Cryogenic Design of a Superconducting Solenoid for Muonium Hyperfine Structure Measurement
Cryogenic Design of a Superconducting Solenoid for Muonium Hyperfine Structure Measurement
复制标题
用于μ超精细结构测量的超导螺线管的低温设计
DOI：
10.1109/tasc.2012.2233259
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and A. Yamamoto
中科院分区：
文献类型：
--
作者：
M. Sugano;K. Sasaki;R. Ohkubo;T. Kume;N. Kimura;R. Okada;T. Okamura;K. Shimomura;N;Saito;T. Ogitsu;and A. Yamamoto
精确测量μ 鎓超精细结构（MuHFS）已计划在J-PARC进行。该实验的关键部件是场均匀度高达1 ppm的超导螺线管磁体。在本文中，我们专注于这种磁体的低温设计。估计了磁体系统的总热量输入，并确定了制冷机的组合。为了将漏热降低到4K，考虑了氦排气管的结构和挡板的不同布置。基于射线追踪模型，计算了弯管的辐射热输入。对当前电极导线进行了冷却测试。我们证实，聚酰亚胺胶带绝缘铜引线与施加的电流为400 A，可以传导冷却的温度差为5 K的制冷机的冷阶段。机械振动是实现所需场均匀性的关键问题。我们还开始使用He再冷凝低温恒温器进行振动测量，以考虑线圈的支撑结构。
Precise measurement of the muonium hyperfine structure (MuHFS) has been planned at J-PARC. The key component of this experiment is a superconducting solenoid magnet with field homogeneity as high as 1 ppm. In this paper, we focus on the cryogenic design of this magnet. The total heat input to the magnet system was estimated and a combination of cryocoolers was determined. To reduce the heat leakage to 4 K, the structure of a He exhaust pipe and different arrangements of the baffles were considered. Based on the ray-trace model, radiation heat input through a bent pipe was calculated. A cooling test was carried out for the current lead. We confirmed that the polyimide tape-insulated Cu lead with an applied current of 400 A can be conduction-cooled with temperature difference of 5 K from the cold stage of a cryocooler. Mechanical vibration is a critical issue to achieve the required field homogeneity. We have also started vibration measurements using a He re-condensation cryostat to consider support structure of the coils.