High performance stabilization in superfluid helium
โ Scribed by M. Francois
- Publisher
- Elsevier Science
- Year
- 1975
- Tongue
- English
- Weight
- 353 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0011-2275
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โฆ Synopsis
A simple and automatic system for temperature stabilization, between 1.8 and 2.2 K, is presented. The thermometers used together in this system are a second or fourth sound cavity and a germanium resistance thermometer. One gives results showing a stability of better than 1t78 degree.
๐ SIMILAR VOLUMES
Flowing superflu~d hehum cav=tates much more readdy than normal hqu=d hehum, and there ts a marked difference =n the cavitation behav=our of the two flmds as the lambda point is traversed Examples of cavJtatton m a turbine meter and centnfugal pump are gtven together wtth measurements of the cavttat
Superconductor stability against local heat pulses in saturated He-I at 4.2 K and pressurized and saturated He-II at 2.05 K has been reported. It is shown that the stability increases in pressurized He-I I as compared to saturated He-I I which only increases in the range of low normal zone propagati
For stabilizing the temperature of superfluid helium dc 1 or ac 2,3 bridge circuits are usually employed, in which the temperature probe is a resistance thermometer and the power dissipated in a wire heater is proportional to the out-of-balance signal.
The behaviour of nearly-saturated superfluid helium films, several hundred Angstroms thick was investigated under zero gravity conditions in a small cryostat carried on a 0.3 m diameter, 3 m long sounding rocket, using a quartz microbalance technique 1'2. The flight provided 30 s of high acceleratio