CMS Pixel Detector Miscellaneous
Phase 1 Phase 2
Layer 1 Replacement Layers 2-4
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Message ID: 272     Entry time: Mon May 25 16:58:23 2020
Author: Andrey Starodumov 
Category: XRay HR tests 
Subject: a few commments 
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.
3.
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