Development and operating experience of a 1.2-m long helical superconducting undulator at the Argonne Advanced Photon Source

Abstract

Development of superconducting undulators (SCUs) continues at the Advanced Photon Source (APS). Several planar SCUs were designed and built, and two of them are currently in operation at the APS. In January 2018 a new helical SCU (HSCU) was installed on the storage ring at the APS. It has a 1.2 m-long magnet with bifilar winding that generates on its axis a single harmonic of about 6 keV x-rays. The magnet is housed in the newly designed compact cryostat equipped with four cryocoolers. The HSCU was extensively tested prior to its installation on the APS storage ring, and it demonstrated cryogenic and magnetic performance in accordance with the design specifications. The HSCU was rapidly and successfully commissioned, and in February 2018 it was transferred to user operations. Its performance as an x-ray radiation source has been studied and spectral characteristics confirmed. The HSCU is currently used to support unique scientific program at the APS.