[Primexd] FCAL bad channel status

[Alexander Somov]

Thanks. Your list is likely more uptodate. I had data from the
FCAL HV scan, which we did together a couple of weeks ago.
Please go ahead and replace bad channels, which you know
(and we'll take LED data afterwards, just let me know when you
are done).

It's a good idea to check channels on the scope. I'll be in the
hall after lunch (just in case you'll need my help).

Cheers,
        Sasha





On Wed, 28 Nov 2018, Colin Gleason wrote:

> I will make the replacements in an hour or so. If you take LED data and see
> any suspicious channels, let me know and I can replace them anytime during
> the access this week.
>
> Do you know of any other suspicious channels? I got my list by checking the
> scalers a week or two ago. I will need to check signals on the scope to
> make sure they're bad.
>
> On Wed, Nov 28, 2018 at 11:48 AM Alexander Somov <somov at jlab.org> wrote:
>
>>
>> Thanks a lot Colin for the update (and quick response). It would
>> be great if can replace these bases during this week (the hall
>> will be closed later today and will be re-opened tomorrow).
>>
>> We can take LED data today and check the status.
>>
>> Cheers,
>>         Sasha
>>
>>
>> On Wed, 28 Nov 2018, Colin Gleason wrote:
>>
>>> Hi Sasha,
>>>
>>> I suspect there are around 5-10 bad/suspicious FCAL channels. I know of 2
>>> that are dead and 3 that are just showing noise. I will replace these
>> after
>>> lunch. Someone either forgot to turn on the FCAL communications yesterday
>>> or has turned it off today, so I do not know all channels. The ones I
>> know
>>> of are in (X,Y):
>>> bad signal:
>>> 16 8
>>> 26 0
>>> 27 -6HV:
>>> -8 28
>>> 14 21
>>>
>>> There are likely a few bases whose HV is below their set point. We
>> usually
>>> keep these in the FCAL until they die, or, if we have enough spares
>>> available, will swap them out.
>>>
>>> Currently we have 16 spares ready to go in, with more ready to be
>> repaired
>>> by Chris and Nick. The base failure rate had dropped to less than 2 per
>>> week by the end of the run, so we should be able to manage replacements
>>> through the rest of the Fall run. I think Chris and Nick have been busy
>>> with installation, but once that is complete we can get them to repair
>> more
>>> bases for the spring.
>>>
>>> -Colin
>>>
>>> On Wed, Nov 28, 2018 at 11:25 AM Alexander Somov <somov at jlab.org> wrote:
>>>
>>>>
>>>>
>>>> Hi Colin,
>>>>
>>>> Could you update us on the status of bad (suspicious)
>>>> channels in the FCAL.
>>>>
>>>> Could you send a list of bad/suspicious channels
>>>>
>>>> Did you have a chance to replace bases during
>>>> this shut down ? How many spare bases do you have ?
>>>>
>>>> We'll need to take LED data when you turn HVs on.
>>>>
>>>> Thanks,
>>>>         Sasha
>>>>
>>>>
>>>
>>> --
>>> Colin Gleason
>>> Postdoctoral Fellow
>>> Indiana University
>>> Department of Physics
>>>
>>
>
>
> -- 
> Colin Gleason
> Postdoctoral Fellow
> Indiana University
> Department of Physics
>