2014 Vol. 31, No. 1
Display Method:
2014, 31(1): 1-7.
doi: 10.11804/NuclPhysRev.31.01.001
Abstract:
The neck variable plays a key role in the dynamical processes of nuclear fusion or fission. Generally speaking, the definition for this variable is different for various parameterizations describing macroscopic nuclear shapes. In order to investigate the effects of increased neck in nuclear fusion, we extend the dumbbell parameterization by taking deformations of both the target and projectile into account. The potential energy surface (PES) with different shapes of nuclei is calculated, as well as the inertia mass and friction tensors. These calculations lay the foundation for Langevin dynamics. Analysis of the results shows that the neck variable in the proposed five-parameter dumbbell model is an unstable degree of freedom and play an important role in nuclear fusion.
The neck variable plays a key role in the dynamical processes of nuclear fusion or fission. Generally speaking, the definition for this variable is different for various parameterizations describing macroscopic nuclear shapes. In order to investigate the effects of increased neck in nuclear fusion, we extend the dumbbell parameterization by taking deformations of both the target and projectile into account. The potential energy surface (PES) with different shapes of nuclei is calculated, as well as the inertia mass and friction tensors. These calculations lay the foundation for Langevin dynamics. Analysis of the results shows that the neck variable in the proposed five-parameter dumbbell model is an unstable degree of freedom and play an important role in nuclear fusion.
2014, 31(1): 8-13.
doi: 10.11804/NuclPhysRev.31.01.008
Abstract:
In a p+p collision, there are only two leading particles. One is in projectile fragmentation region,the other is in target fragmentation region. The investigation of present paper shows that, just like in nucleus-nucleus collisions, the revised Landau hydrodynamic model alone is not enough to have a good description to the measured pseudorapidity distributions of charged particles in p+p collisions. Only after the leading particles are taken into account as well, can the experimental data be matched up properly. The theoretical model works well in p+p collisions in the whole available energy region from ps=23.6 to 900 GeV.
In a p+p collision, there are only two leading particles. One is in projectile fragmentation region,the other is in target fragmentation region. The investigation of present paper shows that, just like in nucleus-nucleus collisions, the revised Landau hydrodynamic model alone is not enough to have a good description to the measured pseudorapidity distributions of charged particles in p+p collisions. Only after the leading particles are taken into account as well, can the experimental data be matched up properly. The theoretical model works well in p+p collisions in the whole available energy region from ps=23.6 to 900 GeV.
2014, 31(1): 14-18.
doi: 10.11804/NuclPhysRev.31.01.014
Abstract:
By taking into account the effects of shadowing and jet quenching, the production of high-pT kaon and pion originating from photoproduction processes in pp and PbPb collisions is calculated based on perturbative quantum chromodynamics(pQCD). The enhancement of K+/π+ is found in photoproduction processes. The numerical results indicate that the photoproduction processes considering in our calculation are a good modification for kaon and pion production.
By taking into account the effects of shadowing and jet quenching, the production of high-pT kaon and pion originating from photoproduction processes in pp and PbPb collisions is calculated based on perturbative quantum chromodynamics(pQCD). The enhancement of K+/π+ is found in photoproduction processes. The numerical results indicate that the photoproduction processes considering in our calculation are a good modification for kaon and pion production.
2014, 31(1): 19-22.
doi: 10.11804/NuclPhysRev.31.01.019
Abstract:
Within non-relativistic framework and using deuteron wave function produced by the Paris potential which is designed just for describing nuclear process at high momentum transfers, we calculate deuteron electromagnetic form factor A(Q2) which is formulized as a product of the deuteron structure function Z(t) and dipole form factor GD(t). The structure function Z(t) is obtained numerically from the Paris potential wave function calculations. Our theoretical prediction for A(Q2) is in a good agreement with experimental data available. This successful t to data shows that the simple theoretical description of deuteron form factors A(Q2) works quite well, and could be applied to studying other static properties of deuteron.
