Minutes of the ST-Testbeam Run-Meeting - July 8, 2004
=====================================================

General
-------

Short summary of the SPS users meeting.

Vacuum leak:
An explanation was given of what happened
with the septum magnet, and consequently to the
vacuum. In a time span of three minutes,
the vacuum had become three orders of magnitude
worse than it should've been.
A leak test has shown that there was a leak
in the water-cooling of the septum magnet.

Current operation:
the septum magnet is now operated without
water cooling. Twice per day, until Monday,
temperature measurements will be made on
the tank in which the magnet resides.
This takes about 30 minutes per time.

A temperature equilibrium still has not been
reached, and therefore no prediction can be made
whether or not running in this mode is feasible
until the previous septum magnet is ready to be
re-installed.

It expected that such an equilibrium will reached
by Monday.

Consequently, there will be beam until Monday for sure.


Actions since yesterday
-----------------------

- The sampling point for the ADC has been adjusted,
  but no reduction in the noise was observed,
  and neither did the signal/noise improve.

- All Beetle chips have had their gain levelled
  and matched. Again, no improvement at all was
  observed in noise reduction or in signal/noise
  performance. In fact, data analyses indicate that
  the signal/noise behaviour slightly deteriorated.


Hence, it has been decided to not use the levelled/matched
optical receiver, and to leave the sampling point of
the ADC as it was before.

Unfortunately, the night shift was not able to
take any data, due to a broken power supply
in the SPS. After that was solved, there still
was no beam, this time due to problems in transmitting
the beam.

Today's day shift was able to take data, and the first
data points in the pulse shape scan have been taken.

Unfortunately, a wicked thunderstorm caused a power
glitch, and there is no beam since...

Task List
---------

 - log all actions in the *** logbook *** and/or
   in the *** spreadsheet ***

   don't forget to document
     - beam conditions
     - voltages
     - currents
     - temperatures

   These parameters should be logged once per hour,
   NOT only once per HV point!

 - process the data and file the control plots

   Note that most of the processing goes into the
   second step, which produces the root files for the
   final analysis.


 - continue the reduced measurement program:

   The order of measurements has been revised.
   We agreed to first perform pulseshape scans
   for the 'high' HV setting, and the two different
   Vfs settings. When there is time remaining, we
   will perform pulseshape scans for the lower
   HV setting (1.5 times depletion volgate).


   pulseshape scans for two values of HV, two values
   of Vfs and 100K per point.
   HV settings: 450V on all substrates for the 'high' HV
                nomimal (i.e. 1.5 X depletion voltage)
                for the other HV point.
   Vfs: 100 and 400

   Data points: 6 data points around the maximum, with a spacing
                of 5 ns.
                With t = 0 for the maximum, that would be
                -15, -10, -5 0 +5 +10 (in ns)
                +20, +25 +30 +40 +50 +60 +70 +80 +100 +120 (in ns)





Cheers,



	Johan