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User name arvieux
Log entry time 21:45:47 on May 05, 2004
Entry number 84202
keyword=RC Daily Report 4-5 May
Run Coordinator Daily Report for 4 May Owl to 5 May Swing
Summary
Completed thresholds studies with IHWP IN
Completed Hall B leakage studies with Hall A out (4,5
hours)
Did a run with both Hall A and Hall B off, Hall C at 40 uA (1 hour)
In total we had 5.5 hours of leakage studies
Doing further tests with Hall A (at 90 uA), Hall B and Hall C
alternating
40 uA and 0 uA (j`leakage fron`m Hall A+B) as explained below
GMS is still off.
Significant News
Hall B leakage has been measured in Hall C in the following
conditions:
Hall A off, Hall B at 25 nA
(but a few uA in the injector, a number we should keep
track
as
Hall B leakage should depend on it),
Hall C laser shut OFF but slit wide open (which corresponds
to a current of 40 uA).
Leakage is 2/3
of
the total Hall (A + B) leakage (or about 35 nA) , or twice Hall
A leakage which is somewhat bad news.
Good news is that the Hall B asymmetries
, as measured in the the Lumis (the FPD are not analyzed yet) are not
so high (500-700 ppm).
Taken altogether the effect of Hall B is then about 1/2 the
effect of Hall A.
After 5.5 hours of leakage tests (with Hall A off,
including
one hour with both Halls A and B off), we had to let Hall A (now
at 90 uA)
and Hall B have beam again. We are presently doing stability
tests of the leakage with Hall A+B on, by alternating 40
uA runs with 0 uA (leakage) runs
in Hall C, every hour (with IHWP IN and OUT).
Tomorrow, Hall C crew will do detector tests for future
experiments
for one complete shift. During that time we'll do (essentially Jianglai)
an analysis of the leakage data presently taken. Around
14:00-15:00
we should have conclusions and be able to request further
tests
if needed ,to JLab management.
We will most likely require at least one (or more) 4-hours
period
with Hall A off on Friday.
Other tests (including tests at different Hall A intensities or
running longer to compare with data taken before April 17), would require
up to 3 shifts with
Hall A off..
The priority of target boiling studies has been lowered
after Hall A leakage. They could be done on Friday except
if we get more time for leakage studies, in which case they would have
be postponed on Friday or during the week-end.
Completion of thresholds studies with IHWP=OUT
will
be done during Thu Swing-Friday Owl (2 shifts).
Short term Plans
-
Hall A and B on, Hall C at 40 uA, LH2 target, Lumi and BCM 1/2 set to
reduced
gain. We want to take in a systematic way, one beam ON (40ua) run
sandwiched between 2 beam OFF (0 uA) runs with same IHWP settings
.
DO NOT FORGET TO CHANGE LUMI AND BCM1/@
SETTINGS EVERY TIME YOU SWITCH BEAM ON/OFF
(or the other way around).
The instructions are given below
All runs should be of one hour.Then:
-
beam OFF-IHWP = OUT
-
beam ON -IHWP = OUT
-
beam OFF-IHWP = OUT
-
beam OFF-IHWP = IN
-
beam ON -IHWP = IN
-
beam OFF-IHWP = IN
After a full cycle, ask for 20 uA,
-
beam ON -IHWP = IN
-
beam ON -IHWP = OUT
-
beam OFF-IHWP = OUT
Ask for 40 uA
-
beam ON -IHWP = OUT
-
beam OFF-IHWP = OUT
-
beam OFF-IHWP = IN
-
beam ON -IHWP = IN
-
beam OFF-IHWP = IN
Follow that sequence until Thursday morning 8:00. If hall A goes off,
make a g0log entry, start a new run and just follow the same
sequence.
-
Resume threshold studies with IHWP OUT after
detector
tests are completed Thu around 16:00
LH2 target, standard running conditions except thresholds.
Due to differences in FR and NA splitters the thresholds of the FrAm
detectors have to be higher than the FR thresholds. A new Reference file
has
been created with FR thresholds at 100 mV and FrAm thresholds at 140
mV (Reference_FiB_Buddy_Fr100mV_FrAm140mV
). So for the thresholds studies:
- load
Reference_FiB_Buddy_Fr100mV_FrAm140mV
-set NA threshold to 14
-
Run 2 shifts at 40 uA with IHWP = OUT. That
should bring us to Friday morning.
-
When reverting to standard running , don't
forget:
- to load the Reference_FiB_Buddy
- to set the NA thresholds to 7
SETTINGS TO BE USED WHEN RUNNING WITH NO CURRENT IN HALL C
-
Lumi gain has to be multilied by 1000, this being obtained by
gaining
a
factor 100 using an increase in HV and another factor of
10
by
changing the gain of the lumi amplifiers. For that:
- Switch from standard lumi HV file
HV.2004-02-19.lumi_halo_on.hvcto
HV.lumi_highhigh_on.hvc
- Change the 6 lumi amplifier settings in Electronics Shack
upstairs
(if you don't know how to do,ask Mark Pitt or Jianglai or
the
RC).
-
change BCM 1 and BCM gains from 3==>5 in rack CH03B11 in Hall C
electronics room. These will most likely not work as sensivity
is 1 uA only for these settings but it does not hurt.
DON'T FORGET TO SET THESE BACK TO NORMAL
CONDITION
WHEN RUNNING AT HIGH CURRENT.
Longer term Plan
-
Thursday all day will be devoted to SOS calorimeter tests (1
shift). All G0 HV will have to be turned
off.
- disable HV crates (all 10)
- Moeller / SMS turned down (Damon
Spayde)
- target out
- halo target out (MCC)
-
Target boiling studies could be scheduled on Friday if no
other
urgent task (to be decided at the Thursday RC meeting at the
latest.)
-
Next week (tentatively on Tue or Wed): one full Day shift
will
be devoted again to SOS tests.
-
Next week: transverse spin if no other urgent business.
-
If agreed by JLab management we may have several periods of
beam leakage studies with Hall A and/or Hall B OFF.
Detailed
run plans will
be given in due time.
Concerns
A copy of this log entry has been emailed to: beck