G4IDS

An estimation of the source position offset(on the z-ais) respect to the beta detector is requested in order to quantify the beam alignment. The extracted value could be compared to the collimator sie and the tape size. Does the extracted value make sense?

- How to extract the estimated offset?
Experimentally the efficiencies of the left and right detectors are found to be different. This assymetry could be explain by a assymetry of the imp. point-plastic distances.
By moving the source on the z-axis we will try to reproduce the individual experimental efficiencies, and more precisely their ratios for all the combinations.

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O: point-like source

+--> z-axis
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       '
       '
       v
     x-axis

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• O *
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- Go further:
(1). Make the same exercice by moving the point-like source on the y-axis
(2). Make the same exercice than in (1). by moving the point-like source on the zy-plan of the implantation tape.
(3). Make the same exercice that in (1) and (2) for a non-pointlike source.