理研超伝導重イオン線形加速器のヘリウム冷凍システム ―システム概要と運転について―

抄録

A helium cryogenics system for the superconducting heavy-ion linear accelerator (SRILAC) has been introduced at the RIKEN Nishina Center. The SRILAC contains a total of 10 superconducting quarter-wave-length resonators made of pure niobium materials installed in 3 cryomodules; which realizes the beam energy upgrade of the existing room-temperature linear accelerator. The refrigerator, a HELIAL MF manufactured by Air Liquide, has successfully accomplished a cooling capacity of about 730 W and a sufficient helium pressure stability with a fluctuation less than ±0.4 kPa. The cryogenic system started operation in October 2019, and the SRILAC has been supplying beams to experiments since June 2020, along with a stable operation of the cryogenics system. This article provides an overview of the cryomodule and the helium cryogenics system as well as the operational status of the helium cryogenics system.