NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Measurement of the cooling capacity of an RMC-Cryosystems Model LTS 4.5-025 closed-cycle helium refrigeratorThe cooling capacity of a recently purchased RMC-Cryosystems Model LTS 4.5-025 closed-cycle He refrigerator was measured over the range 4-35 K. It is found that the nominal cooling capacity of 250 mW is only met or exceeded over a narrow temperature range around 4.3 + or - 0.5 K, and that, above this range, there exists a considerable region of much lower cooling capacity, not exceeding about 100 mW. It is believed that this behavior results from use of a fixed-aperture Joule-Thompson expansion valve, and might be alleviated if the J-T valve could be adjusted to compensate for changing flow within the 5-20 K temperature range. Present performance may severely limit or prevent effective use in applications where an irreducible heat inflow exists which is greater than about 100 mW, yet substantially less than the quoted capacity at about 4 K.
Document ID
19910051621
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
De Zafra, R. L. (State Univ. of New York Stony Brook, NY, United States)
Mallison, W. H. (State Univ. of New York Stony Brook, NY, United States)
Emmons, L. K. (State Univ. of New York Stony Brook, NY, United States)
Koller, D. (New York, State University Stony Brook, United States)
Date Acquired
August 15, 2013
Publication Date
May 1, 1991
Publication Information
Publication: Review of Scientific Instruments
Volume: 62
ISSN: 0034-6748
Subject Category
ENGINEERING (GENERAL)
Funding Number(s)
CONTRACT_GRANT: NAGW-2182
Distribution Limits
Public
Copyright
Other