Hello, All:
The goal of tonight was to take some (relatively) extended data runs so
that we can start to look for first-order t0's in the cells. In an effort
to try to minimize the events reconstructing downstream from the target, a
modified trigger, demanding a coincidence between the first four and the
back four TOF's was used (as opposed to the trigger demanding a
coincidence between the first 8 and the back 8 TOF's). However, when this
trigger is used, the resulting trigger rate is low (around 10Hz) at
lifetimes of 6minutes. One is forced to go to extremely low lifetimes
(2-3minutes) in order to get decent rates (20-30Hz). Run maintenance
becomes a full-time job...
I managed to take two relatively extended runs this morning. Run 2004
contains 45000 events (then CODA hung). It took roughly three hours to
accumulate. Run 2005 contains 57000 events; it took most of the remainder
of the shift. I also managed a shorter run (Run 2006) with 8000 events.
Looking at these runs shows that both sectors now have good signal to
noise ratios (around 2:1). Additionally, except for boxes L21 and R24
(which both tripped many times), the rest of the boxes all held and had
currents around 1-2microamps; these currents did not increase
significantly with time.
However, most of the events that I viewed using nsed still reconstruct to
a point about a meter downstream from the target.
I have labeled and high-lighted the hot/inefficient wires on a page of
plots from Runs 2004 and 2005.
I was not able to perform tests with the downstream magnet current turned
partially on but with opposite sign of normal running mode. CCR did not
know which magnet I was asking about. They wanted to know its LS number
(i.e. lattice steering number), which I did not know; it was not
sufficient to say the "steering correction magnet located about a meter
downstream from the target."
Aaron
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