Liquid helium-free high-T c superconducting terahertz emission system and its applications

2020 ◽  
Vol 59 (10) ◽  
pp. 105004
Author(s):  
Yoshihiko Saiwai ◽  
Takanari Kashiwagi ◽  
Kurama Nakade ◽  
Manabu Tsujimoto ◽  
Hidetoshi Minami ◽  
...  
Keyword(s):  
Liquid Helium ◽  
Terahertz Emission ◽  
Emission System

Laser terahertz emission system to investigate hydrogen gas sensors

2005 ◽  
Vol 86 (26) ◽  
pp. 261102 ◽  
Author(s):  
Toshihiko Kiwa ◽  
Keiji Tsukada ◽  
Masato Suzuki ◽  
Masayoshi Tonouchi ◽  
Sonoko Migitaka ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Hydrogen Gas ◽  
Terahertz Emission ◽  
Hydrogen Gas Sensors ◽  
Emission System

Terahertz Electroluminescence of 6H-SiC Natural SiC Superlattice in Bloch Oscillations Regime

2012 ◽  
Vol 717-720 ◽  
pp. 553-556 ◽  
Author(s):  
Vladimir Ilich Sankin ◽  
Alexander V. Andrianov ◽  
A.G. Petrov ◽  
P.P. Shkrebiy ◽  
A.O. Zacharin
Keyword(s):  
Steady State ◽  
Field Strength ◽  
Electric Field ◽  
Emission Spectrum ◽  
Liquid Helium ◽  
Linear Dependence ◽  
Bloch Oscillations ◽  
Terahertz Emission ◽  
Natural Superlattice ◽  
Characteristic Field

We report on efficient terahertz emission in the region of 1.5-2 THz from high electric field biased 6H-SiC structures with a natural superlattice at liquid helium temperatures. The shape of the emission spectrum, the linear dependence of its maximum on the bias and the characteristic field strength required to achieve the emission allow the emission to be attributed to steady-state Bloch oscillations of electrons in the SiC natural superlattice.

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.

A Field Emission System For Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 298-299
Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Optical System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Electron Optical System ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Emission System

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).

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.

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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