[Sbs_gems] [EXTERNAL] RE: First* cluster maps of the SBS GEn-RP GEMs

[Gnanvo, Kondo (kg6cq)]

Hi John,
This looks great
Excellent results

Best regards
Kondo

From: John Boyd <jab7bp at virginia.edu>
Sent: Friday, December 3, 2021 3:01 PM
To: Brad Sawatzky <brads at jlab.org>; Gnanvo, Kondo (kg6cq) <kg6cq at virginia.edu>; Liyanage, Nilanga K (nl8n) <nl8n at virginia.edu>; Bogdan Wojtsekhowski <bogdanw at jlab.org>; Bai, Xinzhan (xb4zp) <xb4zp at virginia.edu>
Cc: sbs_gems at jlab.org
Subject: First* cluster maps of the SBS GEn-RP GEMs

To all,

This past Wednesday, I showed some very preliminary cluster maps of the GEMs on the GEn-RP stack. The plots were "hot off the press". Since then we were able to correct some issues with the setup (cable/hardware issues, decoder issues, etc.). With those changes we have seen quite a bit of improvement. The plots are attached.

Please reference these plots for my next comments.

Layer 0 is missing because there is no Layer 0 in the setup. Layer 0 would be the INFN GEMs and they are currently not installed in the setup.

The plots are oriented with G0 (top GEM) on the left, and G3 (bottom GEM) on the right.

Layers 1-6 are the Inline Stack and Layers 7 & 8 are Layers 0 & 1 in the Right Polarimeter stack, respectively.

ISSUES/CONCERNS:

Layer 1: Looks okay to me.

Layer 2:

  *   G1 shows a section of low efficiency. One suggestion for the cause of this is that the MPD may be causing some issue with this efficiency.

Layer 3: Looks okay to me apart from some strips in G2.

Layer 4:

  *   G0 has a 12-slot APV which was determined to be faulty. This was determined through preliminary testing (libtest, etc.). It is disabled and shows this as expected.
Layer 5:

  *   G3 shows some suspicious strips but everything looks okay to me.
Layer 6:

  *   G2 has a 5-slot APV which was loose during this run. I was able to push it in and feel it connect better. I have not taken another set of runs since I did this. I believe this should resolve the issue. I will take new runs and confirm.
Layer 7:

  *   G2 has a 12-slot APV which was presumed to be faulty. The guess is that it is loose. It is a "lower" GEM in the layer and the 12-slot backplane is "hidden". We cannot access the APVs to try and push it in.  It was not disabled and thus you can see some hits.
  *   G3 has a dead sector. This was known from the past.
Layer 8:

  *   G3 has a dead sector. This was also known in the past. Layers 7 and 8 were lined up in this fashion so that the dead sectors will overlap (if you put them back to back the dead sector is in the same place).
All in all, the layers look good. This also is in line with the previous summary that out of the 704 APVs in this setup, 1 is faulty (disabled) and 2 are suspicious/loose.

We will continue to take more data and check back in on the status of the setup.

Best,

John Boyd




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