stations will be built with
electroforming copper as the cryostat. These 4 detectors will be counting for internal
materials. A full scale ULBCoF facility includes the development of new background
rejection techniques, active and passive shielding, veto systems, atmosphere control
systems to reduce radon levels, and low-background detectors. This is to say that we
need to: 1) develop pulse shape discrimination and Compton suppression techniques; 2)
understand the detector efficiency and energy resolution with experimental calibration
and Monte Carlo simulation; 3) study the shielding from various external backgrounds
with experiments and simulations; 4) test the radon free system for the radon exclusion
box; and 5) characterize the site where the counting facility will be set up.

2. Neutron Activation Analysis and RNNA

Even though technically a counting technique, the enhanced signals generated by Neutron
Activation Analysis (NAA) means that this technique does not need a shielded
underground site to achieve ppt sensitivity. A source of neutrons is required to initiate a
neutron capture interaction with the sample. This is generally a reactor with fluxes of
1013 n cm-2 s-1, but new deuterium-tritium plasma generators are approaching this
intensity [4]. The resulting compound nucleus forms in an excited state, almost
instantaneously de-exciting into a more stable configuration through emission of one or
more characteristic prompt gamma rays. In many cases, this new configuration yields a
radioactive nucleus which also decays by emission of one or more characteristic delayed
gamma rays, but at a much slower rate according to the unique half-life of the radioactive
nucleus. Observing the prompt gammas during irradiation is called PGNAA, but the
more common procedure is to remove the sample from the reactor and observe the
delayed gammas, usually via high purity germanium detectors. Since shipment of
samples irradiated at US research reactors can be arranged in a time scale of 2 to 3 days,
short-lived products are most efficiently counted at the irradiation site. For many longer
lived activation products the DUSEL gamma screeners can be used. A typical exercise
would be counting 239Np (t1/2=2.36 d) and 233Pa (t1/2=27 d) from 238U and 232Th.

NAA - Henning Back
For experiments proposed for DUSEL the primary isotopes searched for through NAA
are 238U, 232Th, and 40K. The sensitivities for these isotopes are fairly well established.
Reference [7] shows that for Uranium and Thorium the very best limits reach the 1 ppt
levels and for Potassium the best limits are at the 50 ppb level. Typical limits are 20 ppt
for U and Th, and 50 ppb for K. Both reference [7] and a private communication with
Andreas Piepke tell us that in order to reach these very low limits a dedicated counting
facility in control of the DUSEL low background counting personnel is required.
Typically NAA facilities at reactors are not concerned about reaching such low levels for
U and Th, and therefore their analysis can be flawed. In fact, most of the NAA samples in
reference [ii] were counted in Alabama, but irradiations took place elsewhere.
For an NAA program to exist at DUSEL would require coordination between DUSEL
and facilities that can irradiate samples (an NRC list of research reactors in the United
States is available below). Development of a reactor at DUSEL is, in my opinion, so far
off in the future that a NAA program at DUSEL should rely on outside reactors for
irradiations. On site at DUSEL will require High Purity Germanium (HPGe)
Spectrometers. The number of these detectors depends on the need, but below is a
justification that NAA is as important as direct gamma counting, but can take far less
time. If we assume, with no justification, that the gamma counting portion of NAA takes
a quarter of the time of direct gamma counting, then the NAA gamma counting facility at
DUSEL will require approximately an additional 25% more HPGe detectors as the direct
gamma counting facility. The Gran Sasso counting facility has on the order of 10 HPGe
detectors, and I assume that DUSEL will have approximately the same. Therefore the
NAA facility will need about 3 HPGe detectors with adequate shielding in a low
background environment.

Presumably material assay itself does not need to be justified here, since just the fact that
an entire working group exists for this topic should mean that there is some justification
for its existence. However, the usefulness of NAA has been questioned, but when
compared to the other methods it has both benefits and limitations. The sample size for
NAA is rather small, being on the order of grams or less; whereas direct gamma counting
requires a significant amount of material in order to measure the gamma rays directly
from the U and Th decay chains. Sample size is particularly important when the material
being assayed is very expensive. NAA is also a relatively fast process. Irradiations take
1-24 hrs and after a short cool down period the sample can be sent to a counting facility,
where the most sensitive measurements are made with gamma counting up to 1 week.
Direct gamma counting can take up to three months for the most sensitive measurements.
NAA limitations are primarily with regard to the sample itself. NAA is a destructive
method, in that the sample cannot be used in a low level detector after irradiation, but
mass spectrometry methods also destroy the sample. The bulk material of the sample
(matrix) should also not be able to be activated. Metals, for example, are not ideally
suited for NAA, however MS methods also have sample requirements. Inductively
Coupled Plasma Mass Spectrometry (ICP-MS) requires that the sample be able to go into
solution in strong acids. It is the conclusion of many that there is no one ideal material
assay method and that all methods need to be employed at DUSEL in order to have a
successful experimental program.

