Superconducting multipole wiggler with large magnetic gap for HEPS-TF

A 16-pole superconducting multipole wiggler with a large gap of 68 mm was designed and fabricated to serve as a multipole wiggler for HEPS-TF.The wiggler consists of 16 pairs of NbTi superconducting coils with a period length of 170 mm,and its maximum peak field is 2.6 Tesla.In magnet design,magnet poles were optimized.Furthermore,the Lorentz force on the coils and electromagnetic force between the upper and lower halves were computed and analyzed along with the stored energy and inductance at different currents.To enhance the critical current of the magnet coil,all the pole coils selected for the magnet exhibited excellent performance,and appropriate prestress derived from the coil force analysis was applied to the pole coils during magnet assembly.The entire magnet structure was immersed in 4.2-K liquid helium in the cryostat cooled solely by four two-stage cryocoolers,and the performance test of the superconducting wiggler was appropriately completed.Based on the measured results,the first and second field integrals on the axis of the superconducting wiggler were significantly improved at different field levels after the compensation of the corrector coils.Subsequently,the wiggler was successfully installed in the storage ring of BEPCII operation with beams.

Themagnetic field measurement system for HEPS-TF superconducting wiggler

Background High Energy Photon Source(HEPS)is the fourth-generation synchrotron radiation source to be established in China.HEPS is a high-performance and high-energy synchrotron radiation light source with a beam energy of 6 GeV and an ultra-low emittance of better than 0.06 nm×rad(http://english.ihep.cas.cn/heps/index.html).Superconducting 3W1 wiggler magnet is one of the insertion devices in High Energy Photon Source Test Facility project(HEPS-TF).And it is also the key component to obtain higher brightness in high photon energy range.Purpose In the development process of superconducting wiggler,in order to ensure the magnetic field quality of each processing,it is necessary to monitor the magnetic field performance of before and after the full length bare magnet installed with cryostat.Therefore,different magnetic field measuring devices are being developed for different develop stages.Methods The magnetic field performance of the full length bare magnet should be tested in vertical at low temperature.After the magnetic structure is installed in the horizontal cryostat,the horizontal test is carried out.In view of these two processes,the vertical magnetic field measurement system and the horizontal magnetic field measurement system have been developed,respectively.Results The magnetic performances of the full length bare magnet and assembled with the horizontal cryostat were measured by the vertical and horizontal magnetic field measurement system.The first and second field integrals are corrected to better than the Physical requirements according to the magnetic field measurement results.Detailed magnetic field performances are described in this paper.Conclusion After more than a year operation of 3W1-SCW on the BII line station,the characteristic energy and photon flux of synchrotron radiation have been greatly improved,and the performance is excellent.It indicates that the measurement results of the magnetic field measurement system are reliable and credible.

多极超导扭摆器磁体磁场设计

上海光源二期工程建设计划研制一台多极超导扭摆器用于生物医学的X射线成像及治疗。该多极超导扭摆器由21对NbTi超导线圈组成,磁极气隙为22mm,在储存环束流电子能量为3.5GeV时其特征能量为33keV,覆盖的能量范围为20keV到120keV,可用于K边吸收成像、衍射增强成像、相衬成像、CT和微束放射治疗。文中的主要内容为一个具有21个磁极,周期长度为140mm,气隙中心磁感应强度为4.2T的多极超导扭摆器的磁场设计,包括磁极和线圈的参数设计、端部结构和周期磁场的积分场设计,以及简要的超导线圈应力应变分析。