From: W.J. Llope (llope_at_physics.rice.edu)
Date: Fri Jan 24 2003 - 12:21:10 EST
i think he is in meetings, so i'll try, since he and i discussed
this on the phone this morning....
it would only if star was capable of generating successive
L0's within a usec... the thinking was that trg can't do this.
At 11:18 AM -0600 1/24/03, Frank Geurts wrote:
>John, are we more susceptible for spurious L0s now that we lower our
>busy ~1 tick before we actually expect it to arrive ... ?
>
>-frank
>
>
>
>
>
>W.J. Llope wrote:
>>draft reply to christie. comment or sign-off please....
>>thanks
>>
>>>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.
>>>X-Accept-Language: en-us
>>>X-MailScanner: Found to be clean
>>>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, our response:
>>
>>we believe a delay of the L0 timing by one clock tick would
>>not adversely affect us (or other subsystems when we're running).
>>Our present coincidence window is 7 ticks wide, so we think
>>no changes to our NIM logic or elsewhere are necessary for us
>>to be able to handle this change.
>>
>>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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