Re: Minutes posted, calib goals requested

[David Lawrence <davidl@jlab.org>]

Hi All,

    This sounds very similar to what PrimEx used to monitor the gains 
for our calorimeter. Only we used a large LED bundle with an integrating 
sphere. Same rotating wheel idea though.

Regards,
-David

Alexander Somov wrote:
> Dear all,
>
> I recall at FOPI, GSI, we had a LED trigger to monitor
> TOF pmt's performance. The light from LED (as far as I remember
> it was led)  was sent to a rotating wheel which had different
> attenuation steps and was subsequently splitted and distributed to TOF
> plastic paddles.
>
> The trigger ran quite often (mainly in the beginning of data taking, as
> far as I remember), to monitor linearity/stability.
>
> Cheers,
>       Sascha
>
> P.S. I will check what we had to monitor ECAL pmt's at Hera-B
> (there was a monitoring system as well).
>
>
>
> On Mon, 21 Apr 2008, Elke-Caroline Aschenauer wrote:
>
>   
>> On Mon, 21 Apr 2008, Elton Smith wrote:
>>
>> Dear all,
>>
>> just to give a suggestion it would be very important to vary the light
>> intensity to test and monitor the linearity of the system.
>> In hermes we had a system stepping through 5 different light intensities.
>>
>> cheers elke
>>
>>
>>     
>>> Date: Mon, 21 Apr 2008 12:14:54 -0400 (EDT)
>>> From: Elton Smith <elton@jlab.org>
>>> To: halld-cal@jlab.org
>>> Subject: Minutes posted, calib goals requested
>>>
>>>
>>> HI all,
>>>
>>> Zisis posted the minutes of today's meeting on the wiki. Thanks! I did add
>>> some comments at the end on questions of calibration.
>>>
>>> We need to clearly identify the goals of the calibration system, so that
>>> we build what we need. At the moment, the calibration system is geared
>>> toward gain monitoring of pmts. For the next meeting, we would like the
>>> Fcal and Bcal and other pmt-based systems to specify what needs to be
>>> monitored at to what accuracy. Pavlos suggested that it would also be
>>> useful to give an estimate of the signal size (e.g. number of
>>> photoelectrons) as well as wavelength response of the detector.
>>>
>>> Cheers, Elton.
>>>
>>>
>>>
>>> Elton Smith
>>> Jefferson Lab MS 12H5
>>> 12000 Jefferson Ave
>>> Suite # 16
>>> Newport News, VA 23606
>>> elton@jlab.org
>>> (757) 269-7625
>>> (757) 269-6331 fax
>>>
>>>       
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>>     

-- 

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