2022 Vol. 39, No. 4
Display Method:
2022, 39(4): 413-420.
doi: 10.11804/NuclPhysRev.39.2022047
Abstract:
The rotational properties of the actinides are quite important for revealing the alignment mechanism, pairing correlations, level structure etc., of the nuclei in\begin{document}$A \approx 250$\end{document} ![]()
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\begin{document}$^{235}{\rm{Np}}$\end{document} ![]()
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\begin{document}$^{237}{\rm{Np}}$\end{document} ![]()
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\begin{document}$ab$\end{document} ![]()
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\begin{document}$^{235}{\rm{Np}}$\end{document} ![]()
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\begin{document}$\pi 5/2^-[523]$\end{document} ![]()
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\begin{document}$\varepsilon_6$\end{document} ![]()
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\begin{document}$j_{15/2}$\end{document} ![]()
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\begin{document}$j_{15/2}$\end{document} ![]()
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\begin{document}$^{235,\, 237}{\rm{Np}}$\end{document} ![]()
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\begin{document}$\pi 5/2^-[523]$\end{document} ![]()
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\begin{document}$^{237}{\rm{Np}} $\end{document} ![]()
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\begin{document}$\varepsilon_6$\end{document} ![]()
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The rotational properties of the actinides are quite important for revealing the alignment mechanism, pairing correlations, level structure etc., of the nuclei in
2022, 39(4): 421-433.
doi: 10.11804/NuclPhysRev.39.2022112
Abstract:
We have calculated production cross sections of new superheavy elements with atomic number Z=119, 120 in the fusion-evaporation reactions of\begin{document}$^{48}{\rm{Ca}}$\end{document} ![]()
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\begin{document}$^{252}{\rm{Es}}$\end{document} ![]()
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\begin{document}$^{48}{\rm{Ca}}$\end{document} ![]()
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\begin{document}$^{257}{\rm{Fm}}$\end{document} ![]()
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\begin{document}$^{49}{\rm{Sc}}$\end{document} ![]()
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\begin{document}$^{252}{\rm{Es}}$\end{document} ![]()
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\begin{document}$^{49}{\rm{Sc}}$\end{document} ![]()
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\begin{document}$^{251}{\rm{Cf}}$\end{document} ![]()
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\begin{document}$^{50}{\rm{Ti}}$\end{document} ![]()
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\begin{document}$^{247}{\rm{Bk}}$\end{document} ![]()
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\begin{document}$^{50}{\rm{Ti}}$\end{document} ![]()
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\begin{document}$^{251}{\rm{Cf}}$\end{document} ![]()
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\begin{document}$^{51}{\rm{V}}$\end{document} ![]()
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\begin{document}$^{247}{\rm{Cm}}$\end{document} ![]()
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\begin{document}$^{51}{\rm{V}}$\end{document} ![]()
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\begin{document}$^{247}{\rm{Cf}}$\end{document} ![]()
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\begin{document}$^{54}{\rm{Cr}}$\end{document} ![]()
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\begin{document}$^{243}{\rm{Am}}$\end{document} ![]()
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\begin{document}$^{54}{\rm{Cr}}$\end{document} ![]()
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\begin{document}$^{247}{\rm{Cm}}$\end{document} ![]()
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\begin{document}$^{56}{\rm{Mn}}$\end{document} ![]()
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\begin{document}$^{244}{\rm{Pu}}$\end{document} ![]()
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\begin{document}$^{56}{\rm{Mn}}$\end{document} ![]()
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\begin{document}$^{243}{\rm{Am}}$\end{document} ![]()
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\begin{document}$^{60}{\rm{Fe}}$\end{document} ![]()
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\begin{document}$^{237}{\rm{Np}}$\end{document} ![]()
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\begin{document}$^{60}{\rm{Fe}}$\end{document} ![]()
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\begin{document}$^{244}{\rm{Pu}}$\end{document} ![]()
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\begin{document}$^{61}{\rm{Co}}$\end{document} ![]()
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\begin{document}$^{238}{\rm{U}}$\end{document} ![]()
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\begin{document}$^{61}{\rm{Co}}$\end{document} ![]()
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\begin{document}$^{237}{\rm{Np}}$\end{document} ![]()
