二极铁超导磁体低温恒温器组装测试  

Fabrication and test of a cryostat for superconducting dipole magnet

作　　者：周涛 李超[2] 刘伟 兰贤辉 马鹏 葛正福 Zhou Tao;Li Chao;Liu Wei;Lan Xianhui;Ma Peng;Ge Zhengfu(Xi'an Superconducting Magnet Technologies Co.,Ltd.,Xi'an 710016,China;Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]西安聚能超导磁体科技有限公司,西安710016 [2]西北工业大学,西安710072

出　　处：《低温与超导》2023年第8期17-23,45,共8页Cryogenics and Superconductivity

基　　金：陕西省重点专项项目(2021LLRH-05-13)资助。

摘　　要：依托FRIB二极铁超导磁体样机研制项目,完成磁体低温恒温器系统制作,低温恒温器主要部件有:氦槽(装有两组D型线圈的线圈盒组成)、隔热冷屏、支撑结构、真空腔体、阀箱冷却系统等。磁体系统运行电流为201 A,中心最大磁场达到2 T,线圈使用线径Φ1.14 NbTi超导线,每组线圈的匝数为210匝,束流孔截面空间100 mm*35 mm,弯转角度45度。二极铁超导磁体低温恒温器采用液氦冷却,运行温度为4.2 K,低温液氦挥发的氦气通过阀箱将冷氦气接入冷屏的氦气循环管路对冷屏进行冷却,降低氦槽液氦静态蒸发率。制作过程通过设置专用的绕线工装保证线圈绕制精度,通过杜瓦装配工装保证线圈盒和真空腔的定位精度。二极铁超导磁体低温恒温器支撑结构通过“反拉伸”结构保证强度,同时降低传导漏热,低温下进行磁场中心位置补偿,从而实现磁场中心和束流孔同心度的制作要求。最后对系统进行降温和励磁测试,低温恒温器漏率3×10^(-9)Pa·m^(3)/s,液氦静态蒸发率1.4 L/h,磁场中心和束流孔同心度偏移量为±0.25 mm,达到设计制作要求。Based on the project of FRIB Superconducting Dipole magnet,a cryostat system for cooling the magnet was developed.The cryostat consisted of the helium vessel,the cold shield,the support structure,the vacuum vessel and the distribution cooling system and so on.The magnet system operates at a current of 201 A,the maximum magnetic field is 2 T.The D-coil is constructed usingΦ1.14 NbTi superconducting wire with 210 turns,the section space of beam chamber is 100 mm*35 mm,and with a bending angle of 45 degrees.The operating temperature is 4.2 K.To reduce the static evaporation rate of liquid helium in the helium vessel,low-temperature liquid helium was transferred into the thermal shield through the distribution,which cooled the thermal shield in the helium circulation pipe.In the manufacturing process,a special winding fixture was used to ensure the accuracy of coil winding,while a Dewar fixture is used to ensure the positioning accuracy of the helium vessel and beam chamber.The support structure of superconducting dipole magnet ensures strength through the"reverse tension"structure,reducing heat leakage by conduction.In cold down condition to adjust for center compensation,thus meeting the manufacturing requirements for the magnetic field center.Finally,the cryostat system was cooled and tested.The cryostat has a leakage rate of 3×10^(-9)Pa·m^(3)/s,the static evaporation rate of liquid helium is 1.4 L/h,and the concentricity offset of the magnetic field center and the beam chamber is±0.25 mm,all of them meet the requirements.

关 键 词：超导磁体 二极铁 低温恒温器 冷屏 阀箱 束流孔 

分 类 号：TM26[一般工业技术—材料科学与工程]