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Principles of Operation
Cryogenic Systems Operation
High pressure helium gas is supplied from the helium
compressor to the CCC or helium refrigerator located inside
of the CryoBay. Most of the high pressure helium goes to
driving the GM. A small amount of the high pressure helium
is tapped off and sent through the heat- exchange loop (cold
loop for the probe). The gas that is tapped off for use in
cooling the probe is cooled by the heat exchange loop in the
CCC. Cold helium gas is circulated through a cryogenic
transfer line to the probe and back to the CCC. Probe
components are cooled by the cold helium gas. The
temperature of the cooling gas inside the probe is regulated
by a temperature controller located in the CryoBay. The
temperature controller uses a
proportional- integral- differential (PID) feedback loop to
regulate the temperature of the gas at the set point.
All of the cryogenic portions of the system are insulated
from room temperature by means of vacuum insulation.
Helium gas circulates in a closed loop and is not consumed
during normal operations. The circulating helium gas must
be kept free of contaminants (particularly, air and water
vapor).
Principles of Operation
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