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\begin{document}$^{64}{\rm{Ni}}$\end{document} ![]()
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\begin{document}$^{231}{\rm{Pa}}$\end{document} ![]()
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\begin{document}$^{64}{\rm{Ni}}$\end{document} ![]()
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\begin{document}$^{238}{\rm{U}}$\end{document} ![]()
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\begin{document}$^{65}{\rm{Cu}}$\end{document} ![]()
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\begin{document}$^{232}{\rm{Th}}$\end{document} ![]()
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\begin{document}$^{65}{\rm{Cu}}$\end{document} ![]()
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\begin{document}$^{231}{\rm{Pa}}$\end{document} ![]()
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\begin{document}$^{68}{\rm{Zn}}$\end{document} ![]()
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\begin{document}$^{232}{\rm{Th}}$\end{document} ![]()
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\begin{document}$^{289-293}{\rm{119}}$\end{document} ![]()
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\begin{document}$^{44,\, 46,\, 48,\, 50}{\rm{Ti}}$\end{document} ![]()
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\begin{document}$^{295}{\rm{120}}$\end{document} ![]()
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\begin{document}$^{46}{\rm{Ti}}$\end{document} ![]()
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\begin{document}$^{251}{\rm{Cf}}$\end{document} ![]()
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\begin{document}$^{295}{\rm{120}}$\end{document} ![]()
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\begin{document}$E^*$\end{document} ![]()
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We have calculated production cross sections of new superheavy elements with atomic number Z=119, 120 in the fusion-evaporation reactions of
2022, 39(4): 434-445.
doi: 10.11804/NuclPhysRev.39.2022046
Abstract:
Synthesis Z=119, 120 superheavy nuclei is the goal that nuclear physics laboratories are chasing. Theoretically, it is helpful to design experiments and detect newly synthesized superheavy nuclei by giving reliable information such as projectile-target combination, incident energy, etc. Based on dinuclear system model, we explore the reaction mechanism affecting the generation cross section of the heavy ion nuclear reaction and calculate\begin{document}$^{50}{\rm{Ti}}$\end{document} ![]()
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\begin{document}$^{249}{\rm{Bk}}$\end{document} ![]()
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\begin{document}$^{50}{\rm{Ti}}$\end{document} ![]()
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\begin{document}$^{249}{\rm{Cf}}$\end{document} ![]()
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\begin{document}$^{50}{\rm{Ti}}$\end{document} ![]()
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\begin{document}$^{249}{\rm{Bk}}$\end{document} ![]()
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\begin{document}$^{52-59}{\rm{Cr}}$\end{document} ![]()
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\begin{document}$^{243}{\rm{Am}}$\end{document} ![]()
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\begin{document}$^{54-62}{\rm{Mn}}$\end{document} ![]()
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\begin{document}$^{243}{\rm{Am}}$\end{document} ![]()
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\begin{document}$^{56-72}{\rm{Ni}}$\end{document} ![]()
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\begin{document}$^{238}{\rm{U}}$\end{document} ![]()
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Synthesis Z=119, 120 superheavy nuclei is the goal that nuclear physics laboratories are chasing. Theoretically, it is helpful to design experiments and detect newly synthesized superheavy nuclei by giving reliable information such as projectile-target combination, incident energy, etc. Based on dinuclear system model, we explore the reaction mechanism affecting the generation cross section of the heavy ion nuclear reaction and calculate
2022, 39(4): 446-453.
doi: 10.11804/NuclPhysRev.39.2022033
Abstract:
The single-nucleon mean-field potential, in-medium nucleon–nucleon cross-sections, and initial density distributions of nucleons are obtained from the Skyrme nucleon-nucleon effective interaction, which are self-consistently used in the Boltzmann-Uehling-Uhlenbeck(BUU) transport model. The\begin{document}$^{124}{\rm{Sn}}$\end{document} ![]()
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\begin{document}$^{124}{\rm{Sn}}$\end{document} ![]()
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\begin{document}$^{112}{\rm{Sn}}$\end{document} ![]()
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\begin{document}$^{112}{\rm{Sn}}$\end{document} ![]()
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The single-nucleon mean-field potential, in-medium nucleon–nucleon cross-sections, and initial density distributions of nucleons are obtained from the Skyrme nucleon-nucleon effective interaction, which are self-consistently used in the Boltzmann-Uehling-Uhlenbeck(BUU) transport model. The
2022, 39(4): 454-462.
