Integration and Commissioning of the ARIEL e-linac Cryogenic System at TRIUMF☆

Abstract The Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the Isotope Separationand 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 cryogenicsystem was designed to meet the ARIEL specifications. The HELIAL LL heliumliquefier byAir Liquide Advanced Technologiessupplies 4 K liquid helium(LHe) to cryomodulesvia aLHe distribution system. The cryomoduleshave a top-loaded-coldmass 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 cryomodulesis controlled by pressure control in the sub-atmospheric line. Sub-atmospheric heliumis warmed up in a custom-designed heat exchanger and after passing sub-atmospheric pumps goes to the heliumcompressor suction line. The LN 2 system supplies liquid nitrogen to the liquefier, 80 K shielding of the cryomodulesand LHe distribution system, as well as to the freeze-out heliumpurifier. The installation of the e-linac cryogenicsystem components started in February 2013 while the corresponding subsystems tests started in November 2013. This paper describes the e-linac cryogenicsystem components integration and presents the results of the acceptance testsand commissioning activities performed at TRIUMF since November 2013.