Within non-relativistic framework and using deuteron wave function produced by the Paris potential which is designed just for describing nuclear process at high momentum transfers, we calculate deuteron electromagnetic form factor A(Q2) which is formulized as a product of the deuteron structure function Z(t) and dipole form factor GD(t). The structure function Z(t) is obtained numerically from the Paris potential wave function calculations. Our theoretical prediction for A(Q2) is in a good agreement with experimental data available. This successful t to data shows that the simple theoretical description of deuteron form factors A(Q2) works quite well, and could be applied to studying other static properties of deuteron.
2014, 31(1): 23-31.
doi: 10.11804/NuclPhysRev.31.01.023
Abstract:
To investigate the mass generating problem without Higgs mechanism we present a model in which a new scalar gauge coupling is naturally introduced. Because of the existence of production and annihilation for particles in quantum eld theory, we extend the number of independent variables from conventional four space-time dimensions to ve ones in order to describe all degrees of freedom for eld functions while the conventional space-time is still retained to be the background. The potential fth variable is nothing but the proper time of particles. In response, a mass operator should be introduced. After that, the lagrangian for free fermion elds in terms of ve independent variables and mass operator is written down. By applying the gauge principle, three kinds of vector
gauge couplings and one kind of scalar gauge coupling are naturally introduced. In the current scenario,the mass spectrum for all fundamental particles is accounted for in principle by solving the eigenvalue of mass operator under the function of all kinds of interactions. Moreover, there no any auxiliary mechanism including spontaneous symmetry breaking get involved in the model. Therefore, traditional problems in the standard model such as the vacuum energy problem are removed from our model, as well as the hierarchy problem on the mass spectrum for fundamental particles.
To investigate the mass generating problem without Higgs mechanism we present a model in which a new scalar gauge coupling is naturally introduced. Because of the existence of production and annihilation for particles in quantum eld theory, we extend the number of independent variables from conventional four space-time dimensions to ve ones in order to describe all degrees of freedom for eld functions while the conventional space-time is still retained to be the background. The potential fth variable is nothing but the proper time of particles. In response, a mass operator should be introduced. After that, the lagrangian for free fermion elds in terms of ve independent variables and mass operator is written down. By applying the gauge principle, three kinds of vector
gauge couplings and one kind of scalar gauge coupling are naturally introduced. In the current scenario,the mass spectrum for all fundamental particles is accounted for in principle by solving the eigenvalue of mass operator under the function of all kinds of interactions. Moreover, there no any auxiliary mechanism including spontaneous symmetry breaking get involved in the model. Therefore, traditional problems in the standard model such as the vacuum energy problem are removed from our model, as well as the hierarchy problem on the mass spectrum for fundamental particles.
2014, 31(1): 32-36.
doi: 10.11804/NuclPhysRev.31.01.032
Abstract:
A compact FFAG accelerator for Boron Neutron Capture Therapy (BNCT) has been designed.Firstly, a linear simpli ed magnet model has been applied to calculate the basic parameters of FFAG accelerator; Then the WINAGILE program is used to design and optimize the lattice, as well as to obtain the critical parameters such as the Beta functions, the dispersion functions, the envelopes and the tunes; Also, the MAD program is used to check the design scheme; Finally, the ZGOUBI program is used to simulate the particles movement in the nonlinear magnetic eld. The super period of the FFAG accelerator is 6. The energy is 11 MeV and the eld index k is 1.9. The structure is compact with the circumference of 11.179 5 m. The results show that this optimized design has achieved the proposal object.
A compact FFAG accelerator for Boron Neutron Capture Therapy (BNCT) has been designed.Firstly, a linear simpli ed magnet model has been applied to calculate the basic parameters of FFAG accelerator; Then the WINAGILE program is used to design and optimize the lattice, as well as to obtain the critical parameters such as the Beta functions, the dispersion functions, the envelopes and the tunes; Also, the MAD program is used to check the design scheme; Finally, the ZGOUBI program is used to simulate the particles movement in the nonlinear magnetic eld. The super period of the FFAG accelerator is 6. The energy is 11 MeV and the eld index k is 1.9. The structure is compact with the circumference of 11.179 5 m. The results show that this optimized design has achieved the proposal object.
