Content: T0 status T0 SOR, EOR, Busy Issues Other Running Issues High Background Data Taking

1. T0: Current detector issuesand LS1 plansT.Karavicheva,V.Kaplin,A.Kurepin, A.Maeskaya, W.Trzaskaon behalf of T0 groupT0 review 27 June 2012 Content: T0 status T0 SOR, EOR, Busy Issues Other Running Issues High Background Data Taking Running in p+A T0 LS1 Activities Other TC Questions Tatiana Karavicheva, Review meeting. CERN,27-06-2012

2. T0 status Performance during the pp 2012 run • 100% of channels are working (without aging) • T0 is in a good shape, very stable during p-p physics • Precise start signal for TOF (time resolution ~ 40 ps) • Luminosity measurement Trigger functions (on-line): • Rough vertex position (OTVX) resolution of vertex cuts0.6 cm; Tatiana Karavicheva, Review meeting. CERN,27-06-2012

3. T0 SOR, EOR, Busy Issues • SOR : T00::dcsSorCommandError => the origin of “real” SOR problems not solved …. But rare  runs: 178513, 1785100 • EOR: Hardware Error T00::hardwareError (T0 incomplete events lead to backpressure and TPC busy )runs: 181984, 177858 , 177620 , 177612, 177167, 177166,177120 It happens when interaction occurs close to ORBIT RESET. New DRM firmware will be installed to solve this problem and also Sync events. • EOR:  Busy at SOR T00::detectorBusyruns:177982, 177981, 177980, 177957, 177956 , 177165, 177155 –Ok after FanIn/FanOut module re-initialization Tatiana Karavicheva, Review meeting. CERN,27-06-2012

4. Other Running Issues • One amplifier from A-side was broken, spare amplifier was installed . Ok • Last time when we measure L0 signal with A.Jusco in the pit (on CTP scope outputs), the width of L0 signal was 18ns. During the TS access we measured the signal on the output of T0 FE, and we see 25ns. I.e. the width of the signal seems to be shortened by L0 lvds cable connecting to L0 input to CTP. The length of L0 cable is 45m. Cable equalizers installation is under discussion (should be done now during TS). ->Done last night. • QTC (Charge to time converter) used for amplitude slewing correction. The module has the problem with high interaction rate (the problem is under investigation) • OTVX range is±30 cm (pb-pb it was set ± 10 cm) Tatiana Karavicheva, Review meeting. CERN,27-06-2012

5. High Background Data Taking from 14.06.2012 to TS-2 Tatiana Karavicheva, Review meeting. CERN,27-06-2012

6. Principle issues related to T0 rate • T0 trigger electronics could run now with the bunch repetition rate up to 40 MHz for L0 inputs , luminosity monitoring ; • But the maximum anode average current according to the PMT datasheet is 2 uA Tatiana Karavicheva, Review meeting. CERN,27-06-2012

7. T0 PMTs • We use Russian PMT-187 (R3432-01 was the prototype). • R3432 had the maximum anode average current 10 ua • For T0 detector PMT’s selection were made. • Probably the anode average current specified for PMT-187 was made with a large supply • At T0 lab test going to READY at higher p+p V0_tot rates (laser test result: real width of the signal is ~ 4 ns, 200 kHz per PMT is OK during 5 days) . Tatiana Karavicheva, Review meeting. CERN,27-06-2012

8. p-A running • p-Pb interaction rates of up to 200kHz can be expected i.e. equivalent p-p rates of 700kHz. • At this moment (1380 bunches 1.4x1011 p/bunch) we have V0tot rates of up to 700kHz at the beginning of the p-p fill. • T0 works stable with V0tot rates of up to 400kHz ( it is switched on at the beginning of the fill for short time- OK). • Take into account the shorter width of the signal we estimate max. V0tot rates as ~800 kHz • What will be OTVX range for p-A (p-p ->±30 cm or pb-pb-> ±10 cm)? (install second module to generate second OTVX?) . Tatiana Karavicheva, Review meeting. CERN,27-06-2012

9. LS1 Major Activities (1) • The main expenses for the upcoming years will cover the exchange of the light sensors (PMT) during the major shutdown of LHC. We are currently negotiating the price and specifications with Hamamatsu (V0 aging?). The upgrade will remedy some of the problems with after-pulses and noticed deterioration of the sensors after the major He leak to the system resulting from the 19 September 2008 incident. • Spares are required Tatiana Karavicheva, Review meeting. CERN,27-06-2012

10. ALICE trigger upgradeAfter LS1 (not yet fixed) Mechanical implementations -if ever possible to move T0,V0,TOF FEEs ..? -where to install (contact ALICE technical coordinator) inside magnet, close to CTP (C-side)? necessary space for all FEE and trigger units rack? … Tatiana Karavicheva, Review meeting. CERN,27-06-2012

11. Tatiana Karavicheva, Review meeting. CERN,27-06-2012

12. LS1 Major Activities (2) • Modifications of the mechanical support to accommodate new PMT tubes (start from A-side) and attempt to reduce the length of the detector units to make space for the improvement in the muon detection system (MFT) of ALICE (under discussion). •  There is also an urgent need to modify the trigger electronics and locate it inside of the L3 magnet to significantly reduce the cable delay. To conform with this demand by ALICE new electronic modules have to be build (?). •  repair of replacement of PS, Crates and R/O modules based on the experience accumulated so far. Tatiana Karavicheva, Review meeting. CERN,27-06-2012

13. TC Questions • Cables from CRs to Cavern? no • Hardware Interventions? see list above LS1 activity • Hardware interlocks ? no • Cooling - upgrades and necessary improvements? Now not used. If the scheme of installing our electronics inside of the L3 magnet will be realized, we would need a cooling system for the racks and racks that work in B of up to 0.5 T • Gas – upgrades? Not used Tatiana Karavicheva, Review meeting. CERN,27-06-2012

14. Thank you for your attention! Tatiana Karavicheva, Review meeting. CERN,27-06-2012