Mechanical vibration study of low-energy superconducting linear accelerator (SCL3) in RAON

Recently, the Institute for Rare Isotope Science (IRIS, previously RISP) in the Institute for Basic Science (IBS), Daejeon, South Korea, finished the first beam commissioning for operating of low-energy superconducting linear accelerator (SCL3). SCL3 is composed of two types of cavity, quarter wave resonator (QWR) which has 81.25 MHz RF frequency and half wave resonator (HWR) which has 162.5 MHz RF frequency. During operation, RF control was very complicated due to many issues including mechanical vibrations coming from vacuum pump, cryogenic valve, or undefined source. In this paper, we will discuss the SCL3 mechanical vibration data measured by a laser doppler vibrometer (LDV). In addition, the mechanical vibration of SCL3 cryogenic components such as transfer lines and supports will be also described.