|Message: Optical Reflectivity||Not Logged In (login)|
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I was trying to simulate the response of pixellated NaI to incident 662 keV gamma. With light yield of 38 photons/keV ee, I found that the photon count at the PMT strongly depends on the reflectivity of the surrounding material. As the detector is pixellated 2mmx2mm cross sectional area and length of 2 cm, there are quite significant multiple reflection events from the surrounding wall before the photons reach to the PMT located on one side. The light count I get from 97% reflectivity is like 50% of what is expected (0.97x38 photons/keV x 662keV) at 662 keV energy. When it is 99% reflectivity I get like 77%. If it is 100% then within the statistical limit of what is expected. Does the multiple bouncing result in the loss of counts? I mean increases the chance of photons getting into the surrounding wall and eventually absorbed. I appreciate any comment. Thank you.
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