On saturday we should meet and discuss progress. Here's the exhaustive
run plan...
================================
Plan for 11/07-11/08
read the blast book, make suggestions and contribute (!)
_ while waiting for beam or with hall open take a TOF cosmic run
analyze tof pedestal and channel R6T (came back) and R10b (light guide
problem).
_ tune the beam with field ON, lifetime on an empty target and a good field
off tune was close to 12-14 mins. Optimize background on the any coincs
trigger as well as singles trigger that has a lot of rate and may be more
relevant to the Wch. There is a slits-how-to in blast book
_ You must have CCR move the slits (...) but you must decide where they
have to go, what is good or bad.
_ The Wch plan of yesterday was to run at 0 SCCM, 0.2 SCCM, 1.0 SCCM
_ Ep data should be taken - possibly in parellel - with the
elastic_tof_last8 trigger. This has the NC in x mode
_ Make sure with show_protons.C bckg and radoms level is acceptable
(at least better than with field off! see prev. emails)
_ for each run, check the blast power supply current !!
_ We need a lot more CC data: with field on, HV set at NC_CC_TOF_1300.sql
and NC_CC_TOF_1300_10percent.sql. Let's just do 25 mV threshold.
_ For consistency we also need to take data with field off, NC_..._10percent
after some hardware modifications done yesterday. The focus is to tune
the CC with field on.
_ Tomorrow morning the hall will open for ABS. It may be a few hours only,
check with E. Ihloff and H. Koster. In that case we can continue data
taking, depending on progress and results from the CC analysis.
_ Also, the NC should be able to see some data (electrons). They are
included in the trigger as an x. All software seems to work. There
is a macros/raw_macros/raw_nc_adc.C for your convenience. There is
also the ntuple data.
CC: things to watch out and further plans (read this too !)
=======================================
_ Please do command line analysis. It's so much faster right now.
_ Please also check the CC rate (singles, coincs)
_ We have to monitor possible DC offsets at CC analogue input on
the blue splitters. Do that in the D-tunnel when you get beam
How: just unplug the signal from each box and average it on the scope
on the 2 mV scale. DC offsets screw up the ADC spectra Yesterday it was
tuned to <1 mV. If you find some channels are sitting on a DC level off
zero, then use the zero adjustment on the linear fan-outs in the NIM
crates on the racks with the fastbus crates. All cables are labelled and
the (channel by channel) adjustment obvious to make
_ another concern is the TDC range. We seem to loose some cerenkov data
that go above channel 4096 on the TDC. If you think this is a problem
we can take out delay in the following way: the CC inputs go to a Ledge
discriminator (slot 19 in camac). This has two outputs, only one is used
to go to a delay unit in slot 20. We can in principle by-pass the delay
unit completely by gently disconnecting the cable from the delay unit
output and reconnecting it to the unused output on the LEdge discriminator.
You can do that with the hall open with an expert.
_ can we take data at a lower CC threhsold ?
_ Higher HV ? The maximum HV to a tube is 2800. Do not exceed 2750.
-- ________________________________________________________________________________ Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124 research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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