Design and calibration of a test facility for MLI thermal performance measurements below 80K. [Multilayer insulation (MLI)]

Conference · Wed Apr 01 00:00:00 EST 1992

OSTI ID:5181429

Boroski, W; Kunzelman, R; Ruschman, M; Schoo, C

The design geometry of the SSC dipole cryostat includes active thermal radiation shields operating at 80K and 20K respectively. Extensive measurements conducted in a Heat Leak Test Facility (HLTF) have been used to evaluate the thermal performance of candidate multilayer insulation (MLI) systems for the 80K thermal shield, with the present system design based upon those measurement results. With the 80K MLI geometry established, efforts have focused on measuring the performance of MLI systems near 20K. A redesign of the HLTF has produced a measurement facility capable of conducting measurements with the warm boundary fixed at 80K and the cold boundary variable from 10K to 50K. Removing the 80K shield permits measurements with a warm boundary at 300K. The 80K boundary consists of a copper shield thermally anchored to a liquid nitrogen reservoir. The cold boundary consists of a copper anchor plate whose temperature is varied through boil-off gas from a 500 liter helium supply dewar. A transfer line heat exchanger supplies the boil-off gas to the anchor plate at a constant and controlled rate. The gas, which serves as cooling gas, is routed through a copper cooling tube soldered into the anchor plate. Varying the cooling gas flow rate varies the amount of refrigeration supplied to the anchor plate, thereby determining the plate temperature. A resistance heater installed on the anchor plate is regulated by a cryogenic temperature controller to provide final temperature control. Heat leak values are measured using a heatmeter which senses heat flow as a temperature gradient across a fixed thermal impedance. Since the thermal conductivity of the thermal impedance changes with temperature, the heatmeter is calibrated at key cold boundary temperatures. Thus, the system is capable of obtaining measurement data under a variety of system conditions. 7 refs.

• Research Organization: Fermi National Accelerator Lab., Batavia, IL (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03000
• OSTI ID: 5181429
• Report Number(s): FNAL/C-92/92; CONF-910635-20; ON: DE92016005
• Resource Relation: Conference: Cryogenic engineering conference and international cryogenic materials conference, Huntsville, AL (United States), 11-14 Jun 1991
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYOSTATS
TESTING
SUPERCONDUCTING SUPER COLLIDER
TEST FACILITIES
DESIGN
CALIBRATION
CONFIGURATION
HEAT TRANSFER
LEAK TESTING
PERFORMANCE
SHIELDING
THERMAL INSULATION
VACUUM SYSTEMS
CONTROL EQUIPMENT
ENERGY TRANSFER
EQUIPMENT
STORAGE RINGS
THERMOSTATS
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