MainPage:Nuclear:Summer2017:Casey
Impact of surface and reflector on crystal light uniformity
Abstract
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Introduction
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Description of the crystal light yield measurements
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Summary of results at beginning of summer 2017
I collected all of the Light Yield results for all crystals and found an average light yield for each crystal. The majority of the crystals had multiple trials, and I used those trials to calculate the least mean squared uncertainty. See picture of calculations for example. The solid blue line is the horizontal line of best fit through the data, indicating the average light yield of all crystals combined. The dotted red lines are at 10 pe/MeV and 15 pe/MeV. The crystals must have a light yield of at least 10pe/MeV, and ideally greater that 15pe/MeV. J11 is the only crystal with a light yield below 10pe/MeV. J17 has a light yield of 25.18 pe/MeV, which is too high. Ideally, all crystals would have a similar light yield, and the data for J11 is much higher than the other crystals.
Reflectivity of Materials
Using the spectrometer, I tested the reflectivity of small samples of different refelctive materials to get an idea of which materials would be most effective as a reflector when used to collect data on the light yield of crystals. Some of the materials were not labeled, so I also used these graphs to compare to the results of known materials taken last year.
