Date: Mon, 11 Feb 2002 16:04:38 -0600
From: Elizabeth Gallas <eggs@fnal.gov>
Subject: New prescale file procedure

Dear all,

The prescale sets we have decided to use during a Run
depend on Run conditions as well as the current instantaneous
luminosity.  Sometimes we want to use the set designed for
a different luminosity. -- this is okay, as the filenames are
intended as a guideline, not a strict rule.
It is not possible for us to rename all files instantly and we depend
on DAQ shifters to communicate special instructions
from one shift to the next (and communicate to us any problems).

There are 2  triggers in every global list that are special:
min_bias and zero_bias.

zero_bias (L1 name ALiveBX - a trigger on the beam crossing signal):
the prescale should always be 3400000 regardless of luminosity.

min_bias (L1 name Afastz - a trigger on the North and South LUM counters):
the prescale should be set according to the current instantaneous luminosity
so that we record about 0.5 events per second of this type.  We have entered
the needed prescales for this trigger into files called
minbias_*E30.prescales,
where * is the luminosity factor in E30 units.
Here are the prescales we recommend:
LUM      prescale       prescale file
01E30     56000         minbias_01E30
02E30    110000         minbias_02E30
04E30    220000         minbias_04E30
06E30    340000         minbias_06E30
08E30    440000         minbias_08E30
10E30    560000         minbias_10E30
12E30    670000         minbias_12E30
...
If you use a prescale file that is named a luminosity where there is
a minbias_* file closer to the current luminosity, then
AFTER downloading that set, download the above minbias_*E30 set
which will override the min_bias prescale with the correct value.

Thanks,
Elizabeth and Levan