Minutes of the ALICE Technical Board, November 14 th, 2013 ALICE MIN-2013-6 TB-2013 Date 14.11.2013 1. Minutes The draft minutes of the October 2013 TF meeting were approved without any changes. 2. LS1 progress A. Tauro presented this topic, see Indico agenda for slides: https://indico.cern.ch/conferencedisplay.py?confid=231979 Detector installation and consolidation 1
A new common support structure has already been installed and will accommodate DCal and PHOS moudules. 5 DCaL Super Modules are in and the remaining PHOS and DCaL modules will be inserted in September 2014.This will need a re-routing of services in front of L3 magnet. Other detector installation and consolidation activities TRD: o Overhaul of Low Voltage cables and connectors in the backframe o Installation of counterweights in empty Super Module housings A detailed table of detector activities can be seen in slides 10-13 of this presentation: https://indico.cern.ch/conferencedisplay.py?confid=231979 Upgrade and consolidation of services Electrical infrastructure o UPS upgrade o LV cables insulation repaired and cables re-routed on new support structure for TRD, TPC and TOF: under test. Cooling and ventilation o Chilled water upgrade o L3 ventilation upgrade Cable and fiber campaigns: Requests from detectors should be send to A. Tauro as soon as possible. 2
Safety improvements P2 infrastructue improvements SAA3 upgrade increased insulation to protect ALICE detectors from C-side background. Space at P2: o CR1 renovation o New storage building for 2014 if budget approved ACR renovation 3
Planning Call for beam time requests in 2014 Deadline for ALICE requests 8 th December 2013 More information here: https://espace.cern.ch/be-dep/bedepartmentaldocuments/be/injector_schedule_2014.pdf In reply to a question from G.-J. Nooren on planning for detector commissioning, W. Riegler said that the subject would be addressed in the December TB. Conclusions: LS1 progress according to schedule Main goal of LS1: complete TRD detector, install full DCal detector Several upgrade works well in the way Next cabling campaign beginning 2014 Please send us asap any request of cables to be installed One month CV perturbation between February-March 2014 à detailed plan to follow ACR renovation started, plan to complete the work by March 2014 Plan to close Experiment by beginning December 2014 3. Report from Consolidation Task Force F. Ronchetti gave this presentation, see Indico agenda for slides: https://indico.cern.ch/conferencedisplay.py?confid=231979 There are 3 major issues for start of RUN2 in 2015: Vacuum quality Electron cloud conditions at 25 ns ALICE low lumi requests Vacuum quality 4
TDI has been removed from T12 for refurbishment Vacuum pressure in 2011/2 à 10-7 mbar in 2015 à ~10-9 mbar ALICE Running Conditions RUN2 Lumi Considerations F. Ronchetti said that we would try to have a compromise between these luminosity levels. Beam gas studies show that there are big variations in beam gas levels from fill to fill. The luminous region size with double Gaussian beams can increase by up to 30% at very large separation The machine might be able to increase the gaussianity of the beams by playing tricks at injection à investigating Double gaussian beam parameters can vary strongly from fill to fill, and so can the luminous region size o We should foresee an online monitoring of the luminous region size and possibly tilt. o Task to be implemented in HLT Continuous Running: Run over Error (RoE) F. Ronchetti explained that RoE was not a solution for instabilities but a more efficient way to handle them. The use case for this is the TPC. Evidence from RUN1 shows that a large source of inefficiency is 5
the time taken for SOR/ EOR procedures and pausing the trigger. In most cases, 86%, it is only one TPC Chamber, not a sector, which is misbehaving. The trigger is paused during this time when we could still collect usable data. The tools we would require to run continuously include: Junk data suppression An intermediate HV control signal o TPC is always ready if the majority of detectors are ok. F. Ronchetti then introduced 2 new run concepts: O-RUN (Online): A fixed configuration of DDLs (detectors) together with a CTP trigger partition. It is stopped when: o Change DDLs (include/exclude detectors) o Change Trigger o DDL permanent hick up à PAR failed C-RUN (Calibration): An ordered sequence of chunks taken in a time span of uniform detector response (resolution/acceptance). o It is stopped when a major change in detector response happens. The Full Picture P. Braun-Munzinger remarked that he was afraid of the amount of work this continuous running would mean for the Offline group whose would have to sort out the good from the bad quality data. P. Buncic echoed the same fears saying that the complex issues may break the system. J. Stachel said the apparent increase in efficiency of Continuous Running was window dressing and that it is the quality of the data that counts. W. Riegler underlined that we must be able to run in less than perfect conditions with the much higher luminosity promised for RUN2. P. Braun-Munzinger added that he could see the implications of Continuous Running in calibration mode in the event of frequent chamber instabilities. Different scenarios need to be studied based on different frequencies of instability e.g. every hour, every day etc. In conclusion, he said that although we 6
