Took runs 237, 238, 240, 242 244 and 245 to try to measure the false
asymmetry with the
following run conditions:
BLAST TORROID off due to power problems.
Hydrogen flow set to mimic ABS flow. This was done by trying to set the
flow so as to increase the pressure in Ligit by ~ 0.85 e-7 in reality this
was 3.6 e-7 due to the lack of sensitivty of the mfc. This corresponded
roughly to 0.08 sccm setpoint and readback was 0.06.
Half Wave Plate in every other fill.
Slit positions: L=-9.0 R=5.5 T=3.0 B=-9.0
The Beam Quality Monitor were mysteriously low. i.e. normalized rates were
identically zero for all monitors as seen on MEDM screen. Visual Scalers
window gave ~15 for Top and Left and 0 for Bottom and Right. Voltages
were checked to be ok and when injecting we did see the counts max out.
Lewis in CCR noted that the only difference from tonight than last night
was that they had a much better vacuum, esp Ligit02 which is upstream from
the target. However the vacuum deteriorated throughout the night due
outgassing caused by running the beam.
The data rates were much higher than previous night's runs also without
field--150Hz compared to 40 Hz.However, since the BQM's show zero, there
is no handle by which to tune the beam except lifetime and beam current.
These higher rates resulted in poorer S/B for the WC's compared to last
night from 4:1 down to 3:1 worst case.
PROBLEMS:
1.) Coda froze a twice throughout the night and had to be killed and
restarted.
2.) dblast07 was extremely crippled by an enormous amount of seemingly
useless processes running. The main culprit was "root -splash
hits_vs_TOF_ONLINE.c" which had 102 processes running. Everything sped up
after they were killed.
3.) HV control using the hvdaemon for the Left and Right Sector TOF's/CC's
etc. froze multiple times throughout the night, each one separately.
We noticed this when the scalars for a sector went to zero indicating this
failure must have set the voltages to zero. The hvdaemon had to be
restarted to get it to recover.
NM/AD
On Tue, 15 Oct 2002, John Calarco wrote:
>
> This is a message to BLAST students and their advisors. We are in
> the midst of commissioning BLAST (just in case you hadn't heard)
> and we are in desperate need of students to take shifts. I have
> recently sent out another request for volunteers for shifts for
> later this week, with the usual lack of response. Following is a
> list of shifts by graduate students on BLAST for the last 7 weeks.
>
> Sindile 18
> Karpius 17
> Filoti 16
> Degrush 13
> Maschinot 9
> Crawford 8
> C. Zhang 6
> Meitanis 5
> Xiao 2
> Seely 2
> Ziskin 2
> Clasie 0
> Y. Zhang 0
> Stave 0
> (Burton 0) but I think Richard said he was no longer in the program
>
> The message is clear. A few students are carrying the load for the many.
> It is time for advisors to kick some grad student butt, or decide they
> are no longer interested in theses on BLAST. We need people on shift if
> we are going to successfully commission this detector. Please see my
> earlier message: there are 4 weekend shifts lacking any volunteers.
>
>
>
> --
> John R. Calarco
> Dept. of Physics
> Univ. of New Hampshire
> Durham, NH 03824
> phone: (603)862-2088
> FAX: (603)862-2998
> email: calarco@unh.edu
>
>
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