Nucleate Cooling Stability for Superconductor-Normal Metal Composite Conductors in Liquid Helium

1995 ◽  
pp. 68-79 ◽  
Author(s):  
C. N. Whetstone ◽  
R. W. Boom
Keyword(s):  
Liquid Helium ◽  
Normal Metal ◽  
Metal Composite ◽  
Composite Conductors

A Superconducting Microscope

1971 ◽  
Vol 29 ◽  
pp. 10-11 ◽  
Author(s):  
R. E. Worsham ◽  
J. E. Mann ◽  
E. G. Richardson
Keyword(s):  
Liquid Helium ◽  
Focal Length ◽  
Vacuum System ◽  
Objective Lens ◽  
Electrical Instability ◽  
Radiation Shields ◽  
And Control ◽  
Thermal Oscillations ◽  
Flux Pump

This superconducting microscope, Figure 1, was first operated in May, 1970. The column, which started life as a Siemens Elmiskop I, was modified by removing the objective and intermediate lenses, the specimen chamber, and the complete vacuum system. The large cryostat contains the objective lens and stage. They are attached to the bottom of the 7-liter helium vessel and are surrounded by two vapor-cooled radiation shields.In the initial operational period 5-mm and 2-mm focal length objective lens pole pieces were used giving magnification up to 45000X. Without a stigmator and precision ground pole pieces, a resolution of about 50-100Å was achieved. The boil-off rate of the liquid helium was reduced to 0.2-0.3ℓ/hour after elimination of thermal oscillations in the cryostat. The calculated boil-off was 0.2ℓ/hour. No effect caused by mechanical or electrical instability was found. Both 4.2°K and 1.7-1.9°K operation were routine. Flux pump excitation and control of the lens were quite smooth, simple, and, apparently highly stable. Alignment of the objective lens proved quite awkward, however, with the long-thin epoxy glass posts used for supporting the lens.

Water accumulation as a function of temperature on specimens in an electron microscope cold stage

1986 ◽  
Vol 44 ◽  
pp. 114-115 ◽  
Author(s):  
M.K. Lamvik ◽  
D.A. Kopf ◽  
S.D. Davilla ◽  
J.D. Robertson
Keyword(s):  
Electron Microscope ◽  
Mass Loss ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Cold Stage ◽  
Water Accumulation ◽  
Better Than

Last year we reported1 that there is a striking reduction in the rate of mass loss when a specimen is observed at liquid helium temperature. It is important to determine whether liquid helium temperature is significantly better than liquid nitrogen temperature. This requires a good understanding of mass loss effects in cold stages around 100K.

RAYLEIGH AND BRILLOUIN SCATTERING FROM LIQUID HELIUM

1972 ◽  
Vol 33 (C1) ◽  
pp. C1-25-C1-26 ◽  
Author(s):  
E. R. PIKE
Keyword(s):  
Liquid Helium ◽  
Brillouin Scattering

Instability of the charged surface of liquid helium

1978 ◽  
Vol 126 (12) ◽  
pp. 693-694
Author(s):  
D.M. Chernikova ◽  
L.P. Gor'kov
Keyword(s):  
Liquid Helium ◽  
Charged Surface

Electrons above the surface of liquid helium

1978 ◽  
Vol 126 (12) ◽  
pp. 690-691
Author(s):  
V.B. Shikin
Keyword(s):  
Liquid Helium
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