Cryo-Torr High-Vacuum Pump Installation, Operation and Maintenance Instructions
P/N 8040613
3-3
C
HELIX TECHNOLOGY CORPORATION
-
TI
CRYOGENICS
5. When the condensing arrays reach ambient temperature, rough the
cryopump to an initial starting pressure, usually between 50 and
100 microns.
NOTE: After roughing, perform a rate-of-rise (ROR) test to ensure that
your cryopump regeneration has been thorough and that no air-to-vacuum
leaks are present.
6. Perform the rate-of-rise test as follows:
a. Once the roughing cycle has roughed the cryopump starting
pressure to between 50 - 100 microns, close the roughing
valve.
b. Observe the rate of pressure rise (ROR) over a five minute
period.
NOTE: The ROR should be less than 10 microns/minute over a five minute
period (50 microns total).
c. If the ROR is greater than 50 microns, repurge the cry-
opump, check for leaks, and repeat steps 5 and 6.
7. Close the cryopump roughing valve and start the cryopump.
8. The cryopump is ready for use when the second stage array reaches
a temperature of 20K or lower.
