Method for Reducing Outgas from Materials Used at the Vacuum Layer in Cryogenic Vessels and Its Evaluation

Abstract

The outgas from constituent materials in the vacuum jacket of a cryogenic vessel may seriously affect the degree of vacuum and it leads to deterioration of heat insulation performance. We measured the outgassing rates from each material that comprises the vacuum vessel. We also measured the effect on outgassing rate when the materials are heated to remove the gas from the materials before measurement. Based on experimental results, the effect of heat treatment for each material based on the outgassing model was discussed. It was found that coating the materials with GFRP is effective for reducing the outgassing rate.