共查询到18条相似文献,搜索用时 46 毫秒
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本文介绍BEPC储存环插入一块高场水平扭摆磁铁情况下一种可能的补偿方法。利用位于扭摆磁铁附近消失差区域中的由独立电源供电的四块四极磁铁,按Twiss参量重新匹配的要求改变其强度,在扭摆磁铁和四块四极磁铁所在区域及其以外区域,均可获得Twiss参量补偿的满意结果。 相似文献
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陶瓷真空盒作为中国散裂中子源(CSNS)快循环同步加速器(RCS)真空系统的关键部件,能避免RCS二极、四极交流磁铁因快速变化的磁场而产生的涡旋电流。因安装空间限制,RCS陶瓷真空盒支架固定在磁铁线圈上。在CSNS/RCS交流磁铁长时间加电测试中,出现陶瓷真空盒断裂、真空破坏的情况。为避免后期出现类似问题,从磁铁发热进而引起陶瓷真空盒不均匀升温的角度出发,对陶瓷真空盒的热特性进行了分析,同时基于双目视觉测量技术,对陶瓷真空盒的振动情况进行了监测,针对部分真空盒水平方向振动异常的问题,确定其影响因素为快卸链条的磁导率超标。最后开展了陶瓷真空盒的支架减振技术研究。 相似文献
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中国科学院近代物理研究所研制的医用重离子加速器装置是我国第1台拥有自主知识产权的医用重离子加速器,其高频脉冲二极磁铁使用RAMPING工作模式且磁场上升速率为1.6 T/s,所以安装在高频脉冲磁铁内的真空室采用一种薄壁加筋结构不锈钢真空室以减少涡流对离子束稳定性的影响。然而由于薄壁加筋不锈钢真空室占用磁铁气隙尺寸偏大,不仅造成了磁铁造价成本偏高,更是提高了运维成本。基于以上原因,本文提出陶瓷内衬薄壁(0.3 mm)真空室,并研制了原理样机。测试结果表明:样机真空度进入了10-10 Pa量级范围,并可有效减小磁铁气隙,是未来加速器薄壁真空室的发展方向。 相似文献
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LUO Cheng YANG Weishun XIE Wenjun LI Changchun CHAI Zhen ZHU Xiaorong LIU Jianlong JIAO Jiqiang WAN Yapeng LIN Xiaojian MA Xiangli ZHANG Xiping MENG Jun CHEN Shuping 《原子能科学技术》1959,54(11):2245-2251
Heavy Ion Medical Machine (HIMM), developed by the Institute of Modern Physics, Chinese Academy of Sciences, is the first medical heavy ion accelerator with independent intellectual property rights in China. Because the RAMPING mode was used for high frequency pulse dipole magnets of HIMM and the rising rate of magnetic field is 1.6 T/s, the vacuum chamber installed in the high frequency pulsed magnet is a thin-wall stainless vacuum chamber with reinforcing ribs to reduce the influence of eddy current on the ion beam stability. However, the gap size of magnet occupied by thin-wall stainless vacuum chamber with reinforcing ribs is too large, and it not only causes the high cost of magnets, but also greatly improves the maintenance cost. Based on these reasons, a new thin-wall vacuum chamber (0.3 mm) with ceramic lining was put forward and the prototype was designed and manufactured. The test results show that the obtained pressure of the prototype is in the order magnitude of 10-10 Pa, and the magnet gap can be effectively reduced. And it is the development direction of thin-wall vacuum chamber of accelerator in the future. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(12):1077-1080
Parallel-plate free-air ionization chambers are used for X-ray air-kerma rate standards at the National Metrology Institute of Japan (NMIJ), AIST. The electron-loss and photon-scattering correction factors are needed for the evaluation of air-kerma rate from measured current. The electron-loss correction factor (Ke) is a correction of the charge loss by giving energy to the electrode part without the high-speed electron stopping in the air area where the charges are collected. The scattering correction factor (Ksc) is for a correction of extra charges produced by scattered photons generated after an incidence photon is interactive. The electron-loss and photon-scattering correction factors for 3 different size parallel-plate free-air chambers are estimated by the EGS4 code. One chamber is used to get primary standards for absolute measurements of air kerma in beams of medium-energy X-rays and the other two are used for the same purpose in beams of low-energy X-rays. These correction factors are calculated for mono-energetic photons. It is found that electron-loss and photon-scattering correction factors depend on the chamber size, and the latter especially changes greatly depending on the size. The Ke and Ksc value for medium-and low-energy X-ray fields at AIST are estimated by averaging the energy deposition contributions over the X-ray spectrum. 相似文献
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介绍了T34035型Hp(10)次级标准电离室的结构和技术特性,实验测量了Hp(10)次级标准电离室的校准系数NH和修正因子k(R,α),并评定给出校准系数NH的相对扩展不确定度为4.6%(k=2),修正因子k(R,α)的相对扩展不确定度为6.0%(k=2)。在辐射质入射角≤75 °时,12~1 250 keV范围内能量响应好于±20%;个人剂量当量率非线性在100 μSv/h~3 Sv/h范围内好于±3%。采用 MCNP5模拟计算了该电离室对部分窄谱N系列和低空气比释动能L系列的k(R,α)值,结果表明计算值与实验测量值之间的相对误差在±6%范围内。说明该电离室性能满足次级标准电离室要求,可以直接用于Hp(10)量值的传递。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(11):847-852
A thin film thermometer with high sensitivity and small response time has been developed. A nickel film was deposited in a vacuum on a backing plate of stainless steel 0.05 mm thick. The pattern of nickel film was so designed to provide sufficient accuracy. A small heat flux of 0.5 W/cm2 is measurable with a response time of less than 1 ms. The thermometer was applied to radiation loss measurement in JFT-2 tokamak. The power loss due to the radiation was found to be about 30% of the total power input. 相似文献