Prototype HTS Quadrupole Magnet for the In-Flight Fragment Separator of RISP

Abstract

The Rare Isotope Science Project (RISP) for constructing a heavy ion accelerator complex was launched in 2011 in Korea. As one of the rare isotope production systems, an in-flight fragment (IF) separator system will be installed for the RISP. We plan to use high-temperature superconducting (HTS) quadrupole magnets in the forepart of the IF separator to cool efficiently the magnets from large radiation heat load at around 40 K. The HTS quadrupole magnet should withstand a high radiation dose (~10 MGy/year). A prototype HTS quadrupole magnet was designed and fabricated taking into account the radiation damage and heating. The magnet employs two kinds of HTS wires, and the HTS wire is cowound with a stainless steel tape for electrical insulation. The magnet is cooled by circulation of cold helium gas through the cooling channels. Various tests were performed under normal and abnormal operating conditions. The test results show that the HTS quadrupole magnet can operate in the required field gradient stably. The magnet can also be self-protected by metal insulation under the abnormal operating conditions.