ATLAS muon small wheels for ATLAS phase1 upgrade

ATLAS muon small wheels for ATLAS phase-1 upgrade • • (New) small wheels ? Why new small wheels for high luminosity ? Detector technologies Schedule LHCC 25. 09. 2012 T. Kawamoto 1

The small wheels EI station small wheel L 1 trigger chambers The innermost station of the muon endcap Located between endcap calo and toroid 25. 09. 2012 T. Kawamoto 2

h = 1. 3 – 2. 0 : MDT (precision R) + TGC (f coordinate) h = 2. 0 – 2. 7 : CSC (precision R and f) 25. 09. 2012 T. Kawamoto 3

Motivation of upgrade – 1/2 Cavern background Hit rate 1 x 1034 is OK, but little margin for higher lumi 14 Te. V Al beam pipe Extrapolated cavern background in the small wheel Measured cavern background in the small wheel MDT rate limit 7 Te. V 25. 09. 2012 T. Kawamoto 4

Motivation of upgrade – 1/2 CSC limit 25. 09. 2012 T. Kawamoto 5

Motivation of upgrade – 2/2 L 1 background MU 20 vs h 2010/2011 data 50 ns interval ~ 6 -7 x higher L 1 rate in Endcap than in the barrel MU 11 vs h 25 ns test in 2011 Additional background (+40%) In h = 1. 0 – 1. 5 25. 09. 2012 T. Kawamoto 6

Motivation of upgrade – 2/2 What is the origin of these fakes ? TOF measurement with MDT EM and EO b ced u d o id – pr o r s o t n o Prot r the EC l Wheels l te in/af s in Sma it No h FLUGG MC EM EO Slow particles ! FLUGG MC 25. 09. 2012 timing protons and their birth position (*) T. Kawamoto 7

New small wheels Present L 1 • Kill the fake trigger by requiring high quality (sq~ 1 mrad) IP pointing segments In New small wheels (NSW) • New precision tracker in NSW that works up to the ultimate luminosity, 5 -7 x 1034 , with some safety margin Upgrade L 1 with NSW 25. 09. 2012 T. Kawamoto 8

Extrapolated L 1 rate at 14 Te. V, 25 ns At L = 3 x 1034 Single m L 1 rate (k. Hz) Mu 20 Mu 40 Without NSW 60 29 With NSW 22 10 NSW + phase-0 17 8 NSW is vital for running at high luminosity. Total L 1 bandwidth is ~75 k. Hz, will be 100 k. Hz after phase-0 25. 09. 2012 Allowing low p. T thresholds T. Kawamoto 9

NSW detector technology The baseline technology, defined in May, is a combination of s. TGC and Micro. Megas Critical milestones end 2012 s. TGC MM s. TGC trigger, bunch id precision tracking but each has both functions ~100 mm precision • Complementarity • Redundancy • Robust detector Micromegas Important feature for a detector of limited access (space, ALARA) s. TGC MM s. TGC 25. 09. 2012 T. Kawamoto 10

NSW detector technology MM resistive strip structure : spark protection 2 M+ r/o channels 128 mm New front-end ASIC, designed for both MM and s. TGC ~0. 5 mm pitch s. TGC with charge r/o from strips 1 st prototype, VMM 1 successfully deployed in recent beam tests 25. 09. 2012 T. Kawamoto 11

NSW detector technology 1 x 1 m 2 MM in test beam Large Micro. Megas : built with PCB technology Full size 1 x 2 m 2 MM will be built and tested this year. Industrialization is a next important step. 25. 09. 2012 T. Kawamoto 12

The goal is establishing a firm base for achieving the timetable like this. Establish the procedure of prod & QA 25. 09. 2012 T. Kawamoto Full commissioning on surface 13

Approval process Timeline for the Approval process: • Initial design review: August 29 -30 • Kick off Meeting: August 31 • EB approval: September 14 • CB approval: October 5 • TDR & IMOU: 31. May 2013 25. 09. 2012 T. Kawamoto 14

NSW will bring the muon spectrometer significant enhancements that cannot be achieved by simple modifications. 25. 09. 2012 T. Kawamoto 15

Back up 25. 09. 2012 T. Kawamoto 16

LHC and ATLAS upgrade Possible upgrade timeline ∫ L dt 7 Te. V → 5 x 1034 cm-2 s-1 luminosity leveling → 14 Te. V • new shielding • elevator hole chambers 1 x 1034 → • trigger in barrel feet region 34 -2 ~2 x 10 cm s-1 LS 3 winter 2011 -12 3000 fb-1 phase-2 → 1 x 1034 cm-2 s-1 1027 → 2 x 1033 cm-2 s-1 LS 2 ~300 fb-1 phase-1 LS 1 • And more ~50 fb-1 phase-0 • New small wheel ~20 fb-1 2013/14 Now 25. 09. 2012 2018 Integrating small wheel TGC in Endcap L 1 : update SL programing T. Kawamoto ~2022 Year 17

New small wheels Expected L 1 improvement Study using pp collision data. Emulation of NSW using MDT+CSC data m dependence of rejection Trigger rate reduction ~ 1/6 ent EI m seg i IP po ~ 1/6 in 1. 3<h<2. 4 nting Matched to BW No visible m dependence 25. 09. 2012 T. Kawamoto 18

Phase-0 : integrating EI in L 1 Require hits in EI associated to the BW TGC track. Coverage : h = 1. 05 – 1. 9 SL firmware update Reduction for “L 1 MU 11” Eff. for offline Pt>MU 10 81. 0% 98. 6% ~ 1/2 reduction in the region of coverage 25. 09. 2012 T. Kawamoto 19

Phase-1 NSW coverage -0 ase ge a r ove c Ph Trigger and tracking improved by NSW 25. 09. 2012 T. Kawamoto 20

NSW spec is designed for further upgrade p. T after fake removal with NSW initial goal : to remove fakes. Designed also for improving p. T of L 1 nominal threshold • size of luminous region • multiple scattering in the calorimeter • multiple scattering in the EC toroid • angular resolution of BW 25. 09. 2012 1 -2 mrad 2 -3 mrad 1 mrad 3 mrad T. Kawamoto measure and correct with NSW: need 1 mrad resolution upgrade of BW (phase-2) 21

NSW critical milestones To be achieved by the end of 2012 finalizing the technology MM • Validation of detector resolution for inclined tracks (m. TPC mode) • Realization of full size detector • Investigation of possible damages by sparks (large ionization) s. TGC • Demonstrator of trigger ess r g Common items pro d goo • Geometrical accuracy and alignment g in k a • Effect of magnetic field M Reporting items • MM industrialization • MM trigger • Combination of trigger information from s. TGC and MM • TGC production sites • Alignment • NSW layout • Long term ageing tests • Performance under radiation background 25. 09. 2012 T. Kawamoto 22

Resistive MM Mesh Resistive strips y strips PCB Resistivity values RG ≈ 55 MΩ Rstrip ≈ 35 MΩ/cm 25. 09. 2012 x strips T. Kawamoto 23

Max. NSW rates Gain ≈ 5000 25. 09. 2012 Clean signals up to >1 MHz/cm 2, but some loss of gain T. Kawamoto 24