1. Detector parameters and modelling
M. Abolins, J.C. Vermeulen
Input for modelling:
Number of ROLs and ROL mapping onto detector
(ROL mapping, together with trigger menu, sequential processing
strategy and associated reduction factors, determines LVL2 RoI
request rate)
Fragment sizes per ROL
Detector parameters and modelling, TDAQ week December 2002

2. Current knowledge of # of ROLs (from Annecy ROD workshop) # of ROLs
Detector
# of ROLs
Frag. size (avg., 10^34)
Pixel
120->192?
1300
SCT 92
1600
TRT
256
525
Tilecal 64
1100
LAr
768
1400
MDT
192
800
RPC 32
1000
TGC 16
200
CSC
LVL1 55
1500 (not for all)
not
used by
LVL2
Detector parameters and modelling, TDAQ week December 2002

3. +16 PP ROLs + 1 Central muon trigger ROD = 55 RODs
Detector parameters and modelling, TDAQ week December 2002

4. ROL mapping onto detector is important for subdetectors that
provide data to LVL2. No indications, so far, of important changes
in the mapping. For the muon barrel trigger chambers the mapping
used for the paper model has been updated this year.
NB: further optimisation of ROL mapping may be possible (in view of the
relatively high LVL2 request rates for some of the ROBs), example (em cal):
A few ROBIn’s
Receive an RoI
Request for as many
As 8% of jets while
For most it is ~3%.
Detector parameters and modelling, TDAQ week December 2002

5. Fragment sizes From: overview of parameters used for 2001 paper
model and of modifications in 2002 model, June 6, 2002
Apart from muon trigger chambers, numbers more or less in
line with ROD workshop numbers. The paper model
numbers for the inner tracker have been obtained from
ATL-COM-DAQ and ATL-COM-DAQ
= truncating
event
fragment
Detector parameters and modelling, TDAQ week December 2002

6. Fragment sizes (cont.)
Distributions of fragment sizes tend to have relatively small
tails. Example from ATL-COM-DAQ (R. Scholte,
Event Fragment Size Distributions for the Inner Detector), for
barrel SCT ROBs:
Detector parameters and modelling, TDAQ week December 2002

7. Fragment sizes (cont.) From ATL-COM-DAQ-2002-002: endcap pixels
Detector parameters and modelling, TDAQ week December 2002

8. Fragment sizes (cont.)
From ATL-COM-DAQ : TRT ROBS with data compression
Detector parameters and modelling, TDAQ week December 2002

9. No dramatic changes in number of ROL’s, ROL mapping and
fragment sizes, but fragment sizes may require further study.
It would be nice to have also for the calorimeters and for
the muon detectors the type of results that are available in
ATL-COM-DAQ and ATL-COM-DAQ
Further optimisation of ROL mapping may be possible (in view
of relatively high LVL2 request rates)
NB: For modelling, ideal detectors without holes for services have been
assumed until now. It is felt that taking holes into account will not affect
the main modelling conclusions, as the rates will decrease somewhat in that
case and somewhat more "headroom" will be available in a system
designed on the basis of the current assumptions (i.e. "no holes" in the
detector).
Detector parameters and modelling, TDAQ week December 2002