| 摘要 |
PURPOSE:To improve cooling efficiency of a gas exhaust surface and heating efficiency in reproducing, by disposing a heater for reproducing a gas discharge surface at a space to be evacuated to vacuum in front of the gas discharge surface which is cooled to an ultra-low temperature for condensing or absorbing gas. CONSTITUTION:Gas such as helium gas is supplied to a gas discharge surface 2 through a shevron type baffle 9 in a vacuum vessel 10. Since the gas is discharged from a gas phase by being condensed or absorbed by the gas discharge surface 2, a degree of vacuum in the vacuum vessel 10 is increased. When the discharged gas is accumulated in the gas discharge surface 2, activated charcoal 3 on the gas discharge surface 2 is heated for removing the accumulated gas and it is discharged to the outside of a system by a turbo molecule pump 11. A heater 14 for heating the activated charcoal 3 is supported by a support frame 15 which is cooled to a temperature of liquid nitrogen in a vacuum space in front of the gas discharge surface 2 and the support frame 15 is fixed to a radiant shield 8.
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