Although the only true measure of how much NAA is required is to probe the proposed
DUSEL experiments, I think that we can look at history to tell us something of its need.
The EXO-200 experiment, which is a neutrinoless double beta decay search, recently
published a paper [8] detailing 225 materials assayed for the EXO-200 detector. This
paper included which of four material assay methods were used: direct gamma counting,
NAA, alpha counting, and mass spectrometry (MS) methods. Of all the materials 27% of
them were assayed by NAA, 28% through direct gamma counting and the remainder by
MS methods; only one object used alpha counting. If we rank the assay method
importance by how many samples were used then NAA is clearly as important as direct
gamma counting.

Research reactor facilities in the United States that may be able to provide irradiation
Aerotest Operations Inc., San Ramon, CA
Armed Forces Radiobiological Research Institute, Bethesda, MD
Dow Chemical Company, Midland, MI
General Electric Company, Sunol, CA
Idaho State University, Pocatello, ID
Kansas State University, Manhattan, KS
Massachusetts Institute of Technology, Cambridge, MA
National Institute of Standards and Technology, Gaithersburg, MD
North Carolina State University, Raleigh, NC
Ohio State University, Columbus, OH
Oregon State University, Corvallis, OR
Penn State University, University Park, PA
Purdue University, West Lafayette, IN
Reed College, Portland, OR
Rensselaer Polytechnic Institute, Schenectady, NY
Rhode Island Atomic Energy Commission, Narrangansett, RI
Texas A&M University, College Station, TX (two reactors)
University of Arizona, Tucson, AZ
University of California-Davis, Sacramento, CA
University of California, Irvine, CA
University of Florida, Gainesville, FL
University of Maryland, College Park, MD
University of Massachusetts, Lowell, MA
University of Missouri, Columbia, MO
University of Missouri, Rolla, MO
University of New Mexico, Albuquerque, NM
University of Texas, Austin, TX
University of Utah, Salt Lake City, UT
University of Wisconsin, Madison, WI
U.S. Geological Survey, Denver, CO
Washington State University, Pullman, WA
Worcester Polytechnic Institute, Worcester, MA

Experts in NAA within neutrino physics and Dark mater searches
(Not nearly complete or representative of the NAA field)
Andreas Piepke, Dept. of Physics, University of Alabama
Ila Pillalamari, Dept. of Earth Atmospheric & Planetary Sciences, MIT

Engineer type and hours required to finalize design
I believe what is required here is not so much an engineer, but a project manger type that
can develop a coordination between irradiation facilities and the DUSEL counting
facilities. Detector facility would be identical to the gamma counting facility.

Personnel and operating costs
The operation of the NAA facility will require coordination between DUSEL and
irradiation facilities and operation of the HPGe detectors. This operation can be handled
by one person, and perhaps even by the same person running the direct gamma counting
NAA will need funds for shipping samples to and from irradiation facilities, power to run
detectors and liquid nitrogen. Irradiation costs can be expensive. Costs for irradiations
vary from $70/hour to ~$600/hour (depending on n-flux). Assuming 1 week counting per
sample, with three HPGe detectors DUSEL will have an NAA throughput of 150
samples/year. In addition to sample measurement having a standard irradiated and
counted in order to establish neutron flux during irradiation maybe necessary. This will
require funds

A private communication with a NC State NAA technician gave a cost of approximately
$100/sample for shipping; at 150 samples per year we will need $15K for shipping per

Liquid nitrogen (this is just a very rough estimate)
The detectors I have experience will use approximately 50L/week. Three detectors give
us about 7500L/year. Assuming $0.25/liter (guess) we can round up the cost to
$2000/year. (does not include delivery charges or another other fees)

Irradiation costs
This is cost that needs more input from reactor operators, but I believe that over
estimating between $500 and $1k is not far from the real cost. The irradiation cost a year
could be as much as $150k.

I do not know enough to make this estimate, or know if it is needed at this stage or at all.

3. Mass Spec Study (e.g. cost of local vs commercial, sample prep)
                    ICPMS, AMS, GDMS (Eric Hoppe, John contacts)
4. Cold/Wet Chemistry Lab (for NAA, ..MS and ??)
                    (Andreas, Craig, John contacts)

5. Alpha (Andrew Sonneshein - outline, Jodi Cooley review and add text)
1 Applications.
1.1 Health physics
1.2 Semiconductor industry
1.3 Dark matter experiments
1.3.1 The (alpha,n) problem
1.4 Double beta decay
1.5 Solar neutrinos

2. Counting techniques
2.1 Solid samples
2.1.1 Silicon detectors for small samples
2.1.2 MWPC
2.1.3 Ion chambers
2.2 Liquid samples
2.2.1 Liquid scintillation counting
2.2.2 Chemical extraction
2.2.3 Radium and radon in water

2.3 Gas samples- Radon, Thoron
2.3.1 Electrostatic collectors
2.3.2 Proportional counters
2.3.3 Radon concentration schemes

2.4 Summary table of available alpha counting techniques and their sensitivities.

3 New R&D
[Do we need any? Who would do it?]

4. Recommended suite of instruments for DUSEL.
4.1 Silicon detectors for small surface samples
4.2 Large gaseous device for surface screening
4.3 Conventional radon survey instruments
4.4 Low level radon instrument
        4.4.1 Radium and radon water assay
        4.4.2 Radon emanation from materials

