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["Ye, Zhenyu" <yezhenyu AT uic.edu>]

No, I don’t expect APV timing shift due to that incident that the shifter forgot to turn off the FST

when the beam was terminated (I told Ziyue it is impossible). There could be other reasons like 

these APVs were on the edge and so a small fluctuation led to different conclusion. It will be 

good to see how the MaxAdcTimebin plots for those APVs evolved over the last few days when 

the latency setting was changed.

Zhenyu

On May 29, 2023, at 10:45 PM, videbaek <videbaek AT bnl.gov> wrote:

Hi,

The APV chips are really much more radiation hardened as they were desing and used for LHC.
Too, I do not recall we ever have seen such shifts with APV chips for either IST or FST last year. I might be wrong,. Zhenyu can you confirm if we have seen such behavior ever before


best Flemming





On 2023-05-29 16:06, Visser, Gerard wrote:

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
-------------------------
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
-------------------------
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
[1].
Best regards,
Ziyue

Links:
------
[1] https://nam04.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fblog%2Fzyzhang%2FFST-Operation-Log-May-10-July-4-2023&data=05%7C01%7Cyezhenyu%40uic.edu%7C575988fd6ee0480f97f508db60859538%7Ce202cd477a564baa99e3e3b71a7c77dd%7C0%7C0%7C638209899096443526%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=dWP1MonNRHxNXP66jK9M7pLozbRRyLFUFPhuksFSojY%3D&reserved=0
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-- 
Flemming Videbaek
senior scientist, emeritus
videbaek @ bnl.gov
Brookhaven National Lab
Physics Department
Bldg 510D
Upton, NY 11973

phone: 631-344-4106
cell     :  631-681-1596
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