2011 Vol. 28, No. 4
Display Method:
2011, 28(4): 377-395.
doi: 10.11804/NuclPhysRev.28.04.377
Abstract:
Nuclear symmetry energy plays an important role in the properties of nuclei and neutron stars. Since theoretical predictions of the density dependence of symmetry energy S(ρ) from microscopic nucleonnucleon interactions show large uncertainties, especially in the region of suprasaturation density, constraining the density dependence of symmetry energy has become one of the main goals in nuclear physics and has stimulated many theoretical and experimental studies. In this paper, we have reviewed the ImQMD05 code and its description on charge distribution, collective flow and nuclearnuclear stopping. By comparing ImQMD05 prediction with data, the isoscalar part of nucleonic mean field, the energy and density dependence of inmedium NN cross sectoin in the ImQMD05 were determined. In order to extracting the symmetry energy information by comparing the ImQMD05 calculations with the data for 112, 124Sn+112, 124 Sn at Ebeam=50 MeV/u, the influence of symmetry potential and inmedium NN cross section on the isospin sensitive observables of intermediateenergy heavyion collisions was investigated. Focusing on the region above the Fermi energy, our results show that the symmetry potential plays a more important role in the experimental observables, such as double neutron to proton ratio and the isospin transport ratio Ri, than that the inmedium nucleonnucleon cross section does. Since the copious production of intermediate mass fragments is a distinguishing feature of intermediateenergy heavyion collisions, we also examined the influence of cluster emission on the isospin transport ratio using different isospin tracers. The values of the isospin transport ratios with the tracer defined by the isospin asymmetry of the heaviest fragments with Z≥20 in the projectile region is greater than those obtained from projectile residues (emitting source). This phenomenon can be tested experimentally. By comparing the ImQMD05 predictions with the data for three observables, the selfconsistent constraints on the symmetry energy at subsaturation density were obtained.
Nuclear symmetry energy plays an important role in the properties of nuclei and neutron stars. Since theoretical predictions of the density dependence of symmetry energy S(ρ) from microscopic nucleonnucleon interactions show large uncertainties, especially in the region of suprasaturation density, constraining the density dependence of symmetry energy has become one of the main goals in nuclear physics and has stimulated many theoretical and experimental studies. In this paper, we have reviewed the ImQMD05 code and its description on charge distribution, collective flow and nuclearnuclear stopping. By comparing ImQMD05 prediction with data, the isoscalar part of nucleonic mean field, the energy and density dependence of inmedium NN cross sectoin in the ImQMD05 were determined. In order to extracting the symmetry energy information by comparing the ImQMD05 calculations with the data for 112, 124Sn+112, 124 Sn at Ebeam=50 MeV/u, the influence of symmetry potential and inmedium NN cross section on the isospin sensitive observables of intermediateenergy heavyion collisions was investigated. Focusing on the region above the Fermi energy, our results show that the symmetry potential plays a more important role in the experimental observables, such as double neutron to proton ratio and the isospin transport ratio Ri, than that the inmedium nucleonnucleon cross section does. Since the copious production of intermediate mass fragments is a distinguishing feature of intermediateenergy heavyion collisions, we also examined the influence of cluster emission on the isospin transport ratio using different isospin tracers. The values of the isospin transport ratios with the tracer defined by the isospin asymmetry of the heaviest fragments with Z≥20 in the projectile region is greater than those obtained from projectile residues (emitting source). This phenomenon can be tested experimentally. By comparing the ImQMD05 predictions with the data for three observables, the selfconsistent constraints on the symmetry energy at subsaturation density were obtained.
2011, 28(4): 396-403.
doi: 10.11804/NuclPhysRev.28.04.396
Abstract:
We have investigated the incompressibility of asymmetric nuclear matter within the BruecknerHartreeFock approach extended to include a microscopic threebody force. The isospindependence and densitydependence of the nuclear incompressibility have been obtained and discussed. It is shown that the incompressibility at a fixed density increases monotonically as a function of isospin asymmetry. The isospin asymmetry dependence of the equilibrium properties of asymmetric nuclear matter is also predicted and compared with the results of other theoretical approaches.