2014, 31(1): 37-42.
doi: 10.11804/NuclPhysRev.31.01.037
Abstract:
The electromagnetic optimizations of a superconducting Spoke021 cavity is studied in detail for C-ADS project, in this paper. The cavity model has been parameterized, in order to find the possible maxima or minima of the key electro-magnetic parameters, the parameter sweep is performed. The cavity model has been parameterized. For finding the key electromagnetic feature, the geometric parameter sweep is performed. The physical interpretation for the variation of these electromagnetic parameters has been elaborated. The electromagnetic simulation gives the optimum parameters Ep/Eacc of 3.14 and Bp/Eacc of 4.77 mT/(MV/m).In addition, the Multipacting(MP) has a great effect on the electromagnetic properties of superconducting Spoke021 cavity. So the MP simulations have been done for this cavity, which shows that there is no MP
phenomenon at 10 MV/m accelerator gradient. Therefore, the optimized cavity parameters can satisfy the requirements of the C-ADS project. Finally, the TTF(Transit Time Factor) curve of this cavity is calculated and it shows that this cavity has wide velocity acceptance.
The electromagnetic optimizations of a superconducting Spoke021 cavity is studied in detail for C-ADS project, in this paper. The cavity model has been parameterized, in order to find the possible maxima or minima of the key electro-magnetic parameters, the parameter sweep is performed. The cavity model has been parameterized. For finding the key electromagnetic feature, the geometric parameter sweep is performed. The physical interpretation for the variation of these electromagnetic parameters has been elaborated. The electromagnetic simulation gives the optimum parameters Ep/Eacc of 3.14 and Bp/Eacc of 4.77 mT/(MV/m).In addition, the Multipacting(MP) has a great effect on the electromagnetic properties of superconducting Spoke021 cavity. So the MP simulations have been done for this cavity, which shows that there is no MP
phenomenon at 10 MV/m accelerator gradient. Therefore, the optimized cavity parameters can satisfy the requirements of the C-ADS project. Finally, the TTF(Transit Time Factor) curve of this cavity is calculated and it shows that this cavity has wide velocity acceptance.
2014, 31(1): 43-47.
doi: 10.11804/NuclPhysRev.31.01.043
Abstract:
Based on the technology of the DG series electron accelerator, a 500 kV/150 mA electron accelerator was designed and manufactured at IMP(Institute of Modern Physics, Chinese Academy of Sciences). The new structure of high voltage and shorter accelerating tube have been used in this accelerator for high current. The specific features of this accelerator are compact of structure and higher power conversion efficiency. It has already passed the running test of 500 kV/170 mA, and the parameter is better than the designed value.
Based on the technology of the DG series electron accelerator, a 500 kV/150 mA electron accelerator was designed and manufactured at IMP(Institute of Modern Physics, Chinese Academy of Sciences). The new structure of high voltage and shorter accelerating tube have been used in this accelerator for high current. The specific features of this accelerator are compact of structure and higher power conversion efficiency. It has already passed the running test of 500 kV/170 mA, and the parameter is better than the designed value.
2014, 31(1): 48-52.
doi: 10.11804/NuclPhysRev.31.01.048
Abstract:
In view of the complexity environment and the urgent need of eld fault diagnosis for Heavy Ion Research Facility in Lanzhou-Cooling Storage Ring(HIRFL-CSR), the detection alarm circuit for equipment fault is designed by using TI's MSP430 mixed signal processor, and using negative feedback to the stability of the circuit, and combining with RS-485 eld bus technology. The hardware system is introduced mainly in this paper, including the constitution and the working principle of the system, the function of the controller, the design of hardware and software. The circuit have the characteristics of fast response, high accuracy, good stability, high reliability, strong adaptability and ascendant quality-to-cost, etc. It can be widely used in the elds of switch quantity diagnosis and alarm system. It has been successfully used in the leakage detection alarm system of HIRFL-CSR.
In view of the complexity environment and the urgent need of eld fault diagnosis for Heavy Ion Research Facility in Lanzhou-Cooling Storage Ring(HIRFL-CSR), the detection alarm circuit for equipment fault is designed by using TI's MSP430 mixed signal processor, and using negative feedback to the stability of the circuit, and combining with RS-485 eld bus technology. The hardware system is introduced mainly in this paper, including the constitution and the working principle of the system, the function of the controller, the design of hardware and software. The circuit have the characteristics of fast response, high accuracy, good stability, high reliability, strong adaptability and ascendant quality-to-cost, etc. It can be widely used in the elds of switch quantity diagnosis and alarm system. It has been successfully used in the leakage detection alarm system of HIRFL-CSR.
