Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Liquid helium cold finger

A thermally produced beam of atomic hydrogen was allowed to react on a carbon target at temperatures between 30° and 950° C. The reaction products were isolated on a liquid helium cold finger and then analyzed by gas chromatography. [Pg.62]

The glass liquid helium cold finger used to freeze out reaction products was about 2 inches in diameter and had a 1 liter capacity. To minimize heat leakage it was surrounded by a liquid nitrogen heat shield. All surfaces in the Dewar system were silvered. After an experiment the cryo-... [Pg.64]

Measurements are usually performed under UHV conditions (i.e., the pressure within the sample chamber is in the 1(T Pa region to minimize deposition of residual gas onto the sample, which would then be analyzed just like an original contamination and would thus enhance the background signal). Some instruments are equipped with a cold-finger shroud or cryoshroud for liquid nitrogen or, rarely, helium to improve the vacuum by trapping residual gas components. [Pg.902]

See other pages where Liquid helium cold finger is mentioned: [Pg.165]    [Pg.29]    [Pg.5]    [Pg.105]    [Pg.109]    [Pg.532]    [Pg.73]    [Pg.181]    [Pg.291]    [Pg.158]    [Pg.296]    [Pg.783]    [Pg.299]    [Pg.158]    [Pg.26]    [Pg.117]    [Pg.396]    [Pg.63]    [Pg.68]    [Pg.76]    [Pg.832]    [Pg.164]    [Pg.1358]    [Pg.1438]   
See also in sourсe #XX -- [ Pg.55 ]



SEARCH



Cold finger

Finger

Fingering

© 2024 chempedia.info