Development and Operation of a Three-pole Hybrid Wiggler Consisting of Superconducting and Normal-conducting Magnets at Saga Light Source:

Study of a Highly Practical Superconducting Wiggler

Abstract

A three-pole hybrid wiggler has been developed at the Saga Light Source synchrotron radiation facility. The development goal was to realize a three-pole wiggler with high operational stability and reliability under conditions of limited human resources and maintenance cost. The wiggler consists of a 4 T superconducting main pole and two 1 T normal-conducting side poles. The main pole can generate hard X-rays in the energy range up to approximately 40 keV. Use of the normalconducting side poles ensures significant margins for stationary and transient heat loads on the cryogenic system. The cryocooler cools the superconducting coils and iron poles via mechanical contact without liquid helium. To suppress the beam displacement due to the second integral of the magnetic field of the main pole, the main pole was designed to have relatively large field clamps at both pole ends. The wiggler was manufactured in FY2009 and was installed at the Saga Light Source storage ring in March 2010. Synchrotron radiation from the wiggler was observed at the beam line BL7 in late June 2010. Official user operation of the wiggler started in November 2010. To date, the wiggler has operated stably.