TOF Response to Fwd: Input requested concerning change to trigger L0 timing.

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From: W.J. Llope (llope_at_physics.rice.edu)
Date: Fri Jan 24 2003 - 15:31:09 EST

>Delivered-To: llope_at_physics.rice.edu
>Date: Thu, 23 Jan 2003 13:03:52 -0500
>Reply-To: starops-l_at_bnl.gov
>Sender: owner-starops-l_at_bnl.gov
>From: Bill Christie <christie_at_bnl.gov>
>To: starops-l_at_bnl.gov, starops-hn <starops-hn_at_connery.star.BNL.GOV>
>Subject: Input requested concerning change to trigger L0 timing.
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>Status:
>
>Dear Sub System managers,
> It appears that in order to get the BEMC trigger data properly
>lined up with the trigger data from the other STAR trigger detectors
>(i.e. CTB, BBC, and ZDC) that we'll have to insert a one "STAR clock
>tick" delay into the trigger timing. Note: One "STAR clock tick" is
>~ 107 ns. This will change the time between when the collision
>happens, and when trigger sends out the L0 trigger to the
>subsystems, from the 13 clock ticks that were used last year to 14
>clock ticks.
> We plan to test this scheme soon. I'd like to hear back from sub
>system managers any concerns that they may have about this change,
>and in particular, if this change will necessitate a change to your
>sub systems setup (logic, delays, NIM setup, etc.) to account for
>this change. Please get back to me on this ASAP.
> Greetings from frigid Long Island,
> Bill

hello bill, we have discussed this in the group, here's our response:

Our present coincidence window is ~7.4 ticks wide, and
we are presently timed in at roughly the middle of this window
(~4.1 ticks before and ~3.3 ticks after)...
we thus believe a delay of the L0 timing by one clock tick would
not adversely affect us (or other subsystems when we're running).
no changes to our NIM logic or elsewhere would be necessary.

please proceed with your test of this configuration.

but.... when will this test be done?

and.... if there is a problem w/ tof systems during this
test, please contact tofp_at_physics.rice.edu (all
detector experts) immediately...

thanks, regards,
        bill 

-- 

  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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