Ulvac CRYO-U Series Instruction Manual page 21

CRYO-U Baking Type Cryopump Instruction Manual
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７．Stop the rough pumping exhaust system by closing the cryopump roughing valve
(RV1), the vacuum chamber roughing valve (RV2), and the turbo molecular pump
valve (RV3) sequentially when the temperature of the 15K cryopanel has been
cooled down to 20K or lower.
When the temperature of the 15K cryopanel has been cooled to 20K or lower, and the
80K shield cooled to 130K or lower, start exhausting the vacuum chamber by opening
the main valve (V1). (Refer to CRYO-U
information.)
Regarding step 4 of the process above, if a large amount of gas is emitted by the bake-out
of the vacuum chamber and the pressure inside the cryopump does not achieves 0.1Pa
easily, give priority to the bake-out of the cryopump over that of the vacuum chamber.
Subsequently perform baking for the vacuum chamber and then exhaust with the
cryopump. By doing so, the best ultimate pressure in clean condition can be achieved.
cryopump instruction manual for detailed
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ULVAC CRYOGENICS INCORPORATED 3-3