1. Multi-step Runs – an L1Calo Perspective
Norman Gee 28-Apr-05

2. Outline – three sets of multi-step (run) requirements.
1. Internal Timing measurements.
Use data replayed from memories inside our electronics modules
2. Timing measurements with fixed Calorimeter pulses
A combined run where L1Calo timing changes relative to calorimeters.
3. Energy Calibrations
Where range of calo energies are scanned and measurements made in trigger electronics (receivers + L1Calo)
General Comments
28 April 2005
C N P Gee – Installation & Commissioning

3. C N P Gee – Installation & Commissioning
1. L1Calo internal timing.
Many examples of timing scans needed in L1Calo
Most are needed to optimise capture of data sent over a link.
e.g. CPM-CPM; CPM-CMM; CMM-CMM; JEM-JEM; JEM-CMM
All our link data carry parity info. We use the parity error rate as a sensitive measure, and it’s quick. So a measurement consists of:
Load test vectors which exercise lots of bits. Then enter loop:
Set a timing value;
Clear error counters;
Wait ~1 second;
Read error counters from the modules, (as not available to RODs) insert values in Gmonitoring stream;
Iterate.
Analyse Gmonitoring stream. At end of loop, decide on best setting
Record to database.
28 April 2005
C N P Gee – Installation & Commissioning

4. Timing example – scan TTC for CPM-CPM backplane link
28 April 2005
C N P Gee – Installation & Commissioning

5. C N P Gee – Installation & Commissioning
Overall architecture
Sequencer
Root Ctrl
Crate Ctrl
Analysis
Module Serv.
Module Serv.
Module Serv.
Electronics
Electronics
Rod
Electronics
28 April 2005
C N P Gee – Installation & Commissioning

6. 2. Timing measurements with Calorimeters.
Measure the precise time and shape of calorimeter analogue pulses
Add delays to compensate for unequal pulse arrival times
Position the FADC sampling to sit at peak of calo pulse
Measure pulse shape to compute Bunch-Crossing identification coeffs.
Ensure equal timing of individual calo cells which are being summed.
Use a continuous stream of equal-amplitude calo pulses. So a measurement consists of:
Start calo pulse train, with the required raw cells enabled.
Set a timing value for the FADC sampling;
Read out 100 events from L1Calo via RODs
Iterate.
Analyse event stream (not necessarily synchronous with steps). Compute mean FADC output. At the end, determine optimum settings.
Record to database.
28 April 2005
C N P Gee – Installation & Commissioning

7. 3. Energy Calibrations with Calorimeters
Adjust analogue receivers and Preprocessor to give exact GeV ET
Final adjustment of gain vs sin 
Requires synchronised steps between calo and L1calo
Set up combined trigger, agree details of sequence to be executed
Calo sets the next analogue pulse amplitude
Calo (?) generates 100 L1As
L1Calo readout of Preprocessor ( and calo?) response via RODs.
Iterate
Analyse event stream (not necessarily synchronous with realtime steps). Compute mean observed ET per set of events. At the end, determine optimum settings taking account of detector effects.
Record to database.
28 April 2005
C N P Gee – Installation & Commissioning

8. C N P Gee – Installation & Commissioning
General Comments - 1
At present we have a first version of a multi-step run, using pause-resume transition
Much faster than starting a new run for each point
The Crate Controllers interpret the run types and do special things.
Need to understand if this will work with calorimeters.
The analysis program needs to know the step number
We insert it in the detector-specific event type. Would be nice to have somewhere better.
We have the concept of a “plan” to set up the joint runs
A database extract containing all necessary details (eg energies, no of L1As, settings for LTPs,…) for the complete run.
Avoids need for cross-communication between L1Calo and a calorimeter.
Details to be defined
28 April 2005
C N P Gee – Installation & Commissioning

9. C N P Gee – Installation & Commissioning
Generall Comments - 2
Database Issue
Electronics module settings are loaded from database
But during a calibration run they need to be changed but not preserved
Do we need any nested loops? Well unfortunately we may.
Does pulse timing stay constant with pulse amplitude?
Outer loop to change calo pulse amplitude
Inner loop to scan L1Calo timing
Do all raw cells contribute in the same way to analogue sums?
Outer loop over raw calo cell number
Inner loop over L1Calo pulse timing
28 April 2005
C N P Gee – Installation & Commissioning