Abstract
For Mössbauer studies at very low temperatures, the target holder kept at 11°K with the help of a closed He cycle Mössbauer shroud, has to be insulated by evacuating the outside enclosure surrounding the shroud. The target is kept in thermal contact with the cryostat cold finger through He gas at atmospheric pressure. This provides a vibrationless thermal contact between the two. The evacuation of the outside chamber has to be vibration free which can be accomplished by means of a suitable ion pump which is totally vibration free. However, use of Vac-ion pump here could not be made successful because the pump did not work at all after little pumping. To find out the cause of pump's failure, RGA was employed which showed the presence of He gas in the outside chamber at the time of purging of He gas in the internal chamber. The pump, however, worked efficiently again when the dry N2 gas purged in place of Helium. This points out that totally vibration free Vac-ion pumps cannot be used for evacuation of such cryostats. Here, diffusion pump was used subsequantly taking extra precautions to minimise the vibrations.
Similar content being viewed by others
References
Air-Product Operational Manual for the DMX-20 Mossbauer Cryostat and Catalog No. LCS-Aug. 1977, p-21.
M. McClintock, Cryogenics (Reinhold Publishing Corporation, Chapman and Hall, London, 1964) pp. 36–61.
A. Roth, in Vacuum Technology (North Holland Amsterdam, 1982) pp 232–241 and cited references.
W.L. Fite and P. Irving, J. Vac. Sci. Technol. 11 (1974) 351–356. Also see Anavac-2 Residual Gas Analyser User's Manual p-34 (VG Gas Analysis, U.K., 1983).
U.K. Chaturvedi, V. Shrinet, S.K. Agrawal and A.K. Nigam Ion Implantation: Equipments and Techniques (eds. H. Ryssel and H. Glawisching, Springer-Verlag, Berlin, 1983) pp 176–184.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nigam, A.K., Pathak, R. & Chaturvedi, U.K. Suitability of ion pump for evacuation of a closed He cycled Mössbauer cryostat. Hyperfine Interact 42, 1153–1156 (1988). https://doi.org/10.1007/BF02395595
Issue Date:
DOI: https://doi.org/10.1007/BF02395595