2014, 31(1): 53-57.
doi: 10.11804/NuclPhysRev.31.01.053
Abstract:
In a typical nuclear elastic scattering experiment, differential cross section is very sensitive to the scattered angle and therefore the main source of systematic errors come from a millimetric uncertainties in the position measurement of detectors. A method for detector misalignment correction has been successfully applied to the elastic scattering of 7Be on Pb target at Elab=17.9 MeV/u at Radioactive Ion Beam Line in Lanzhou (RIBLL) at Heavy Ion Research Facility in Lanzhou (HIRFL). The correction method is based on the fact that the ratio of elastic scattering and Rutherford cross sections should be independent of scattering angle, and equal to unity for very forward angles. A Monte Carlo simulation was performed to examine the angular distribution of cross sections for a given shift of detector position.
In a typical nuclear elastic scattering experiment, differential cross section is very sensitive to the scattered angle and therefore the main source of systematic errors come from a millimetric uncertainties in the position measurement of detectors. A method for detector misalignment correction has been successfully applied to the elastic scattering of 7Be on Pb target at Elab=17.9 MeV/u at Radioactive Ion Beam Line in Lanzhou (RIBLL) at Heavy Ion Research Facility in Lanzhou (HIRFL). The correction method is based on the fact that the ratio of elastic scattering and Rutherford cross sections should be independent of scattering angle, and equal to unity for very forward angles. A Monte Carlo simulation was performed to examine the angular distribution of cross sections for a given shift of detector position.
2014, 31(1): 58-62.
doi: 10.11804/NuclPhysRev.31.01.058
Abstract:
The influence of sample volume and cocktail quantity on tritium measurement in liquid scintillation counter (LSC) was investigated experimentally in this paper to optimize the counting conditions. Results indicate that the optimal counting volume is between 7 mL and 17 mL using 22 mL glass vials, which should be mainly attributed to the sensitive character of photon multiplier tubes(PMTs) in LSC. With the obtained optimal volume, we also present the detailed procedure to determine the influence of cocktail quantity, which shows that the ratio of cocktail and sample water should be kept higher than 2.4 to obtain accurate results. In addition, experiments on the influence of light were also performed with pure cocktail and results indicate that 2 h is long enough to eliminate luminescence before counting.
The influence of sample volume and cocktail quantity on tritium measurement in liquid scintillation counter (LSC) was investigated experimentally in this paper to optimize the counting conditions. Results indicate that the optimal counting volume is between 7 mL and 17 mL using 22 mL glass vials, which should be mainly attributed to the sensitive character of photon multiplier tubes(PMTs) in LSC. With the obtained optimal volume, we also present the detailed procedure to determine the influence of cocktail quantity, which shows that the ratio of cocktail and sample water should be kept higher than 2.4 to obtain accurate results. In addition, experiments on the influence of light were also performed with pure cocktail and results indicate that 2 h is long enough to eliminate luminescence before counting.
2014, 31(1): 63-68.
doi: 10.11804/NuclPhysRev.31.01.063
Abstract:
Silicon micro-strip detectors have been widely used in the world-famous nuclear physics laboratories due to their better position resolution and energy resolution. Double-sided silicon micro-strip detectors with a position resolution of 0.5 mm0.5 mm, have been fabricated in the IMP(Institute of Moder Physics,CAS) by using microelectronics technology. These detectors have been used in the ETF (External Target Facility) of HIRFL-CSR, as ΔE detectors of the ΔE-E telescope system and the track detectors. With the help of flexibility printed circuit board (FPCB) and the integrated ASIC chips, a compact multi-channel front-end electronic board has been designed to fulfill the acquisition of the energy and position information of the Silicon micro-strip detectors. It is described in this paper that the build-up of the Silicon micro-strip detector array in ETF of HIRFL-CSR, the determination of the energy resolution of the detector units, and the energy resolution of approximately 1% obtained for 5~9 MeV particles in vacuum.
