分类： 物理学 >> 核物理学 提交时间： 2025-04-17
Deng, Mr. Lin-Jin
Wang, Dr. Chen-Yang
Cheng, Dr. Hui
Xue, Mr. Ruihao
Cheng, Prof. Fa-Liang
Yuan, Dr. Bao
Bai, Mr. Bo
Sun, Dr. Yuan
Ye, Mr. Fan
Dou, Dr. Meng-Jia
Huang, Mr. Zhiqiang
Luo, Dr. Wan-ju
Hu, Dr. Hai-Tao
Tong, Dr. Xin
摘要： Metal foil element furnaces are widely used in neutron scattering sample environments. However, since the metal foil blocks the neutron beam, these furnaces typically have a large background from the metal foil. Therefore, we designed a special heating element with an innovative perforated structure for the furnace. This novel heating element can significantly reduce the instrumental background, and is specifically applicable to the Multi-Physics Instrument and High-Pressure Neutron Diffractometer in CSNS. This structure reduces material obstruction of the neutron beam, thereby greatly lowering the experimental background. Additionally, we performed electro-thermal-mechanical coupled finite element simulation on the heating element to analyze its temperature and stress distribution, and identified the locations most susceptible to failure. We adjusted the heating element's hole size to study temperature and stress changes, providing a theoretical basis for future optimization of the heating element. This furnace is extensively applied in CSNS, facilitating users in accomplishing neutron scattering experiments and achieving a series of research outcomes.
分类： 物理学 >> 核物理学 提交时间： 2025-02-27
Chen, Mr. Ji-Xin
Jixin, Mr. Chen
Bai, Dr. Bo 白波
Cheng, Prof. Fa-Liang
Sun, Dr. Yuan
Cheng, Dr. Hui
Yuan, Dr. Bao
Dou, Dr. Meng-Jia
Wang, Dr. Chen-Yang
Lin, Mr. Quan
Lu, Mr. Zi-Cong
Deng, Mr. Lin-Jin
Hu, Dr. Hai-Tao
Tong, Dr. Xin
摘要： The use of automatic sample exchange technology can greatly improve the efficiency of neutron scattering experiments. China spallation neutron source (CSNS) has currently developed a cryogenic sample changer that design for exchange sample in the temperature range of 100K to 300K and finally achieve the minimum operating temperature is 80K. Samples are provided with a temperature ranging from 4.2K to 800K by CCR-02 through a closed cycle refrigerator (CCR) and a heater. This paper introduces the structure of the sample changer, which can accommodate up to 24 samples and the replacement time of each sample does not exceed 2 minutes. CSNS II phase will develop a second generation sample changer with an operating temperature range from 10K to 350K. For this requirement, we researched why the chain drive jammed in 80K and redesigned the chain and the support. By simulating in Ansys Workbench, we concluded that the new chain has more excellent performance in low-temperature and its stress is small and uniform. Because of the stress concentration, the S chain plate with a clamping angle of 20°is selected. The new support under Fluent can get the lowest temperature is 4.48K (316 stainless steel) and 4.23K (titanium). The new design will be tested after processing is completed.
分类： 物理学 >> 核物理学 提交时间： 2025-02-19
Huang, Dr. Liangsheng
Xu, Dr. Shou-Yan
Liu, Prof. Yuntao
Liu, Miss Yi-Qin
Chen, Dr. Jianliang
Deng, Mr. Changdong
Huang, Dr. Ming-Yang
Rao, Mr. Li
Liu, Dr. Hanyang
Qi, Dr. Xin
摘要： The Rapid Cycling Synchrotron (RCS) in the China Spallation Neutron Source (CSNS) operates as a high-intensity proton accelerator. The coupled bunch instability was observed during the RCS beam commissioning, which highly limits the beam power. To investigate the dynamics of instability under increased beam power, a pulsed octupole magnet with a gradient of 900T/m3 is developed. The magnet system integrates an octupole magnet with a pulsed power supply. The field is carefully measured to examine the performance before installation into the tunnel. After the installation of the magnets, beam measurements are performed to confirm the effectiveness of the instability mitigation on an actual proton beam. The measurement results show that the instability can be suppressed by using the pulsed octupole magnet, particularly at the high energy stage in an acceleration cycle, meeting the requirements for stable operation of the accelerator. Additionally, when the instability is completely suppressed through chromaticity optimization, octupole magnets can significantly enhance the RCS transmission efficiency, which is crucial for controlling beam loss. The pulsed octupole magnet offers significant progress of beam stability in the RCS, providing valuable experience for further beam power enhancement.
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