ATLAS SCT Endcap Detector Modules Lutz Feld University of Freiburg for the ATLAS SCT Collaboration Vertex m

Vertex 2002Lutz Feld, Freiburg University2 Endcap Disks covered by 3 Rings of Modules outer modules inner modules cooling block power tapes middle modules (on backside) 9 disks in each endcap, ~1.2m diameter CF structure 132 detector modules on a full disk, 1976 endcap modules in total modules have central mounting and cooling point  module overlap easy each module serviced by a power tape and 3 optical fibres evaporative cooling circuits serve up to 13 modules

Vertex 2002Lutz Feld, Freiburg University3 3 Module Types outer module (52 per ring) inner module (40 per ring) middle module (40 per ring)

Vertex 2002Lutz Feld, Freiburg University4 Endcap Module Design: Silicon Sensors strip direction 4 wedge shape silicon sensors 768 p-in-n strips, single sided supplied by Hamamatsu and CiS sensor alignment < 5µm 40mrad stereo angle

Vertex 2002Lutz Feld, Freiburg University5 Endcap Module Design: „Spine“ strip direction sensors are glued to „spine“: TPG bar for heat removal (1700 W/m/K) AlN wings for mechanical stability mounting points and cooling contacts

Vertex 2002Lutz Feld, Freiburg University6 Endcap Module Design: Hybrid strip direction hybrid: flex circuit on carbon-carbon hybrid connected to sensors only by fanins  thermal split 12 ABCD3TA binary read-out chips (DMILL)

Vertex 2002Lutz Feld, Freiburg University7 Hybrid development of hybrid was critical and needed several iterations very low impedance is key for successful operation of binary ABCD chips requirements: double sided, 12 readout chips supply well filtered analogue/digital power com/data lines and drivers for optical link detector bias supply (up to 500V) heat removal (7W) low mass implementation: 6 layer copper/Kapton flex circuit ~75µm feature size, ~3000 micro vias flex folded around carbon-carbon substrate full assembly and basic testing in industry

Vertex 2002Lutz Feld, Freiburg University8 Thermal Performance of Endcap Module evaporative C 3 F 8 cooling system, capable to cool down to –30°C central module cooling block, split between hybrid and detectors, long modules have additional far end cooling block detailed simulations, confirmed by measurements of non-irradiated and irradiated modules on an evaporative cooling test rig expected after 10 years inner moduleouter module detector temperature vs. radiation damage for coolant at –21°C

Vertex 2002Lutz Feld, Freiburg University9 Electrical Performance binary front-end chip  occupancy vs. threshold  „s-curves“ signal height and noise are derived from „s-curves“ relevant for operation: hit efficiency and noise occupancy noise occupancy determined by –front-end noise (fixed for given ASIC and detector) –channel-to-channel threshold variations (threshold trim per channel) –additional noise: common mode, feedback etc. (the difficult part...) occupancy vs. channel and thresholdoccupancy vs. threshold

Vertex 2002Lutz Feld, Freiburg University10 16 Prototype Modules 9 outer, 2 middle, 5 inner modules built reliably inside tolerances, in several institutes noise 1500 e or less noise ~10 -5 gain ~50mV/fC threshold spread 150 e ENC noise threshold spread gain

Vertex 2002Lutz Feld, Freiburg University11 System Test: 4 Modules on a Disk Sector with 4 modules on disk no extra noise common mode noise negligible noise for each chip when operated  simultaneously  singly common mode noise

Vertex 2002Lutz Feld, Freiburg University12 Testbeam Results binary read-out: efficiency and noise occupancy at given threshold spec: single hit efficiency > 99% while noise occupancy < 5E-4 long modules before / after irradiation to 1.6 or 3.3 E14 24GeV-p/cm 2 in a beam of 180 GeV pions 10 years LHC operation ~2.6 E14 p/cm 2 spatial resolution of 23µm achieved, as expected from pitch/sqrt(12) 150V bias 1.6E14 24GeV-p/cm 480V bias 3.3E14 24GeV-p/cm 480V bias

Vertex 2002Lutz Feld, Freiburg University13 Summary & Outlook ATLAS SCT endcap modules final design review in August 02 now preparing for production of 2000 modules (+spares): –ASICs and detectors: ~80% delivered –hybrid: pre-series of 100 pieces in production, first samples delivered; for production: full assembly and basic testing in industry –spines and fan-ins: pre-series in production, first samples delivered; production can start soon module assembly and QA at 7 sites –good experience with assembly of prototype modules (>20) –preparation of production tooling and qualification over next months –production will take about 1.5 years