were doing everything to improve the reliability of the TPC (e.g. gas change to Ar), we always want higher and higher rates and so we are always running at the limit. W. Riegler closed the discussion by saying that this was work in progress and the discussions will continue. He said also that if the Muon and pixel detectors keep on taking good data without TPC then this would increase the running efficiency. Summary RUN2 is approaching us fast Need quantitative studies to asses our lumi requests based on realistic background scenarios and machine conditions Need more flexible tools to face potentially harsh running conditions o Enhance running efficiency AND physics output o Convene a RoE focus group next week o DAQ, ECS, HLT, DCS, CTP, OFF, TPC, PP o RoE Focus Group should release a feasibility study in the next weeks and decision should be taken soon (next ALICE mini-week in December) 4. TDRs, LS2 schedule, integration This topic was presented by W. Riegler, see Indico agenda for slides: https://indico.cern.ch/conferencedisplay.py?confid=231979 ALICE TDRs summary 7
Review of LHC and Injector Upgrade Plans (RLIUP); Workshop, Oct 2013 The Input Matrix, see below, is a vision of the LHC schedule from 2015 until 2035. It has still to be settled and the final decision lies with the DG, LHC and the experiments. It can be assumed that LS2 will start between December 2017 and December 2018 and is likely to last for about 18 months. More information can be found at: https://indico.cern.ch/conferencedisplay.py?confid=260492 and summary presentation at CERN https://indico.cern.ch/conferencetimetable.py?confid=281478#20131107 Urgent actions include: Decide on the shutdown scenario (Management of CERN and detectors) Implementation of new plan A global resources loaded schedule for accelerators and experiments Limitations imposed on personnel by radiation Improve access to tunnel Start now with requests, to identify and strengthen weak areas of expertise 8
Integration ITS/MFT/FIT Integration ITS/MFT/FIT integration meeting Nov. 13th 2013. The area between ITS and frontabsorber is clearly very very complex. Follow-up meeting in next Miniweek and detailed presentation in Dec. 19th TB Timing of HI Runs in Run2 In answer to a question on this subject, W. Riegler said that HI runs are not contested and will take place at the end of the running years. 5. Fast Interaction Trigger W.H. Trzaska gave this presentation, see Indico agenda for slides: https://indico.cern.ch/conferencedisplay.py?confid=231979 Required functionality for FIT in Run3 This must be better than the present T0 and V0 and includes: Minimum Bias trigger for pp collisions with efficiency comparable to the current V0, i.e. at least 83 % for vertex (A&C) and 93% for the OR signal (A C). Event Multiplicity determination capable of selecting and triggering on central as well as on semi-central collisions. The centrality selection should match the performance of the present V0. Vertex location with a performance comparable to the present T0 system. Evaluation and rejection of beam-induced background and in particular beam gas event sensitivity on the level of the current V0 detector. 9
Time resolution better than 50 ps for pp collisions, as in the present T0 system. Determination of collision time for TOF with resolution better than 50 ps. Event plane determination with a precision similar to the present V0 system. Minimal ageing over the ALICE operation period. No after pulses or other spurious signals. Direct feedback to LHC on luminosity and beam conditions. T0-Plus detector unit Advantage will be taken of the progress made in MCP technology FIT electronics and readout will follow the T0/ TOF solution. V0 versus V0-Plus 10
FIT schedule 2013-2016 prototyping of detector modules and electronics; in-beam tests 2017 Purchase of MCP-PMT sensors and assembly of detector modules and electronics 2018 FIT installation Integration on the C-side (ITS, MFT, FIT) The conclusions from the integration exercise show: There is no place for the second trigger detector on the C-side! But no restriction on the A-side Simulations taking into account the latest geometry are needed (already started) Evaluation of services for FIT-C (in progress) Radiation effects The expected dose in the sensor region for Run3 is less than 10 krad Bandwidth calculations 11
This shows that T0 is already close to the bandwidth limit for a single crate readout system. V0- Plus would require a second one or a new way of processing the data. 6. ZDC upgrade P. Cortese gave this presentation; see Indico agenda for slides: https://indico.cern.ch/conferencedisplay.py?confid=231979 Strategy Improvement of the readout performance to 100 khz without dead time New DDL link, new trigger link Self-triggering operation for calibration Pedestal: to monitor baseline evolutions in different run conditions Laser: to check stability gain Cosmic ray trigger: to check stability gain Energy calibration with minimum bias ZDC trigger signal L1 calibration Readout electronics Replace the QCDs with 12 bit digitizers with 1 GSamples/s. On board FPGAs will allow fast pre-processing of the data. The V1290 TDC modules will be upgraded to obtain high transfer rates Payload is ~600 B per event = 60 MB/s at 100 khz Triggers ZDC L1: o Redundancy gives time to eliminate PMT noise o Minimum latency = 2.2 µs ZDC L0 12
Schedule and costs AOB 13
Presentations 1. A.Tauro LS1 progress 2. F. Ronchetti Report from the Consolidation Task Force 3. W.Riegler TDRs, LS2 Schedule, Integration 4. W.H. Trzaska Fast Interaction Trigger 5. P. Cortese ZDC upgrade All the presentations from the TB of 14 th November, 2013 can be found at: https://indico.cern.ch/conferencedisplay.py?confid=231979 14