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1. chinaXiv:202302.00250 [pdf]

A Beam Switchyard for Parallel Operation of Multiple Beamlines at the SXFEL User Facility

Si Chen
Comment:已投稿核科学与技术技术英文版Nuclear Science and Techniques
Subjects: Nuclear Science and Technology >> Particle Accelerator

As an important measure of improving the efficiency and usability of X-ray free electron laser facilities, parallel operation of multiple undulator lines realized by a beam switchyard has become a standard configuration in the recent built XFEL facilities. SXFEL-UF, the first soft X-ray free electron laser user facility in China, has finished construction and commissioning recently. The electron beams from the linac are separated and delivered alternately to the two parallel undulator beam lines through a beam switchyard. A stable and fast kicker magnet is used to achieve bunch-by-bunch separation. Optics measures are applied to mitigate the impact of various collective effects, such as coherent synchrotron radiation and micro-bunching instability, on the beam quality after passing through the deflection line of the beam switchyard. In this study, the comprehensive physical design of the beam switchyard is described and the latest results of its commissioning process are presented.

submitted time 2023-02-22 Hits481Downloads100 Comment 0

2. chinaXiv:202301.00118 [pdf]


Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics

随着硅光电倍增管(SiPM)技术的发展,用于SiPM信号处理的前端电子器件在各个领域备受追捧。本文通过构建并开发基于现场可编程门阵列的电荷数字转换器(FPGA-QDC),实现了紧凑型的64通道前端电子(FEE)系统。FEE由模拟板和FPGA板组成。模拟板包含商用放大器、电阻器和电容器。FPGA 板由低成本 FPGA 组成。本文从噪声、线性度和均匀性方面评估了FEE的电子学性能。通过设计具有三种不同读出配置的正电子发射断层扫描(PET)探测器,来验证基于SiPM探测器的FEE读出能力。PET探测器由15×15 LYSO晶体阵列与SiPM阵列探测器直接耦合而成。实验结果表明,FEE可以处理来自SiPM探测器的双极性电荷信号。此外,在Na-22源照射的LYSO晶体阵列的双端读数下,它显示了511-keV伽马光子的良好能量分辨率。总体而言,基于FPGA-QDC的FEE有望应用于各类基于SiPM的辐射探测器。

submitted time 2023-01-15 Hits2484Downloads147 Comment 0

3. chinaXiv:202208.00047 [pdf]

Thin-film Approximate Point Scattered Function and its Application to Neutron Radiography

倪嘉雨; 覃骏; 叶林峰; 高德宏; 蒋维军
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics

A simpler and improved utility approximate point scattered function for thin-fifilm converters currently used in neutron photographic devices is proposed as a correction method to produce clearer, more realistic images. The validity of the model was demonstrated through a simulation experiment. Based on the results, an error  analysis was carried out, certain corrections were made to the original model, and the fifinal model achieved a very low relative error in the simulation experiment. The model can also be optimized for quantitative neutron photographic analysis using iterative algorithms to obtain realistic neutron photographic images more quickly. At the end of the article, the model is extended to consider the case of energy spectrum hardening by introducing a temperature correction parameter.

submitted time 2022-08-08 Hits1817Downloads283 Comment 0

4. chinaXiv:202205.00171 [pdf]


Subjects: Nuclear Science and Technology >> Reprocessing Technology of Spent Nuclear Fuel

Nuclear material license holder should develop a nuclear material accounting management system and achieve the closed balance. According to regulations requirements, nuclear material accountancy implementation is based on  physical inventory and material measurement. Generally, the spent fuel reprocessing plant operates uninterrupted, annual throughput of  nuclear  materials  is  huge, different  measurement and analysis techniques are configured combing the reprocessing process. So the closed balance approach of nuclear materials accounting is a great challenge. In order to improve  the accuracy and reliability of nuclear material, enhance the timeliness of abnormal detection, near-real time accounting prospect of spent fuel reprocessing plant was researched. In this paper, the crucial aspect affecting the closed balance of nuclear materials was discussed, the factors such as the head-end receiver-shipper difference, the on-line process monitoring accuracy, the applicability of the international target value of nuclear material measurement uncertainty, and also the nuclear material balance model of reprocessing plants. As summarized, proposed suggestions and solutions for nuclear material balance in spent fuel reprocessing plant was put forward on the end of the paper.

