Design of a horizontal test cryostat for superconducting RF cavities for the FREIA facility at Uppsala University

Abstract

Uppsala University is constructing a large scale facility, called FREIA (Facility for Research Instrumentation and Accelerator Development). FREIA includes a helium liquefier and an accelerator test facility and has the capacity to test superconducting radio-frequency (RF) cavities with the same RF system and RF power level as in an accelerator. A central element of FREIA is a horizontal test cryostat connected in closed loop to a helium liquefier. This cryostat can house two fully equipped (tuners, piezo, power coupler, helium tank) superconducting cavities to perform full RF high power tests and operate at temperatures between 1.8 K and 4.2 K. The cryostat is designed to accommodate a large array of superconducting cavities and magnets, among which the European Spallation Source (ESS) type spoke and high-β elliptical cavities as well as TESLA/ILC type elliptical cavities. The present status of the project and the design of the cryostat are reported..

Accelerator development at the FREIA Laboratory

“…A third route passes the 4 K helium via a heat exchanger to a Joule-Thomson valve, where the helium temperature is lowered by isenthalpic expansion. The resulting helium, at temperatures down to 1.8 K, is collected in a second dewar, called the 2 K pot, from where it is delivered to the cavities [15]. A bypass line for the Joule-Thompson valve allows us to operate fully in 4 K mode.…”

Accelerator Development at the FREIA Laboratory

“…A third route passes the 4 K Helium via a heat exchanger to a Joule-Thomson valve, where the helium temperature is lowered by isenthalpic expansion. The resulting helium, at temperatures down to 1.8 K, is collected in a second dewar, called the 2K pot, from where it is delivered to the cavities [15]. A bypass line for the Joule-Thompson valve allows us to operate fully in 4 K mode.…”