2014 Vol. 31, No. 2
Display Method:
2014, 31(2): 119-125.
doi: 10.11804/NuclPhysRev.31.02.119
Abstract:
The study of the properties of the nucleon and nucleon resonances is an important field in the high and intermediate energy nuclear physics, however, until now, our understanding about the structure of the nucleon and nucleon resonances is still in its infancy. We give a brief review on the current researches of the nucleon and nucleon resonances, and point out that the classical quark model can not successfully describe the structure of the nucleon and nucleon resonances. For doing this, a new idea claims that although the five-quark state does not exist, but, there could be significant five-quark components in the nucleon and nucleon resonances.This five-quark configure gives different predictions for the nucleon resonances which will be tested by the future experiments. Now, the proposed Electron-Ion Collider (EIC) will be the most important accelerator installation for studying the nucleon structure, and it is called ”super-electronic-microscope”. Because of the high energy and luminosity, and also low background, we can study the properties of the nucleon and nucleon resonances and new hadron states on EIC.
The study of the properties of the nucleon and nucleon resonances is an important field in the high and intermediate energy nuclear physics, however, until now, our understanding about the structure of the nucleon and nucleon resonances is still in its infancy. We give a brief review on the current researches of the nucleon and nucleon resonances, and point out that the classical quark model can not successfully describe the structure of the nucleon and nucleon resonances. For doing this, a new idea claims that although the five-quark state does not exist, but, there could be significant five-quark components in the nucleon and nucleon resonances.This five-quark configure gives different predictions for the nucleon resonances which will be tested by the future experiments. Now, the proposed Electron-Ion Collider (EIC) will be the most important accelerator installation for studying the nucleon structure, and it is called ”super-electronic-microscope”. Because of the high energy and luminosity, and also low background, we can study the properties of the nucleon and nucleon resonances and new hadron states on EIC.
2014, 31(2): 126-134.
doi: 10.11804/NuclPhysRev.31.02.126
Abstract:
The multiplicity distributions and correlations of target fragments produced in 150 AMeV 150 AMeV 4He，290 AMeV 12C，400 AMeV 12C，400 AMeV 20Ne and 500 AMeV 56Fe induced different emulsion target interactions are investigated. It is found that the averaged multiplicity of grey track particle,black track particle and heavily ionized track particle increase with the increase of target size.There is a linear correlation between the multiplicity of different target fragments. The experimental results can be well explained based on the geometrical picture and the cascade evaporation model of nucleus-nucleus interactions.
The multiplicity distributions and correlations of target fragments produced in 150 AMeV 150 AMeV 4He，290 AMeV 12C，400 AMeV 12C，400 AMeV 20Ne and 500 AMeV 56Fe induced different emulsion target interactions are investigated. It is found that the averaged multiplicity of grey track particle,black track particle and heavily ionized track particle increase with the increase of target size.There is a linear correlation between the multiplicity of different target fragments. The experimental results can be well explained based on the geometrical picture and the cascade evaporation model of nucleus-nucleus interactions.
2014, 31(2): 135-141.
doi: 10.11804/NuclPhysRev.31.02.135
Abstract:
The properties of light particles’ collective flows from 40Ca+40Ca, 50Ca+40Ca, 64Cu+64Cu and 197Au+197Au systems are simulated by Isospin-dependent Quantum Molecular Dynamics model. Transverse momentum dependent elliptic flows from different systems are found to be scaled by nucleon numbers of fragment in intermediate energy, and v4=v 22 scaling is also found and nearly to be a constant 0.5 for different light fragments.These scaling behaviors are investigated for different collision energies, impact parameters, nuclear equation of states and found insensitive to the above physical quantities, which may be the result of coalescence mechanism that describes the formation of fragments.
The properties of light particles’ collective flows from 40Ca+40Ca, 50Ca+40Ca, 64Cu+64Cu and 197Au+197Au systems are simulated by Isospin-dependent Quantum Molecular Dynamics model. Transverse momentum dependent elliptic flows from different systems are found to be scaled by nucleon numbers of fragment in intermediate energy, and v4=v 22 scaling is also found and nearly to be a constant 0.5 for different light fragments.These scaling behaviors are investigated for different collision energies, impact parameters, nuclear equation of states and found insensitive to the above physical quantities, which may be the result of coalescence mechanism that describes the formation of fragments.
