A new cost effective composite getter for application in high-vacuum-multilayer-insulation tank

H-2 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 H-2 in HVMIT than the other getters investigated. H-2 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. H-2 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. (C) 2016 Elsevier Ltd. All rights reserved.