CMS Pixel Detector
Miscellaneous
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Phase 1
Phase 2
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Layer 1 Replacement
Layers 2-4
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Layer 1 Replacement Elog |
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Message ID: 272
Entry time: Mon May 25 16:58:23 2020
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Author: |
Andrey Starodumov |
Category: |
XRay HR tests |
Subject: |
a few commments |
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These is just to record the information:
1. measured hit rates at which Efficiency and Xray hits Maps are taken are 40-50% of the 50-400MHz/cm2 that in the titles of corresponding plots
2. in 2016 the maximum rate was 400MHz/cm2 but with such rate (or better corresponding settings of HV and current of Xray tube) in double columns of certain modules (likely depending on a module position with respect to Xray beam spot) the measured rate was smaller than 300MHz/cm2 that is target rate. Somtimes extrapolation of efficiency curve to 300MHz/cm2 is too large. I think this is not correct. Unfortunately higher rates cause too many readout errors that prevent a proper measurement of the hit efficiency. May be a new DTB with than 1.2A maximum digital current will help.
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