2014, 31(2): 142-146.
doi: 10.11804/NuclPhysRev.31.02.142
Abstract:
We calculate the photoproduction processes of light vector meson(ρ, ω and Φ) in heavy ion collisions. Based on the narrow-width approximation, we rigorously derive the exclusive and inclusive cross sections of ρ, ω and Φ produced by the semielastic and inelastic photoproduction processes in relativistic heavy ion collisions. The numerical results indicate that contribution of photoproduction processes of light vector meson is not prominent for p-p collisions, but thecontribution becomes evident for pT >2.5 GeV in Au-Au collisions and pT >3 GeV in Pb-Pb collisions.
We calculate the photoproduction processes of light vector meson(ρ, ω and Φ) in heavy ion collisions. Based on the narrow-width approximation, we rigorously derive the exclusive and inclusive cross sections of ρ, ω and Φ produced by the semielastic and inelastic photoproduction processes in relativistic heavy ion collisions. The numerical results indicate that contribution of photoproduction processes of light vector meson is not prominent for p-p collisions, but thecontribution becomes evident for pT >2.5 GeV in Au-Au collisions and pT >3 GeV in Pb-Pb collisions.
2014, 31(2): 147-151.
doi: 10.11804/NuclPhysRev.31.02.147
Abstract:
Based on the Dyson-Schwinger Equations (DSEs) with the rainbow truncation, and Operator Product Expansion, the structure of nonlocal quark vacuum condensate in QCD, described by quark self-energy functions Af and Bf given usually by the solutions of the DSEs of quark propagator,is predicted numerically. We also calculate the local quark vacuum condensate, quark-gluon mixed local vacuum condensate, and quark virtuality. The self-energy functions Af and Bf are given by the parameterized quark propagator functions fv(p2) and fs (p2) of Roberts and Williams, instead of the numerical solutions of the DSEs. Our calculated results are in reasonable agreement with those of QCD sum rules, Lattice QCD calculations, and instanton model predictions, although the resulting local quark vacuum condensate for light quarks, u, d, s, are a little bit larger than those of the above theoretical predictions. We think the differences are caused by model dependence. The larger of strange quark vacuum condensate than u, d quark is due to the s quark mass which is more larger than u, d quark masses. Of course, the Roberts-Williams parameterized quark propagator is an empirical formulism, which approximately describes quark propagation.
Based on the Dyson-Schwinger Equations (DSEs) with the rainbow truncation, and Operator Product Expansion, the structure of nonlocal quark vacuum condensate in QCD, described by quark self-energy functions Af and Bf given usually by the solutions of the DSEs of quark propagator,is predicted numerically. We also calculate the local quark vacuum condensate, quark-gluon mixed local vacuum condensate, and quark virtuality. The self-energy functions Af and Bf are given by the parameterized quark propagator functions fv(p2) and fs (p2) of Roberts and Williams, instead of the numerical solutions of the DSEs. Our calculated results are in reasonable agreement with those of QCD sum rules, Lattice QCD calculations, and instanton model predictions, although the resulting local quark vacuum condensate for light quarks, u, d, s, are a little bit larger than those of the above theoretical predictions. We think the differences are caused by model dependence. The larger of strange quark vacuum condensate than u, d quark is due to the s quark mass which is more larger than u, d quark masses. Of course, the Roberts-Williams parameterized quark propagator is an empirical formulism, which approximately describes quark propagation.
2014, 31(2): 152-155.
doi: 10.11804/NuclPhysRev.31.02.152
Abstract:
The main issue of this paper is to introduce the application of phase lock loop (PLL) in superconducting RF technology. The voltage-controlled oscillator phase lock loop (VCO-PLL) can be used for locking the eigen frequency of the superconducting cavity. It can keep superconducting cavity resonant stably. In thispaper, the principle of the cavity locking by the VCO-PLL is verified by a simulation, which is done by using NI-Labview software. The simulation result shows that the different gain of the PLL system can impact the locking situation of the whole system. In the test stage, the locking test plant is set up and passed validation. Finally, at the low temperature test stage, the frequency of the IMP-HWR010 superconducting cavity is locked by the test plant. The frequency change with helium pressure of the cavity is about 0.73 Hz/Pa.
The main issue of this paper is to introduce the application of phase lock loop (PLL) in superconducting RF technology. The voltage-controlled oscillator phase lock loop (VCO-PLL) can be used for locking the eigen frequency of the superconducting cavity. It can keep superconducting cavity resonant stably. In thispaper, the principle of the cavity locking by the VCO-PLL is verified by a simulation, which is done by using NI-Labview software. The simulation result shows that the different gain of the PLL system can impact the locking situation of the whole system. In the test stage, the locking test plant is set up and passed validation. Finally, at the low temperature test stage, the frequency of the IMP-HWR010 superconducting cavity is locked by the test plant. The frequency change with helium pressure of the cavity is about 0.73 Hz/Pa.
