| Summary: | 碩士 === 輔仁大學 === 物理學系 === 96 === High Energy Accelerator Research Organization (KEK) located in Tsukuba city of Japan intends to upgrade the B factory to be the Super B factory. The upgrade contains two parts: the KEKB accelerator and the Belle detector. After the upgrade, the KEKB accelerator will increase the number of events produced in each collision and the Belle detector will also increase its ability to deal with the signal-to-background ratio.
This thesis is related to the upgrade plan of Electromagnetic Calorimeter (ECL), the sub-detector inside the Belle detector. We measured the performance of Photopentode Tubes (P.P.) and Avalanche photodiodes (APD) to understand if it would be possible to replace the original installed Photodiode (PD).
The P.P.s and APDs were placed in a aluminum box. We used the blue LEDs as the light source for the two samples during their gain ratio measurement. The blue LED is about 450 nm in wavelength. We found that the gain ratio of the three P.P. samples were about 165, 195 and 220. The gain ratio between these three P.P.s differed a lot, but each of them showed stable performance. Besides, no obvious relation existed between the gain ratio and the temperature. The gain ratio of the two APD samples were about 50 and 70, smaller than P.P.s. Similar to P.P., APD had no obvious relation between the gain ratio and the temperature.
Our result indicated that the gain ratio of these two samples, P.P. and APD, were stable and not related to the temperature of the environment. The gain ratio of APDs were smaller than the P.P.s. Therefore, if we want the better gain ratio, it would be a better choice to use P.P.s to replace the PDs. If we want a smaller size, APDs would be a better choice, too.
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