BigBite Optics #10

This week I continued my work on determination of the matrix elements "[TgY|xyz]", "[TgPh|xyz]" and "[TgTh|xyz]". I was removing the matrix elements for variables TgPh and ThY. I haven't considered TgTh yet. I have removed majority of forth-order matrix elements for ThY and approximately 20 various matrix element for ThPh. Now I have started my optimization again and when it will finish I will be able to see, if I can remove some more elements.

I have also changed the way I am isolating events that correspond to each sieve-hole for the TgPh calibration. So far I was using focal-plane cuts for the holes I was not able to see in the beginning and Sieve cuts for those that were visible from the start. Now I have decided to use FP cuts only for all the holes. This way I will also be able to easily determine the TgPh and TgTh resolution.

For the TgY calibration I applied cuts on FpPh and FpY in addition to HRS-L cuts. These cuts gave me more clean set of events, that I used in my calibration. I have also considered cuts on coincidence-time. This way I am almost certain that I am considering only good events. For this clean set of data the current TgY resolution is sigma = 1.0cm (HRS-L sigma is 0.97cm). Without any cuts I have estimated resolution to be sigma = 1.3cm.

TgPh Plots:

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TgY Plots:

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Last modified: 04/21/10