Nuclear_ Particle and Radiation Physics by sdsdfqw21

VIEWS: 232 PAGES: 6

									 Track B
Nuclear, Particle and
R adiation Physics
Day 1 – Wednesday


Nuclear Reactions
Session Chair: Simon Mullins

10:30 AM                                                       11:10 AM
Title The K600 zero degree facility. (72)                      Title Probing the fine structure of the giant quadrupole
Presenter r. Neveling iThemba Laboratory for Accel-            resonance in 28Si using hadronic and leptonic reactions.
erator Based Sciences                                          (106)
Authors r.Neveling; r.W. Fearick; S.V.Foertsch;                Presenter Iyabo Usman iThemba Laboratory for Accel-
D.T. Fourie; Y Fujita; J. Goerres; k. Hatanaka; a.M.           erator Based Sciences
Heilmann; M. Jingo; J.P. Mira; S.H.T. Murray; P. von Neu-      Authors Iyabo Usman ; Z Buthelezi ; J Carter ; G.R.J
mann; S O’Brien; a richter; J.a. Swartz; a Tamii; J.J van      Cooper; R.W. Fearick; S.V Förtsch; H Fujita; Y Fujita;
Zyl; G.P.a Berg; c.O. kureba.                                  Y Kalmykov ; P von Neumann ; R Neveling ; A Richter;
Content The K600 zero degree facility at iThemba LABS          A Shevchenko ; F.D. Smit
was recently successfully commissioned. The setup and          Content The comparison of proton inelastic scatter-
experimental techniques for the high energy resolution         ing from 28Si with data from other probes exciting the
measurement of (p,p’) and (p,t) reactions at intermedi-        Isoscalar Giant Quadrupole Resonance (ISGQR) is investi-
ate energies are described, and preliminary results are        gated. Wavelet coefficients of the ISGQR for the various
presented.                                                     probes are compared to that of (p,p’) using the newly-
                                                               developed techniques.
10:50 AM
Title Search for the Giant Pairing Vibration via (p,t) reac-   11:30 AM
tions around 60 MeV. (141)                                     Title Direct projectile break-up of 12C at 33.3 MeV/nu-
Presenter Siegfried Förtsch iThemba LABS                       cleon. (181)
Authors Siegfried Förtsch; J.P. Mira; a.ramus; J.a. Scar-      Presenter Joele Mira. University of Stellenbosch/
paci; F.D. Smit; I. Stefan; J.a. Swartz; I.T. Usman;           iThemba LaBS
B. Mouginot; E. khan; S.Franchoo; r. Neveling;                 Authors Joele Mira; S. V Fortsch; G. F Steyn; E. Z Buthele-
F. azaiez; E.Z. iThemba; H. Fujita; J. Mabiala                 zi; S. H Connell ; A. A Cowley; J Mabiala; R Neveling;
Content A Giant Pairing Vibration (GPV) is a collective        P Papka; F. D Smit; I. T Usman.
mode involving two-neutron transfer. This mode which           Content The binary breakup of 12C into 8Be fragments
is of fundamental importance, since it is analogous to         and alpha particles were measured in coincidence in
a giant resonance in the particle-particle channel, has        the interaction of 33.3 MeV/nucleon 12C projectiles with
however not yet been detected and important uncer-             197Au, 93Nb and 12C target nuclei. Preliminary experi-
tainties concerning its cross section, width and position      mental cross-section contributions are extracted for both
remain.                                                        quasi-elastic and the inelastic break-up processes.




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30 55 th A nnua l Confer ence of the South A fr ic a n Institute of Physics
11:50 AM                                                     of giant resonance fine structure. Our study suggests
Title Nuclear Structure and Scattering in 20Ne, 44Ti,        that the spreading widths of collective excitations in
94Mo and 212Po. (60)                                         nuclei are determined by the number of fragmentations
Presenter Joram Ndayishimye Stellenbosch University          seen in the power spectrum of the scales.
Authors Joram Ndayishimye
Content We investigate the nuclear structure and             1:50 PM