We have investigated the incompressibility of asymmetric nuclear matter within the BruecknerHartreeFock approach extended to include a microscopic threebody force. The isospindependence and densitydependence of the nuclear incompressibility have been obtained and discussed. It is shown that the incompressibility at a fixed density increases monotonically as a function of isospin asymmetry. The isospin asymmetry dependence of the equilibrium properties of asymmetric nuclear matter is also predicted and compared with the results of other theoretical approaches.
2011, 28(4): 404-407.
doi: 10.11804/NuclPhysRev.28.04.404
Abstract:
On the basis of nuclear and comover absorption theories， we have derived out the differential cross section of J/Ψ production in high-energy heavy-ion collisions under the situation that QGP phase transition occurs， and analyzed the experimental data of NA50 Collaboration at CERN in Pb-Pb collisions at 158 AGeV/c. Our theory favors the data well.
On the basis of nuclear and comover absorption theories， we have derived out the differential cross section of J/Ψ production in high-energy heavy-ion collisions under the situation that QGP phase transition occurs， and analyzed the experimental data of NA50 Collaboration at CERN in Pb-Pb collisions at 158 AGeV/c. Our theory favors the data well.
2011, 28(4): 408-415.
doi: 10.11804/NuclPhysRev.28.04.408
Abstract:
In the present paper, we briefly review the progress in the study of kaon production in heavy\|ion collisions at intermediate and high energies and introduce the covariant kaon dynamics model. The collective flows of positively charged kaon and the lambda hyperon associated produced with kaon are studied in the framework of the dynamics. It shows that the directed differential flow of K+ meson and Λ hyperon can be reasonably reproduced in the covariant kaon dynamics model. The calculated results with soft equation of nuclear matter are in better agrement with experimental data. Meawhile, a detailed comparison of the properites of different quasi\|particle models in various transport model and the influence of nucleon’s movement on the effective mass and energy of the quasi\|particle in the covariant kaon dynamics model are discussed.
In the present paper, we briefly review the progress in the study of kaon production in heavy\|ion collisions at intermediate and high energies and introduce the covariant kaon dynamics model. The collective flows of positively charged kaon and the lambda hyperon associated produced with kaon are studied in the framework of the dynamics. It shows that the directed differential flow of K+ meson and Λ hyperon can be reasonably reproduced in the covariant kaon dynamics model. The calculated results with soft equation of nuclear matter are in better agrement with experimental data. Meawhile, a detailed comparison of the properites of different quasi\|particle models in various transport model and the influence of nucleon’s movement on the effective mass and energy of the quasi\|particle in the covariant kaon dynamics model are discussed.
2011, 28(4): 416-422.
doi: 10.11804/NuclPhysRev.28.04.416
Abstract:
With an oscillator basis, the nuclear Hamiltonian is defined in a nocore model space. It consists of an effective nucleonnucleon interaction obtained with Brueckner theory from the Reid soft core interaction, a Coulomb potential, nucleondelta transition potentials, and deltadelta interaction terms. By performing spherical HartreeFock (SHF) calculations with the realistic baryon Hamiltonian, the ground state properties of 40Ca are studied. For an estimate of how the delta degree of freedom is excited, SHF calculations are performed with a radial constraint to compress the nucleus. The delta degree of freedom is gradually populated as the nucleus is compressed. The number of Δ’s is decreased by increasing model space. Large amount of the compressive energy is delivered to create massive Δ in the nucleus. There is a significant reduction in the static compression modulus for RSC static compressions which is reduced by including the Δ excitations. The static compression modulus is decreased significantly by en larging the nucleon model space. The results suggest that inclusion of the delta in the nuclear dynamics could head to a significant softening of the nuclear equation of state.