5. S4 budget requests
Facility layout seems very straightforward, like conventional, above ground laboratory
space with some simple chemistry facilities. One possibility is the design of a general
purpose radon emanation and low level counting apparatus, as this is not commercially

6. Beta Screening (Richard Schnee)
While the previously described methods generally provide superior diagnostic screening
information, direct beta counting is sometimes the only means to screen against low
energy contamination, provide isotope dating, or determine the amount and location of a
suitable radiological tracer. Compared to gamma screening, techniques for low
background counting of betas are not as well developed. Thus, experiments which require
screening for alpha, beta or x-ray emission that is not accompanied by gamma emission
are not well served. Low energy x-rays are a background for many types of low-
background experiments, especially solar neutrino projects. Assaying materials for low-
energy x-ray emission in order to eliminate such activities or to quantify the effect is
required. Another example is identification of 210Pb contamination. 210Pb and its progeny
do not have a penetrating radioactivity signature. Since Pb is often used in circuitry and
alpha activity within the Pb can create difficulties for the circuit, there is a need to search
for samples of Pb that are low in 210Pb. 210Po will eventually result from any 210Pb
contamination, and its alpha decay can cause single event upsets in any circuit that
contains the host Pb. Surface contaminants such as 40K and anthropogenic contaminants
like 125Sb and 137Cs are also detectable by beta screening. Beta-emitters contaminating
the surface can compromise beta rejection in solid state detectors used for dark matter
experiments such as CDMS since their charge is inefficiently collected compared to that
of betas which interact in the bulk.

Beta Screening for Dark Matter Searches
The dominant background for CDMS arises from radioisotopes on or in the thin films on
the detector surfaces that emit low-energy electrons. To reach 10-46 cm2 with no further
reductions in electron misidentification, the low-energy electron rate must be reduced to
~2 x 10-5/keV/cm2/day, accessible to the BetaCage. Initially, the BetaCage will be used
by CDMS to screen existing detectors whose background levels have been measured in
situ and to screen roughly 1 m2 of less expensive silicon and germanium wafers that have
been subjected to the same processing and handling steps as the CDMS detectors. The
energy spectrum of the emitted electrons will be used to identify contaminants. Then,
new sets of test wafers will be subjected to variations on the processing and handling
steps to isolate in detail the steps that cause contamination. Because the BetaCage
running time needed to reach a sensitivity of 10-5/keV/cm2/day is only a few days, many
different variations can be tested within a short time. Once a process has been established
that meets the contamination goals, full-size detectors will be produced and screened in
the BetaCage prior to installation in the experiment. The EDELWEISS collaboration
uses detectors similar to CDMS that thus have similar requirements for low-energy
electron emitters. The BetaCage would be equally applicable for EDELWEISS [?] and its
proposed successor, EURECA [?]. The energy resolution of the BetaCage will be worse
than that of Si(Li) or B-implanted HPGe detectors. However, because the goal is to
measure beta emission spectra, which typically have no sharp features, energy resolution
is not critical. The advantage of better sensitivity is more important.

Isotope Dating with Beta Counting.
This BetaCage will also be useful for isotope dating, such as with 14C. It is already a
common practice to convert organic material for 14C analysis to CO2. Such a gas could be
used as the detector medium in the BetaCage if the electron attachment length is long
enough; it is expected in the range 30-60 cm. Should electron attachment, or the
relatively low avalanche gain in CO2, become problematic, then one would instead
convert the carbon source to CH4, which is already the planned quench gas, and use 90%
neon, 10% CH4. There would be a proportional loss in rate. For the background level
expected here, a sensitivity to 10-17 is possible if CO2 is used, 10-16 if C can only be
introduced in the quench gas. With an aggressive effort on the cleanliness of the shield
and detector, a sensitivity of 10 times better is possible, potentially more sensitive even
than accelerator mass spectrometry and less expensive. Similarly, to perform dating with
tritium, the material may also be converted into the 10% CH4 quench gas. With the
moderate shielding proposed here, the BetaCage could reach levels of 3H/H of 3 x 10-19
in a single day's counting, greatly improving the available sensitivity. Such sensitivities
are of interest to pollution control agencies: the amount of tritium provides information
about general water quality because it measures downward migration of contaminants.
Additional dating can be done with beta-emitting isotopes such as 210Pb, used for dating
sediment and organisms such as coral, and with very long-lived isotopes 10Be and 36Cl
(cosmic-ray spallation products), which are used to study geology, hydrology, climate,
and planetary physics by extending dating to ancient times.