Silicon micro-strip detectors have been widely used in the world-famous nuclear physics laboratories due to their better position resolution and energy resolution. Double-sided silicon micro-strip detectors with a position resolution of 0.5 mm0.5 mm, have been fabricated in the IMP(Institute of Moder Physics,CAS) by using microelectronics technology. These detectors have been used in the ETF (External Target Facility) of HIRFL-CSR, as ΔE detectors of the ΔE-E telescope system and the track detectors. With the help of flexibility printed circuit board (FPCB) and the integrated ASIC chips, a compact multi-channel front-end electronic board has been designed to fulfill the acquisition of the energy and position information of the Silicon micro-strip detectors. It is described in this paper that the build-up of the Silicon micro-strip detector array in ETF of HIRFL-CSR, the determination of the energy resolution of the detector units, and the energy resolution of approximately 1% obtained for 5~9 MeV particles in vacuum.
2014, 31(1): 69-74.
doi: 10.11804/NuclPhysRev.31.01.069
Abstract:
The performance of a boron-coated GEM (Gas Electron Multiplier) neutron beam monitor is outstanding, with the counting rate up to 10 MHz, radiation resistance, flexible readout patterns, high resolution in position and time, which is considered as a good candidate for the next generation of neutron beam monitor. This new kind of neutron beam monitor mainly consists of boron convertor, GEM and two-dimensional readout electrode. In this paper, the Monte Carlo simulation on the physical process of the detector has been carried out by using Geant4 package, including the conversion efficiency of the boron layer influenced by the thickness and the neutron wavelength, the spectrum of emitted ions, and the energy deposition of the ions and the gamma in the different gas thickness of several gas volume ratio. Besides, the effect by the fast neutrons with GEM foils has also been calculated. The results show that the ions energy deposited in the drift region is almost independent of the gas volume ratio, the thickness 6 mm of the drift region is adequate for the full energy deposition and the boron thickness smaller than 0:1 m is the best choice for n/ separation. This work would be helpful for the detector design and provide an optimized option for the development of the boron-coated GEM neutron beam monitor.
The performance of a boron-coated GEM (Gas Electron Multiplier) neutron beam monitor is outstanding, with the counting rate up to 10 MHz, radiation resistance, flexible readout patterns, high resolution in position and time, which is considered as a good candidate for the next generation of neutron beam monitor. This new kind of neutron beam monitor mainly consists of boron convertor, GEM and two-dimensional readout electrode. In this paper, the Monte Carlo simulation on the physical process of the detector has been carried out by using Geant4 package, including the conversion efficiency of the boron layer influenced by the thickness and the neutron wavelength, the spectrum of emitted ions, and the energy deposition of the ions and the gamma in the different gas thickness of several gas volume ratio. Besides, the effect by the fast neutrons with GEM foils has also been calculated. The results show that the ions energy deposited in the drift region is almost independent of the gas volume ratio, the thickness 6 mm of the drift region is adequate for the full energy deposition and the boron thickness smaller than 0:1 m is the best choice for n/ separation. This work would be helpful for the detector design and provide an optimized option for the development of the boron-coated GEM neutron beam monitor.
2014, 31(1): 75-80.
doi: 10.11804/NuclPhysRev.31.01.075
Abstract:
The NpO, NpO2, NpO3 and Np2O3 molecules geometric configurations have been optimized by using the B3LYP method of density functional theory (DFT), and the information of the electron transfers from Np to O atoms has also been analyzed. The results show that NpO, NpO2, NpO3 and Np2O3 molecules stay in the stable structure when their spin multiplicities are 6, 2, 2 and 9, and symmetries are C∞v, D∞h, C2v and D3h, respectively; For all molecules, molecular orbitals were formed from Np-6s orbital when energy near 50 eV, formed from Np-6p mixture with O-2s orbitals when the energy near 20 eV, and formed from Np-5f mixture with O-2p orbitals when the energy greater than 11 eV. Meanwhile, the vibrational frequencies and spectral data of the ground state structure have been given. We also identified vibrational modes corresponding to the maximal peaks of infrared spectrum.
