1. SDD in February ‘08 cosmic run
Davide Falchieri
Universita’ e INFN, Bologna
Francesco Prino
INFN Sezione di Torino
Commissioning workshop – April 1st 2008

2. Summary SDD running conditions in Feb08 cosmic run
Calibration runs and data in OCDB
PEDESTAL and PULSER
Baselines, Noise, Gain
INJECTOR
Drift speed
Cosmic hits on SDD
Outlook

3. SDD running conditions

4. ECS/DCS/HLT DCS ECS HLT Operated and controlled via PVSS SW
Experienced quite frequent blockings of the user interface
DCS Finite State Machine integrated in the ECS
ECS
Operation sequence:
DAQ initialization (reset RORC, DIU, SIU) – Send JTAG commands
Initializes TTC (resetting TTCrx  requires extra initialization procedures done by the CARLOSrx acquisition cards)
PULSER and INJECTOR runs types (used for SDD calibration, see next slide) correctly implemented (i.e. with proper DA launched at EOR and limitation on number of events) starting from March 5th
HLT
Not used

5. ECS run types and SDD config
STANDALONE
No DA launched at the end of run
PEDESTAL
To measure baselines and noise (using ITSSDDBASda)
No zero-suppression and no baseline equalization
PULSER
To measure gain from test pulse (using ITSSDDGAINda)
Turn on PASCAL test pulse
INJECTOR
To measure drift speed from injectors
With baseline equalized and zero-suppression active
Switch on pre-pulse trigger
PHYSICS
Baseline equalized and zero-suppression active
Masking of noisy anodes not activated
Output written in OCDB
in directory CalibSDD
Output written in OCDB
in directory DriftSpeedSDD

6. Ladders used Cooling available only on the top half of the SDD layers
# of modules: 36
 coverage: ˚
Layer 4
Ladder used: 1-12
# of modules: 96
 coverage: 0-196˚

7. DDLs used

8. Excluded modules
Some modules gave problems when running at high trigger rate (> 500 Hz)
Data synchronization is lost after short time
Acquisition is blocked
Problem affecting 37 modules, presently under investigation
These 37 modules have been removed from the configuration used in February run
Other 3 modules of ladder 4 of layer 3 are dead
Resulting module statistics:
Total number of modules with cooling 132
Modules excluded for various problems 40
Total number of modules in DAQ 92
88 of them supplied at the nominal HV of 1800 V

9. SDD geometrical coverage

10. Problems with BUSY
Starting from Feb 27th we observed the SDD go in busy and block the acquisition after few minutes with the ACORDE trigger (95 Hz) in the global partition
Problem appears only when SDD are slowest detector in the global partition
No problem when running with in the global partition with TOF trigger (rate 1 Hz)
Everything OK in standalone mode
In order to be able to take data in the global run on March 5th we increased the busy time from 407 ms to 2025 ms, to be sure that AMBRA chips work in single buffer mode
In this configuration data taking was stable for the following days also as slowest detector in the partition
Under investigation (together with synchronization problems)

11. Calibration Runs and data in the OCDB

12. CalibSDD objects in OCDB
Baselines, noise and gain for each anode extracted by DAs from PEDESTAL and PULSER runs
PULSER runs (with DA automatically starting at EOR) implemented and correctly working starting from March 5th
Previous calibration runs were taken as standalone (no DA)
Should be analyzed offline
DA+preprocessor for baselines noise and gain properly working starting from run 25410
Results checked offline for few runs and are ok
Conclusion: OCDB/ITS/Calib/CalibSDD files are ok for first reconstruction pass for runs > 25410
To-do:
Offline analysis of calibration runs < 25410
Complete validation of DA output

13. Example plots: PEDESTAL run 23665
Noise distribution for good anodes
Baseline distribution for good anodes

14. Example plots: PULSER run 23668
Gain from test pulse signal to pre-amplifier input
Anode statistics:
Total number of anodes in DAQ
Number of noisy and bad anodes (from PEDESTAL) (0.7 %)
Number of dead anodes (from PULSER) (0.2 %)