Isotope dating will be needed by researchers engaged in underground science (geologists,
hydrologists, and biologists) as well as outside users in archaelogy, limnology and
forensics. The main candidates are 14C and tritium, both of which would bene_t from
sensitive beta screening. Tritium, for example, is used to date ancient glacial
groundwaters. 14C is used for cores and solid samples. For microgram samples, counting
is time-limited, not background limited. Thus AMS is better, giving 0.3% precision on
  C: 12C ratios of 10-14. However, gram samples can be cheaply processed in a counting
facility with modest sensitivity. Large gaseous (or gasi_ed) samples can actually push the
  C: 12C ratio down to 10-16 with 3% precision in 100 the process of filling the vacancy
created by the electron capture. days of counting, extending the 14C dating method 10,000
years beyond what is available by any other method. In another application, trace tritium
in water is tied to general water quality since it measures downward migration of
contaminants, thus it is of interest to Pollution Control Agencies. Short lived isotopes
benefit from underground counting, since their utility is often detection limited. 137Cs and
    Am from nuclear testing are used for recent dating, since they provide a 1963
benchmark, but as the tracer decays, it requires ever more sensitive detectors. 7Be,
formed by cosmic-ray spallation of nitrogen and oxygen in the atmosphere has a 53 day
half-life; it can be used to assess sediment mixing and marine environments. 210Pb is a
mainstay for sediment dating, and can also be used to date organisms, such as coral, all of
which contain daughters from the U/Th chain. Very long lived isotopes like 10Be, 36Cl,
and 26Al (cosmic ray spallation products) extend dating to ancient times and are used to
study rock exposure and erosion history, meteorite studies, ground water in deep
sedimentary basins, planetary physics, soil science, and climate. Ultra-sensitive counting
is useful in any medical applications where the amount of radiotracers injected must be
kept to the minimum. Bodily fluids and tissue samples would be scanned. Cancer
epidemiology studies using expectorated samples or lung tissue would be able to probe
lower doses: 14C is a tracer for particulates from combustion, other isotopes can be found
in radiation workers.

Beta Screening for Other Applications
clipped from white paper:

The geomicrobiology community uses radioactive tracers such as 35SO4 or 14CH4.
Detecting ever smaller amounts of these tracers in environmental water or rock samples
enables researchers to detect and quantify the extremely low, in situ, subsurface microbial
respiration rates. Contamination of the tracer itself is sometimes the limiting factor, but
the availability of on site, ultra-sensitive counting could enable advances in tracer purity
as well. Microbiologists are also interested in developing tracer detectors with several
micron scale spatial resolution in order to image microbial interactions with mineral or
material surfaces (e.g. metal corrosion). Low background counting could be combined
with DNA microarray to determined the phylogenetic identity of the microorganisms that
have incorporated a radiotracer into their DNA. This effort could be advanced by
collaborative detector R&Dwith physicists using the reconfigurable shielded bays.

Research and Development to Provide Beta-Screening Capabilities
The common challenge in the above applications is the detection of particles with very
short mean free path. Low-energy electrons and alpha particles cannot penetrate through
a vacuum window or through the dead layer of a conventional HPGe detector. Even
special purpose detectors with very thin dead layers (e.g., Si(Li), B-implanted HPGe, or
silicon surface-barrier detectors) have deficiencies: there remains a vacuum window,
there will be backscattering effects that distort the energy spectrum, and it is difficult to
obtain the ~m2 sensitive area desired to obtain high screening throughput and to
minimize edge effects. An ideal detector would place the sample directly in a gaseous
detection medium to eliminate backscattering and dead layer effects while providing a
large sensitive area. The BetaCage is designed around this principle. BetaCage One novel
beta detector, the BetaCage, is under construction as a DUSEL R&Dproject. The
BetaCage will be an ultra-low-background drift chamber optimized for detection of <200
keV electrons and alpha particles. As explained above, the ideal detector for these
particles would place the sample directly in a gaseous detection medium to eliminate
backscattering and dead layer effects while simultaneously providing a large sensitive

Three goals have guided the design from this starting point. First, we use the minimum
amount of gas needed to stop particles of interest in order to minimize background from
ambient penetrating gammas. Second, the detector should have the minimum possible
surface area that itself can be a source of background particles. Third, the detector must
provide sufficient spatial information about events to distinguish between those coming
from the sample surface and those due to scattering of background particles in the gas.
Samples are placed in the gas. An open multi-wire proportional counter (MWPC) directly
above the sample provides a trigger for particles emanating from the sample. Above this
“trigger" MWPC is a large region in which the emitted particles stop. The depth and
width of the drift region sets the energy of betas whose full energy is contained in the
detector. An electric field in this region drifts the ionization to the top of the chamber,
where a second open (“bulk") MWPC collects it. Proportional avalanching in both
MWPCs provides gain. Crossed grids in both MWPCs provide x-y position
determination. The time profile of charge collection in the bulk MWPC determines the
spatial profile of the track in the z dimension. The design minimizes backgrounds due to
the chamber itself and provides excellent rejection of residual and unavoidable
backgrounds. By design, the only surface of the detector near the sample is that of the
wires, whose area is only a few percent of the sample surface area. Events whose tracks
do not originate at the sample or do not terminate inside the drift region will be vetoed
using the full 3D information. A third, “veto" MWPC is placed below the sample to veto
throughgoing events. With appropriate construction materials, the limiting background in
the BetaCage is ejection of electrons from the sample surface by Compton-scattering
photons. These photons come from contamination in the shield. It is straightforward to
achieve background photon rates that would result in about 1 keV/kg/day in a HPGe
detector. A low-activity Pb or Cu shield and/or an ultra-pure water shield would provide
even lower rates.

