A pulsed beam of polarised electrons has been successfully produced by means of spin exchange collisions between the atoms of a polarised atomic beam and groups of initially unpolarised electrons trapped in the atomic beam. In several experimental runs electron polarisations of more than 0.5 were indicated at electron trapping times as low as 5 Although the residual ?7 gas pressure in the electron trap was probably more than 10 torr, there was no conclusive evidence of the presence of spin relaxation effects. Reassessment of the design of the present apparatus in the light of the experimental results suggests that the intensity of the trapped electron beam will he significantly increased after suitable modifications are made to "che electrode system which removes the electrons from the electron trap. Once this problem and the problem of atomic beam stability have been solved, this technique should yield highly polarised pulsed beams of electrons at useful intensities. The limitations of the present apparatus as a means of measuring accurately the spin exchange cross sections for collisions of eleotrons with alkali atoms would be significantly reduced in an apparatus specifically designed to give as much direct information as possible about what is happening within the electron trap from the point of view of the electrons, the atomic beam and the residual gases.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:641904 |
| Date | January 1969 |
| Creators | Brash, Harry M. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/26350 |
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