With an oscillator basis, the nuclear Hamiltonian is defined in a nocore model space. It consists of an effective nucleonnucleon interaction obtained with Brueckner theory from the Reid soft core interaction, a Coulomb potential, nucleondelta transition potentials, and deltadelta interaction terms. By performing spherical HartreeFock (SHF) calculations with the realistic baryon Hamiltonian, the ground state properties of 40Ca are studied. For an estimate of how the delta degree of freedom is excited, SHF calculations are performed with a radial constraint to compress the nucleus. The delta degree of freedom is gradually populated as the nucleus is compressed. The number of Δ’s is decreased by increasing model space. Large amount of the compressive energy is delivered to create massive Δ in the nucleus. There is a significant reduction in the static compression modulus for RSC static compressions which is reduced by including the Δ excitations. The static compression modulus is decreased significantly by en larging the nucleon model space. The results suggest that inclusion of the delta in the nuclear dynamics could head to a significant softening of the nuclear equation of state.
2011, 28(4): 423-427.
doi: 10.11804/NuclPhysRev.28.04.423
Abstract:
The ground-state two-proton decay is an exotic decay beyond proton drip line. It deals with the structure behavior of the proton pair at outside orbital in a proton dripline nucleus, and can be used to check the current nuclear model under extreme condition. Experimental observation of groundstate twoproton decay has been widely considered as a challenge because of very low production cross section. In this short paper, the breakthrough of searching groundstate twoproton decay is briefly reviewed, which was made more than 40 years after the early theoretical prediction was proposed.
The ground-state two-proton decay is an exotic decay beyond proton drip line. It deals with the structure behavior of the proton pair at outside orbital in a proton dripline nucleus, and can be used to check the current nuclear model under extreme condition. Experimental observation of groundstate twoproton decay has been widely considered as a challenge because of very low production cross section. In this short paper, the breakthrough of searching groundstate twoproton decay is briefly reviewed, which was made more than 40 years after the early theoretical prediction was proposed.
2011, 28(4): 428-432.
doi: 10.11804/NuclPhysRev.28.04.428
Abstract:
Resonant properties in18Ne relevant to the stellar reaction of 14O(α, p)17F have been investigated through a resonant elastic scattering of 17F+p. The 17F RI beam was produced via a projectilefragmentation reaction， and subsequently separated and purified by Radioactive Ion beam Line in Lanzhou(RIBLL). After a series of energy degradation，a 4.22 AMeV 17F beam bombarded a thick(CH2)ntarget at T2 terminal. Energy and angle of the recoiled protons were measured by two sets of ∆E-E silicon telescope at θlab≈2.3°，14° respectively. Several resonances in 18Ne were observed，and their resonant parametersincluding energy，spinparity and decay width have been determined by an R-Matrix analysis of the experimental excitation function.
Resonant properties in18Ne relevant to the stellar reaction of 14O(α, p)17F have been investigated through a resonant elastic scattering of 17F+p. The 17F RI beam was produced via a projectilefragmentation reaction， and subsequently separated and purified by Radioactive Ion beam Line in Lanzhou(RIBLL). After a series of energy degradation，a 4.22 AMeV 17F beam bombarded a thick(CH2)ntarget at T2 terminal. Energy and angle of the recoiled protons were measured by two sets of ∆E-E silicon telescope at θlab≈2.3°，14° respectively. Several resonances in 18Ne were observed，and their resonant parametersincluding energy，spinparity and decay width have been determined by an R-Matrix analysis of the experimental excitation function.
2011, 28(4): 433-438.
doi: 10.11804/NuclPhysRev.28.04.433
Abstract:
With great significance in describing the state of quantum system, the Wigner function of the spin half noncommutative Landau problem is studied in this paper. On the basis of the review of the Wigner function in the commutative space, which is subject to the *eigenvalue equation, Hamiltonian of the spin half Landau problem in the noncommutative phase space is given. Then, energy levels and Wigner functions in the form of a matrix of the spin half Landau problem in the noncommutative phase space are obtained by means of the *-eigenvalue equation (or Moyal equation).
