CPC G01T 1/185 (2013.01) [G01T 1/17 (2013.01); G01T 1/2935 (2013.01)] | 16 Claims |
1. Converter unit comprising a converter and a gas-electron multiplier, wherein said converter comprises a substrate with an ionizing radiation-receiving major surface and an electron-emitting major surface and a stack of accelerator plates in contact with the electron-emitting major surface, wherein said stack comprises a plurality of perforated accelerator plates, each perforated accelerator plate provided with an insulating layer to insulate each perforated accelerator plate from one another in order to be able to provide separate potential to each perforated accelerator plate, wherein perforations of the perforated accelerator plates are aligned to form a matrix of blind holes, wherein said gas-electron multiplier comprises a matrix formed of a plurality of regularly spaced-apart groups of GEM through holes wherein:
each group comprises between one and twenty GEM through holes and wherein a longitudinal axis of the center of each of said groups of GEM through holes is aligned with a longitudinal axis of a respective blind hole, wherein a surface of each blind hole is covered with an insulator except for a portion which is exposed in order to be able to attract and neutralize ions;
the gas-electron multiplier comprises a first major surface and a second major surface made of a conducting material and wherein at least one of said first and second major surfaces is formed as a plurality of electrically unconnected regions; and
a potential difference drops non-linearly along a length of a blind hole from a closed end to an open end; or
the gas-electron multiplier further comprises additional GEM through holes that are not aligned with blind holes.
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