                                                                                                                            Track B Nuclear, Particle and radiation Physics
elastic scattering in nuclei (20Ne, 44Ti, 94Mo, and 212Po)   Title Relativistic description of nucleon-nucleus scatter-
using a model of alpha-cluster orbiting a closed shell       ing with DWIA and RPA. (117)
core. A purely phenomenological cluster-core potential       Presenter David Van Niekerk Stellenbosch University
was found to provide a successful description of low         Authors David Van Niekerk
lying positive parity spectra, electromagnetic transi-       Content We have formulated a fully relativistic model
tion strengths of these nuclei and alpha-decay rates         for inclusive quasielastic nucleon-nucleus scattering.
of these states in 212Po. We then consider the same          Using RIA we show how the behaviours of projectile and
phenomenological potential as the real part of opti-         target can be separated into two independent tensors.
cal model to describe the differential elastic scatter-      Subsequently we investigate the RPWIA as well as DWIA
ing cross-sections for the systems corresponding to          descriptions of the projectile. We also examine the Har-
20Ne=16O+alpha, 44Ti=40Ca+alpha, 94Mo=90Zr+alpha,            tree and the RRPA responses of the target.
212Po=208Pb+alpha.
                                                             2:10 PM
12:10 PM                                                     Title Theoretical description of quasielastic neutrino-
Title Effects of target resonances in Multi-Channel Alge-    induced strange particle production. (81)
braic Scattering. (341)                                      Presenter Gashaw adera University of Stellenbosch
Presenter Steven karataglidis University of Johannesburg     Department of Physics
Authors Steven karataglidis; Paul Fraser; ken amos;          Authors Gashaw adera
Luciano canton; Juris Svenne; Dirk van der knijff            Content We present calculations of the quasifree
Content Low-energy nucleon-nucleus elastic scattering        associate production via the neutrino-nucleus weak
involving particle-unbound states in the target spectrum     interaction. Our formalism is done in the relativistic plane
is developed within the framework of a Multi-Channel         wave impulse approximation. In the plane wave limit,
Algebraic Scattering theory. The effects on the scatter-     the spectator approximation is used to construct the
ing observables when the particle-emission widths are        invariant matrix element. The cross section is constructed
significantly different from zero are discussed.             as the contraction between the leptonic and hadronic
                                                             tensors. The numerical results are generated based on
luNCh                                                        the Born-term approximation. The distributions of the
                                                             differential cross section with respect to varies kinemati-
                                                             cal inputs are presented.
Nuclear Theory                                               2:30 PM
                                                             Title Chi-square, Maximum Likelihood and Bayes: a sim-
Session Chair: Sifiso Ntshangase                             ple example. (150)
                                                             Presenter Michiel De kock University of Stellenbosch
1:30 PM                                                      Authors Michiel De kock
Title Time Scales in Nuclear Giant Resonances. (251)         Content Given a histogram of measurements, we
Presenter W.D. Heiss National Institute for Theoretical      compare the chi-squared goodness-of-fit test and the
Physics                                                      Kullback-Leibler divergence of different models. We then
Authors W.D. Heiss; r.G. Nazmitdinov; J. carter;             apply these methods for parameter estimation and relate
r.W. Fearick; F.D. Smit                                      them to the principle of Maximum Likelihood. These
Content A many-body approach is used to investigate          non-Bayesian approaches are finally viewed in the
the regular patterns in scales found in a wavelet analysis   light of a Bayesian solution.


                                                                 PROGR AMME & BOOK OF ABSTR ACTS                      31
2:50 PM
Title Studying Chirality in Nuclei. (31)
Presenter Obed Shirinda iThemba LABS/University of
the Western Cape
Authors Obed Shirinda; Elena atanassova Lawrie;
Lukisi Paulus Masiteng; robert Lindsay
Content Characteristic conditions that should be met
for two-quasiparticle chiral bands to reach degeneracy
were examined using the two-quasiparticle-plus-rotor
model for the A ~ 100, 130, 190 mass regions. Previously
proposed fingerprints of chirality (like intra- and inter-
band B(M1) staggering, energy staggering, etc) were also
studied.


