Hello,
all shifts are ON until monday morning. The effect of the collimator
is still a very positive one and we should redo all the data taking of
friday-tuesday last week.
Plan for the night is to continue to take study the effect of the
collimator on detector rates and beam tunes.
so far we have collected 430 C on empty target and 200 C on gas
target (0.1 SCCM). This is sufficient data for some first analysis.
Plan for the night is to measure for a number of beam position
settings around the present position using the local bump at the target
Please refer to the paper logbook, pg 30, for an extensive scan of bqm
rates vs beam positions. Note the slits were out. Our "nominal" beam
position is 0,0 (H,V). Plan is to have CCR move the beam to +- 1 mm on
the H (V=0) and then move to +- 1 mm vertical (H=0). At each position
re-optimize the slits. Have the Wch OFF when beam tuning. Cumulate ca. 400
C of charge at each setting. In addition run charge.C and lrn
If we run into un-expected problems we can always take more h2 runs. D2
runs and single arm triggers will be done tomorrow and in the next days.
*Note that the total incoming rate (phys0+phys1+phys2) can easily exceed 1
kHz and the dead time ca 50 % or more. This is inconvenient of course but
in this configuration (collimator, reverse polarity) clearly total rates
are becoming an issue. Nevertherless - for now - the dead time issue only
complicates the analysis but it can be addressed later (with a "wch"
trigger).
Please make a rate/dead-time map as a function of beam position (plot
would be nice)
*NOTE: do NOT run lrn without any options IN PARTICULAR if you don't know
what these options should do or how.
*Note there is a small adjustment to be done with beam for gas on/off
running in order to have a smooth lifetime
-- ________________________________________________________________________________ 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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