Final Set-up at DUSEL.
Ultimately there should be many (say 4?) beta-counting stations in the multi-user Low
Level Counting Facility at DUSEL.

The first BetaCage will be run at the Soudan Low-Bcakground Counting Facility. Its
operation should indicate the cause of its limiting background and provide information on
how to increase the sensitivity of a second-generation beta screener.

High Purity Materials Production and Storage

Solid Shielding (Reyco)
Cosmic-ray activation of materials is and will be a background for future DUSEL
experiments. As detectors become more sensitive, this background will become a bigger
concern. DUSEL can provide, at little cost, space to stockpile raw materials at a few
hundred feet or deeper where cosmic-ray activation is negligible. Examples of such
materials include copper, where 60Co and 3H are a concern and germanium, where 68Ge,
  Co and 3H are a concern. Although a systematic study of cosmogenic activation of most
materials has not been performed, we can envision storing stock samples of Mg, Al, Ti,
Cr, V, Mn, Co, Ni, Zn, W, Hg, Nd, lead shielding, ceramics, steel alloys, brass alloys, etc.
Having samples of these elements where the cosmogenic activities with half-lives of a
few years have died away will be invaluable to future experiments and systematic studies
of cosmic-ray activation. This facility will consist of a storage drift where stock samples
are inventoried, double-bagged and placed in storage containers. Air has to be filtered for
particulates, but no other requirements are foreseen (ie. Rn filtering).

2. Radon-free storage of small parts (Reyco)
Perhaps this is not necessary since the needs differ widely? Comments?

3. Purification and storage of water
                       (Dick Hahn, John contacts)
4. Purification, liquification and storage of cryogens (Yuri)
1. Identify requirements for the centralize cryogenic plan and radon free air for the First
Site of Experiments
2. Evaluate potential future expansion (if needed)
3. Develop requirements for the types, production capacity and purity of cryogens.
4. Develop engineering model of the plant, estimate cost, space and power requirements.
Evaluate safety aspects.
5. Develop scheme of delivery cryogens and radon free air to experiments.
6. Develop managemental and operational requirements to run such plant.

       5. Cu (and other?) Electroforming (Craig, Eric)
C. Background Quantification and Requirements
        1. Complete site characterization of the DUSEL site (plan and cost)
                         chemical composition (geology) (Jordon)
                         compilation of old data (School of Mines, Bill Roggentheim)
                         gamma measurements U/Th/K
                         radon survey
                         Jan Kiesel-ILIAS (Prisca contact)
        2. Radon Abatement (Henning Back, Facilities contacts)
                         Staged Plan per room
                         Other users (radiation biology-McTaggart)
        3. Neutron Background (prisca)
Most passive shielding will not be be able to stop high energy cosmic muon-induced
neutrons, and as one moves deeper, this neutron spectrum becomes even harder. Thus, it
has become very important to develop active neutron shielding, as well as the simulation
tools necessary to predict punch-through rates, production of fission neutrons, and
neutron producing radioactive isotopes in the material around the detectors. Resulting
nuclear recoils in the detectors will become the irreducible background for even the
deepest dark matter searches, as well as in double beta decay experiments where elastic
and inelastic events produce gamma rays near the 2 MeV endpoint. The rate in a
particular detector and shielding must be estimated using Monte Carlo simulations. Both
Fluka and Geant4 still have considerable uncertainty in the normalization of the
cosmogenic neutrons and their multiplicities. Although many studies have been done,
[9,10] there is still controversy [11]. It is not unusual to find simulations predicting a
factor of two difference in flux, and being unable to do much better in comparison to

Cosmogenic neutron production can proceed by direct muon spallation and through
hadronic showers generated by the muons interacting in the rock. The CERN NA55
experiment measured neutron production via direct muon spallation in a 190 GeV muon
beam on graphite, copper and lead targets [9] at multiple angles. Their data lies a factor
of 3-10 above the Monte Carlo simulations (depending on measured angle) [10]. Their
large systematic uncertainties leave the matter inconclusive, however. The rate may be
overestimated due to contamination by neutrons produced by secondaries of the muon-
nucleus interaction and or underestimated due to poorly understood neutron detection
efficiency in the small target. Other underground neutron measurements reported in the
literature are not entirely applicable to the situation for WIMP experiments. They
involve either primary muon interactions in hydrocarbon liquid scintillator followed by
cascade processes within the detector [7,11], or muon interactions in higher-Z material
such as Pb and Cu [12] in which neutron production is dominated by relatively low-
energy electromagnetic properties. Dark matter experiments are particularly interested in
the situation where high-energy neutrons are produced in the rock through muon
interactions, followed by hadronic cascades initiated by spallation in high-Z shielding,
leading to a flux of lower energy neutrons which make it to the dark matter detectors.
in double beta decay experiments, which use similar lead/poly shielding to attenuate
gamma rays and moderate neutrons. In addition, knowledge of the neutron background is
Thus two major classes of DUSEL experiments, dark matter and double beta decay,
would benefit from a more precise measurement of the neutron background produced in
their shield components, both in the design phase and in the estimation of final

                 a. R&D on neutron shielding
                 b. cosmogenic benchmarking (long term measurements)
                 c. Geant4/Fluka/MCNP code repository