3:10 PM
Title Do (anti)neutrinos influence radioactive decay
rates?. (262)
Presenter r.J.de Meijer Stichting EARTH and UWC
Authors r.J. de Meijer; M. Blaauw; F.D. Smit.
Content A recent paper by Jenkins et al. suggested that
the radioactive decay rate of certain radionuclides may
be influenced by the neutrino flux from the Sun which
varies with the distance between the Sun and Earth. This
paper reports on measurements made at a reactor to
test this claim.


PleNARy will sTART AT 4PM




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32 55 th A nnua l Confer ence of the South A fr ic a n Institute of Physics
                                                             partner band, were found. The measured B(M1)/B(E2)
Day 2 – Thursday                                             ratios for the partner bands show similarities, in accord-
                                                             ance with possible chiral nature. A measurement of the
                                                             gamma ray intensities is in progress.

Nuclear structure                                            11:30 AM
Session Chair: Steven Karataglidis




                                                                                                                            Track B Nuclear, Particle and radiation Physics
                                                             Title Establishment of the Exact Quantum Numbers of
                                                             Critical Rotational Bands in Gd-155. (191)
                                                             Presenter Tshepo Dinoko iThemba LABS/University of
10:30 AM                                                     the Western Cape
Title Status of the iThemba LABS radioactive beam            Authors Tshepo Dinoko; John Sharpey-Shafer
project. (270)                                               Content Excited states in 155Gd nuclei were populated
Presenter robert Bark iThemba LABS                           in the 154Sm (α, 3n) reaction at a beam energy of 33MeV.
Authors robert Bark                                          The aim is to establish firm spin and parity assignments
Content A proposal to develop a radioactive beam             for the many complex rotational bands that have been
facility at iThemba LABS is being developed. It envis-       observed in this nucleus and to observe which cou-
ages the addition of a new cyclotron, a k70 negative-ion     plings are blocked by which quasi-neutrons in order to
accelerator. Such an accelerator can supply two beams        establish the under lying microstructure of the collective
simultaneously, one to be used for isotope production        excitations of the 154Gd core.
and neutron therapy, the other to create radioactive
ions. These can be post accelerated by the existing SSC      11:50 AM
accelerator to energies of 5~7 MeV/A. It is envisaged that   Title Study of fusion evaporation channels in the 18O +
the beamtime available for nuclear physics, presently        18O E_{lab} = 65 MeV reaction}. (154)
restricted to weekends only, will more than double.          Presenter Esra khaleel Stellenbosch University
                                                             Authors Esra khaleel; Paul Papka
10:50 AM                                                     Content The AFRODITE and DIAMANT detectors
Title Octupole Excitations in U isotopes. (208)              were used to measure the evaporation channels in
Presenter Sifiso Senzo Ntshangase University of Cape         the 18O+18O reaction. Emission of (p, d, t) and alpha
Town / iThemba LABS                                          particles were identified with excellent particle iden-
Authors Sifiso Senzo Ntshangase                              tification. The cross sections for evaporation residues
Content The actinide region attracts considerable            production are calculated with the statistical model
interest due to the rich variety of octupole phenomena       code CASCADE.
encountered both theoretically and experimentally. These
include octupole vibrational bands which, as a function      12:10 PM
of neutron number an angular momentum, develop into          Title Lifetimes and transition probabilities in 194Tl. (151)
alternating parity bands that have been interpreted as the   Presenter Paulus Masiteng iThemba LABS/University of
onset of octupole deformation, or more recently, in terms    the Western Cape
of refection-asymmetric tidal waves. The most spectacular    Authors r.M Lieder; P. Papka; S.P Bvumbi; T.E Madiba;
example of octupole shape may well be the hyperde-           S.M. Mullins; S.H.T. Murray; S.S. Ntshangase; D.G. roux;
formed bands known from fission resonances.                  O. Shirinda; J.F. Sharpey-Shafer; E.a Lawrie; a.a Paster-
                                                             nak; J.J Lawrie; r.a Bark; N.V kheswa;
11:10 AM                                                     E.O Lieder
Title Possible chirality in 195Tl, associated with a three   Content Lifetimes (τ) of high spin states in 194Tl have
quasiparticle configuration. (195)                           been studied using the DSAM technique with the
Presenter Hussam Mohammed iThemba LABS - UCT                 AFRODITE array. The deduced B(M1) and B(E2) transition
Authors Hussam Mohammed                                      probabilities suggest that the two negative parity bands
Content The level scheme of 195Tl was studied and            in the 194Tl are built on the same configuration and cor-
a few new transitions, belonging to a possible chiral        respond to similar nuclear deformation.


