X-ray induced electrostatic charging of helium films
| Autor: | Issac F. Silvera, Peter S. Pershan, M. J. Regan, K. Penanen |
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| Rok vydání: | 1995 |
| Předmět: |
Materials science
Liquid helium chemistry.chemical_element Atmospheric temperature range Photoelectric effect Condensed Matter Physics Electric charge Atomic and Molecular Physics and Optics law.invention Helium-4 chemistry law Electric field General Materials Science Atomic physics Thin film Helium |
| Zdroj: | Journal of Low Temperature Physics. 101:489-494 |
| ISSN: | 1573-7357 0022-2291 |
| DOI: | 10.1007/bf00753342 |
| Popis: | It is well known that free electrons can be held onto the free surface of liquid helium through either their own image charges or through the effect of an externally applied electric field. The resultant electrostatic pressure causes films to thin. We have recently measured x-ray reflectivity from static films of isotopic mixtures of helium with an intense x-ray beam in the temperature range between 0.37 K and 1.3 K. Normally, no significant thickness variation with x-ray intensity is expected over a wide range of temperatures when the film is superfluid. We have found that even modest x-ray intensities affect the thickness of films containing only trace amounts of3He. We believe that the effect is due to x-ray produced photoelectrons, which thermalize in the vapor and then reside on the surface, attracted by both the film and a charged substrate. The temperature and concentration dependence is then due to the transport properties of the electrons at the surface. It may be possible to study the 2-D electron gas produced in this way by diffraction techniques. |
| Databáze: | OpenAIRE |
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