The NpO, NpO2, NpO3 and Np2O3 molecules geometric configurations have been optimized by using the B3LYP method of density functional theory (DFT), and the information of the electron transfers from Np to O atoms has also been analyzed. The results show that NpO, NpO2, NpO3 and Np2O3 molecules stay in the stable structure when their spin multiplicities are 6, 2, 2 and 9, and symmetries are C∞v, D∞h, C2v and D3h, respectively; For all molecules, molecular orbitals were formed from Np-6s orbital when energy near 50 eV, formed from Np-6p mixture with O-2s orbitals when the energy near 20 eV, and formed from Np-5f mixture with O-2p orbitals when the energy greater than 11 eV. Meanwhile, the vibrational frequencies and spectral data of the ground state structure have been given. We also identified vibrational modes corresponding to the maximal peaks of infrared spectrum.
2014, 31(1): 81-85.
doi: 10.11804/NuclPhysRev.31.01.081
Abstract:
As the size of the transistor sensitive volume is decreased with the technology generation, the radial distribution of -electrons around the ion path has become more and more important to SEE(Single Event Effects) in semiconductor devices. Because it tends to, by causing MBU(Multiple-bit Upsets), invalidate error correcting codes which allow the device to work properly even when errors occur. In this work, Geant4 toolkit was used to simulate the radial ionization profile of heavy ions with different parameters. From the simulation,the certain rules were deduced: the higher the ion energy per nucleon, the wider the radial ionization track;for an identical energy per nucleon, the heavier the ion, the higher the electron density in track core. Then by simulating SEU(Single Event Upsets) of a 45 nm static random access memory (SRAM), effects of ion track structure on its MBU were illustrated. The maximum value of the MBU probability is determined not only by the structure of the device but also by the distribution of the -electrons generated by the incident ion. For ion energies between the top of the curve and the Bragg Peak, the MBU probability of the device decreases with the increasing LET values. For other ion energies, the probability increases as LET increasing.
As the size of the transistor sensitive volume is decreased with the technology generation, the radial distribution of -electrons around the ion path has become more and more important to SEE(Single Event Effects) in semiconductor devices. Because it tends to, by causing MBU(Multiple-bit Upsets), invalidate error correcting codes which allow the device to work properly even when errors occur. In this work, Geant4 toolkit was used to simulate the radial ionization profile of heavy ions with different parameters. From the simulation,the certain rules were deduced: the higher the ion energy per nucleon, the wider the radial ionization track;for an identical energy per nucleon, the heavier the ion, the higher the electron density in track core. Then by simulating SEU(Single Event Upsets) of a 45 nm static random access memory (SRAM), effects of ion track structure on its MBU were illustrated. The maximum value of the MBU probability is determined not only by the structure of the device but also by the distribution of the -electrons generated by the incident ion. For ion energies between the top of the curve and the Bragg Peak, the MBU probability of the device decreases with the increasing LET values. For other ion energies, the probability increases as LET increasing.
2014, 31(1): 86-91.
doi: 10.11804/NuclPhysRev.31.01.086
Abstract:
Polyacrylonitrile/polyethylene oxide (PAN/PEO, 5% PAN and 5% PEO) was irradiated by 1.0 MeV electron beam with different doses in this work. FTIR result indicated that PAN/PEO crosslinked after irradiation. It was pointed outby analysis that gel fraction of PAN/PEO increased with EB irradiation dose.The increasing rate of gel fraction could be divided into three stages, which were rapidly increasing stage (0 s 39 kGy), decreasing stage (39 s 130 kGy) and stable stage (more than 130 kGy). Theoretical calculation results showed that the values fitting by half-experience equation presented by Zhang Wanxi were closer to the measured values than Charlesby-Pinner equation fitting ones because of the introduction of rigidity parameter in the half-experience equation (for PAN/PEO, was 0.166). The curve of crosslinking degree vs irradiation dose showed that the crosslinking degree increased with the irradiation dose, and it could provide a referential irradiation dose when materials with fixed crosslinking degree were needed in new functional materials.