With great significance in describing the state of quantum system, the Wigner function of the spin half noncommutative Landau problem is studied in this paper. On the basis of the review of the Wigner function in the commutative space, which is subject to the *eigenvalue equation, Hamiltonian of the spin half Landau problem in the noncommutative phase space is given. Then, energy levels and Wigner functions in the form of a matrix of the spin half Landau problem in the noncommutative phase space are obtained by means of the *-eigenvalue equation (or Moyal equation).
2011, 28(4): 439-443.
doi: 10.11804/NuclPhysRev.28.04.439
Abstract:
There are two kinds of ion sources, LiquidMetal Ion Source and Gas Field Ion Source, used to provide ion beams for the Focus Ion Beam system. The working mechanism of the two kinds of sources is presented and their advantages and disadvantages are summarized. With the rapid development in the nano technology, the requirements are hardly met with these two kinds of ion sources. Therefore, a new kind of ion source, electron beam ion source, is developed for the Focus Ion Beam system. The basic principle of the electron beam ion source is introduced and the design parameters, the result of the simulation (20 kV Ar+, extracted emittance is 5.8×10-5π·mm·mrad, raduis of the ion beam about 1 μm.) and the primary experimental results are presented.
There are two kinds of ion sources, LiquidMetal Ion Source and Gas Field Ion Source, used to provide ion beams for the Focus Ion Beam system. The working mechanism of the two kinds of sources is presented and their advantages and disadvantages are summarized. With the rapid development in the nano technology, the requirements are hardly met with these two kinds of ion sources. Therefore, a new kind of ion source, electron beam ion source, is developed for the Focus Ion Beam system. The basic principle of the electron beam ion source is introduced and the design parameters, the result of the simulation (20 kV Ar+, extracted emittance is 5.8×10-5π·mm·mrad, raduis of the ion beam about 1 μm.) and the primary experimental results are presented.
2011, 28(4): 444-447.
doi: 10.11804/NuclPhysRev.28.04.444
Abstract:
A high voltage RF cavity is required to compress the beam bunch in the longitudinal for high energy density physics and plasma physics research at HIRFLCSRm. A magnetic alloy (MA)loaded cavity which has high acceleration gradient and without tuning loop (can simplify the RF control system), can meet the requirement. In order to select a proper MA material with higher permeability and shunt impe dance, Q< 1 value to load the RF compression cavity, two different MA materials V and A have been tes ted. The results indicate that the material V will be better for the construction of the RF cavity than material A because of its higher permeability and shunt impedance, Q< 1 value.
A high voltage RF cavity is required to compress the beam bunch in the longitudinal for high energy density physics and plasma physics research at HIRFLCSRm. A magnetic alloy (MA)loaded cavity which has high acceleration gradient and without tuning loop (can simplify the RF control system), can meet the requirement. In order to select a proper MA material with higher permeability and shunt impe dance, Q< 1 value to load the RF compression cavity, two different MA materials V and A have been tes ted. The results indicate that the material V will be better for the construction of the RF cavity than material A because of its higher permeability and shunt impedance, Q< 1 value.
2011, 28(4): 448-453.
doi: 10.11804/NuclPhysRev.28.04.448
Abstract:
It is very difficalt to calculate the nonlinear transport of a intense beam, because the particle trajectories depend on the electric potentials excited by the particle beams, and the electric potentials of the beams depend on the particle trajectories and the particle distributions in the phase spaces. So, it is necessary to solve the problem by iterations to get selfconsistent solutions.We use transport matrix method to analyze the transportation in quadrupole magnet of nonintense pulsed beam and intense pulsed beam respectively, and write a computer code for the pulsed beam transporting in quadrupole magnet. The selfconsistent solution can obtained by using iteration calculation method. During the calculation, the result can be shown by the prompt graph.