15. Zero suppression thresholds
Thresholds for zero suppression kept low in the first part of the run (i.e. before March 4th)
For few anodes with larger noise, all time bins pass the thresholds and are recorded
Typically occurring on anodes 0 – 64 – 128 – 192 which stay on chip edges and are more affected by common mode noise

16. DriftSpeedSDD objects in OCDB
Drift speed for each module extracted by DAs from INJECTOR runs
INJECTOR runs (with DA automatically starting at EOR) implemented and working starting from March 5th
BUT problems with:
Modules with injectors not working
Threshold for injector cluster finding (optimized for non zero suppressed data)
Solution (OK for first reco pass):
Calibration object produced offline by analyzing run and put in the OCDB with validity from run to run
Drift speed for modules with bad injectors set to the average value
To-do:
Offline analysis of all injector runs
Extrapolate drift speed for modules with bad injectors according to the observed ladder dependence

17. Drift speed from injectors
33 (1 each 8 anodes) x 3 injectors on each half module
Drift speed depends on anode number
Drift speed depends on temperature
vdrift = meE with meT-2.4
Heat sources on detector edges
Fit with 3rd order polynomial
Fit parameters stored in OCDB

18. Drift speed vs. ladder position
Drift speed depends on temperature
vdrift = meE with meT-2.4
Heat goes up
Top ladders: higher T, lower drift speed
temperature
Drift Speed (mm/ns)
Module number
LAYER 3
LAYER 4

19. Drift speed stability From run 24906 collected with muon trigger
about 5 triggers/minute, 200 analyzed events from 1 raw data file
Drift speed constant on a time scale of 1 hour of data taking
Timestamp=
Mon, 03 Mar :51:32 GMT
Timestamp=
Tue, 04 Mar :05:26 GMT

20. Cosmic hits on SDD

21. Strategy Start from SPD points (global coord. provided by Henrik)
Perform a simple tracking (linear fit) and calculate (with simplified geometry) which modules are hit on SDD layers
Run ev 31 (32 online)

22. SDD raw data (I) Look at SDD data on the modules pointed by SPD track
Run ev 31 (32 online)
Layer 4 – Ladder 9 – Det 4
Low momentum particle
(≈3 MIP)
Cosmic Hit

23. Reconstructed cluster (I)
Calculate cluster coordinates using an average value of drift speed and no correction for time offset
Plot with EVE

24. Reconstructed cluster (II)
Other 2 golden events from run 22252
Run ev 84 (85 online)
Run ev 100 (101 online)

25. Outlook

26. Cooling development (F. Tosello)
78 pressure sensors (mounted as near as possible to the detector)
calibrated and installed but not yet electrically connected (new PLC not yet available)
52 flow meters
All calibrated
34 out of the 52 : calibrated and mounted, the remaining ones will be delivered this week.
Planning proposed by A.Tauro
wk 15 (or 16): Plant in stop mode; cutting of SSD(16) & SDD(5) lines in C-side and connection to the new tubes (18mm return lines)
wk 16 (April 14): the 'detector' PLC installation in the pit
wk 17 (April 21): cabling of the 'detector' PLCs; cabling of the HW interlocks
wk 18 (April 28): plant in RUN mode, debugging.
wk 19 (May 5) : plant (hopefully) available

27. DCS development (J. Kral)
J.Kral tried to install the new ISEG OPC server (HV).
It has more stability problems than the old one.
J.Kral is in contact with Lionell Wallet (CERN) to understand were the problem can be.
The old OPC server has still to be used for the next weeks.

28. Data Analysis
Implement a method for noise suppression in the cluster finder to reduce the number of noise clusters due to the use of low zero-suppression thresholds
Include SDD points in the ITS tracking
Tune time offset
Parameter to be used to convert from measured drift time to drift coordinate (accounts for trigger and electronics delays)
To be tuned from the residual between track reconstructed from SPD (and SSD) and cluster position
Extract (if possible) some info about alignment (at least for the z coordinate measured by anodes)
Tune ADC to keV charge conversion constant
To be tuned from the charge deposit by a cosmic muon (MIP)

29. Backup

30. Injector status