Re: TOFr TDC range

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From: W.J. Llope (llope_at_physics.rice.edu)
Date: Wed Apr 16 2003 - 15:15:20 EDT

At 2:44 PM -0400 4/16/03, Frank Geurts wrote:
>Other scenarios were far more involving and would mean replacing the
>pVPD discriminators

with what? whatever you put in there will still have internal delay.
the present ones are only like ~6ns or something like that.
or was the reasoning based on s'th other than the internal delay spec?

>or replacing the EAST/WEST/TRIG logic with a single
>OR (for pp only, though)

how do you require at least one hit on each side w/out looking
at each side separately w/ such a decision tree? one hit on
each side is the minimum requirement no matter what beam
species rhic is runnign ....

> or delaying all 72 logic cables ...

(shudder)

>This brings me to another point: have we -or are we planning to do so
>this week- changed the TRIG logic to 1.OR.1 ... i haven't seen any
>messages w.r.t. this.

that's becuase running 1.OR.1 is really not that productive....
this will collect a lot of data w/ a single lit channel in the
pVPD. this makes the TDC dist for this channel in those events
a delta function by definition, and a direct start slewing
corrrection is thus not possible by definition.
1.AND.1 is the minimum, most open, local trigger we can
run and still do corrected timing....

there is however the possibility that we will want to run
2.AND.2 during the TOF-triggered data collection here in run-3
pp collisions.
the 1.and.1 rates may be too much for the DAQ (?). 2.and.2
would drop the rate by a big factor, and also lead to
somewhat better start resn (because of averaging) over the
sample of triggered events.... rgds

>
>cheers,
>frank
>
>
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-- 

  W.J. Llope, Ph.D.                      Res. Assoc. Professor
  T.W. Bonner Nuclear Laboratory         phone:  713-348-4741
  Rice University, MS-315                fax:    713-348-5215
  6100 S. Main St.                  
  Houston, TX 77005-1892            
             e-mail:     llope_at_physics.rice.edu
             WWW home:   http://wjllope.rice.edu/default.html

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