Re: Minutes posted, calib goals requested

[Alexander Somov <somov@jlab.org>]

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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