From: Frank Geurts (geurts_at_rice.edu)
Date: Fri Jan 24 2003 - 12:18:53 EST
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
>
>
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