submitted time 2022-05-28 Hits2232Downloads427 Comment 0

5. chinaXiv:202205.00141 [pdf]

Development of an ultrafast detector and demonstration of its oscillographic application

Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics

A dilation X-ray detector (DIXD) based on time dilation and microchannel plate (MCP) gated technology has been reported. The DIXD passes a driving pulse along the transmission photocathode (PC) to obtain a dilated electron signal and finally achieves a high time resolution of 12 ps. Furthermore, the waveform of the PC driving pulse can be obtained using the DIXD, and a DIXD oscillographic function can be obtained. An experiment is presented to demonstrate the DIXD oscilloscope. The waveform of the PC driving pulse from points t1 to t12 is achieved by the DIXD. The waveform agrees well with that measured by a high-speed oscilloscope with a difference of less than 6%. The maximum theoretical bandwidth of the DIXD oscilloscope is theoretically studied. The bandwidth is limited by the potential difference between the PC and mesh. When the potential difference is 3.4 kV, the theoretical limiting bandwidth is 1000 GHz. The bandwidth increases with an increase in the potential difference.

submitted time 2022-05-20 Hits2715Downloads500 Comment 0

6. chinaXiv:202201.00028 [pdf]

Precise calibration of cavity forward and reflected signals using low-level radio-frequency system

Ma, Jin-Ying ; Qiu, Feng ; Shi, Long-Bo ; Zhu, Zheng-Long ; Jiang, Tian-Cai ; Xue, Zong-Heng ; Jin, Ke-An ; Chen, Qi ; Xu, Cheng-Ye ; Ding, Xing-Hao ; Gao, Zheng ; Sun, Lie-Peng ; Huang, Gui-Rong ; He, Yuan
Subjects: Nuclear Science and Technology >> Particle Accelerator

Precise measurements of the cavity forward (Vf) and reflected signals (Vr) are essential for characterizing other key parameters such as the cavity detuning and forward power. In practice, it is challenging to measure Vf and Vr precisely because of crosstalk between the forward and reflected channels (e.g., coupling between the cavity reflected and forward signals in a directional coupler with limited directivity). For DESY, a method based on the cavity differential equation was proposed to precisely calibrate the actual Vf and Vr. In this study, we verified the validity and practicability of this approach for the Chinese ADS front-end demo superconducting linac (CAFe) facility at the Institute of Modern Physics and a compact energy recovery linac (cERL) test ma#2;chine at KEK. At the CAFe facility, we successfully calibrated the actual Vf signal using this method. The result demonstrated that the directivity of directional couplers might seriously affect the accuracy of Vf measurement. At the cERL facility, we calibrated the Lorentz force detuning (LFD) using the actual Vf. Our study confirmed that the precise calibration of Vf significantly improves the accuracy of the cavity LFD measurement.

submitted time 2021-12-31 Cooperative journals:《Nuclear Science and Techniques》 Hits3338Downloads644 Comment 0

7. chinaXiv:202201.00027 [pdf]

Calibrating the linearity between grayscale and element content for X-ray KES imaging of alloys

Ju, Xiao-Lu ; Deng, Biao ; Li, Ke ; Yu, Fu-Cheng ; Zhang, Hai-Peng ; Xu, Ming-Wei ; Du, Guo-Hao ; Xie, Hong-Lan ; Li, Bin ; Xiao, Ti-Qiao
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology

Doped elements in alloys significantly impact their performance. Conventional methods usually sputter the surface material of the sample, or their performance is limited to the surface of alloys owing to their poor penetration ability. The X-ray K-edge subtraction (KES) method exhibits great potential for the nondestructive in situ detection of element contents in alloys. However, the signal of doped elements usually deteriorates because of the strong absorption of the principal component and scattering of crystal grains. This in turn prevents the extensive application of X-ray KES imaging to alloys. In this study, methods were developed to calibrate the linearity between the grayscale of the KES image and element content. The methods were aimed at the sensitive analysis of elements in alloys. Furthermore, experiments with phantoms and alloys demonstrated that, after elaborate calibration, X-ray KES imaging is capable of nondestructive and sensitive analysis of doped elements in alloys.

submitted time 2021-12-31 Cooperative journals:《Nuclear Science and Techniques》 Hits3393Downloads695 Comment 0

