Goals: Find the source of the left right timing difference; find
protons in the left sector.
Tancredi generously spent a lot of time in the d tunnel trying to trace
the remaining l/r timing difference. At his request we delayed the start
timer (at the LTOFTopDel) from 20 ns to 24, and 30 ns. There was no shift
in the right sector TOF tdc means (that is, for each paddle:
retimingOR-startMean). We then reduced the delays in the right TOFs by 10
ns each, and still no shift in the right TDC means (rtOR-startMean). The
idea was to make sure that the start counter was coming later than at
least one other TOF. In the end, the extra delays didn't change anything.
We put them all back to normal and started looking for protons in the left
sector. We took two runs (835 adn 836) with correlated paddles. We set
the trigger such that paddle 3 (counting from 0) in one sector, and paddle
12 or 13 in the other. (835 has paddle 3 on the left, and 836 has paddle
3 on the right). We found protons in the left sector! Plots of
(top-bottom)right vs. (top-bottom)left show the expected corrleations in
both paddle 12 and 13 (see plot). Curiously, we did not see protons in
the right sector in run 835, but this may be due (at least in part) to low
statistics.
The updated electronics.map is now electronics.map, and the
electronics.map (before the cables were fixed) has been saved as
el07232002.map. Please note that the retimingOR is labeled as a neutron
counter.
Summary: no resolution to remaining timing problems. Protons have been
observed in the left sector.
J.S., A.S., D.H.
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jason seely
26.650b
massachusetts institute of technology
77 massachusetts avenue
cambridge, ma 02139-4307
email: seely@mit.edu
phone: 617.253.4772/6734
html: web.mit.edu/seely/www
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