Positron lifetime spectrometer using a DC positron beam
AssigneeUT-Battelle, LLC
InventorsJun Xu, Jeremy Moxom
Life of this patent
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Abstract
An entrance grid is positioned in the incident beam path of a DC beam positron lifetime spectrometer. The electrical potential difference between the sample and the entrance grid provides simultaneous acceleration of both the primary positrons and the secondary electrons. The result is a reduction in the time spread induced by the energy distribution of the secondary electrons. In addition, the sample, sample holder, entrance grid, and entrance face of the multichannel plate electron detector assembly are made parallel to each other, and are arranged at a tilt angle to the axis of the positron beam to effectively separate the path of the secondary electrons from the path of the incident positrons.
Claims4
A spectrometer for positron lifetime characterization studies, wherein a DC positron beam is directed onto a sample surface to produce annihilation gamma radiation and secondary electrons from the sample, the annihilation gamma radiation is detected by a gamma detector, and the secondary electrons are detected by an electron detector, comprising:
- an entrance grid situated in the incident positron beam, said entrance grid positioned parallel to the sample surface, and said entrance grid arranged to have a higher electrical potential than the sample potential;
- wherein:
- the entrance face of the electron detector assembly is situated parallel to the entrance grid,
- the entrance face of the electron detector assembly is arranged to have the same potential as the entrance grid,
- and the sample surface, said entrance grid, and said entrance face of said electron detector assembly are disposed at a tilt angle to the incident DC positron beam.
Dependencies are inferred from the claim text.