L0Calo Status

1. Patrick Robbe, LAL Orsay & CERN, 26 Aug 2008 L0Calo Status

2. Hardware Status (1)‏ • Tests of the optical links with 9 dB attenuator (30 minutes): • 1 hadron link with ~20 errors in 30 minutes -> individual fiber not plugged correctly in the patch panel, OK after cleaning and re-plugging. • 3 SPD multiplicity links in error: OK after cleaning the female connector of the emitter on the SPD control board • All optical links are then certified. • 1 SPD transfer connector affecting SPD multiplicity -> repaired

3. Hardware Status (2)‏ • Problems with M24 serializer: 5 boards had the problem and were replaced (and the faulty serializers replaced). No new problem since 6 weeks. • One board with a delay chip problem: this board was also showing errors for the trigger which disappeared when the board was replaced. • 3 boards with non reproducible errors: from time to time sending bursts of bad trigger data, everything is OK after replacing the boards in the pit, but the problem is not seen on the test bench. • 1 TVB also having an intermittent and rare problem on one of its HCAL input (bad addresses for ~ 0.1 % of the events) -> OK after replacement of the board.

4. Commissioning Status (1)‏ • Main debugging (powerful) tool is to compare the trigger result with the trigger emulation from ECAL/HCAL/PSSPD banks, TVB by TVB. • Plots available online in the monitoring, no single error observed since ~1 month in Cosmics configuration. • HCAL only and ECAL only parts of the L0 trigger work as expected • Highest HCAL candidate and Sum of HCAL Et, without adding ECAL • Photon, Electron, pi0 local (sum of 8x4) without PS/SPD validation • Global pi0 (sum of 2 maxima on adjacent boards) in the final configuration

5. Commissining Status (2)‏ • Online error monitoring plot yesterday night:

6. Commissioning Status (3)‏ • SPD Multiplicity trigger also used for Cosmics and injection tests. • Even with a rather high threshold (>10) triggers on (nice) cosmics ! (at a rate of ~ 0.1 Hz)‏ • Detailed checks ongoing by Barcelona. • With Cosmics setting: • rate(HCAL > 5): ~100 Hz • rate(ECAL > 20): ~300 kHz • rate(SPD > 1): ~20 Hz

7. Commissioning Status (4)‏ • Validation of ECAL by PRS/SPD: • PRS/SPD trigger information arrives 17 clock cycles after ECAL trigger information in TVB. • In order to fit in the trigger time budget modifications were needed to shorten the total computation length of L0Calo: • TVB: new firmware for the « EPPI » (ECAL) FPGA to gain 1 clock cycle. It was foreseen to monitor in the TVB the BCId values sent by the different boards (PRS, HCAL, TVB) to check that they are always identical, but this is not possible now because of the time constraint. • Selection Boards: new firmware to gain 2 clock cycles, removing adjustable alignment blocks. Boards have now different behaviours depending if they handle ECAL or HCAL candidates. • In the current configuration (+/-7 TAE events, ECAL Coarse delay of 2 clock cycles) there is no margin left, but so far it allows to be time aligned with MUON, OT, IT, and VELO. [eg: moving the ECAL Coarse delay to 1 -> 1 clock cycle margin in L0DU]

8. Commissioning Status (5)‏ • Validation of ECAL by PS/SPD: • Various delays and phases for the trigger data exchange between ECAL, PS and TVB have been set by Eric Conte in configuration recipes. • First try: • ~ 1 Hz with Electron trigger (ie validation by PS and SPD) of clear cosmics • ~150 Hz with Photon trigger (ie validation by PS only) due to VFE resets of PS (in conjunction with the 300 kHz rate of ECAL noise) ! VFE resets should be moved to the last 3 clock cycles of the LHC cycle in order to fall in the BC where the Selection Boards send the IDLEs to the L0DU. (But quite useful way of debugging)‏

9. Commissioning Status (6)‏ PRS1/ECAL10: timing problem (misunderstanding between Eric and me) -> Fixed One PS Front-End board not sending data, to be investigated • Comparison expected/seen for photon candidates (for each event, compare 28 candidates, one per validation board)‏ • All validation boards linked to PS half boards show errors, and no error in the other validation boards -> all problems seem related to PS half boards (either in the software or in the hardware, still under investigation)‏ • But this shows that ECAL/PS/SPD are time aligned in the trigger path and that the TVB validate ECAL candidates with PS/SPD information as expected.

10. Commissioning Status (7)‏ • All monitoring plots that we had foreseen are in place and available in the presenter (M-H Schune)‏ • One embryon of user analysis code exists (automatic detection of hot cells, which are printed at the end of the run), to be developped. • The 2 TELL1 for L0Calo pass the « high rate » tests, in July one problem appeared (Selection Boards sending occasionaly one extra event to the TELL1) which was fixed. • Last points to fix: • error status transmitted to L0DU by the Selection Boards which was always in error for the moment. Fixed in a recent version of the firmware that is not yet tested. • Test of the error banks system in the TELL1s (implemented in the firmware but not yet tested)‏

11. ECS for L0Calo • Improvements in the ECS of L0Calo: • Possibility to update recipes from current configuration by a click on a button for the ECAL/HCAL FEB, TVB and Selection Boards (basically to mask permanently a noisy channel). • Help button on the Selection Board panels to obtain explanations on the panel. • Alarms implemented in the Selection Boards to alert shifters of possible problems: • Status of input links: one validation board does not send data (happened once because one CROC was in error, not the TVB: at the reconfiguration of the CROC, all TVB registers were reset)‏ • Time alignment: the Selection Boards check permanently that the BCId sent by the TVB are equal • Status of CCSERV, temperatures, ...

12. Piquets, plans, etc... • Rather smooth running since one month, already several L0 piquets are trained to use the system, which were able to solve the basic problems alone. • Prepare now « physics » running, exercising possible thresholds for minimum bias trigger (next week). • Main remaining work is to test ECAL addition to HCAL in TVB, as soon as possible.

13. Conclusion • Stable situation for ECAL/HCAL: no more serializer failures since 6 weeks, but replacement of the serializers during shutdown will be the ultimate solution. • « Global pi0 » candidate is operational • SPD multiplicity, electron, photon and local pi0 are almost commissioned, last checks to be performed • Hadron candidates to commission still (HCAL alone is OK and ready to be used as interaction trigger for the first beams).