doi: 10.11804/NuclPhysRev.39.2022016
Abstract:
LEAF(Low Energy high intensity highly charged ion Accelerator Facility) built by the Institute of Modern Physics, Chinese Academy of Sciences, is a high intensity highly charged heavy ion linear accelerator complex for multi-discipline researches such as low energy nuclear astrophysics, atomic physics, material irradiation physics, etc. The main part of the LEAF accelerator is a 4-vane RFQ. To achieve stable control of the cavity frequency, Radio Frequency (RF) amplitude and phase, the RF control system uses the scheme of digital low levels. According to the special requirements of LEAF-RFQ, this low-level system develops unique functions such as automatic frequency tracking, dual port drive for high power RF amplifier, and rapid phase switching of mixed ion beams, and realizes stable beam commissioning. Meanwhile, the one-click automatic RF power loading and closed loop of the cavity are realized by using the code development.
LEAF(Low Energy high intensity highly charged ion Accelerator Facility) built by the Institute of Modern Physics, Chinese Academy of Sciences, is a high intensity highly charged heavy ion linear accelerator complex for multi-discipline researches such as low energy nuclear astrophysics, atomic physics, material irradiation physics, etc. The main part of the LEAF accelerator is a 4-vane RFQ. To achieve stable control of the cavity frequency, Radio Frequency (RF) amplitude and phase, the RF control system uses the scheme of digital low levels. According to the special requirements of LEAF-RFQ, this low-level system develops unique functions such as automatic frequency tracking, dual port drive for high power RF amplifier, and rapid phase switching of mixed ion beams, and realizes stable beam commissioning. Meanwhile, the one-click automatic RF power loading and closed loop of the cavity are realized by using the code development.
2022, 39(4): 463-469.
doi: 10.11804/NuclPhysRev.39.2022003
Abstract:
With the development of accelerator technology, the working frequency and current rising rate of the pulse power supply of heavy ion accelerator are gradually increased. The magnet load of pulse power supply has the resistive characteristic, and it will absorb a large amount of reactive power in the rising section of current waveform, which will have a strong periodic impact on the power grid. At the same time, the high precision requirement of fast current rising rate poses new challenges to power supply design. In this paper, a suspension type H-bridge cascade topology based on capacitor energy storage is designed, which uses the energy storage capacitance and load inductance of the power supply to carry out reactive power interaction, and realizes the internal circulation of the reactive power, so as to reduce the impact on the power grid. At the same time, multilevel modulation and multiple frequency phase shift method is adopted to ensure the high precision demand under the fast dynamic response of power supply. The experimental results of the prototype verify the feasibility of the power supply topology and control principle, providing a new solution for the pulse power supply of accelerator based on fast current rising rate.
With the development of accelerator technology, the working frequency and current rising rate of the pulse power supply of heavy ion accelerator are gradually increased. The magnet load of pulse power supply has the resistive characteristic, and it will absorb a large amount of reactive power in the rising section of current waveform, which will have a strong periodic impact on the power grid. At the same time, the high precision requirement of fast current rising rate poses new challenges to power supply design. In this paper, a suspension type H-bridge cascade topology based on capacitor energy storage is designed, which uses the energy storage capacitance and load inductance of the power supply to carry out reactive power interaction, and realizes the internal circulation of the reactive power, so as to reduce the impact on the power grid. At the same time, multilevel modulation and multiple frequency phase shift method is adopted to ensure the high precision demand under the fast dynamic response of power supply. The experimental results of the prototype verify the feasibility of the power supply topology and control principle, providing a new solution for the pulse power supply of accelerator based on fast current rising rate.
2022, 39(4): 470-475.
doi: 10.11804/NuclPhysRev.39.2022027
Abstract:
The fast-ramping dipole magnet's performance indices, test specifications, and measurement techniques of BRing in HIAF project are presented, and the components of the fast-ramping dipole magnet steady-state magnetic field measurement system and dynamic magnetic field measurement system are described. In the steady-state magnetic field measurement, the on fly measurement technique is adopted for the long coil measurement system to improve the integrated magnetic field measurement accuracy and test efficiency. In the dynamic magnetic field measurement, the matrix coil for magnetic field delay and magnetic field distortion measurement is developed. Through the testing of the magnet prototype, the performance index verification of the test system and steady-state magnetic field measurement of the prototype magnet are completed. Based on the test data, the secondary trimming of the magnet is completed.
