[Halld-cal] [Revised Logentry] FCAL HV scan

[Alexander Somov]

Hi Ashot,

Yes, we do. All bases/PMT should be rather similar. We saw problems
with setting up 1.75 kV on some modules (there was no load, the
LED was off).

This can be an indication of some problems with the base. But may
be there is smth. different; we'll figure out, one step in time...

Cheers,
       Sasha



On Mon, 19 Nov 2018, gasparan at jlab.org wrote:

>
>  Hi Sasha,
>
> a very good test. It looks like we may have serious problems if we need
> to set 1800 V range.
> We will need to have more information (gains, electronic noise, ...)
> before making some decision.
>
> Thanks,
> Ashot
>
>
>>
>> Logentry Text:
>> --
>> FCAL readout: RAW mode (mode 10)
>>
>> Use violet LED, 500 Hz
>>
>> 1500 V
>> ----------
>>
>> Run  51604,  130 K events,  17 V
>> Run  51605,  122 K events,  22 V
>>
>> 1550 V
>> ---------
>>
>> Run 51606,  120 K events, 17 V
>> Run 51607,  120 K events,  22 V
>>
>> 1600 V
>> ----------
>>
>> Run 51608, 17 V
>> Run 51609,  22 V
>>
>> 1650 V
>> ----------
>>
>> Run 51610, 17 V
>> Run 51611, 22 V
>>
>> 1700 V
>> ----------
>>
>> Problems with setting HV on channel (22,22 ;  -8,-8)
>>
>> Run 51612,  17 V
>> Run 51613,  22 V
>>
>>
>> 1750 V
>> ----------
>>
>> Not able to set this voltage on the following channels:
>> Channel, Read back voltage
>>
>> (1, 31) 1610 V
>> (7, 46) 1601
>> (13, 23) 1618
>> (13, 47) 1651
>> (20, 26) 1600
>> (22, 22) 1607
>> (25, 26) 1620
>> (29,7) 1640
>> (33,47) 1609
>> (35, 37) 1630
>> (44, 30) 1590
>> (41, 39) 1660
>> (44, 30) 1590
>> (47, 38) 1625
>> (49, 31) 1612
>>
>> Run 51614,  17 V
>> Run 51615,  22 V
>>
>> 1800 V
>> ---------
>>
>> Cannot set HVs on 41 channels
>>
>> Run 51616,  17 V
>> Run 51617,  22 V
>>
>>
>>
>>
>>
>>
>> ---
>>
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>> https://logbooks.jlab.org/entry/3628470_______________________________________________
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>
>
>