First demonstration of a cryocooler conduction cooled superconducting radiofrequency cavity operating at practical cw accelerating gradients

• Published in: Superconductor science & technology Vol. 33; no. 6
• Main Authors: Dhuley, R. C., Posen, S., Geelhoed, M. I., Prokofiev, O., Thangaraj, J. C. T.
• Format: Journal Article
• Language: English
• Published: United Kingdom IOP Publishing 20.04.2020
• Subjects: INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; PARTICLE ACCELERATORS
• ISSN: 0953-2048; 1361-6668

Abstract We demonstrate practical accelerating gradients on a superconducting radiofrequency (SRF) accelerator cavity with cryocooler conduction cooling, a cooling technique that does not involve the complexities of the conventional liquid helium bath. A design is first presented that enables conduction cooling an elliptical-cell SRF cavity. Implementing this design, a single cell 650 MHz Nb 3 Sn cavity coupled using high purity aluminum thermal links to a 4 K pulse tube cryocooler generated accelerating gradients up to 6.6 MV m −1 at 100% duty cycle. The experiments were carried out with the cavity-cryocooler assembly in a simple vacuum vessel, completely free of circulating liquid cryogens. We anticipate that this cryocooling technique will make the SRF technology accessible to interested accelerator researchers who lack access to full-stack helium cryogenic systems. Furthermore, the technique can lead to SRF based compact sources of high average power electron beams for environmental protection and industrial applications. A concept of such an SRF compact accelerator is presented.