2014, 31(2): 156-160.
doi: 10.11804/NuclPhysRev.31.02.156
Abstract:
According to the requirements of ADS project for superconducting magnet power supply system,a controller with high stability for superconducting magnet power supply system is designed, and it mainly consists of optical ber module, digital to analog converter (DAC) and analog to digital converter (ADC) circuit. The DAC based on digitally controlled potentiometer (DCP) and eld rogrammable gate array (FPGA) can achieve high stability control of superconducting magnet power supply, and the value of current can be given by the DAC. The output stability of this DAC can be more than 2x105, which can fully meet the requirement of 5x105 for superconducting magnet power supply. The test data of the system is given, which veri ed the rationality and reliability of this design.
According to the requirements of ADS project for superconducting magnet power supply system,a controller with high stability for superconducting magnet power supply system is designed, and it mainly consists of optical ber module, digital to analog converter (DAC) and analog to digital converter (ADC) circuit. The DAC based on digitally controlled potentiometer (DCP) and eld rogrammable gate array (FPGA) can achieve high stability control of superconducting magnet power supply, and the value of current can be given by the DAC. The output stability of this DAC can be more than 2x105, which can fully meet the requirement of 5x105 for superconducting magnet power supply. The test data of the system is given, which veri ed the rationality and reliability of this design.
2014, 31(2): 161-165.
doi: 10.11804/NuclPhysRev.31.02.161
Abstract:
In order to get experiences of design, tuning and running of a four-vane RFQ for theChina ADS project, a one-meter four-vane RFQ was designed and fabricated. The quadruple frequency of the RFQ was designed to be 162.5 MHz (operating frequency), but the measured frequency after fabrication was 163.7 MHz even without tuners in the cavity. To reduce the frequency the four-wire line model theory was used, and the endplates were redesigned. Dipole mode stabilizer rods were employed to expand the span of the quadruple frequency and the adjacent dipole frequency. As a result, the quadruple frequency was altered to the operating frequency without rippling voltage distribution along the RFQ severely. Meanwhile, the Q value was reduced by 1%, which means more RF power was required to be fed into the RFQ. The dipole mode stabilizer rods were cooled by water to make the RFQ work stably.
In order to get experiences of design, tuning and running of a four-vane RFQ for theChina ADS project, a one-meter four-vane RFQ was designed and fabricated. The quadruple frequency of the RFQ was designed to be 162.5 MHz (operating frequency), but the measured frequency after fabrication was 163.7 MHz even without tuners in the cavity. To reduce the frequency the four-wire line model theory was used, and the endplates were redesigned. Dipole mode stabilizer rods were employed to expand the span of the quadruple frequency and the adjacent dipole frequency. As a result, the quadruple frequency was altered to the operating frequency without rippling voltage distribution along the RFQ severely. Meanwhile, the Q value was reduced by 1%, which means more RF power was required to be fed into the RFQ. The dipole mode stabilizer rods were cooled by water to make the RFQ work stably.
2014, 31(2): 166-169.
doi: 10.11804/NuclPhysRev.31.02.166
Abstract:
Due to the difficulties of the Coulomb barrier and electron screening potential in directly measuring the cross sections of nuclear reaction for low-energy charged particle, Trojan-horse method based onquasi-free reaction was paidspecialattention. For the first time the Geant4 simulation is used for the indirect measurement of Trojan-horse method in the indirect measurment of two-body reaction 9Be+1H->8Be+2H by three-body reaction 9Be+2H->8Be+2H+n in Tandem accelerator of China Institute of Atomic Energy. The stability and reliability of the simulation system are examined by comparing the experimental data and simulated results, the simulation can provide useful comments for the design and improvements of future experiments.
Due to the difficulties of the Coulomb barrier and electron screening potential in directly measuring the cross sections of nuclear reaction for low-energy charged particle, Trojan-horse method based onquasi-free reaction was paidspecialattention. For the first time the Geant4 simulation is used for the indirect measurement of Trojan-horse method in the indirect measurment of two-body reaction 9Be+1H->8Be+2H by three-body reaction 9Be+2H->8Be+2H+n in Tandem accelerator of China Institute of Atomic Energy. The stability and reliability of the simulation system are examined by comparing the experimental data and simulated results, the simulation can provide useful comments for the design and improvements of future experiments.
