A refrigerator capable of operating both in evaporation and dilution modes is described. The refrigerator provides preliminary cooling of investigated samples down to a starting temperature of about 0.3 K and permits the location of samples directly in the mixing chamber as well as their replacement
Can He3 - He4 dilution refrigerators operate aboard spacecraft?
β Scribed by H.W. Jackson
- Publisher
- Elsevier Science
- Year
- 1982
- Tongue
- English
- Weight
- 319 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0011-2275
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β¦ Synopsis
Cooling to temperatures in the millikelvin range could be beneficial as a means of reducing noise and increasing sensitivity of instruments in certain experiments and measurements that are being considered for future space missions. The possibility of using a He 3 -He 4 dilution refrigerator for that purpose is explored in this paper. Calculations reported here indicate that electrostriction can be substituted for gravity as a practical means of achieving phase separation with well-defined interfaces in mixing chambers of dilution refrigerators operating aboard spacecraft.
π SIMILAR VOLUMES
A 3He/4He dilution refrigerator is described where the instreaming 3He is precooled and liquefied by a counterflow heat exchanger which makes use of the enthalpy of the cold 3He gas pumped out of the still, and by subsequent Joule-Thomson expansion. This condenser replaces the usual 4He condenser.
torque on the tight contacts improved the contact resistances from values between 5 and I0 /~ to values between 1 and 2/zQ. 6 Tests with variable forces on the contacts were also carried out. The effect of the force was not reversible and the results for a particular force depended on whether the le
Arp, V.D. Thermodynamics of single-phase one-dimensional fluid flow Cryogenics 15 (1975) 285 33 Arp, V.D. New forms of state equations for helium Cryogenics 14 (1974) 593 34 l~ney, D.E. Friction factors for flow of near-critical helium in curved tubes Cryogenics 18 (1978) 345 35 Ito, IL Friction fac