Investigation of vacuum properties of CuCrZr alloy for high-heat-load absorber

The Taiwan Photon Source (TPS) uses high-heat-load (HHL) absorbers to protect downstream ultrahigh vacuum chambers from overheating. In this work, we propose to use the CuCrZr alloy (ASTM C18150) for the HHL absorber body and the ConFlat (R) flanges. We use the throughput method to measure the thermal outgassing rate and a helium leak detector to verify the vacuum seal between the CuCrZr alloy and stainless steel flanges. The measured outgassing rate of the CuCrZr alloy was 5.8x10(-10) Pa m/s after 72 h of pumping and decreased to 2.0x 10(-10) Pa m/s after 100 h of pumping. The leak rate through the vacuum seal between a CuCrZr flange and a stainless-steel flange was less than 1 x 10(-10) Pa m(3)/s even after mounting and unmounling the flanges ten times and baking them at 250 degrees C. These results indicate that CuCrZr alloy is suitable for integrating HHL components with ConFlat (R) CuCrZr flanges for the absorption of the synchrotron radiation generated by the TPS.