It is very difficalt to calculate the nonlinear transport of a intense beam, because the particle trajectories depend on the electric potentials excited by the particle beams, and the electric potentials of the beams depend on the particle trajectories and the particle distributions in the phase spaces. So, it is necessary to solve the problem by iterations to get selfconsistent solutions.We use transport matrix method to analyze the transportation in quadrupole magnet of nonintense pulsed beam and intense pulsed beam respectively, and write a computer code for the pulsed beam transporting in quadrupole magnet. The selfconsistent solution can obtained by using iteration calculation method. During the calculation, the result can be shown by the prompt graph.
2011, 28(4): 454-458.
doi: 10.11804/NuclPhysRev.28.04.454
Abstract:
In the classical mechanics frame and with a dipole approximation the particle motion equation in the periodic bent crystal is reduced to the general pendulum equation with a damping term and the forced term by using the sinesquared potential． This paper discusses the problem of the subharmonic bifurcation of the periodic orbit and the stabilities of the channeling motion by using Melnikov method, so as to derive the critical condition and the dechanneling length of the periodic bent crystal. The results show that channeling motion must be stable in addition that the crystal length is smaller than the dechanneling length in order to ensure higher extracted efficiency. The analysis of the critical condition shows that the system stabilities are related to its parameters. Just by properly regulating the parameters of the system, the dynamic stabilities by the use of periodic bent crystal as beam control cell can be ensured.
In the classical mechanics frame and with a dipole approximation the particle motion equation in the periodic bent crystal is reduced to the general pendulum equation with a damping term and the forced term by using the sinesquared potential． This paper discusses the problem of the subharmonic bifurcation of the periodic orbit and the stabilities of the channeling motion by using Melnikov method, so as to derive the critical condition and the dechanneling length of the periodic bent crystal. The results show that channeling motion must be stable in addition that the crystal length is smaller than the dechanneling length in order to ensure higher extracted efficiency. The analysis of the critical condition shows that the system stabilities are related to its parameters. Just by properly regulating the parameters of the system, the dynamic stabilities by the use of periodic bent crystal as beam control cell can be ensured.
2011, 28(4): 459-463.
doi: 10.11804/NuclPhysRev.28.04.459
Abstract:
The basic principles and implementation of onedimensional position encoding readout for MICROMEGAS have been introduced in this paper. A 10 cm×10 cm prototype of onedimensional position encoding readout electrode based on printed circuit board was designed. Preliminary test indicates that the induction readout is feasible and the ideal charge distribution is 1∶2. X rays emitted from 55Fe source were collimated to one of strips on the readout electrode through a slit of 200 μm, position decoding well reproduced the position of the 55Fe source. For its limitations, we have proposed a onedimensional grouped position encoding readout technique to address a neighboring strips simultaneously fired situation. The amount of readout electronics is very easy to approach a obduction of 75% with position encoding read out technology.
The basic principles and implementation of onedimensional position encoding readout for MICROMEGAS have been introduced in this paper. A 10 cm×10 cm prototype of onedimensional position encoding readout electrode based on printed circuit board was designed. Preliminary test indicates that the induction readout is feasible and the ideal charge distribution is 1∶2. X rays emitted from 55Fe source were collimated to one of strips on the readout electrode through a slit of 200 μm, position decoding well reproduced the position of the 55Fe source. For its limitations, we have proposed a onedimensional grouped position encoding readout technique to address a neighboring strips simultaneously fired situation. The amount of readout electronics is very easy to approach a obduction of 75% with position encoding read out technology.
2011, 28(4): 464-468.
doi: 10.11804/NuclPhysRev.28.04.464
Abstract:
A data acquisition system for array detectors is described. The system is based on PXI bus with standard NIM modules used as front\|end electronics. The system software is written in C/C++ language with its online analysis modules realized by ROOT class library. Several runs of the system under Linux show that it is reliable and is capable of handling event rates up to 40 k events/s for 1 ADC channel.
A data acquisition system for array detectors is described. The system is based on PXI bus with standard NIM modules used as front\|end electronics. The system software is written in C/C++ language with its online analysis modules realized by ROOT class library. Several runs of the system under Linux show that it is reliable and is capable of handling event rates up to 40 k events/s for 1 ADC channel.