Polyacrylonitrile/polyethylene oxide (PAN/PEO, 5% PAN and 5% PEO) was irradiated by 1.0 MeV electron beam with different doses in this work. FTIR result indicated that PAN/PEO crosslinked after irradiation. It was pointed outby analysis that gel fraction of PAN/PEO increased with EB irradiation dose.The increasing rate of gel fraction could be divided into three stages, which were rapidly increasing stage (0 s 39 kGy), decreasing stage (39 s 130 kGy) and stable stage (more than 130 kGy). Theoretical calculation results showed that the values fitting by half-experience equation presented by Zhang Wanxi were closer to the measured values than Charlesby-Pinner equation fitting ones because of the introduction of rigidity parameter in the half-experience equation (for PAN/PEO, was 0.166). The curve of crosslinking degree vs irradiation dose showed that the crosslinking degree increased with the irradiation dose, and it could provide a referential irradiation dose when materials with fixed crosslinking degree were needed in new functional materials.
2014, 31(1): 92-95.
doi: 10.11804/NuclPhysRev.31.01.092
Abstract:
We have measured the secondary electron emission yields in forward and backward directions from the carbon foils, which are penetrated by O2+ ion of the energy form 1.9 to 11.3 keV/u. In the experiment, the role of electronic energy loss and ion beam intensity in forward and backward electron emission yields have been systematically studied by changing the projectile ion energy and ion beam intensity. The results show that,forward and backward electron emission yields are approximately proportional to the electron energy loss at the exit surfaces and entrance surfaces respectively, and they are independent of the ion beam intensity. Further analyses show that, the kinetic energy threshold for the backward electron emission is about 0.2 keV/u, where the electron emission yield due to the potential energy deposition was roughly 1 e-/ion in the experiment.
We have measured the secondary electron emission yields in forward and backward directions from the carbon foils, which are penetrated by O2+ ion of the energy form 1.9 to 11.3 keV/u. In the experiment, the role of electronic energy loss and ion beam intensity in forward and backward electron emission yields have been systematically studied by changing the projectile ion energy and ion beam intensity. The results show that,forward and backward electron emission yields are approximately proportional to the electron energy loss at the exit surfaces and entrance surfaces respectively, and they are independent of the ion beam intensity. Further analyses show that, the kinetic energy threshold for the backward electron emission is about 0.2 keV/u, where the electron emission yield due to the potential energy deposition was roughly 1 e-/ion in the experiment.
2014, 31(1): 96-100.
doi: 10.11804/NuclPhysRev.31.01.096
Abstract:
Owing to the excellent optical properties such as high quantum yield of emission, photo-stability and anti-photobleaching, uorescent quantum dots(QDs) now have been extensively applied in bioscience research. Labeling cells by quantum dots allow long-term observation of the cellular processes. In this paper, we employed both QDs and DiO dye to label cells and thus showed the superior anti-photobleaching property of QDs directly, and also reported the method of application of QDs in observing the damage process of A549 cells induced by particle irradiation, demonstrating the advantage of application of QDs in the radiobiology research.
Owing to the excellent optical properties such as high quantum yield of emission, photo-stability and anti-photobleaching, uorescent quantum dots(QDs) now have been extensively applied in bioscience research. Labeling cells by quantum dots allow long-term observation of the cellular processes. In this paper, we employed both QDs and DiO dye to label cells and thus showed the superior anti-photobleaching property of QDs directly, and also reported the method of application of QDs in observing the damage process of A549 cells induced by particle irradiation, demonstrating the advantage of application of QDs in the radiobiology research.
2014, 31(1): 101-105.
doi: 10.11804/NuclPhysRev.31.01.101
Abstract:
The protective effect of Curcumin (Cur) against the irradiation damage of testis in mice induced by 12C6+ ion beams was studied. Male Kung-Ming mice were exposed to whole body uniformly irradiated with 12C6+ ion beams at 4 Gy after pretreated with Cur of different concentration. Then histological alterations were observed. Moreover, malonaldehyde (MDA) level, superoxide dismutase (SOD) activity and catalase (CAT) activity were also measured at 24 h after irradiation. The result showed that middle and high dose Cur pretreated have a good protective effect. Compared with irradiated group, MDA level decreased dramatically in the group of pretreatment with low and middle dose Cur (P < 0:05). On the contrary, SOD activity in the pretreated group with low dose Cur significantly increased (P <0:05). Similarly, CAT activity in the pretreated group with middle dose Cur significantly increased (P <0:05). Data suggested that Cur could activate antioxidant system of testis in mice induced by12C6+ ion beams, it have some protective effect to radiation damage. The mechanism may involve in its scavenging reactive oxidant species and thenprotecting lipid and protein capability.
