Integration and commissioning of the ARIEL e-linac cryogenic system at TRIUMF

The Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the Isotope Separation and Acceleration (ISAC) facility at TRIUMF. The key part of the ARIEL project is a superconducting radiofrequency (SRF) linear electron accelerator (e-linac). The e-linac helium cryogenic system was designed to meet the ARIEL specifications. The HELIAL LL helium liquefier by Air Liquide Advanced Technologies supplies 4 K liquid helium (LHe) to cryomodules via a LHe distribution system. The cryomodules have a top-loaded-cold mass design. The 4 K -2 K temperature conversion is achieved by a counter flow heat exchanger and a JT-valve installed onboard each cryomodule [ 1]. The temperature in the 2 K volume of the cryomodules is controlled by pressure control in the sub-atmospheric line. Sub-atmospheric helium is warmed up in a custom-designed heat exchanger and after passing sub-atmospheric pumps goes to the helium compressor suction line. The LN2 system supplies liquid nitrogen to the liquefier, 80 K shielding of the cryomodules and LHe distribution system, as well as to the freeze-out helium purifier. The installation of the e-linac cryogenic system components started in February 2013 while the corresponding subsystems tests started in November 2013. This paper describes the e-linac cryogenic system components integration and presents the results of the acceptance tests and commissioning activities performed at TRIUMF since November 2013. Crown Copyright (C) 2015 The Authors. Published by Elsevier B.V.