2014, 31(2): 170-176.
doi: 10.11804/NuclPhysRev.31.02.170
Abstract:
The material research center in Institute of Modern Physics, Chinese Academy of Sciences (IMP,CAS) have made a fruitful achievements in the research of single event effects(SEEs) occurring in static random access memory (SRAM). However, there are some drawbacks exist in the two systems of detecting SEE owning by the material research center. Therefore, an improved method of detecting SEE is proposed, and the method functionality is implemented in a circuit. Further, a sequence of experiments are carried out in the beam radiation terminal of the Heavy Ion Facility in Lanzhou (HIRFL), and a bunch of experimental data are collected. The irradiation tests were carried out using 129Xe for the SEE research of 65 nm SRAMs; Using 12C for the SEE research of the 65, 130 and 150 nm SRAMs with ECC module; Using 129Xe for the SEL research of the common commercial SRAMs and so on. These experiments provide a statistical evidence of the effectiveness and robustness of the improved system. It is believed that the proposed system will be beneficial for detecting SEE in diverse settings, and it could be taken advantage of as a platform for future research on SEE tests in more intricate devices.
The material research center in Institute of Modern Physics, Chinese Academy of Sciences (IMP,CAS) have made a fruitful achievements in the research of single event effects(SEEs) occurring in static random access memory (SRAM). However, there are some drawbacks exist in the two systems of detecting SEE owning by the material research center. Therefore, an improved method of detecting SEE is proposed, and the method functionality is implemented in a circuit. Further, a sequence of experiments are carried out in the beam radiation terminal of the Heavy Ion Facility in Lanzhou (HIRFL), and a bunch of experimental data are collected. The irradiation tests were carried out using 129Xe for the SEE research of 65 nm SRAMs; Using 12C for the SEE research of the 65, 130 and 150 nm SRAMs with ECC module; Using 129Xe for the SEL research of the common commercial SRAMs and so on. These experiments provide a statistical evidence of the effectiveness and robustness of the improved system. It is believed that the proposed system will be beneficial for detecting SEE in diverse settings, and it could be taken advantage of as a platform for future research on SEE tests in more intricate devices.
2014, 31(2): 177-182.
doi: 10.11804/NuclPhysRev.31.02.177
Abstract:
The double pulse method was applied to study the pulse linear current property of R3809U-52 type MCP-PMT (micro-channel plate photo-multiplier tube) from amamatsu Photonics Co.Ltd. When the FWHM of pulse are 20 and 100 ns, the pulse linear currents are 150 and 25 mA, respectively. According to the experiments results, we deduced the functions of pluses' FWHM lower than 100 ns with linear current, which extends the range of parameters available.
The double pulse method was applied to study the pulse linear current property of R3809U-52 type MCP-PMT (micro-channel plate photo-multiplier tube) from amamatsu Photonics Co.Ltd. When the FWHM of pulse are 20 and 100 ns, the pulse linear currents are 150 and 25 mA, respectively. According to the experiments results, we deduced the functions of pluses' FWHM lower than 100 ns with linear current, which extends the range of parameters available.
2014, 31(2): 183-188.
doi: 10.11804/NuclPhysRev.31.02.183
Abstract:
Using the Lomb-Scargle period grams and temporal variation folded into one period for statistical analysis, the radon concentration in the ARGO-YBJ experiment hall from Aug. 2009 through Apr. 2011 was investigated. Our results show that the radon concentration has main periods of half-day and 1-day with the period of 1 day being dominant. In one day the radon concentration reaches its peak at 11:20 (Beijing Time) and reaches the minimum at 23:20(Beijing Time). In one year, the radon concentration is lower in June, the monthly variation amplitudes and initial phases folded into one day are various. These results are of importance to the study of variation of radon concentration and theoretical models, and provide a good chance to estimate the living environment in Tibet.
Using the Lomb-Scargle period grams and temporal variation folded into one period for statistical analysis, the radon concentration in the ARGO-YBJ experiment hall from Aug. 2009 through Apr. 2011 was investigated. Our results show that the radon concentration has main periods of half-day and 1-day with the period of 1 day being dominant. In one day the radon concentration reaches its peak at 11:20 (Beijing Time) and reaches the minimum at 23:20(Beijing Time). In one year, the radon concentration is lower in June, the monthly variation amplitudes and initial phases folded into one day are various. These results are of importance to the study of variation of radon concentration and theoretical models, and provide a good chance to estimate the living environment in Tibet.