        D. Other (future?) infrastructure (prisca)
               1. Shielded, equipped Prototyping Bays for interchangeable R&D
Reconfigurable, shielded bays should be available for developing such new detector
concepts or for housing specialized detectors or prototypes of new experiments. Modular
shielding of known purity, both hydrogenous and high-Z, should be provided, along with
crane coverage to reassemble these into custom rooms. This footprint should be at least 8
m x 16 m to allow for staging outside the shield and for setting up data acquisition

At the activity levels needed for next-generation experiments, raw count rate is a
significant limitation. 1 uBq/kg implies only 8 decays in ten days per 10 kg of sample.
Methods for assaying large quantities of material can also be developed in the
prototyping facility and eventually become part of the suite of screeners. For gamma
screening, a typical large sample might be a sheet of copper 40 cm tall, 120 cm wide and
1 cm thick. When formed into a hollow annulus surrounding a large (1.4 kg) HPGe
detector, the geometrical efficiency is only about 0.25%, leading to very long counting
times. A moderately sized detector (70 cm diameter, 70 cm long, 0.29 m3) lled with Xe at
10 bar, has nearly an order of magnitude greater overall e_ciency than a 1.4 kg Ge for
low energy gamma rays from such a sample. Another example of a detector design
capable of measuring the radiopurity of many large samples could be a planar sandwich
of samples interspersed with NaI cystals or proportional counters. Though scintillation-
proportional counters and gas ionization have worse energy resolution than Ge, this
enters the LDA as the square root, and hence need not seriously impair the screening
power of such devices. Laser cooling techniques can be used to trap atoms, excite them to
a metastable state, and then detect their uorescence, thus determining abundances by
directly counting atoms. AtomTrap Trace Analysis is already used for radioisotope dating
and environmental monitoring [16], and has been suggested [17] as a fast turn-around
method of measuring radioactive background from 85Kr and 39Ar to a few parts in 10-
14. Beta decays from these impurities are a significant background for experiments that
use noble liquids as scintillation media. This apparatus is inexpensive compared to AMS
and could be installed underground where it can be used to screen user samples, as well
as aid in the purification of Ar, Ne, Xe. Reconfigurable, shielded bays should be
available for developing such new detector concepts or for housing specialized detectors
or prototypes of new experiments. Modular shielding of known purity, both hydrogenous
and high-Z, should be provided, along with crane coverage to reassemble these into
custom rooms. This footprint should be at least 8 m x 16 m to allow for staging outside
the shield and for setting up data acquisition systems. HPGe screening may be
insufficient for screening some rare-event searches because of its energy threshold
(usually limited by a vacuum window and the detectors' dead layer) or reliance on
gamma-ray lines. Dark matter searches (e.g., CDMS [?]) and pp neutrino detectors (e.g.,
CLEAN [?]) require thresholds of a few keV to tens of keV, rendering them vulnerable to
low-energy electrons and photons that in many cases do not have associated high-energy
gamma-ray emission. Mass spectroscopy is sensitive enough to search for some of these
isotopes. Nevertheless, of the 79 long-lived isotopes listed in Table ?? that decay by beta
emission or electron capture1, as many as 26 are inaccessible unless _ or _ screening is
employed, or one is able to obtain 1Isotopes that decay via electron capture have
associated low-energy X-rays and/or Auger electrons, which are emitted in
requires sample processing that may introduce new contaminants or cloud the relation
between the intrinsic contamination level and the measured signal. Low-energy electrons
can be detected with thin-dead-layer detectors such as Si(Li) or B-implanted HPGe, but
such detectors are available only with small e_ective areas (at most tens of cm2), have
vacuum windows that may stop or scatter some particles, and su_er from backscattering
at the detector surface.

                2. Whole Body counting
Although the bulk of screening can be done in the production facility, ultrasensitive
screening applications (according to figure 2) will require detectors capable of handling
up to 500 samples/yr. While the production facility (Section 3.1) provides convenience
and cost efficiency, the ultra-low counting facility is unique and should be sited at
DUSEL, although development must be proceeding elsewhere with proof of principle
prototypes, in order to keep on schedule.

The next generation low background experiments (solar neutrino, dark matter and double
beta decay) will need to reach background levels that are far below what can be screened
in even the best HPGe counters. To achieve these levels, a combination of mass
spectrometry and NAA may be useful for certain radioactive isotopes. These techniques,
while powerful, do not provide an ultimate check on the total activity from all isotopes in
the material, including short-lived isotopes which are essentially impossible to detect
chemically. An advanced direct counting technique with orders of magnitude
improvement in sensitivity is therefore needed to cover all bases. For experiments based
largely on advances in material purity, such screening would play an essential enabling

A tank made of stainless steel or carved into rock and lined with a radon-impermeable
plastic such as urylon would provide the vessel for such an ultra-low counting facility. It
would be filled with pure water (~ 10-14 g/g U/Th) and covered by a hermetic deck with a
radon-free, clean chamber above for handling and insertion of counters and samples into
the water and a nitrogen purge between the water surface and the deck. Reconfigurable
slots would allow for simultaneous immersion of up to 6 detectors. Additional side-entry
ports can also be imagined. To prevent interference from multiple screeners, the tank
should be at least 16 m in diameter. The height should be at least 10 meters. This will
insure at least 4 m of water shielding around each screener to reduce cosmogenic
neutrons, as well as radioactivity from the rock itself. Bulk assay of large amounts of
material to be used in shielding, supports, and front end electronics can be done here at
the 10-13-10-14 g/g U/Th level.