                                                                 PROGR AMME & BOOK OF ABSTR ACTS                       33
12:30 PM                                                            2:30 PM
Title Simulation studies of TIGRESS type Clover detector            Title Determination of neutron energy spectra inside a
at iThemba LABS. (13)                                               water phantom irradiated by neutrons of energy up to ~
Presenter Pradip Datta iThemba LABS                                 64 MeV. (369)
Authors Pradip Datta; rob Bark                                      Presenter Mark Herbert University of the Western Cape
Content This work presents the results obtained from                Authors Mark Herbert; Saalih allie; Frank Brooks;
GEANT4 simulation study on TIGRESS type segmented HPGe              rudolph Nchodu; andy Buffler
detector. Unlike the usual Clover detector, TIGRESS detector        Content A neutron spectrometer based on NE230
has both longitudinal and lateral segmentation in each cy-          deuterated liquid scintillator was developed to measure
lindrical crystal. The focus of the present study is to calculate   neutron energy spectra in water. Neutron energy spectra
the optimal later segmentation depth in the crystals.               were obtained from measurements of pulse height spec-
                                                                    tra using the Bayesian unfolding code MAXED. Results
luNCh                                                               from measurements made along the beam-axis compare
                                                                    well with Monte Carlo calculations using MCNPX.

Applied & Neutrons                                                  2:50 PM
                                                                    Title Radiometric analyses of iThemba LABS dam water
Session Chair: Rob Bark                                             samples by gamma-ray spectrometry. (235)
                                                                    Presenter Peane Peter Maleka iThemba LABS and Uni-
1:50 PM                                                             versity of the Western Cape
Title Test of Fast Neutron Detectors for Spectroscopy. (288)        Authors Peane Peter Maleka; Israel N. Hlatshwayo;
Presenter Mohamed Elbasher University of Stellenbosch               richard T. Newman
Authors Mohamed Elbasher                                            Content The iThemba LABS dam water samples were
Content A large volume neutron detector was devel-                  radiometrically analysed using the low-background high-
oped to investigate the very selective (3He,n)                      resolution gamma-ray spectrometry for traces of anthro-
reaction. The performance of the detector was tested                pogenic radionuclides. The samples were prepared in a
using muon cosmic rays and neutrons emitted from                    1-l Marinelli beaker geometry. Traces of anthropogenic
the 232Th(4He,xn) reaction.                                         radionuclides have been recorded in samples with activ-
                                                                    ity concentrations ranging from 0.3 to 40 Bq/l.
2:10 PM
Title Measuring neutron fluence at the fast neutron facil-          3:30 PM
ity at iThemba LABS. (166)                                          Title Status Of The Ion Sources At iThemba LABS. (202)
Presenter Emmanuel. T Musonza University of Cape Town               Presenter Sifiso Senzo Ntshangase University of Cape
Authors Emmanuel. T Musonza; ricky Smit; ralph                      Town / iThemba LABS
Nolte; andy Buffler                                                 Authors Sifiso Senzo Ntshangase
Content A new neutron beam monitoring system was                    Content Heavy ion beams at iThemba LABS have been
installed at iThemba LABS. The instruments included                 produced in a 10GHz Minimaf”i”os Electron Cyclotron
a parallel plate U238 fission ionization chamber, a gain            Resonance (ECRIS) for the past two decades. The increase
stabilized NE213 detector which is a high resolution                in demand for new ion species and high intensity beams
instrument for measuring the spectral distribution of               from the nuclear physics community has led to a deci-
the beam using the time-of-flight method and an NE102               sion to procure a new 2nd generation ECRIS. The source
transmission detector. A measurement campaign was                   is a room temperature ECRIS based on the Grenoble Test
successfully performed over three runs at iThemba LABS              Source (GTS) design.The source has been assembled and
in August 2009 at 66 MeV, 100 MeV and 200 MeV proton                is being commissioned at iThemba LABS. The Hahn-
beam energies and the data collected will be used to                Meitner-Institute (HMI) in Berlin donated their 14.5GHz
obtain measurements of the relative fluence and the                 ECRIS to iThemba LABS where it is presently operational.
spectral fluence of the neutron beam.                               iThemba LABS also produce polarized proton beams.


