TDR Updates - Algorithms
This page provides information on changes to the calorimeter trigger design made after
submission of the TDR. Information on changes to TDR
Technologies and External Systems is also available.
TDR- Page 31 |
Updated Version |
16 sets of thresholds are organised as 8 for em and
8 for tau triggers. |
16 sets of thresholds. The first 8 are for em
triggers only. The second 8 can be programmed to define em or tau triggers, giving
the flexibility to run more em (and less tau) triggers if needed. |
Presented: Level-1 Collaboration Meeting at CERN
4-Sep-1998 (A Watson), Level-1 UK at RAL 23-Nov-1998 (A Watson), Level-1 Collaboration
Meeting Heidelberg 30-Nov-1998 (P Watkins) and Birmingham 6 March 1998 (A Watson). |
Status: Agreed |
TDR- Page 30 |
Updated Version |
All 16 towers in the 4*4 tower region
are summed and compared with a single Hadronic isolation threshold. |
An inner 2*2 region (4 towers) and an
outer ring of 12 towers are summed separately and compared to two separate thresholds. The
threshold conditions must both be satisfied to produce a trigger. The change offers
increased flexibility and may marginally improve rejection. |
Presented: Level-1 UK at RAL 23-Nov-1998 (A Watson),
Level-1 Collaboration Meeting at Heidelberg 30-Nov-1998 ( P Watkins) and Birmingham 6
March 1998 (A Watson). |
Status: Approved by T/DAQ Steering
Group 22/7/99. No adverse effects on signal efficiency seen in any situation simulated,
and possibly slight benefits. Atlas note in preparation. |
TDR- Pages 36-40, 49-50 |
Updated Version |
The position is defined by the highest of the
overlapping 2*2 area sums which satisfy the threshold criteria. The sum is over the em
calorimetry only for em triggers and over em and hadronic calorimetry for tau triggers. |
The position is defined by the highest 2*2 area sum
satisfying the threshold criteria. For both em and tau triggers, the sum is over em and
hadronic calorimetry. If the em trigger fires, isolation ensures a very small energy
deposit in the hadronic layer. The common algorithm simplifies implementation and
marginally improves jet rejection (when used with 2-region hadronic isolation), and also
slightly simplifies the RoI format. |
Presented: Level-1 UK at RAL 23-Nov-1998 (A Watson),
Level-1 Collaboration Meeting at Heidelberg 30-Nov-1998 (P Watkins) and Birmingham 6 March
1998 (A Watson). |
Status: Approved by T/DAQ
Steering Group 22/7/99. No adverse effects on signal efficiency seen in any situation
simulated, and possibly slight benefits. Atlas note in preparation. |
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