8. chinaXiv:202201.00019 [pdf]

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

Chen, Jun-Liang ; Yun, Su-Jun ; Dong, Tie-Kuang ; Ren, Zhong-Zhou ; Zhang, Xiao-Ping
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology

The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet. In this study, a simple geometrical model was built for simulating the radiation environment on the Mars surface caused by galactic cosmic rays (GCRs); the model was built and studied using the Geant4 toolkit. The simulation results were compared with the data reported by a radiation assessment detector (RAD).

submitted time 2021-12-31 Cooperative journals:《Nuclear Science and Techniques》 Hits3144Downloads622 Comment 0

9. chinaXiv:202201.00018 [pdf]

Improved formation density measurement using controllable D-D neutron source and its lithological correction for porosity prediction

Zhang, Li ; Yu, Hua-Wei ; Li, Yang ; Jia, Wen-Bao ; Han, Xiao ; Geng, Xue-Sen
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology

Controllable D-D neutron sources have a long service life, low cost, and non-radioactivity. There are favorable prospects for its application in geophysical well logging, since traditional chemical radioactive sources used for well logging pose potential threats to the safety of the human body and environment. This paper presents an improved method to measure formation density that employs a D-D neutron source. In addition, the lithological effect on the measured density was removed to better estimate the formation porosity. First, we investigated the spatial distribution of capture gamma rays through Monte Carlo simulations as well as the relationship between the ratio of capture gamma ray counts and formation density to establish theoretical support for the design of density logging tools and their corresponding data processing methods. Second, we obtained the far to near detector counts of captured gamma rays for an optimized tool structure, and then established its correlation with the density and porosity of three typical formations with pure quartz, calcite, and dolomite minerals. Third, we determined the values for correcting the densities of sandstone and dolomite with the same porosity using limestone data as the reference and established the equations for calculating the correction values, which lays a solid foundation for accurately calculating formation porosity. We observed that the capture gamma ray counts first increased then decreased and varied in different formations; this was especially observed in high-porosity formations. Under the same lithologic conditions (rock matrix), as the porosity increases, the peak value of gamma ray counts moves toward the neutron source. At different detector-source distances, the ratio of the capture gamma ray counts was well correlated with the formation density. An equation of the formation density conversion was established based on the ratio of capture gamma ray counts at the detector-source distances of 30 cm and 65 cm, and the calculated values were consistent with the true values. After correction, the formation density was highly consistent with the true value of the limestone density, and the mean absolute error was -0.013 g/cm3. The calculated porosity values were very close to the true values, and the mean relative error was 2.33%, highlighting the accuracy of the proposed method. These findings provide a new method for developing D-D neutron source logging tools and their well-log data processing methods.

submitted time 2021-12-31 Cooperative journals:《Nuclear Science and Techniques》 Hits3441Downloads709 Comment 0

10. chinaXiv:202201.00017 [pdf]

A novel 4D resolution imaging method for low and medium atomic number objects at the centimeter scale by coincidence detection technique of cosmic-ray muon and its secondary particles

Ji, Xuan-Tao ; Luo, Si-Yuan ; Huang, Yu-He ; Zhu, Kun ; Jin, Zhu ; Peng, Xiao-Yu ; Xiao, Min; Wang, Xiao-Dong
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology

The muon radiography imaging technique for high-atomic-number objects (Z) and large-volume objects via muon transmission imaging and muon multiple scattering imaging remains a popular topic in the field of radiation detection imaging. However, few imaging studies have been reported on low and medium Z objects at the centimeter scale. This paper presents an imaging system that consists of three layers of a position-sensitive detector and four plastic scintillation detectors. It acquires data by coincidence detection technique of cosmic-ray muon and its secondary particles. A 3D imaging algorithm based on the density of the coinciding muon trajectory was developed, and 4D imaging that takes the atomic number dimension into account by considering the secondary particle ratio information was achieved. The resultant reconstructed 3D images could distinguish between a series of cubes with 5-mm side lengths and 2-mm intervals. If the imaging time is more than 20 days, this method can distinguish intervals with a width of 1 mm. The 4D images can specify target objects with low, medium, and high Z values.

submitted time 2021-12-31 Cooperative journals:《Nuclear Science and Techniques》 Hits3297Downloads672 Comment 0

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