TRT (and a bit beyond) – Overview

1. TRT (and a bit beyond) – Overview A.Loginov, A.Romaniouk For the ATLAS TRT Collaboration TRT Days June 25 2013

2. DQ @ 99.8% in pp @ 2012 • TRT Desynchronization • [206248: 1 -> 206248: 533), elog • ROD firmware issue • Reverted to the before-the-TS settings to resolve the issue • HV Crate issues • [215027: 1 -> 215027: 268) : (TRT_NODATA_06, HV Crate in the barrel tripped and had to be replaced) • [215414: 1 -> 215414: 163) : (TRT_NODATA_06, HV Crate tripped and had to be replaced) • An environmental / external issue? • Lacquered contacts in the end of last year, no problems since then • DQ @ 100% in other runs, despite gas leaks and minor problems • Got a number of tolerable defects (TRT_BADGAS_01, TRT_BADGAS_02) • Number of dead channels Is stable • within declared 2.7% (2.4%) TRT Days, June 2013

3. TRT DAQ in Run 2 • Goal: 100kHz trigger rate @ high occupancy • Bottlenecks: • Front End to ROD bandwidth • Changing from full readout mode (27 low threshold bits) to reduced mode (23 low threshold bits) increases trigger rate limit from 89 kHz to 105 kHz (ongoing activity) • Dropping last 4 LT bits – minimal impact on tracking (not losing the leading age) • ROD processing rate • Event processing time proportional to occupancy due to on-board compression • Solutions include: • Increasing clock speed from 80 MHz to 100 MHz on compression chip increases bandwidth • Hard-coding common words to decrease occupancy that compression chip must process • Applying validity gate on all words to decrease overall occupancy • ROD to ROS bandwidth • Extrapolation to high lumi indicates that this is not limiting factor • Optimization of compression table reduces load • Monitoring of fragment size in place TRT Days, June 2013

4. Other TRT DAQ Issues • Increasing number of automatic resyncs during stable beams at end of 2012 (order once per hour) • May be caused by power instabilities in VME crate which affect sensitive components on ROD • Crates will undergo upgrade to increase current limits on relevant lines • Maraton LV power supply upgrades (connector upgrade and internal wire replacement) • Rolling upgrade to be completed during LS1, currently on-schedule • Sufficient number of spares TRT Days, June 2013

5. Other TRT DAQ Issues • Increasing number of automatic resyncs during stable beams at end of 2012 (order once per hour) • May be caused by power instabilities in VME crate which affect sensitive components on ROD • Crates will undergo upgrade to increase current limits on relevant lines • Maraton LV power supply upgrades (connector upgrade and internal wire replacement) • Rolling upgrade to be completed during LS1, currently on-schedule • Sufficient number of spares TRT Days, June 2013

6. eFastOr • Upgrade the existing FastOr trigger • https://cds.cern.ch/record/1516518 • Physics motivation: HIP (monopole, Q-ball…) • Potential timeline TRT Days, June 2013

7. High Voltage • February’2012: crates 003 (tripped), found that crate 004 had similar damage • Crates in the same rack – external factor? • To solve the problem: HV pins were covered with lacquer • November’2012: Two issues caused by the same problem • Small debris of Al / dust found on the board • The issues got addressed (cleaning + protection lacquer), no problems since then • Have 3 spare crates (1 x USA15, 2 x SR1) • And a few spare HVM modules • Lacquer all the contacts to prevent similar issues • Ongoing activity TRT Days, June 2013

8. Active gas issues • Excellent work of TRT active gas team • Despite all the leaks, the DQ didn’t suffer • TDR specs: Xe leak @ 100 l/day • Before early 2012 the leaks were a few times smaller • By the end of 2012 we got ~200 l/day • Leaks • Stress corrosion enhanced by Ozone presence • Strategy discussions since few months, study insitu / repair during last few weeks • Repair work finished TRT Days, June 2013

9. Leaks Detector connector • Repaired whatever was accessible • Both EC Side C / Side A A1 crack along the pipe (PPF1 connector) PPF1 brackets TRT Days, June 2013

10. EC wheel type A connectivity Electronics Electronics PEEK pipes shown in pink Gas OUT Gas IN Gas manifold Gas manifold Straws/radiator Straws/radiator Places of stress Gas Gas TRT Days, June 2013

11. What’s then? • Will do our best to start running in 2015 with in Xemode only • Work is ongoing to automate active gas system operation • 80 channels to regulate • Adjustments of leaking channels have been done manually so far • Can we stabilize leaks at 150 l/h? • Ar affects quite a few physics aspects (TR!) • Had a combined Ar / Xe mode of operation in 2013 to study • Will post a note summarizing this in the coming days • Electron ID, triggers are affected… • What about tracking with Ar? TRT Days, June 2013

12. XevsAr: Tracking • Resolution (tracking @ Ar is not affected) • Run 218391: Ar/CO2/O2 @ 80/17/3, HV @ 1365 V • Barrel: 0.123 mm (Xe) / 0.131 mm (Ar) • EndCap: 0.123 (Xe) / 0.127 (Ar) TRT Days, June 2013

