[BLAST_TOF] notes on retiming

From: Tancredi Botto (tancredi@mitlns.mit.edu)
Date: Thu Sep 05 2002 - 11:53:23 EDT


A few things also about how the retiming was done, should you
need to go back at it.

To retime the R sector we put the start counter physically on the
right side and connect it to channel L16
When you retime (or check) the L sector we connect it to R16

It is very important to make sure that you are using only the meantimer
output relative to the sector your are studying. To do this, you need to
shift the ecl out on the back of the meantimer from output #8 (any one of
the L/R sectors) to #3 or #4 (R or L sector only, please check)

The retime check is (t_retime_or - t_start_counter_mean). t_retime_or
is connected to neutron counter #0, right sector (sorry, I was wrong in
the previous email)

however, if the start coutner mean is made from channels L16top/bot or
R16top/bot it will change due to different tdc offsets

Therefore, if you don't want to include the offset in your analysis, you
should also check the retime of the R sector with a start counter in R16,
and the L sector with a start counter in L16

However if you do so, the start counter is plugged into the meantimer
input for the sector you study, and you may end up with a self timing
peak. We got around this by replacing the ribbon cable at the input of
the meantimer with an equal lenght cable for which channel16 was cut out!
Peter should remember that. To avoid confusion make a new cable

- tancredi
________________________________________________________________________________
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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