The protective effect of Curcumin (Cur) against the irradiation damage of testis in mice induced by 12C6+ ion beams was studied. Male Kung-Ming mice were exposed to whole body uniformly irradiated with 12C6+ ion beams at 4 Gy after pretreated with Cur of different concentration. Then histological alterations were observed. Moreover, malonaldehyde (MDA) level, superoxide dismutase (SOD) activity and catalase (CAT) activity were also measured at 24 h after irradiation. The result showed that middle and high dose Cur pretreated have a good protective effect. Compared with irradiated group, MDA level decreased dramatically in the group of pretreatment with low and middle dose Cur (P < 0:05). On the contrary, SOD activity in the pretreated group with low dose Cur significantly increased (P <0:05). Similarly, CAT activity in the pretreated group with middle dose Cur significantly increased (P <0:05). Data suggested that Cur could activate antioxidant system of testis in mice induced by12C6+ ion beams, it have some protective effect to radiation damage. The mechanism may involve in its scavenging reactive oxidant species and thenprotecting lipid and protein capability.
2014, 31(1): 106-111.
doi: 10.11804/NuclPhysRev.31.01.106
Abstract:
To determine the optimal mutagenic parameters to Lavendula, the biological effects on the development of dry seeds of two Lavendula varieties (701 and 702) were comparatively studied between 100 MeV 12C6+ ion and 1.2MeV electron beam. The results showed that the germination percentage of 701 and 702 increased firstly and then decreased with the dose increased by using carbon ion irradiation. However, the germination percentage of 701 and 702 decreased with the increment of radiation dosage after being irradiated by electron beam. Furthermore, the results also showed that the germination percentage of Lavendula irradiated by electron beam was lower than that of carbon ion irradiation. In addition, the length of hypocotyl, embryonic root and fresh weight of seedlings of 701 and 702 irradiated by carbon ions were superior to those of electron beam irradiation. In brief, carbon ions are moresuitable for the mutation breeding of Lavendula compared to electron beams, which would contribute to obtain more novel mutants in the future.
To determine the optimal mutagenic parameters to Lavendula, the biological effects on the development of dry seeds of two Lavendula varieties (701 and 702) were comparatively studied between 100 MeV 12C6+ ion and 1.2MeV electron beam. The results showed that the germination percentage of 701 and 702 increased firstly and then decreased with the dose increased by using carbon ion irradiation. However, the germination percentage of 701 and 702 decreased with the increment of radiation dosage after being irradiated by electron beam. Furthermore, the results also showed that the germination percentage of Lavendula irradiated by electron beam was lower than that of carbon ion irradiation. In addition, the length of hypocotyl, embryonic root and fresh weight of seedlings of 701 and 702 irradiated by carbon ions were superior to those of electron beam irradiation. In brief, carbon ions are moresuitable for the mutation breeding of Lavendula compared to electron beams, which would contribute to obtain more novel mutants in the future.
2014, 31(1): 112-117.
doi: 10.11804/NuclPhysRev.31.01.112
Abstract:
It is a more complex data processing problem of the data of -ray spectrum, which were collected by Chang'E-1 from lunar surface. It is presented that MCNP simulation for the spectra, according to three kinds of physical events, such as natural radioactive elements emission, the rays induced by inelastic neutron scattering and neutron capture on the lunar surface in this paper. The simulated results were superimposed and compared with the measured spectrum by Chang'E-1. The results show that 40K and 214Bi can be identi ed
from the measured data with our MCNP models.
It is a more complex data processing problem of the data of -ray spectrum, which were collected by Chang'E-1 from lunar surface. It is presented that MCNP simulation for the spectra, according to three kinds of physical events, such as natural radioactive elements emission, the rays induced by inelastic neutron scattering and neutron capture on the lunar surface in this paper. The simulated results were superimposed and compared with the measured spectrum by Chang'E-1. The results show that 40K and 214Bi can be identi ed
from the measured data with our MCNP models.
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