The fast-ramping dipole magnet's performance indices, test specifications, and measurement techniques of BRing in HIAF project are presented, and the components of the fast-ramping dipole magnet steady-state magnetic field measurement system and dynamic magnetic field measurement system are described. In the steady-state magnetic field measurement, the on fly measurement technique is adopted for the long coil measurement system to improve the integrated magnetic field measurement accuracy and test efficiency. In the dynamic magnetic field measurement, the matrix coil for magnetic field delay and magnetic field distortion measurement is developed. Through the testing of the magnet prototype, the performance index verification of the test system and steady-state magnetic field measurement of the prototype magnet are completed. Based on the test data, the secondary trimming of the magnet is completed.
2022, 39(4): 476-483.
doi: 10.11804/NuclPhysRev.39.2022014
Abstract:
Precise time measurement based on high-speed waveform digitalization is a research hotspot in nuclear and particle physics experiment readout electronics. In this paper, a prototype of 16-channel time measurement electronics aiming for high-precision time measurement is designed, based on a Switched Capacitor Array(SCA) Application Specific Integrated Circuit(ASIC) designed by the laboratory where I am. After being sampled and digitized by the SCA ASIC, signals are directly transmitted to one Field Programmable Gate Array(FPGA), in which mismatch error correction, linear interpolation, and digital discrimination are integrated into it to extract the time information. The laboratory test results indicate that a time resolution of better than 10 ps RMS can be achieved in electronics.
Precise time measurement based on high-speed waveform digitalization is a research hotspot in nuclear and particle physics experiment readout electronics. In this paper, a prototype of 16-channel time measurement electronics aiming for high-precision time measurement is designed, based on a Switched Capacitor Array(SCA) Application Specific Integrated Circuit(ASIC) designed by the laboratory where I am. After being sampled and digitized by the SCA ASIC, signals are directly transmitted to one Field Programmable Gate Array(FPGA), in which mismatch error correction, linear interpolation, and digital discrimination are integrated into it to extract the time information. The laboratory test results indicate that a time resolution of better than 10 ps RMS can be achieved in electronics.
2022, 39(4): 484-489.
doi: 10.11804/NuclPhysRev.39.2022010
Abstract:
The output signal of PSD(plastic scintillation detector) is fed to the preamplifier and the shaping circuit to output a quasi-Gaussian waveform. The peak holding circuit can be used to sample and hold the peak value of the quasi-Gaussian waveform signal, so that the subsequent electronic system can further analyze it. This paper presents a peak holding circuit ASIC(application specific integrated circuit) chip which is designed based on 180 nm CMOS technology. Each channel of the ASIC includes an OTA(Operational Transconductance Amplifier) circuit, a current mirror circuit, and a charging capacitor. Laboratory electronics function and performance test results indicate that the function of the peak hold circuit is achieved. The input dynamic range is 33~940 mV, and the nonlinear error is better than 0.8%. The droop rate is better than 8.6 μV/μs, the peak detection delay time is lower than 35 ns, and the single-channel power consumption of the chip is 825 μW, which meets the design requirements.
The output signal of PSD(plastic scintillation detector) is fed to the preamplifier and the shaping circuit to output a quasi-Gaussian waveform. The peak holding circuit can be used to sample and hold the peak value of the quasi-Gaussian waveform signal, so that the subsequent electronic system can further analyze it. This paper presents a peak holding circuit ASIC(application specific integrated circuit) chip which is designed based on 180 nm CMOS technology. Each channel of the ASIC includes an OTA(Operational Transconductance Amplifier) circuit, a current mirror circuit, and a charging capacitor. Laboratory electronics function and performance test results indicate that the function of the peak hold circuit is achieved. The input dynamic range is 33~940 mV, and the nonlinear error is better than 0.8%. The droop rate is better than 8.6 μV/μs, the peak detection delay time is lower than 35 ns, and the single-channel power consumption of the chip is 825 μW, which meets the design requirements.
