The magnetic 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.