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User name dalton
Log entry time 17:43:03 on October 16, 2009
Entry number 295253
keyword=Target: pressure the silver bullet?We have recently had trouble keeping target boiling under control (as
measured in the luminosity monitor asymmetry widths.) Figure 1 is a
history of this quantity since 10 October. Each point is composed from
~4.5 k pairs representing about 5 minutes of time.
Figure 2 is the target pressure and Figure 3 the ballast pressure -
showing a strong correlation. Figure 4 shows the beam current, note
where we have where we have changed it around in the last day to reduce
the boiling. The points are epics reads in our coda data file and line
up roughly vertically with Figure 1.
Figure 5 shows how the arbitrary epics event numbers are mapped to real
time (Figure 1 follows same pattern). Figures 6 through 10 show
quantities with which the correlation is weaker: the cryo input
temperature, target temperature, JT valve setting and heater value.
The naive conclusion is that a small pressure increase in the target
would reduce the boiling significantly.
A copy of this log entry has been emailed to: meekins@jlab.org
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