2022, 39(4): 490-496.
doi: 10.11804/NuclPhysRev.39.2022008
Abstract:
The research on the interaction between ions and matter, based on the ions accelerator complex, play the important roles in both fundamental physics and the application aspects in many fields, such as atomic physics, material and biology researches. A novel magnetic spectrometer ion detector is developed, which is mainly composed of a high stability deflector magnet, a large-area position-sensitive detector and a space-matched scattering chamber. The new detector can accurately in-situ measure the ions’ charge state distribution and the corresponding energy spectrum. Based on the HIRFL accelerator, the calibration of the detector was completed by using the quasi-monoenergy ions and the quantitative relationship between the ion position and its energy was obtained. The optimal energy spectrum accuracy and energy resolution of the detector system are found as 0.1% and 0.8% respectively, which are shown in the calibration experiment.
The research on the interaction between ions and matter, based on the ions accelerator complex, play the important roles in both fundamental physics and the application aspects in many fields, such as atomic physics, material and biology researches. A novel magnetic spectrometer ion detector is developed, which is mainly composed of a high stability deflector magnet, a large-area position-sensitive detector and a space-matched scattering chamber. The new detector can accurately in-situ measure the ions’ charge state distribution and the corresponding energy spectrum. Based on the HIRFL accelerator, the calibration of the detector was completed by using the quasi-monoenergy ions and the quantitative relationship between the ion position and its energy was obtained. The optimal energy spectrum accuracy and energy resolution of the detector system are found as 0.1% and 0.8% respectively, which are shown in the calibration experiment.
2022, 39(4): 497-504.
doi: 10.11804/NuclPhysRev.39.2022006
Abstract:
Eukaryotic DNA molecule is highly compressed and exist in the form of chromatin in the nucleus. The dynamic structure of chromatin plays an important role in the process of DNA replication, gene transcription and DNA repair. In situ high-resolution analysis of chromatin structure and quantitative characterization of its structural changes have been limited by the optical resolution of microscopic imaging. The super-resolution chromatin structure image in the nucleus was obtained by click-reaction labeled EdU and the STORM single-molecule-localization microscopy. Based on the proposed single molecule cluster analysis and nearest neighbor distance algorithm, we found that the number of nuclear nucleosome clusters increased significantly after X-ray irradiation and TSA treatment, the area ratio of nucleosome clusters in the cell nucleus increased compared with the control group, and the average number of EdU molecules in the cluster decreased. At the same time, the rate constant of XRCC1 recruitment kinetics obtained from the on-line imaging experiment of heavy ion irradiated living cells showed that acetylation reduced the density of DNA damage. These results showed that both ionizing radiation and acetylation led to the decondensation of chromatin structure. The imaging method, analysis algorithm and the distribution of nucleosome clusters provide direct quantitative characterization data support for the decondensation of chromatin structure in cell nucleus.
Eukaryotic DNA molecule is highly compressed and exist in the form of chromatin in the nucleus. The dynamic structure of chromatin plays an important role in the process of DNA replication, gene transcription and DNA repair. In situ high-resolution analysis of chromatin structure and quantitative characterization of its structural changes have been limited by the optical resolution of microscopic imaging. The super-resolution chromatin structure image in the nucleus was obtained by click-reaction labeled EdU and the STORM single-molecule-localization microscopy. Based on the proposed single molecule cluster analysis and nearest neighbor distance algorithm, we found that the number of nuclear nucleosome clusters increased significantly after X-ray irradiation and TSA treatment, the area ratio of nucleosome clusters in the cell nucleus increased compared with the control group, and the average number of EdU molecules in the cluster decreased. At the same time, the rate constant of XRCC1 recruitment kinetics obtained from the on-line imaging experiment of heavy ion irradiated living cells showed that acetylation reduced the density of DNA damage. These results showed that both ionizing radiation and acetylation led to the decondensation of chromatin structure. The imaging method, analysis algorithm and the distribution of nucleosome clusters provide direct quantitative characterization data support for the decondensation of chromatin structure in cell nucleus.
2022, 39(4): 505-511.
doi: 10.11804/NuclPhysRev.39.2022061
Abstract:
Microfilament is a multi-functional sub-cell structure, and it is also a sensor for ionizing radiation. In order to clarify the regulatory effect of long non-coding RNAs(lncRNA) in the alteration of microfilament dynamics caused by ionizing radiation, Swinholide A was used to depolymerize the microfilament and then, the lncRNA chip was used to detect the differentially expressed lncRNAs. Microfilament staining and network/structure analysis were used to evaluate the changes in microfilament skeleton. It was found that the expression of lncRNA XR_923426 was decreased after the microfilament depolymerization. Meanwhile, the overexpression of lncRNA XR_923426 could significantly alleviate the microfilament depolymerization caused by ionizing radiation. This provides a new clue for the research on the regulatory relationship between lncRNA targeted microfilament dynamics and radiation induced tumor death or metastasis, which is expected to develop into a new target for tumor treatment or normal tissue protection.
