evening shift 07/17/2002

From: Adrian T Sindile (asindile@cisunix.unh.edu)
Date: Thu Jul 18 2002 - 01:10:18 EDT


We started the shift masking out channels in the trigger GUI and we
realized we had two noisy TDC channels (they were firing even if the tubes
were masked out!).
Those are the TDC channels corresponding to LTOF12 bottom (13 starting
from 1) and RTOF11 top (12 starting from 1).
Runs 693 thru 703 were taken just with cosmics in order to diagnose this.

Following Ricardo's advice, we raised the voltages on 3 Cerenkov boxes:
15% for the two big boxes on the left sector, 10% for the second box on
the right sector.
We got good beam around 9:30 - 10 PM (they had problems for a while) and
took runs 706, 707, 709.
Looking at the Cerenkov ADCs, it looks like we fixed the problem for the
right sector.
The two big boxes on the left still have problems, despite the 15%
increase.

We went to the D-tunnel and we saw the left HV crate was tripping for
channels 0.2, 0.6 and 1.2 (probably because of the injection).
We fixed that and we also swapped the right top TDC cable with the
retiming OR - hoping the RTOF11 problem will go away if we stop using
those TDC channels.
We also updated the map to reflect the changes.
Run 710 was taken after this - the suspected channels were still masked
out.

Analyzing run 710, WE STILL SAW THE NOISE in RTOF11, even if it was masked
out and moved to another TDC channel!!!!!
We do not understand that. If it is not a tube problem, and it is not a
TDC channel problem, then what is it???

Other problems:
- For RTOF 16 both top and bottom we only see pedestals.
- RTOF 6 top is missing totally now (no scaler rate) - this problem was
not reported before; it might be a new one...

I am making public my macro for looking at raw signals, and the newest
electronics map:

Jason called the older one "electronics_7_17.map" and the new one is
"electronics.map".

What is good about the new map and macro is that the retiming OR is read
as a neutron counter, so we do not confuse it with the Cerenkovs. The
macro, called "comBLAST.C" also works on the spuds.
It is in the commis/phase1/ directory and I am pretty sure it works well,
I have been tested it for days now.

People can start adding TDC diffs and means and ADC sums (they are in the
ntuple already) and place Cerenkov cuts for e-p analysis.

Jason and Tavi are taking over! We are out...

Adrian, Chi, Yuan

-------------------------------
Adrian Sindile
Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)862-1691
FAX: (603)862-2998
email: asindile@alberti.unh.edu
http://einstein.unh.edu/~adrian/



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