2011, 28(4): 469-473.
doi: 10.11804/NuclPhysRev.28.04.469
Abstract:
The influence of the Fourier Transform on long cable in the measurement of fall time of DPF neutron profile is discussed by mathematical methods. The application of anticonvolution function with the Fourier Transform on long cable is analysed. The time interval between the peak
time and the time that the height falls 3 orders of magnitude after peak is measured with gateddetector array system which consists of PMT(photomultiplier tube) and organic scintillation crystal.
The influence of the Fourier Transform on long cable in the measurement of fall time of DPF neutron profile is discussed by mathematical methods. The application of anticonvolution function with the Fourier Transform on long cable is analysed. The time interval between the peak
time and the time that the height falls 3 orders of magnitude after peak is measured with gateddetector array system which consists of PMT(photomultiplier tube) and organic scintillation crystal.
2011, 28(4): 474-478.
doi: 10.11804/NuclPhysRev.28.04.474
Abstract:
In this work， PAN/PEO (polyacrylonitrile/polyethylene oxide)based gel electrolyte was irradiated by electron beam (EB) with dose from 13 to 260 kGy. Then， DSSC (dyesensitized solar cell) was fabricated by the irradiated electrolyte and characterized. The results show that the efficiency of the DSSC fabricated by irradiated electrolyte is promoted comparing with DSSC fabricated by unirradiated electrolyte. And with irradiation dose increasing， the DSSC efficiency increases rapidly at first (0～65 kGy)， then， drops down slowly (65～130 kGy)， finally trends to a stable value (130～260 kGy). It indicates that there is an optimal irradiation dose， at which the promotion of DSSC efficiency is the highest， approximate 36%. Observed from the change of shortcircuit current， opencircuit voltage and fill factor， shortcircuit current promotion by EB irradiation is found to be the main reason of DSSC performance promotion. The time stability measurement of the DSSC indicates that EB irradiation on PAN/PEO electrolyte reduces the loss of efficiency and the limitingeffects become more apparent as the irradiation dose increases.
In this work， PAN/PEO (polyacrylonitrile/polyethylene oxide)based gel electrolyte was irradiated by electron beam (EB) with dose from 13 to 260 kGy. Then， DSSC (dyesensitized solar cell) was fabricated by the irradiated electrolyte and characterized. The results show that the efficiency of the DSSC fabricated by irradiated electrolyte is promoted comparing with DSSC fabricated by unirradiated electrolyte. And with irradiation dose increasing， the DSSC efficiency increases rapidly at first (0～65 kGy)， then， drops down slowly (65～130 kGy)， finally trends to a stable value (130～260 kGy). It indicates that there is an optimal irradiation dose， at which the promotion of DSSC efficiency is the highest， approximate 36%. Observed from the change of shortcircuit current， opencircuit voltage and fill factor， shortcircuit current promotion by EB irradiation is found to be the main reason of DSSC performance promotion. The time stability measurement of the DSSC indicates that EB irradiation on PAN/PEO electrolyte reduces the loss of efficiency and the limitingeffects become more apparent as the irradiation dose increases.
2011, 28(4): 479-484.
doi: 10.11804/NuclPhysRev.28.04.479
Abstract:
Along the way, the mutagenic mechanism of lowenergy ions irradiation is a debatable issue. Recently, the existence of radiation induced longrange (mutagenic) effects in vivo in plants has been performed in a series of studies of our group, which account for the mutagenesis of lowenergy ions irradiation in a new perspective. However, numerous distinct biology phenomena remain to be addressed, which bear obvious characteristics to epigenetic. In the present study, using the expression of methylationrelated AtDML3 gene and methylation level of specific gene segments as end points, the methylation of cytosine, the most important feature of epigenetic, was investigated. It was shown that, in A. thaliana, rootloca lized αirradiation could induce epigenetic changes in aerial parts which avoided the direct irradiation. The radiation induced longrange epigenetic changes were confirmed in this study, which supplied innovative ideas for the further investigation of the mutagenetic mechanism of lowenergy ions irradiation.
