STAR HardProbes PWG

[Nihar Sahoo <nihar AT rcf.rhic.bnl.gov>]

Hello HP-pwg,

Please have a look at Carl's email on lowering trigger threshold due to 
low rate.
If you have any comment or suggestion, please let us know.

Thank you
Nihar

-------- Original Message --------
Subject: [Star-triggerboard-l] Changes to B/EMC threshold settings
Date: 2024-06-12 21:13
From: Carl Gagliardi via Star-triggerboard-l 
<star-triggerboard-l AT lists.bnl.gov>
To: "'STAR experiment operations mailing list'" 
<star-ops-l AT lists.bnl.gov>, "'STAR trigger board mailing list'" 
<star-triggerboard-l AT lists.bnl.gov>
Cc: Carl Gagliardi <c-gagliardi AT tamu.edu>, 'STAR cold QCD / spin physics 
working group' <star-spin-l AT lists.bnl.gov>
Reply-To: STAR trigger board mailing list 
<star-triggerboard-l AT lists.bnl.gov>

Hi Jeff, All--

Once Oleg cleaned up the hot/warm towers in the BEMC (and Will for the
EEMC), the mid-rapidity calorimeter trigger rates have been running
quite low compared to Run 15.  Turns out the HV settings have not been
adjusted to compensate for aging since at least the start of Run 17 -
and maybe not since the start of Run 15.  The BEMC gain was observed to
drop ~10% over the course of Run 17.  Since then, we've also had Run 22,
but also times with little or no activity, which have seemed to enable
some gain recovery in the past.

Last night I took a couple of brief test runs with adjusted trigger
thresholds to determine the effective gain shift from Run 15 to now.
Lots of other things have changed in the interim, which makes a precise
number impossible.  However, a good approximation is that the gain is
now 16-20% lower.  The data that we have recorded to date are all
usable, but we've been less efficient than intended.  I propose that we
change several trigger thresholds to provide a first-order compensation:

EEMC-HT-th0                                      18 -> 17

EEMC-JP-th0                                       20 -> 17

EEMC-JP-th1                                       28 -> 25

EEMC-JP-th2                                       36 -> 31

BEMC-EEMC-overlapJP-th0                20 -> 17

BEMC-EEMC-overlapJP-th1                28 -> 25

BEMC-EEMC-overlapJP-th2                36 -> 31

BEMC-JP-th0                                       20 -> 17

BEMC-JP-th1                                       28 -> 25

BEMC-JP-th2-East                               36 -> 31

BEMC-JP-th2-Mid                               36 -> 31

BEMC-JP-th2-West                             36 -> 31

BEMC_HT_th1                                    11 -> 10

BEMC_HT_th2                                    18 -> 15

BEMC_HT_th3                                    25 -> 21

The following trigger IDs will need to be incremented:

EHT0

EHT0*L2EGamma

BHT3_bsmd

BHT1*VPD100

BHT2*BBCMB

BHT3*L2BGamma

JP1

JP2

JP2-L2JetHigh

Note that these changes should be implemented in all three current
trigger configurations:  production_radial, production_HighLuminosity,
and production_unpolarized.

Jeff, I'd appreciate it if you take a dummy run after you've made the
changes.

Stay Healthy!

Carl

p.s.  Rongrong and Nihar:  Could one of you please forward this to Hard
Probes?  I could send it myself.  But the HP PWG members might be more
likely to read a message coming from one of you.
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