DEPTH-DOSE DISTRIBUTION DEPENDENCE ON THE ENERGY PROFILE OF LINEAR AND LASER WAKEFIELD ACCELERATOR ELECTRON BEAMS
N.A.Tuan, C.V.Tao, R.Chary
12th Int. Particle Acc. Conf.
Abstract:
The depth-dose distributions of 10 MeV electron beams used for food irradiation and sterilization purposes at Research and Development Center for Radiation Technology, HCMC, Vietnam are measured and the results are well re-produced by the MCNP simulations. We extend the simulations to predict the dose depth distribution for 10 MeV electron beams with the energy profiles of a model Laser Wake Field accelerator (LWFA). The dosimetry and simulation results show that the maximum dose of the depth-dose curve inside the product are 1.4 times surface dose with an area density limit of 8.6 g/cm2 for two-sided irradiation with nearly mono-energetic beams from linear accelerator and the corresponding parameters for LWFA are 1.2 times surface dose and 13.0 g/cm2, respectively.
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Constraining the α-nucleus potential for α-decay calculation with nuclear rainbow scattering
Nguyen Tri Toan Phuc, Le Hoang Chien, Chau Van Tao
Science & Technology Development Journal, 25(1):1-9
Abstract:
Introduction: The emission of a particles is a powerful probe for the α-cluster structure of heavy nuclei. The α-nucleus potential is a crucial ingredient in the a-decay calculation within the preformed cluster model. One of the most reliable ways to construct this potential is the double folding model, where an effective nucleon-nucleon interaction is folded with the nuclear densities. In the folding model calculation, there are many ambiguities in the choice of the nuclear densities of the daughter nucleus for α-decay. We propose to directly constrain the α-nucleus potential for α- decay and choose the daughter nuclear density using the nuclear rainbow scattering phenomenon.
Methods: The refractive rainbow pattern in the elastic scattering cross section within the optical model can probe deep into the interior region of the α-nucleus potential. We apply this method to investigate the reliability of the nuclear potential used in the α-decay of the 212Po nucleus leading to the 208Pb daughter nucleus by examining the elastic a scattering on 208Pb. In such an approach, we perform the double-folding calculation to construct the α-nucleus potential using several common parametrizations of the daughter nuclear densities. These parametrizations include the mean-field Hartree-Fock-Bogoliubov calculations with the BSk14 and D1S interactions, the independent particle model, and the 2-parameter Fermi distributions. The obtained nuclear potentials are applied to the optical model to calculate the elastic α-208Pb scattering cross sections that are compared with the experimental data. These nuclear potentials are further used in the preformed cluster model to study thea-decay half-life of 212Po.
Results: The nuclear densities from the Hartree-Fock-Bogoliubov calculations are shown to provide the best description for both the nuclear rainbow scattering anda-decay half-life. The results indicate a strong correspondence between the capabilities of the nuclear potential to reproduce the cross section ofa scattering and the α-decay half-life. The extracteda preformation factors from the semiclassical preformed cluster model with folding potentials are in good agreement with those from other studies.
Conclusion: The nuclear rainbow scattering phenomenon can be used to provide reliable a-nucleus potential
for α-decay studies within the preformed cluster model. The nuclear densities from the mean-field Hartree-Fock-Bogoliubov method with the BSk14 and D1S interactions are the appropriate choices for the DFM calculation used in the α-decay study.
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Consistent mean-field description of the 12C+12C optical potential at low energies and the astrophysical S factor
Abstract:
The nuclear mean-field potential built up by the 12C+12C interaction at energies relevant for the carbon burning process is calculated in the double-folding model (DFM) using the realistic ground-state density of 12C and the CDM3Y3 density dependent nucleon-nucleon (NN) interaction, with the rearrangement term properly included. To validate the use of a density dependent NN interaction in the DFM calculation in the low-energy regime, an adiabatic approximation is suggested for the nucleus-nucleus overlap density. The reliability of the nuclear mean-field potential predicted by this low-energy version of the DFM is tested in a detailed optical model analysis of the elastic 12C+12C scattering data at energies below 10 MeV/nucleon. The folded mean-field potential is then used to study the astrophysical S factor of 12C+12C fusion in the barrier penetration model. Without any adjustment of the potential strength, our results reproduce very well the nonresonant behavior of the S factor of 12C+12C fusion over a wide range of energies.
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Consistency test of coincidence-summing calculation methods for extended sources
O.Sima, A.De Vismes Ott, M.S.Dias, P.Dryak, L.Ferreux, D.Gurau, S.Hurtado, P.Jodlowski, K.Karfopoulos, M.F.Koskinas, M.Laubenstein, Y.K.LeeM.C.Lépy, A.Luca, M.O.Menezes, D.S.Moreira, J.Nikolič, V.Peyres, P.Saganowski, M.I.Savva, R.Semmler, J.Solc, T.T.Thanh, K.Tyminska, Z.Tyminski, T.Vidmar, I.Vukanac, H.Yucel
Abstract:
An internal consistency test of the calculation of coincidence-summing correction factors FC for volume sources is presented. The test is based on exact equations relating the values of FC calculated for three ideal measurement configurations. The test is applied to a number of 33 sets of FC values sent by 21 teams. Most sets passed the test, but not the results obtained using the quasi-point source approximation; in the latter case the test qualitatively indicated the magnitude of the bias of FC.
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The COMET Collaboration
Abstract:
The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of an aluminum nucleus (μ–e conversion, μ−N → e−N); a lepton flavor- violating process. The experimental sensitivity goal for this process in the Phase-I experiment is 3.1 × 10−15, or 90% upper limit of a branching ratio of 7 × 10−15, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the μ–e conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described.
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