To take advantage of the water purification plant associated with the ultra-low facility, a
leaching and emanation chamber should be nearby. Vacuum degassing followed by
counting in small scintillator-coated cells (Lucas cells) read out by a photomultiplier tube
will provide 10-12 g/g sensitivity to U/Th leached out of samples placed in the ultra-pure
water. The footprint is roughly 3m x 1m to accommodate 3 leaching tanks with
associated pumps and degassing.

If the location of the water pool is shallower than 5000 mwe, an active muon veto shield
on the outside would reduce the neutron background produced in the water shield by
another factor of 100 or so, bringing it down to the level of that produced by muons in the
rock. Natural progression to an even more sensitive bulk assay could include replacing
the water with Gd-loaded scintillator and instrumenting the walls with photodetectors.
However, rather than retrofitting a facility which is still doing useful screening, it would
be better to build a second, even more sensitive screening pool, envisioned as a mini-CTF
[18] like that built by Borexino at Gran Sasso. It is not included in the LBCF footprint,
since it should be located deeper, in an experimental hall that will be available later, in
recognition of the longer development time required.

Designs of the ultra-low background counting facility have been formulated by many
groups [1,2]. The Homestake report includes figure E-16 (see below), which is an
example of an LBCF which combines both production and ultra-low background
elements. Since none of DUSEL sites will have deep access immediately, this design
should be modified to put the production elements in first at a moderate depth and the
low background elements later in a deeper location. Other than the CTF, there are no
proof of principle prototypes. Such a tank of purified water or liquid scintillator could be
built at a current underground site and provide both an engineering prototype of the ultra-
low DUSEL facility, as well as serve the community as a screening facility for designing
the next generation of experiments that will be sited at DUSEL. Water is the most cost-
effective shielding available for large installations or multiple smaller screeners, and has
become even more attractive as the cost of ancient lead has skyrocketed.

       E. Operating model and plan for facility itself
       (Jose, Facilities: Kevin Lesko - engineer)
               1. Manager, trained technicians and training center
               2. Shared infrastructure between experiments
               3. How the rooms should be connected – requires integration engineer

III. Efficient use of the facility and cost recovery
Although the sensitivities and throughput are being driven by the needs of the physics
groups, many other research fields will be able to use elements of the low background
facility and its very existance will spawn new research areas that can take advantage of
either the low background environment or the sensitivities of the screeners. Fostering
these new research fields and creating connections with existing fields will provide a
diverse user community which can help in cost recovery as well as contribute to the
breadth of research performed at DUSEL.

Identified fields which are also putting in a Cross Cutting S4 proposal are radiation
biology, underground agriculture, algal biomass, and microelectronics testing. In the
future, low dose radiation biology has the best rationale for being completely integrated
into a low background counting facility, as it will benefit the most from shielding,
reduced Radon air, and other items. 4850 would be deeper than any other underground
facility that currently studies low dose effects. Brookhaven is currently looking at low
dose effects in the shielded room once used by Ray Davis (which reduces the cosmic ray
flux by a factor of 10).

Initial studies for radiation biology at Homestake (or elsewhere) with a glove box made
of low activity material within or nearby low background counting (or with a “MULE”
used in biology) may suffice. However, both the irradiation of native microbes (for
biofuels and deep life studies), and low dose radiation biology of human/mammalian
tissue samples will eventually require a source of ionizing radiation, which most likely
will be an X-ray source. Autoclaves, incubators, refrigerators, chemical storage, etc.
commonly used in biology will also be needed. Radiation biology will also need a surface
facility to process/prepare incoming and outgoing samples and study control samples.
Biological containment and/or physical separation from sensitive detectors for low
background counting must be addressed.

Underground agriculture and algal biomass can be users of LBC to assay mineral content
in soils, plant material, etc. However, they are different enough that integration with LBC
for S4/S5 may be unwarranted since (1) they could use space throughout the Mine, and
(2) most plants are radiation resistant enough that these projects do not require shielding
or Radon mitigation. Radon levels are roughly 3-4 pCi/Liter throughout the Mine, which
is similar to surface levels at Homestake.