Microfilament is a multi-functional sub-cell structure, and it is also a sensor for ionizing radiation. In order to clarify the regulatory effect of long non-coding RNAs(lncRNA) in the alteration of microfilament dynamics caused by ionizing radiation, Swinholide A was used to depolymerize the microfilament and then, the lncRNA chip was used to detect the differentially expressed lncRNAs. Microfilament staining and network/structure analysis were used to evaluate the changes in microfilament skeleton. It was found that the expression of lncRNA XR_923426 was decreased after the microfilament depolymerization. Meanwhile, the overexpression of lncRNA XR_923426 could significantly alleviate the microfilament depolymerization caused by ionizing radiation. This provides a new clue for the research on the regulatory relationship between lncRNA targeted microfilament dynamics and radiation induced tumor death or metastasis, which is expected to develop into a new target for tumor treatment or normal tissue protection.
2022, 39(4): 512-518.
doi: 10.11804/NuclPhysRev.39.2022063
Abstract:
Protein content in feed is a key index for evaluating feed quality, However, recent reports of determine the protein content of feed on dietary for feeds tuffs investigated as potential sources of protein content (yeast, lactic acid bacteria, etc.) and protein content of the forage. The protein content of feed yeast strains directly determines the protein content of feed, so it becomes the key to obtain good feed yeast strains. In this study, a heavy ion 12C6+ beam with an energy of 80 MeV/u was used for irradiation mutagenesis and breeding of starter yeast NJ3236(protein content of 40.64%), and the strains were screened and rescreened to obtain 100G-2 strain with high protein content. The protein content of the 100G-2 strain increased by 10.08% compared with that of the strain NJ3236. Then response surface analysis was used to optimize the fermentation medium. The optimal ratio of medium showed that sweet sorghum juice 20.95 g/L, corn steep liquor 18.17 g/L and magnesium sulfate 1.60 g/L. Under this condition, the soluble protein concentration reached 1.381 mg/mL, which was 8.7% higher than that before optimization.
Protein content in feed is a key index for evaluating feed quality, However, recent reports of determine the protein content of feed on dietary for feeds tuffs investigated as potential sources of protein content (yeast, lactic acid bacteria, etc.) and protein content of the forage. The protein content of feed yeast strains directly determines the protein content of feed, so it becomes the key to obtain good feed yeast strains. In this study, a heavy ion 12C6+ beam with an energy of 80 MeV/u was used for irradiation mutagenesis and breeding of starter yeast NJ3236(protein content of 40.64%), and the strains were screened and rescreened to obtain 100G-2 strain with high protein content. The protein content of the 100G-2 strain increased by 10.08% compared with that of the strain NJ3236. Then response surface analysis was used to optimize the fermentation medium. The optimal ratio of medium showed that sweet sorghum juice 20.95 g/L, corn steep liquor 18.17 g/L and magnesium sulfate 1.60 g/L. Under this condition, the soluble protein concentration reached 1.381 mg/mL, which was 8.7% higher than that before optimization.
2022, 39(4): 519-526.
doi: 10.11804/NuclPhysRev.39.2021088
Abstract:
This study investigated the influence of incident electron beam parameters on dose distribution generated by the XHA600D accelerator based on Monte Carlo method, and then determined the optimal incident electron beam parameters. According to the geometric and material parameters of XHA600D accelerator treatment head provided by the manufacturer, the dose distributions in the water phantom generated by different incident electron beam parameters were simulated and recorded using Monte Carlo code EGSnrc, and the simulated dose distributions were compared with the measured results. The simulated incident electron beam parameters include mean energy, radial intensity distribution, angular divergency and energy spread. The experimental measurements include percentage depth doses and off-axis doses for 4 cm×4 cm, 10 cm×10 cm, 30 cm×30 cm fields. The results show that the simulated data are in excellent agreement with the measurements when the mean energy is monoenergetic 6 MeV, the FWHM(Full Width at Half Maximum) radial intensity is 0.25 cm and the angular divergency is 0.15°. These parameters can be used as the basic parameters to establish the dose calculation model of TPS(Treatment Planning System) for XHA600D accelerator.