2014, 31(2): 189-194.
doi: 10.11804/NuclPhysRev.31.02.189
Abstract:
As the first layer of engineering barriers, glass will be irradiated by electron in the long-term disposal of high level radioactive waste (HLW). It is significant to study the electron irradiation effects of glass for the safe disposal of HLW. In this paper, the effects induced by electron irradiation were studied in situ by transmission electron microscope (TEM). Under electron beam, the phase separation occurred very soon in both glasses, which was correlated to the network relaxation processes as a consequence of diffusion and desorption of sodium species during electron irradiation. A simple structural model was introduced to explain the difference in separated phase in two different glasses, which indicates that the phase separation induced by electron irradiation is closely related to the sodium contents in the glass sample.
As the first layer of engineering barriers, glass will be irradiated by electron in the long-term disposal of high level radioactive waste (HLW). It is significant to study the electron irradiation effects of glass for the safe disposal of HLW. In this paper, the effects induced by electron irradiation were studied in situ by transmission electron microscope (TEM). Under electron beam, the phase separation occurred very soon in both glasses, which was correlated to the network relaxation processes as a consequence of diffusion and desorption of sodium species during electron irradiation. A simple structural model was introduced to explain the difference in separated phase in two different glasses, which indicates that the phase separation induced by electron irradiation is closely related to the sodium contents in the glass sample.
2014, 31(2): 195-200.
doi: 10.11804/NuclPhysRev.31.02.195
Abstract:
Heavy ion experimental results reveal that the ratio of multiple-bit upset (MBU) in static random access memory (SRAM) increases for ions with higher linear energy transfer (LET) value or at larger angle of incidence, even exceeds the ratio of single-bit upset. The diffusion distance of charges in single ion track can be several micrometers. The MBU patterns of device under test are influenced by both the anisotropic distribution of sensitive volumes and the track direction. Horizontal configuration turns out to be the predominant double-bit upset pattern due to the vertical isolation (bit-line contacts) of adjacent sensitive volumes. L-shaped and squareshaped configurations are the main triple-bit upset and quadruple-bit upset patterns, respectively. Finally,implications for MBU hardness strategies and evaluation methods are discussed.
Heavy ion experimental results reveal that the ratio of multiple-bit upset (MBU) in static random access memory (SRAM) increases for ions with higher linear energy transfer (LET) value or at larger angle of incidence, even exceeds the ratio of single-bit upset. The diffusion distance of charges in single ion track can be several micrometers. The MBU patterns of device under test are influenced by both the anisotropic distribution of sensitive volumes and the track direction. Horizontal configuration turns out to be the predominant double-bit upset pattern due to the vertical isolation (bit-line contacts) of adjacent sensitive volumes. L-shaped and squareshaped configurations are the main triple-bit upset and quadruple-bit upset patterns, respectively. Finally,implications for MBU hardness strategies and evaluation methods are discussed.
2014, 31(2): 201-209.
doi: 10.11804/NuclPhysRev.31.02.201
Abstract:
Cellular senescence played double roles in the genesis and development of cancer, which was put forward through reviewing the cases and characteristics of cellular senescence. In addition, human uveal melanoma cells and human fetal lung broblast (MRC5) cells were irradiated by X-rays or 12C6+ ion beam. DNA damage response (DDR) and cellular senescence were analyzed. The results showed that DDR was activated persistently by the unrepairable clustered DNA damage, which indicated that inducing same ratios of cellular senescence needed lower doses of 12C6+ ion beam than X-rays. Furthermore, both 92-1 cells and MRC5 cells treated by carbon ion beam underwent cellular senescence. These results pointed out the urgency to investigate the mechanism of cellular senescence induced by 12C6+ ion beam.
Cellular senescence played double roles in the genesis and development of cancer, which was put forward through reviewing the cases and characteristics of cellular senescence. In addition, human uveal melanoma cells and human fetal lung broblast (MRC5) cells were irradiated by X-rays or 12C6+ ion beam. DNA damage response (DDR) and cellular senescence were analyzed. The results showed that DDR was activated persistently by the unrepairable clustered DNA damage, which indicated that inducing same ratios of cellular senescence needed lower doses of 12C6+ ion beam than X-rays. Furthermore, both 92-1 cells and MRC5 cells treated by carbon ion beam underwent cellular senescence. These results pointed out the urgency to investigate the mechanism of cellular senescence induced by 12C6+ ion beam.