Another element of the energetic particles working group is the testing of
microelectronics. It has been proposed that an environmentally controlled facility at the
300 foot level (to reduce, but not eliminate cosmics) would be feasible to study the
response that radiation-hardened circuits have to lower doses of radiation. Such circuit
testing is often done at much higher levels than are seen in practice (for instance in
telecommunication satellites). This affects the predicted lifetime of many systems since
the response to lower doses is often different. Reduced Radon air, HEPA filtration,
temperature/humidity control would be needed. In the future, actual production of such
electronics or other materials would probably need access to clean rooms in another part
of the mine that may share infrastructure with other detector development.
A. Integration between Working groups (as part of S4/S5 process)
                1. Cross working group contacts (need travel money at least!)
         B. Integration within the DUSEL Physics community
                1. SUSEL era, including integration of existing sites
                2. DUSEL era, including visiting experts, training & staffing
         C. Creating/facilitating a larger user community
                1. Workshops
                2. Coordinating website
         D. Integration within the world community
                ILIAS JRA-1 and New ILIAS
         E. Tools required to make this happen
                Open database of material radiopurities, assay capabilities (JohnW?)
                Code repository and background studies (Reyco, others?)
A centralized repository server where simulation and analysis codes are stored will be
required. Such a server can be hosted and maintained at an appropriate university with
little cost (~$2k/yr). The code on the repository will be managed by the low-background
software manager.

IV. Management
      A. Management of the S5
      B. Management of the facility (this is not really OUR job…)
      C. Timeline of the facility
         1st pass at schedule, integration engineering to pull together the elements into a
          facility (not sure this is either…)

V. Education and Outreach (Tina)
1) Education
   a) Undergraduates
      i) Site Characterization – Data Collection, Database Contributions- will pull
          language from USD DOE submission
   b) Graduate Students/Post-Docs
      i) The proposed activity will provide a training ground in the area of nuclear,
          particle and astro-physics for the graduate students and postdocs directly
          involved in the project. Graduate students would be involved from the
          beginning in the shield design, measurement of ultra pure water, radon and
          other background measurement techniques, installation and operation of the
          detectors, as well as in data analysis. Students will perform GEANT4
          simulations of the detector, shield and sample geometry for efficiency
          calculations on user samples, gaining important experience.
   c) In-service/Pre-service K-12 Teachers
      i) Physics of Atomic Nuclei - Underground (SD Pilot Workshop – Summer
          2008) ongoing, alternating between east and west side of state – Peggy
      ii) Development of Curriculum Materials based on SD State Standards – Work
           with Cathy Ezrailson – Science Education Faculty – USD School of
      iii) Annual visit to South Dakota combined meeting of Math and Science
           Teachers in January/February
   d) K-12 Students
      i) Physics of Atomic Nuclei - Underground (SD Pilot Workshop – Summer
           2008) ongoing, alternating between east and west side of state – Peggy
           McMahan (Summer 2009 include students)
      ii) Native American serving high schools, tribal colleges – will contact Chuck
           Swick (director of Trio programs) for individuals to include, and pertinent
           data, possibly Edward Valandra – new chair of USD Department of American
           Indian Studies
   e) Other Disciplines
      i) Geology – ask Bill Roggenthen
      ii) Public Health – contact USD School of Medicine

2) Outreach
   a) Sanford Center – Contributions from T. Denny Sanford, contact Ben Sayler to see
      how LBC can contribute material for center
   b) 300 ft level – access to public, tours
   c) Tourist area via Mount Rushmore, Crazy Horse and other area attractions brings
      millions of visitors to Black Hills area (find 2001 white paper with information
   d) Summer support for K-12 in-service/pre-service teachers to act as docents
   e) Connection to Science on the Move program in SD to take regular counting
      equipment (i.e., radiation monitors, cosmic ray detectors) and curriculum
      materials to relate this equipment to the idea of LBC.

VI. Budget
       A. Timeline and Gantt chart of the S4/S5 over 3 years
       B. Budget Justification

VII. Conclusion and References (incl. an extensive web-based reference system?)

[1] 2. J. Nico, A. Piepke, and T. Shutt, NUSL White Paper: Ultra Low Background
Counting Facility (Oct 2001, Lead, SD)
[2] Lee Petersen’s S1 Infrastructure Matrix
[3] TechReport for S1
[4] G. Heusser, Ann. Rev. Nucl. Part. Sci. 45 (1995) 543.
[5] http://majorana.pnl.gov/
[6] R. Bernabei etal., INFN/AE-01/19, Nov. 7, 2001.
[7] J. Suhonen and O. Civaterese, Phy. Rep. 300 (1998) 123.
[4] Canberra Eurysis, 800 Research Parkway, Meriden, CT 06450, USA.
[5] S. R. Elliott et al., NIM A 558 504 (2006).
[7] Ila Pillalamarri, AIP Conference Proceedings; 2005, Vol. 785 Issue 1, p57-62, 6p
[8] D.S. Leonard, et al., Nucl. Instr. and Meth. A (2008), doi:10.1016/j.nima.2008.03.001
[9] M. Aglietta et al., (LVD Collaboration), in Proc. of 26th Intern. Cosmic Ray Conf.,
Salt Lake City (USA), August 17-25, 1999 (hep-x/9905047).

[10] D.-M. Mei and A. Hime, Phys. Rev. D73, 053004 (2006).
[11] V. Chazal et al., Nucl. Instrum. and Meth. A490, 334 (2002).
22. M. Laubenstein et al., IAEA-MEL's underground counting laboratory: CAVE, (see
also http://www-naweb.iaea.org/naml/rmlfacilities.asp and Laubenstein talk in Agenda
of http://www.hep.umn.edu/lbcf/workshop)

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