From: W.J. Llope (llope_at_physics.rice.edu)
Date: Wed Apr 16 2003 - 15:47:49 EDT
At 2:33 PM -0500 4/16/03, Frank Geurts wrote:
>W.J. Llope wrote:
>>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?
>
>that was exactly my understanding. Internal delay and cables could
>allow for ~8ns. Maybe John can elaborate a little bit more on this.
don't forget - the pVPD platform discriminators are performing
two functions. they're providing the inputs to the hit-counting logic that
is the front-end of the local trigger *and* they're "line-driving"
the logic signals from the pVPD FEE on their way to the pVPD TDCs.
whatever goes in the place of the pVPD discriminators has
to perform both functions (fast clean discrimination with two
outputs) w/ the present level of accuracy.
seems like a discriminator is tailor-made to perform these
two functions in the most-efficient way....
and anyway, different discriminators will still have internal delay...
also, other discs may not be able to live up to our
timing cross-talk specs (which, rightly, are rather strict)..
or what were you thinking about john? cheers
--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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