35
34 55 th A nnua l Confer ence of the South A fr ic a n Institute of Physics
Day 3 – Friday
                                                              11:30 AM
                                                              Title Biological Shield Design for a 20 MW Materials Test-

Reactors                                                      ing Reactor. (367)
                                                              Presenter andrew Esau NECSA
Session Chair: Dieter Heiss                                   Authors andrew Esau; Johann Van rooyen




                                                                                                                            Track B Nuclear, Particle and radiation Physics
                                                              Content In this study we focus on the biological shield-
10:30 AM                                                      ing around a 20 MW Oak-Ridge type Materials Testing
Title High Flux Neutron Detection System. (244)               Reactor. The design of the biological shielding around
Presenter Thifhelimbilu Daphney Singo University of           this type of research reactor was performed at ORNL in
Stellenbosch and iThemba LABS                                 the USA in the late 1950s and early 1960s, i.e. in the days
Authors Thifhelimbilu Daphney Singo; Paul Papka;              before powerful digital computers, powerful codes or ac-
Shaun Wyngaardt; robert Dobson; ricky Smit                    curate cross-section data were available. We investigate
Content A high flux neutron detection system, integrat-       several shielding materials and propose an optimal shield
ing the neutron converter material 6Li and 12C and a          design. This proposed design is campared with the exist-
highly sensitive mass spectrometer, is been developed         ing shield.
to detect slow and fast neutrons. The reaction rates and
neutron flux will be deduced from the analysis of the         11:50 AM
4He atoms released with the mass spectrometer.                Title Development of a software to package for the
                                                              design and calculation of Research Reactors using Monte
10:50 AM                                                      Carlo and Analytical Methods. (356)
Title MTR Reflector Modelling making use of Equiva-           Presenter Nicolin Govender Necsa,UKZN,UJ
lence Theory. (108)                                           Authors Nicolin Govender
Presenter Suzanne Theron NECSA                                Content There is a global drive to build new research
Authors Suzanne Theron; Frederik reitsma                      reactors, currently the calculation of various saftely and
Content This research focuses on modelling reflectors         perfomance parameters is very time consuming for a
in typical material testing reactors (MTRs). Equivalence      single design. In the calculation process there are two
theory is used to homogenise and collapse detailed            classes of solutions , Monte Carlo methods which are
transport solutions to generate equivalent nodal pa-          accurate and flexible but slow and anyalatical methods
rameters and albedo boundary conditions, for subse-           which are very fast but not as accurate or flexible. This
quent use in full core diffusion codes. This study aims to    paper will look at creating a hybrid solution between
determine if this approach to MTR reflector modelling is      MCNP (MonteCarlo) and OSCAR(analytical) as well as
an accurate and plausible homogenisation technique for        create input sets for both code systems using AI, this
the modelling of small MTR cores.                             will take months to do without a code system. The code
                                                              system will be easy to use and aid in reactor calculation.
11:10 AM
Title Nuclear Reactor Core Reloads with OSCAR-4. (17)
Presenter Bernard Erasmus Necsa                               NPRP sG Meeting
Authors Bernard Erasmus; Danniëll Botes;
SuzanneTheron                                                 Session Chair: Simon Mullins
Content Nuclear reactor core reload calculations are
used to determine safety and operational parameters of a      AGM will sTART AT 3 PM
nuclear reactor. Accurately determining these parameters
plays an important role in the safe operating of a reactor.
The OSCAR-4 code was used to simulate reactor reloads,
and the simulation results were compared to experimental
plant data as verification of the simulation methods.




                                                                  PROGR AMME & BOOK OF ABSTR ACTS                     35

								
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