Cooling properties of HOM absorber model for cERL in Japan

Sawamura, Masaru; Furuya, Takaaki*; Sakai, Hiroshi*; Umemori, Kensei*; Shinoe, Kenji*; Cenni, E.*

The HOM absorber model was designed and fabricated according to results of ferrites and ceramic properties measurement at low temperature. The HOM absorber model uses the RF absorber of HIP (Hot Isostatic Press) ferrite attached on the copper base. The comb-type RF bridge is adopted at the beam pipe connection between the HIP ferrite part and the flange part. Both parts of the RF bridge are connected with a bellows to reduce the heat load into the superconducting cavity. The HOM absorbers are also required to have good thermal transmission properties to effectively remove the HOM absorption power. The HOM absorber without ferrite was used to measure the thermal properties at liquid nitrogen temperature. Prototype of HIP ferrite model was fabricated. The thermal simulation calculation was also performed. Thermal cycle test between the room temperature and 80 K with a GM refrigerator was also carried out to check the thermal tolerance of the HIP ferrite.