2014, 31(2): 210-217.
doi: 10.11804/NuclPhysRev.31.02.210
Abstract:
The cell damage yield was simulated to investigate the micro-damage mechanism of the contaminative electron to the skin cell in external radiotherapy. The physical interaction and the energy deposited events of contaminative electrons in the cell DNA were modeled based on Geant4-DNA low energy physical model. The density-based cluster mining algorithm was used to analyze the micro-damage yield and obtain its detailed compositive information. By taking the irradiation sensitive parameter and the clinical feature dose threshold of the skin cell into consideration, the damage features of the low energy contaminative electron to the skin cell were studied. The DSB and SSB yield and ratio, the cluster size and the root mean square radius,the cell SF and the lethal coefficient ε of the complex cDSB were researched. The results show that there is about 20% cDSB in the DSB yield, the other is DSB. And the yield of DSB is about 4% of that of the SSB.Generally the cluster size includes less than 3 SSBs, in which 1 or 2 SSBs cluster size is more than 99%and >3 SSBs cluster size is less than 1%. However, for some very low energy electrons such as 20 keV and 100 keV,the cluster size can be more than 5 SSBs. The irradiation protection will be more crucial for the later response and the high tissue. The lethal coefficient " of the complex cDSB will increase with the incident electron number and the accumulative dose increasing for the dose square term in LQ model. If assuming α=0.3 Gy-1 and α/β =10 Gy, the " increment is less than 1% when the incident electron increases up to 103. However, the ε increment will increase 3% s 15% (e.g. 13.8% for 30 keV and 3.4% for 200 keV electrons) when the incident electron increases up to 105. The simulation of the direct physical damage of the cell can be adjusted by a probability parameter to offset the simulation of the indirect biochemical damage. Thus the micro-damage mechanism of the contaminative electron to the skin cell can be detected at a certain extent by Monte Carlo physical simulation. This damage model of the low energy electron to DNA and these simulated results could be used to evaluate the damage effect of the low energy contaminative electron to the skin cells in the external radiotherapy.
The cell damage yield was simulated to investigate the micro-damage mechanism of the contaminative electron to the skin cell in external radiotherapy. The physical interaction and the energy deposited events of contaminative electrons in the cell DNA were modeled based on Geant4-DNA low energy physical model. The density-based cluster mining algorithm was used to analyze the micro-damage yield and obtain its detailed compositive information. By taking the irradiation sensitive parameter and the clinical feature dose threshold of the skin cell into consideration, the damage features of the low energy contaminative electron to the skin cell were studied. The DSB and SSB yield and ratio, the cluster size and the root mean square radius,the cell SF and the lethal coefficient ε of the complex cDSB were researched. The results show that there is about 20% cDSB in the DSB yield, the other is DSB. And the yield of DSB is about 4% of that of the SSB.Generally the cluster size includes less than 3 SSBs, in which 1 or 2 SSBs cluster size is more than 99%and >3 SSBs cluster size is less than 1%. However, for some very low energy electrons such as 20 keV and 100 keV,the cluster size can be more than 5 SSBs. The irradiation protection will be more crucial for the later response and the high tissue. The lethal coefficient " of the complex cDSB will increase with the incident electron number and the accumulative dose increasing for the dose square term in LQ model. If assuming α=0.3 Gy-1 and α/β =10 Gy, the " increment is less than 1% when the incident electron increases up to 103. However, the ε increment will increase 3% s 15% (e.g. 13.8% for 30 keV and 3.4% for 200 keV electrons) when the incident electron increases up to 105. The simulation of the direct physical damage of the cell can be adjusted by a probability parameter to offset the simulation of the indirect biochemical damage. Thus the micro-damage mechanism of the contaminative electron to the skin cell can be detected at a certain extent by Monte Carlo physical simulation. This damage model of the low energy electron to DNA and these simulated results could be used to evaluate the damage effect of the low energy contaminative electron to the skin cells in the external radiotherapy.
2014, 31(2): 218-223.
doi: 10.11804/NuclPhysRev.31.02.218
Abstract:
Electron beams were employed to irradiate liquor samples in various doses to study aging effects.Five samples which had been stored for 1, 2, 4, 6, 8 years were exposed to 500, 750, 1 000, 1 250, and 1 500 Gy doses of electron beams (1.5 MeV/u). After irradiation, liquor samples were scanned spectrophotometrically from 200 nm to 400 nm. According to the difference of the UV spectra, the spectral curve similarities from 280 nm to 300 nm and the change regulations were analyzed. The results showed that the less spectral curve similarities between control samples and irradiation samples were, the better the aging effects of liquor were;The longer the liquor were stored, the lower doses were required to reach the optimum aging effect. For eight year stored liquor, the dynamic balance of liquor system was broken and the monomer material increased when the doses were more than 750 Gy, which implied the retrogradation of liquor aging phenomena were clear. In conclusion, the electron beam irradiation has significant aging effect on short year Luzhou-flavor liquor and is an effective method for aging liquor.