This study investigated the influence of incident electron beam parameters on dose distribution generated by the XHA600D accelerator based on Monte Carlo method, and then determined the optimal incident electron beam parameters. According to the geometric and material parameters of XHA600D accelerator treatment head provided by the manufacturer, the dose distributions in the water phantom generated by different incident electron beam parameters were simulated and recorded using Monte Carlo code EGSnrc, and the simulated dose distributions were compared with the measured results. The simulated incident electron beam parameters include mean energy, radial intensity distribution, angular divergency and energy spread. The experimental measurements include percentage depth doses and off-axis doses for 4 cm×4 cm, 10 cm×10 cm, 30 cm×30 cm fields. The results show that the simulated data are in excellent agreement with the measurements when the mean energy is monoenergetic 6 MeV, the FWHM(Full Width at Half Maximum) radial intensity is 0.25 cm and the angular divergency is 0.15°. These parameters can be used as the basic parameters to establish the dose calculation model of TPS(Treatment Planning System) for XHA600D accelerator.
2022, 39(4): 527-532.
doi: 10.11804/NuclPhysRev.39.2021086
Abstract:
Two dose correction methods were compared for the under-response of EBT3 radiochromic films to the irradiation of mixed-LET carbon-ion beams. Carbon-ion beam of 260 MeV/u was used to obtain carbon-ion beams with multiple dose-averaged LETs by energy degraders. The films were irradiated by these carbon ion beams, and the optimal fitting formula was selected to fit the film dose response calibration curves. Relative Efficiency(RE) was used to quantify the under-response of EBT3 film with LET, and the doses of the films irradiated by mixed-LET carbon ions were corrected by the RE method. In addition, according to the relation between the fitting parameters of the dose response calibration curve and the dose proportions of different LETs, a new dose correction method was proposed and the doses of the films irradiated by mixed-LET irradiation were also corrected. Finally, the results of the two methods are compared, and it is shown that the dose deviation obtained by the fitting parameter method is less than 5%, which is better than the dose deviation obtained by the RE method less than 10%.
Two dose correction methods were compared for the under-response of EBT3 radiochromic films to the irradiation of mixed-LET carbon-ion beams. Carbon-ion beam of 260 MeV/u was used to obtain carbon-ion beams with multiple dose-averaged LETs by energy degraders. The films were irradiated by these carbon ion beams, and the optimal fitting formula was selected to fit the film dose response calibration curves. Relative Efficiency(RE) was used to quantify the under-response of EBT3 film with LET, and the doses of the films irradiated by mixed-LET carbon ions were corrected by the RE method. In addition, according to the relation between the fitting parameters of the dose response calibration curve and the dose proportions of different LETs, a new dose correction method was proposed and the doses of the films irradiated by mixed-LET irradiation were also corrected. Finally, the results of the two methods are compared, and it is shown that the dose deviation obtained by the fitting parameter method is less than 5%, which is better than the dose deviation obtained by the RE method less than 10%.
2022, 39(4): 533-538.
doi: 10.11804/NuclPhysRev.39.2022009
Abstract:
In order to investigate the changes of structure and mechanical properties of silicon carbide irradiated by high energy ions, the 4H-SiC after 122 MeV 20Ne4+ ion gradient multi-dose irradiation was investigated by Raman spectrum and nano indentation technology. The Relative Raman Intensity of the sample decreases exponentially with the increase of dose, and there are scattering peaks representing disordered Si-C bond and homonuclear Si-Si bond. Preliminary fitting based on the DI/DS model shows that the expansion of defect clusters in the low dose range is the main factor causing the disorder, while the disorder in the high dose range is caused by amorphization in the process of direct ion collision and extended defect clusters. The hardness of irradiated silicon carbide is the joint action between dislocation pinning and covalent bond breaking. Between 0~4.00 dpa, the hardness increases with the increase of dose, and between 4.00~8.05 dpa, the hardness decreases with the increase of dose. At 8.05 dpa, the hardness is slightly higher than that unirradiated area. At the same time, the covalent bond breaking and dislocation pinning reach equilibrium.