Along the way, the mutagenic mechanism of lowenergy ions irradiation is a debatable issue. Recently, the existence of radiation induced longrange (mutagenic) effects in vivo in plants has been performed in a series of studies of our group, which account for the mutagenesis of lowenergy ions irradiation in a new perspective. However, numerous distinct biology phenomena remain to be addressed, which bear obvious characteristics to epigenetic. In the present study, using the expression of methylationrelated AtDML3 gene and methylation level of specific gene segments as end points, the methylation of cytosine, the most important feature of epigenetic, was investigated. It was shown that, in A. thaliana, rootloca lized αirradiation could induce epigenetic changes in aerial parts which avoided the direct irradiation. The radiation induced longrange epigenetic changes were confirmed in this study, which supplied innovative ideas for the further investigation of the mutagenetic mechanism of lowenergy ions irradiation.
2011, 28(4): 485-488.
doi: 10.11804/NuclPhysRev.28.04.485
Abstract:
Mutagenic effect on the mutant highproducing strain ZJAVY1203 and the original strain ZJAVA1 irradiated by ion beam of 12C6+ have been investigated. The experimental results indicated that the original strain has higher survival rate and stronger resistance to radiation than mutant highproducing Strain at dose of 10 Gy. The mutant highproducing strain has higher survival rate and stronger resistance to radiation than the original strain at the dose higher than 30 Gy. The lethality was 97% and the highest rate of orthomutation was 34.2%， when ZJAV A1 was irradiated by 50 Gy 12C6+ beam. The lethality was 94.97% and the highest rate of orthomutation was 23.5% when ZJAVY1203 was irradiated by 30 Gy 12C6+ beam. The best radiation dose is decreased by progressivity irradiation.
Mutagenic effect on the mutant highproducing strain ZJAVY1203 and the original strain ZJAVA1 irradiated by ion beam of 12C6+ have been investigated. The experimental results indicated that the original strain has higher survival rate and stronger resistance to radiation than mutant highproducing Strain at dose of 10 Gy. The mutant highproducing strain has higher survival rate and stronger resistance to radiation than the original strain at the dose higher than 30 Gy. The lethality was 97% and the highest rate of orthomutation was 34.2%， when ZJAV A1 was irradiated by 50 Gy 12C6+ beam. The lethality was 94.97% and the highest rate of orthomutation was 23.5% when ZJAVY1203 was irradiated by 30 Gy 12C6+ beam. The best radiation dose is decreased by progressivity irradiation.
2011, 28(4): 489-497.
doi: 10.11804/NuclPhysRev.28.04.489
Abstract:
Based on the spherical optical model, preequilibrium and HauserFeshbach statistical theory, the code MENDF (Medium Energy Nuclear Data for Fission) is written to calculate a complete set of nuclear data for fission nuclei in the mediumlow energy region (≤200 MeV). For neutron and proton induced reactions below 200 MeV, the total cross sections, reaction cross sections, elastic scattering differential cross sections, fission cross section, energy spectra of fission neutron and five kinds of emitting particles, etc. are calculated by MENDF. The calculated data generally agree with their corresponding experimental data. MENDF is widely used for nuclear data calculation and to establish ENDF6 formatted files for the mediumlow energy region in China.
Based on the spherical optical model, preequilibrium and HauserFeshbach statistical theory, the code MENDF (Medium Energy Nuclear Data for Fission) is written to calculate a complete set of nuclear data for fission nuclei in the mediumlow energy region (≤200 MeV). For neutron and proton induced reactions below 200 MeV, the total cross sections, reaction cross sections, elastic scattering differential cross sections, fission cross section, energy spectra of fission neutron and five kinds of emitting particles, etc. are calculated by MENDF. The calculated data generally agree with their corresponding experimental data. MENDF is widely used for nuclear data calculation and to establish ENDF6 formatted files for the mediumlow energy region in China.
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