[Sbs_gems] [EXTERNAL] UV Layer 4 Overview

[Sean Jeffas]

Hi All,

Kondo: Actually we will not need to remove any UV layers from BB to do this
work. Recall that we can slide the layers horizontally on the frame. We
utilize this to replace the 4-slot backplanes with 3-slot backplanes with
probably 5 hours of work in the hall. Also we do not need to wait until the
new batch of APVs arrive. We can take the APVs from the current SBS setup,
if we deem that this is critical to do. So here is the list of tasks
necessary to get UV layer 4 installed into INFN J0's place.

*Tasks:*
Electronics group fixes the 3-slot BPs:* I have no idea how long this will
take. We will need Anu to update. This may be a bottleneck.*
Test the 3-slot BPs in EEL: ~5 hours
Place the 3-slot BPs in the three UV GEMs in BB: ~5 hours of work in the
hall
Assemble UV layer 4 with the frame, and all electronics: *Zeke says he does
not think there are any spare INFN carbon fiber frames. If we have to make
new frame this may be the bottleneck. Is it worth disassembling an INFN
layer, like J2, just to use the frame for UV?*
Flow gas through UV layer and do a HV test: ~3 days
Cosmic test in the INFN test lab: 2 days
Swap the layer with J0: ~8 hours.

*Total: *About 1-2 weeks, if we ignore my comments on things I do not know.

*Overview:*
Assuming everything goes perfectly, and my comments on things I do not know
are all simple solutions, then we could complete the work by Dec 21st. We
would need at least 4 people working on this all day every day. Given the
unknowns and the fact that disturbing all UV layers in BB may cause more
issues I think it is extremely unlikely that this is possible by Dec 21st.
But I will let Anu and Zeke comment, or if anyone else has any ideas.
Overall replacing J0 with another INFN layer will be significantly easier.

Best,
Sean

On Fri, Dec 3, 2021 at 6:20 PM Thir Gautam <tns.gautam at gmail.com> wrote:

> Hi Anu and all,
>
> There are 25 APV cards outside of 9th layer. Those APV cards are not
> tested yet. I believe that there are 20-25 APV cards on the 9th layer.
> Before getting Nilanga’s ordered we won’t have enough cards to populate a
> new uv layer.
>
> Regards,
>
> Thir
>
> Sent from my iPhone
>
> On Dec 3, 2021, at 5:12 PM, Anuruddha Rathnayake <adr4zs at virginia.edu>
> wrote:
>
> 
> Hi Nilanga,
>
> Yes I am working on getting both of the fixes ready with Chris as soon as
> possible.
>
> Layer 9 for GEn-RP  (which is the only one that has not been put on the
> GEn-RP production frames) already donated 60 APVs for the 3rd UV layer. We
> can take the rest out of it too if necessary. Thir might be able to give a
> number on how many good APVs we have outside of that layer.
>
> Best,
> Anu
>
>
> On Fri, Dec 3, 2021 at 4:48 PM Liyanage, Nilanga K (nl8n) <
> nl8n at virginia.edu> wrote:
>
>> 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> on behalf of Gnanvo, Kondo
>> (kg6cq) <kg6cq at virginia.edu>
>> *Sent:* Friday, December 3, 2021 4:43 PM
>> *To:* Jeffas, Sean (sj9ry) <sj9ry at virginia.edu>; sbs_gems at jlab.org <
>> 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> on behalf of Sean Jeffas <
>> sj9ry at virginia.edu>
>> *Sent:* Friday, December 3, 2021 4:35 PM
>> *To:* sbs_gems at jlab.org <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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