In order to investigate the changes of structure and mechanical properties of silicon carbide irradiated by high energy ions, the 4H-SiC after 122 MeV 20Ne4+ ion gradient multi-dose irradiation was investigated by Raman spectrum and nano indentation technology. The Relative Raman Intensity of the sample decreases exponentially with the increase of dose, and there are scattering peaks representing disordered Si-C bond and homonuclear Si-Si bond. Preliminary fitting based on the DI/DS model shows that the expansion of defect clusters in the low dose range is the main factor causing the disorder, while the disorder in the high dose range is caused by amorphization in the process of direct ion collision and extended defect clusters. The hardness of irradiated silicon carbide is the joint action between dislocation pinning and covalent bond breaking. Between 0~4.00 dpa, the hardness increases with the increase of dose, and between 4.00~8.05 dpa, the hardness decreases with the increase of dose. At 8.05 dpa, the hardness is slightly higher than that unirradiated area. At the same time, the covalent bond breaking and dislocation pinning reach equilibrium.
2022, 39(4): 539-545.
doi: 10.11804/NuclPhysRev.39.2022018
Abstract:
According to the characteristics of deep burnup of fluorine salt cooled spherical bed high temperature reactor (FHR), the feasibility of transmutation of minor actinides by FHR is studied in this paper. The results show that: (1) the enrichment of U-235 is 19.75%, and the mass ratio of UO2 to MAO2 in triso is 18:1 after pebble optimized; (2) The flow rate of pebble in the core is 4.59 cm/d and the deepest burnup is 150 GWd/tHM; (3) The total transmutation rate of minor actinides is 26.16%. Among them, Np-237, Am-241 and Am-243 are transmuted by capture absorption and\begin{document}$ \beta $\end{document} ![]()
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According to the characteristics of deep burnup of fluorine salt cooled spherical bed high temperature reactor (FHR), the feasibility of transmutation of minor actinides by FHR is studied in this paper. The results show that: (1) the enrichment of U-235 is 19.75%, and the mass ratio of UO2 to MAO2 in triso is 18:1 after pebble optimized; (2) The flow rate of pebble in the core is 4.59 cm/d and the deepest burnup is 150 GWd/tHM; (3) The total transmutation rate of minor actinides is 26.16%. Among them, Np-237, Am-241 and Am-243 are transmuted by capture absorption and
2022, 39(4): 546-554.
doi: 10.11804/NuclPhysRev.39.2022019
Abstract:
The systems in nuclear power plants have complex sequence failure behaviors due to redundant design, and the traditional static fault tree(SFT) in risk assessment cannot accurately simulate the sequential failure behaviors of the systems in nuclear power plants. In this paper, an accident risk analysis framework based on event tree+Dynamic Fault Tree(DFT) is proposed to solve this problem, and the main steam line break(SLB) accident is used as an example to carry out the analysis. First, an event tree model of the SLB accident and the DFT model of the related system are established; Then, the system fault tree is divided into DFT modules and SFT modules, and the result of the DFT modules are replaced with super events to participate in subsequent calculations; Finally, the cut set method is adopted to calculate and analyze SLB accident risk, and results are compared with the traditional SFT method under the same conditions. The results show that (1) Compared with the SFT method, the result calculated by the proposed method is closer to the real system failure scenario, and the conservativeness of the result is relaxed; (2) The proposed method can accurately simulate the SLB accident, which is beneficial for operational risk management and maintenance optimization in the future.
The systems in nuclear power plants have complex sequence failure behaviors due to redundant design, and the traditional static fault tree(SFT) in risk assessment cannot accurately simulate the sequential failure behaviors of the systems in nuclear power plants. In this paper, an accident risk analysis framework based on event tree+Dynamic Fault Tree(DFT) is proposed to solve this problem, and the main steam line break(SLB) accident is used as an example to carry out the analysis. First, an event tree model of the SLB accident and the DFT model of the related system are established; Then, the system fault tree is divided into DFT modules and SFT modules, and the result of the DFT modules are replaced with super events to participate in subsequent calculations; Finally, the cut set method is adopted to calculate and analyze SLB accident risk, and results are compared with the traditional SFT method under the same conditions. The results show that (1) Compared with the SFT method, the result calculated by the proposed method is closer to the real system failure scenario, and the conservativeness of the result is relaxed; (2) The proposed method can accurately simulate the SLB accident, which is beneficial for operational risk management and maintenance optimization in the future.
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