A new cost effective composite getter for application in high vacuum multilayer insulation tank
Abstract H2 is the main residual gas in the chamber of high vacuum multilayer insulation tank (HVMIT) and is adsorbed by the expensive getter PdO. Adsorption characteristics of more cost effective getters (CuO, CuO 5A and CuO C) were investigated and adsorption products were analyzed by measuring the pressure decrease in a known volume as function of time using our designed experimental setup. CuO C was more suitable to adsorb H2 in HVMIT than the other getters investigated. H2 adsorption amount and pumping speed were significantly larger than CuO and CuO 5A getter systems. Working temperature could be also reduced with respect to these two getter bed, this being advantageous from the operational point of view. Adsorption isotherm was type I as accurately described by Langmuir model. H2 sorption amount was 170.6 mL(stp)/g at equilibrium pressure not higher than 5.8 x 10 2 Pa, saturated sorption amount was 296.4 mL(stp)/g at room temperature, and sorption products were Cu and H2O (g) When adsorption equilibrium was obtained, HVMIT was fed with liquid nitrogen. Interlayer pressure decreased sharply to 5.83 x 10 4 Pa in a stepwise shape for 10 h. This vacuum level is appropriate for ensuring good insulation level in the tank.