Electron beams were employed to irradiate liquor samples in various doses to study aging effects.Five samples which had been stored for 1, 2, 4, 6, 8 years were exposed to 500, 750, 1 000, 1 250, and 1 500 Gy doses of electron beams (1.5 MeV/u). After irradiation, liquor samples were scanned spectrophotometrically from 200 nm to 400 nm. According to the difference of the UV spectra, the spectral curve similarities from 280 nm to 300 nm and the change regulations were analyzed. The results showed that the less spectral curve similarities between control samples and irradiation samples were, the better the aging effects of liquor were;The longer the liquor were stored, the lower doses were required to reach the optimum aging effect. For eight year stored liquor, the dynamic balance of liquor system was broken and the monomer material increased when the doses were more than 750 Gy, which implied the retrogradation of liquor aging phenomena were clear. In conclusion, the electron beam irradiation has significant aging effect on short year Luzhou-flavor liquor and is an effective method for aging liquor.
2014, 31(2): 224-228.
doi: 10.11804/NuclPhysRev.31.02.224
Abstract:
We borrow the concept of virtual state to characterize the strong interacting feature of the two transferred electrons in slow highly charged ions with helium collisions. Consequently, a potential parameter ! is de ned to distinguish the collision systems and to scale the double-electron transfer processes. The Q-value is taken into account according to the classical over-the-barrier model. Comparing with our previous experimental data, it is clearly shown that the true double capture or the autoionizing double capture dominates when ω>1 or ω> 2, respectively. We clarify that the distinction of the collision systems is essentially the ratio between the average excitation energy and the average binding energy of the two transferred electrons at the scattered ion.
We borrow the concept of virtual state to characterize the strong interacting feature of the two transferred electrons in slow highly charged ions with helium collisions. Consequently, a potential parameter ! is de ned to distinguish the collision systems and to scale the double-electron transfer processes. The Q-value is taken into account according to the classical over-the-barrier model. Comparing with our previous experimental data, it is clearly shown that the true double capture or the autoionizing double capture dominates when ω>1 or ω> 2, respectively. We clarify that the distinction of the collision systems is essentially the ratio between the average excitation energy and the average binding energy of the two transferred electrons at the scattered ion.
2014, 31(2): 229-234.
doi: 10.11804/NuclPhysRev.31.02.229
Abstract:
Distribution of charge state for O5+ ions penetrating the H2 gas targets with a certain length and different atomicity densities was measured. Both the average charge state and the equilibrium average charge state were calculated by a computer program, and that agrees well with the experimental data. The results indicate that the electron capture cross section is increased during the collisions, and the charge state is reduced with the increasing target atomicity density. When the atomicity density reaches the order of 1014 cm-3, there is balance between the electron capture and ionization of the incident ions, as a result, the projectile achieves the equilibrium average charge state of 1.2.
Distribution of charge state for O5+ ions penetrating the H2 gas targets with a certain length and different atomicity densities was measured. Both the average charge state and the equilibrium average charge state were calculated by a computer program, and that agrees well with the experimental data. The results indicate that the electron capture cross section is increased during the collisions, and the charge state is reduced with the increasing target atomicity density. When the atomicity density reaches the order of 1014 cm-3, there is balance between the electron capture and ionization of the incident ions, as a result, the projectile achieves the equilibrium average charge state of 1.2.
2014, 31(2): 235-241.
doi: 10.11804/NuclPhysRev.31.02.235
Abstract:
A detailed design of the liquid Pb-Bi spallation target of the Accelerator Driven Systems (ADS) requires powerful and reliable computational tools that can accurately predict particles and nuclides production by the proton induced spallation reactions in the energy range of a few GeV. In this paper, the neutron production double-differential cross sections for Pb and Bi target materials at incident proton kinetic energies between 800 MeV and 3 GeV are studied by calculations with Monte Carlo simulation package Geant4. The simulated results of Geant4 with several physics models are compared with available experimental data. The simulated results generated by QGSP BERT and QGSP INCL ABLA physics models of Geant4 well reproduce the available experimental data. The present results validated that Geant4 Monte Carlo simulation package is suitable for simulations of neutron production double-differential cross sections of proton induced reaction on Pb and Bi targets in the incident energy range up to 3 GeV.