13. Active Gas System: Ar studies • Studies with both the TRT and at test stands • measurements of signal shapes for different gas mixtures and ASDBLR shaping options (report by X.Povedalink) • Main conclusion: afterpulses at 100 ns after the main pulse are observed if Xe shaping has to be used, more pronounced for high HV values • Different mixtures, HV settings (report by K.Vorobevlink) • Study stability, gas gain limitations etc TRT Days, June 2013

14. TRT DCS • Very successful operation in Run 1 • Quickly prepared tools for Xe/Ar combined running • Massive upgrades planned for LS1 (report by E.Banaś, Z.Hajduk, J.Olszowskalink) • As a part of general DCS upgrade (windows -> linux etc) • Need to develop some TRT specific tools • Constraints from central DCS • Overall strategy for the LS1 upgrade • Fully reversible upgraded <-> old DCS • All the time most of TRT hardware is under control • Also will upgrade GGSS (report by B.Mindurlink) • Standard PCs, exchange of all existing internal PCI cards to internal ones, can replace straws if needed • All proposed HW components are linux/windows compatible • Need to rewrite the core of GGSS so that it runs on linux TRT Days, June 2013

15. LHC: Run 2 TRT Days, June 2013

16. ATLAS: Run 2 • Many discussions on how to operate ATLAS • See the “ATLAS Post-LS1 Operation Workshop” https://indico.cern.ch/conferenceDisplay.py?confId=256916 • Fewer shifters • More information to look at (muon system will be completed + IBL + etc) • Better tools / more uniformity (or more headache during the operation) • Updates of the CR layout, calibration procedures, shifters’ training etc etc etc • Will be (again and again) asking for inputs to make sure that TRT is properly taken care of by the shift crew TRT Days, June 2013

17. Summary • Run 1 was success • Thanks to all the expertise and dedication of the TRT team: the team made the TRT a great detector! • Will have things ready for the Run 2 • DAQ updates: get ready for high occupancies and rates (ongoing) • Hardware and firmware improvements • Improved Maratons, HV crates, etc • Active gas system • Possible repairs are (almost) done, have more work ahead (automation and optimization) • Studies of Ar mixture, possible modes of operation are ongoing • eFastOr is progressing well TRT Days, June 2013

18. TRT BBQ this WEDNESDAY @ 18h • BBQ site @ Prevessin: • Map @ https://maps.cern.ch/mapsearch/mapsearch.htm?no=[9401] • Sign up @ http://doodle.com/wft6cuha4gxreu9y TRT Days, June 2013

19. Few backup slides TRT Days, June 2013

20. Active Gas System Plans • Possible to stabilize most leaks. Need to control 2 parameters: • gas flow in a leaking channel • Remote flow regulation? • pressure in the TRT outlet (pump inlet pressure) • Need 0.005 mbar accuracy (with the original requirement of 1 mbar) • precise pressure sensor • additional buffer for pressure sensor • pump input resistance regulation • cavern-USA pressure difference feedback to the pump operation • Ar mixture blow out setup • Have a temporary setup operating for the pPb running • Automate N2 removal (because of the TRT leak) TRT Days, June 2013

21. TRT Performance in Heavy Ion runs • Excellent performance even with extreme occupancies (plots taken from link) TRT Days, June 2013

22. TRT DCS: PCs, Systems and HW… A “simple” drawing TRT Days, June 2013

23. XevsAr Saga • Put Ar in few parts of the detector (both in barrel and EC) • Prepare tools / Learn from the operation / Save Xenon • Vary gas mixtures / HV settings to study operation • Studies with the TRT and on a test stand • Argon shaping issue • Mis-stuffed resistors in a fraction of EndCaps (and hence bit problems) • Under studies • Xe->Ar => electron ID is affected • Argon can be operated with larger gain than Xe • Electron Drift-time for Ar is shorter than Xe • Transition Radiation absorption down by ~10 compared to Xe • Need to understand the consequences TRT Days, June 2013

24. XevsAr Saga: PID • This is under study, but here are few points below • No TRT seeding hits for conversion finding => CPU time for conversion finding increases by a factor of 10 • Overall, back tracking is affected • High-PT electron trigger affected • Increase by 20-30% without HT hits information @ HLT • Jpsi -> ee trigger affected • Rates increase by a factor of 2 • So…many things to try • Find / repair the leaks @ EC • AND Cheaper Xenon (30% lower price) from the Russian supplier? • AND Optimize performance / study combined Xe / Ar operation effect on physics / etc TRT Days, June 2013

25. Leak Hunt and More: few Dates • 8-13 March • ID End-plate leak search (CO2) • 18 April – September • TRT gas leak repair work • Developing tools… • 18 February – November 2014 • Active gas racks test / modifications etc • Replacements ofMaratons • PP2 replacement/tests/repair TRT Days, June 2013