tavi was working in the d-tunnel until 20:00. at this point, we took two
cosmic data runs (#2429 and #2432), both containing 100,000 events. run
#2429 had no power supply; run #2432 did have the power supply 'on'. the
point of these two runs was to check whether or not the new shielding
around the tof's was working. the power supply 'on' run had data rates
equal to about 1/2 of the power supply 'off' run (the 'on' rate was
100Hz; the 'off' was 200Hz), so maybe more shielding is needed???
after this, we attempted to take data using the any_coincs trigger. the
rates were too high (around 2000Hz with 1sccm in the target and 80mA in
the beam). after trying various things, we finally re-positioned the
slits. their new positions are:
l r t b
--- --- --- ---
-5 11 1 -5
with these new slit positions, we got the following trigger rates with no
gas in the target and the power supply off:
I(mA) trigger rate(Hz)
----- ----------------
90 600
70 420
50 270
one more thing CCR pointed out to us... if you do not have any gas in the
target, you should ask CCR to turn off the lattice ion clearer. if you do
not, the trigger rates seem to be higher than they would otherwise be.
aaron and chi
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:28 EST