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Influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5K

It has previously been established that H/sub 2/ emission from condensates and adsorbates on He-cooled cryopumps is enhanced by incident thermal radiation and this effect has produced anomalously high values for the H/sub 2/ saturated vapour pressure. Also it has been indicated that the effect depen...

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Detalles Bibliográficos
Autores principales: Benvenuti, C, Calder, R S, Passardi, Giorgio
Lenguaje:eng
Publicado: 1976
Materias:
Acceso en línea:https://dx.doi.org/10.1116/1.569063
http://cds.cern.ch/record/873960
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author Benvenuti, C
Calder, R S
Passardi, Giorgio
author_facet Benvenuti, C
Calder, R S
Passardi, Giorgio
author_sort Benvenuti, C
collection CERN
description It has previously been established that H/sub 2/ emission from condensates and adsorbates on He-cooled cryopumps is enhanced by incident thermal radiation and this effect has produced anomalously high values for the H/sub 2/ saturated vapour pressure. Also it has been indicated that the effect depends on the substrate used. The subject is reviewed and additional information is given on the desorption characteristics of HD and D/sub 2/. Studies made at CERN with three types of cryopump are discussed. The pumps had stainless steel and silver cryosurfaces and blackened baffles whose temperature determined the nature of the incident thermal radiation. The apparent rise in saturated vapour pressure of condensed hydrogen and its isotopes was attributed to the relase of phonons from the substrate by photons which traversed the condensate without absorption. (11 refs).
id cern-873960
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 1976
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spelling cern-8739602019-09-30T06:29:59Zdoi:10.1116/1.569063http://cds.cern.ch/record/873960engBenvenuti, CCalder, R SPassardi, GiorgioInfluence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5KDetectors and Experimental TechniquesIt has previously been established that H/sub 2/ emission from condensates and adsorbates on He-cooled cryopumps is enhanced by incident thermal radiation and this effect has produced anomalously high values for the H/sub 2/ saturated vapour pressure. Also it has been indicated that the effect depends on the substrate used. The subject is reviewed and additional information is given on the desorption characteristics of HD and D/sub 2/. Studies made at CERN with three types of cryopump are discussed. The pumps had stainless steel and silver cryosurfaces and blackened baffles whose temperature determined the nature of the incident thermal radiation. The apparent rise in saturated vapour pressure of condensed hydrogen and its isotopes was attributed to the relase of phonons from the substrate by photons which traversed the condensate without absorption. (11 refs).oai:cds.cern.ch:8739601976
spellingShingle Detectors and Experimental Techniques
Benvenuti, C
Calder, R S
Passardi, Giorgio
Influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5K
title Influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5K
title_full Influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5K
title_fullStr Influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5K
title_full_unstemmed Influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5K
title_short Influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5K
title_sort influence of thermal radiation on the vapor pressure of condensed hydrogen (and isotopes) between 2 and 4.5k
topic Detectors and Experimental Techniques
url https://dx.doi.org/10.1116/1.569063
http://cds.cern.ch/record/873960
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