Distance Detector Manometer for Measurement and Control of Liquid Helium Temperatures in Magnetic Fields

1964 ◽  
Vol 35 (4) ◽  
pp. 499-502 ◽  
Author(s):  
E. W. Hornung ◽  
G. E. Brodale
Keyword(s):  
Magnetic Fields ◽  
Liquid Helium ◽  
And Control ◽  
Measurement And Control

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.

2. Measurement and Control of Airborne Microorganisms Using Electrostatic Methods

2001 ◽  
Author(s):  
G. Mainelis ◽  
R. Gorny ◽  
K. Willeke ◽  
S. Grinshpun ◽  
T. Reponen ◽  
...  
Keyword(s):  
Airborne Microorganisms ◽  
And Control ◽  
Measurement And Control
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