A preliminary thermal model of the SCAPE undulator cryogen-free cryostat

The SCAPE (Superconducting Arbitrarily Polarizing Emitter) undulator is under development at the Advanced Photon Source (APS) as a part of the APS upgrade at Argonne National Laboratory. This new undulator requires a cryostat to handle the heat load on the beam chamber at a level of 182 W – much higher than in APS planar superconducting undulators. These challenges require careful thermal analysis of the SCAPE cryostat. Despite relatively large heat loads, a cryostat that does not contain any cryogen is a desirable option. Based on the experience on demo scale tests on SCAPE, a cryocooler-based cryogen-free cryostat is proposed. A detailed thermal model of such a cryostat has been created in Thermal Desktop. This paper presents the calculated heat load and temperatures profile of this cryostat under the static and dynamic heat loads