[Sbs_gems] [EXTERNAL] UV Layer 4 Overview

[Gnanvo, Kondo (kg6cq)]

Hi Nilanga,
The point that Sean brought is that even when we have the 3-slot ready, in order to get the 4 U-V layer ready, we will have to replace the 4-slots that were used in these 3 layers in place of unavailable 3-slots.
That means that we take 3 U-V layers out of BB do the replacement in order to have the 4th spare ready for J0 replacement. I don't think it is a good approach.
In my view, we should not in mess with what is working right now and is stable

Best regards
Kondo


From: Liyanage, Nilanga K (nl8n) <nl8n at virginia.edu>
Sent: Friday, December 3, 2021 4:53 PM
To: Gnanvo, Kondo (kg6cq) <kg6cq at virginia.edu>; Jeffas, Sean (sj9ry) <sj9ry at virginia.edu>; sbs_gems at jlab.org
Subject: Re: [Sbs_gems] [EXTERNAL] UV Layer 4 Overview


Also, I guess now we can borrow some APV cards from GEn-RP layers, right ?
________________________________
From: Sbs_gems <sbs_gems-bounces at jlab.org<mailto:sbs_gems-bounces at jlab.org>> on behalf of Liyanage, Nilanga K (nl8n) <nl8n at virginia.edu<mailto:nl8n at virginia.edu>>
Sent: Friday, December 3, 2021 4:48 PM
To: Gnanvo, Kondo (kg6cq) <kg6cq at virginia.edu<mailto:kg6cq at virginia.edu>>; Jeffas, Sean (sj9ry) <sj9ry at virginia.edu<mailto:sj9ry at virginia.edu>>; sbs_gems at jlab.org<mailto:sbs_gems at jlab.org> <sbs_gems at jlab.org<mailto:sbs_gems at jlab.org>>
Subject: Re: [Sbs_gems] [EXTERNAL] UV Layer 4 Overview

Hi Sean, Kondo

Anuruddha is contacting  Chris Cuevas about getting the 3-slot back planes fixed/

Anuruddha: I am assuming that the adapters to flip the wire order in the cables are also being prepared, right ?

We hope to get the APV cards in the next week or so

Best

Nilanga
________________________________
From: Sbs_gems <sbs_gems-bounces at jlab.org<mailto:sbs_gems-bounces at jlab.org>> on behalf of Gnanvo, Kondo (kg6cq) <kg6cq at virginia.edu<mailto:kg6cq at virginia.edu>>
Sent: Friday, December 3, 2021 4:43 PM
To: Jeffas, Sean (sj9ry) <sj9ry at virginia.edu<mailto:sj9ry at virginia.edu>>; sbs_gems at jlab.org<mailto:sbs_gems at jlab.org> <sbs_gems at jlab.org<mailto:sbs_gems at jlab.org>>
Subject: Re: [Sbs_gems] [EXTERNAL] UV Layer 4 Overview

Hi Sean,
Yes, you are right. I forgot that the 4-slots backplanes were designed only for the UV layers, I don't think removing them from the layers on BB and replace it with 3-slot is ever going to be an option for the current run up to end January. In addition to the lack of APV cards,  the 4th UV layer is out of the picture at least for now

Best regards
Kondo

________________________________
From: Sbs_gems <sbs_gems-bounces at jlab.org<mailto:sbs_gems-bounces at jlab.org>> on behalf of Sean Jeffas <sj9ry at virginia.edu<mailto:sj9ry at virginia.edu>>
Sent: Friday, December 3, 2021 4:35 PM
To: sbs_gems at jlab.org<mailto:sbs_gems at jlab.org> <sbs_gems at jlab.org<mailto:sbs_gems at jlab.org>>
Subject: [Sbs_gems] [EXTERNAL] UV Layer 4 Overview

Hi All,

I just wanted to elaborate on the situation on the 4th UV layer, which is sitting in EEL and waiting as a spare. Each UV layer uses 12 4-slot backplanes and 4 3-slot backplanes. The 3-slot BPs are defective so we are using 4-slot BPs in their place. That means that for the three UV layers in BB right now we have used up every single 4-slot BP. Therefore we do not have the BPs to equip UV layer 4 to use as a replacement for anything.

I am not familiar with the fixes needed for the 3-slot BPs, but assuming this is easy and can be done quickly, we still need to recover the 4-slot BPs from the UV GEMs in BB. This can probably be done by sliding the GEMs to the side in the BB frame, as we have done before, so we can reach them. Then we would need to place all the 3-slot BPs on the UV GEMs and test them. I would estimate we would need 2 days of downtime in the hall for this. Then we would need to add all the electronics to UV layer 4 back in EEL, and get it ready in one of the INFN frames and do a cosmic test on it. Then we would need another day of down time to swap it with J0 in the hall as we did with J2 earlier.

Overall I think it would take two weeks of work to do all of this. Again I am completely assuming the fix to the 3-slot BPs is easy, I have no idea. Maybe Anu can elaborate. Also we will have to wait until the new APVs arrive to start any of this work. Between all of this and the holiday break I don't see this layer being used for anything during this run group.

Also as a side note, I will have to dig through some old emails and notes, but I am fairly certain we accounted for all APVs and there are not enough to equip all 10 UVa SBS layers and 4 UV layers.

Best,
Sean
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