Open AccessDemonstration of CW accelerating gradients on a cryogen-free, cryocooler conduction-cooled SRF cavity
Author(s) -
Ram Dhuley,
Michael Geelhoed,
Yunsong Zhao,
I. Terechkine,
M. Alvarez,
O. Prokofiev,
J. C. T. Thangaraj
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/755/1/012136
Subject(s) - cryocooler , niobium , materials science , liquid helium , thermal conduction , cryogenics , continuous wave , pulse tube refrigerator , superconducting radio frequency , temperature gradient , helium , dilution refrigerator , optics , optoelectronics , refrigerator car , atomic physics , particle accelerator , physics , thermodynamics , heat exchanger , laser , composite material , beam (structure) , quantum mechanics , regenerative heat exchanger , metallurgy
Conduction-cooling of superconducting radiofrequency (SRF) cavities using closed-cycle cryocoolers can lead to compact linear accelerators by eliminating liquid helium and the associated infrastructure. In this paper, we present the first-ever experimental demonstration of continuous wave (CW) accelerating gradients on a niobium SRF cavity that is cooled without using liquid helium. In a newly developed experimental apparatus, a single-cell, 650 MHz niobium cavity was conductively coupled to a 2 W @ 4.2 K pulse tube cryocooler using a high-purity aluminum thermal link. The CW accelerating gradient slightly exceeded 1.5 MV/m, a limit imposed by our RF power supply. Using simple scaling, we project that the niobium cavity when coated with Nb 3 Sn and operated on the same experimental setup can produce >10 MV/m CW accelerating gradients.