A detailed design of the liquid Pb-Bi spallation target of the Accelerator Driven Systems (ADS) requires powerful and reliable computational tools that can accurately predict particles and nuclides production by the proton induced spallation reactions in the energy range of a few GeV. In this paper, the neutron production double-differential cross sections for Pb and Bi target materials at incident proton kinetic energies between 800 MeV and 3 GeV are studied by calculations with Monte Carlo simulation package Geant4. The simulated results of Geant4 with several physics models are compared with available experimental data. The simulated results generated by QGSP BERT and QGSP INCL ABLA physics models of Geant4 well reproduce the available experimental data. The present results validated that Geant4 Monte Carlo simulation package is suitable for simulations of neutron production double-differential cross sections of proton induced reaction on Pb and Bi targets in the incident energy range up to 3 GeV.
2014, 31(2): 242-247.
doi: 10.11804/NuclPhysRev.31.02.242
Abstract:
Based on the experimental data of non-elastic and elastic scattering istributions for p+48V,p+51V and p+52Cr reactions, a set of optical potential parameters for p+52Cr reaction with incident proton energies below 150 MeV are obtained. All cross sections, elastic and inelastic scattering angular distributions,energy spectra and double differential cross sections of six outgoing particles (n, p, d, t, helium-3 and ) for p+52Cr reaction are calculated and analyzed. The optical model, the intra-nuclear cascade model, evaporation model, Hauser-Feshbach theory with width fluctuation correction, exciton model including the improved Iwamoto–Harada model and distorted wave Born approximation theory are involved in the calculation. The calculated results are compared with existing experimental data and the evaluated data from TENDL data base.It is found that our calculated results agree with the experimental data and the calculated cross sections are more consistent with the related experimental data than the results from TENDL data base.
Based on the experimental data of non-elastic and elastic scattering istributions for p+48V,p+51V and p+52Cr reactions, a set of optical potential parameters for p+52Cr reaction with incident proton energies below 150 MeV are obtained. All cross sections, elastic and inelastic scattering angular distributions,energy spectra and double differential cross sections of six outgoing particles (n, p, d, t, helium-3 and ) for p+52Cr reaction are calculated and analyzed. The optical model, the intra-nuclear cascade model, evaporation model, Hauser-Feshbach theory with width fluctuation correction, exciton model including the improved Iwamoto–Harada model and distorted wave Born approximation theory are involved in the calculation. The calculated results are compared with existing experimental data and the evaluated data from TENDL data base.It is found that our calculated results agree with the experimental data and the calculated cross sections are more consistent with the related experimental data than the results from TENDL data base.
2014, 31(2): 248-252.
doi: 10.11804/NuclPhysRev.31.02.248
Abstract:
Z-Pinch Inertial confinement fusion is a competitive candidate for future energy solution. A fusion-fission hybrid driven by Z-Pinch can be used to transmute transuranic elements from spent fuels of reactors efficiently. Analysis and numerical simulation of blanket neutronics of In-Zinerater, which is a fusionfission hybrid concept design in Sandia National Laboratories, is given in this paper. Modification to the three dimension transport and burnup code MCORGS are done, so as to simulate continuous feeding and continuous chemical processing of the liquid fuel. Different combination of initial enrichment of 6Li and fuels loading in the blanket are selected to keep the same reactivity at begin of core. By this way, the decreasing trend of reactivity at life of the core can be lowered. The reactivity can be maintained constant by increasing the fuel loading in the core gradually as the burnup deepens. Given a 20 MW fusion power, by reactivity control, the blanket energy multiplication is around 160 ~ 180 and tritium breed ratio 1.5 ~1.7 in 5 years, which is a better result
than Sandia’s original design.
Z-Pinch Inertial confinement fusion is a competitive candidate for future energy solution. A fusion-fission hybrid driven by Z-Pinch can be used to transmute transuranic elements from spent fuels of reactors efficiently. Analysis and numerical simulation of blanket neutronics of In-Zinerater, which is a fusionfission hybrid concept design in Sandia National Laboratories, is given in this paper. Modification to the three dimension transport and burnup code MCORGS are done, so as to simulate continuous feeding and continuous chemical processing of the liquid fuel. Different combination of initial enrichment of 6Li and fuels loading in the blanket are selected to keep the same reactivity at begin of core. By this way, the decreasing trend of reactivity at life of the core can be lowered. The reactivity can be maintained constant by increasing the fuel loading in the core gradually as the burnup deepens. Given a 20 MW fusion power, by reactivity control, the blanket energy multiplication is around 160 ~ 180 and tritium breed ratio 1.5 ~1.7 in 5 years, which is a better result
than Sandia’s original design.
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