Star-fst-l mailing list

["Visser, Gerard" <gvisser AT indiana.edu>]

hi Ziyue,

    It is also possible, of course, that the max timebin plot is just generally unstable i.e. not that it moved in response to a particular beam incident. That might​ be the case, we should watch out for the possibility. (If it is like that, probably adjustments each time it changes is not the right approach, though I can't say for sure.)

• Gerard

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From: Ziyue Zhang <zzhan70 AT uic.edu>
Sent: Monday, May 29, 2023 3:36 PM
To: Visser, Gerard <gvisser AT indiana.edu>
Cc: Star-fst L <star-fst-l AT lists.bnl.gov>
Subject: Re: [Star-fst-l] FST Latency Adjusted

 

Hello Gerard,

Thank you for bringing up your concern. A minor clarification, I should have used the word "accident"... 

You are absolutely correct, I forgot the power cycle step; that will be on my top list next time.

In the case of the current situation, this is my naive understanding: since there was already a trip on every channel, and during the 1-2 days, the shift crews have turned on and off the FST multiple times, so they should effectively have gone over power cycle... I checked the Max Time Bin plots yesterday late afternoon, and noticed this issue, but there was no beam, so I checked again this morning and made the adjustment based on the plot in this morning's PHYS runs.

Sincerely,

Ziyue

On Mon, May 29, 2023, 12:11 Visser, Gerard <gvisser AT indiana.edu> wrote:

Dear Ziyue,

     Thanks, this sounds good. (I didn't look at plots right now, sorry, but I trust you see the correct effects.)

    However I am concerned by the statement " New APVs need adjustment found, which is most likely caused by the "FST not off during beam dump" incident yesterday":

• It should be basically impossible to have any lasting effect of this sort from any beam incident. I'd expect if there is a lasting effect, it would be in the nature of total failure or of an increase in noise level.
• On the other hand though, the hardware might at any time get into a "upset" condition, where some internal states are incorrect and this might (not unlikely) be caused by beam conditions. It would go back to normal upon a power cycling of everything.
• ==> If you think something shifted or is acting abnormally, power cycle!
• If you readjusted something to make it normal instead, I suggest power cycle and check things, and if necessary make adjustments (maybe contrary to prior adjustments.

Sincerely,

        Gerard

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From: Star-fst-l <star-fst-l-bounces AT lists.bnl.gov> on behalf of Ziyue Zhang <zzhan70 AT uic.edu>
Sent: Monday, May 29, 2023 11:40 AM
To: Star-fst L <star-fst-l AT lists.bnl.gov>
Subject: [Star-fst-l] FST Latency Adjusted

 

Dear all,

The FST APV latency has been adjusted. Details can be found here.

Best regards, 

Ziyue