Silicon strip staves and petals for the ATLAS Upgrade tracker of the HL-LHC Sergio Díez Cornell, Berkeley Lab (USA), On behalf of the ATLAS Upgrade strip tracker Collaboration HSTD-8, Taipei, Taiwan, Dec 5th-8th, 2011

Motivation: ATLAS Phase II Upgrade (HL-LHC) Numerous challenges for silicon sensors on ATLAS Phase-II Upgrade Higher granularity to keep same low occupancy Higher radiation tolerance to deal with increased radiation environment Novel powering solutions to power efficiently x7.5 more channels Maintain low cable count to keep detector performance Reduce cost per sensor to cover larger area (~ 200 m2) Replacement of ATLAS Inner detector by an all-silicon tracker: Strips tracker: 3 layers of short strips (2.5 cm) staves 2 layers of long strips (9.6 cm) staves 10 disks of endcap petals Si tracker (Utopia Layout) 300 cm 75 cm 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Stave concept layout and current prototypes Barrel strip stave (short strip version): 1.2 m 12 cm Designed to minimize material Shortened cooling paths Module glued to stave core with embedded pipes No substrate or connectors, hybrids glued to sensors Designed for large scale assembly Simplified build procedure All components testable independently Aimed to be low-cost Minimize specialist components Stave cross-section: Ti coolant tube Carbon honeycomb Carbon fiber facing Readout ICs Si Strip sensor Kapton flex hybrid Cu bus tape High T conductivity foam Short strip module: “Stavelets”: Stave prototype with 4 modules per side Single-sided stavelets (serial and DC-DC powered) already built and under test at RAL[1] 1 n-in-p strip sensor with 4 x2.5cm strips 2 hybrids, each with 10 ABCN130 (256 ch) + 1 HCC/hybrid Binary readout Current prototypes: ABCN250 (128 ch/chip) + BCCs 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

S. Díez Cornell, HSTD-8, Taipei (Taiwan) Stave/petal powering LV: Two powering distributions under study for n hybrids, each with current I HV: Parallel power limited by cable reuse and/or material limitations HV rad-hard switching for multiplexing under study recently (early stage)[2] Current module and stave prototypes have proven to be a powerful test bench for the different powering options considered …… Constant current source 1 2 3 4 5 6 n-1 n Serial powering Total current = I Different GND levels per hybrid AC coupling of data lines Bypass protection required DC-DC powering Total current = n·(I/r*) Switching system Can be noisy High mass *r = voltage conversion ratio Constant voltage source 1 2 3 4 5 6 n-1 n …… + - 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Other components of the stavelet prototypes Basic Control Chip (BCC) boards for data I/O (1 per hybrid) AC coupled multi-drop system LVDS reception Generates 80 MHz DCLK and handles 160Mb/s multiplexed data from each hybrid Serial powering: Power Protection Board (PPB)[3] Fast response and slow-control bypass of modules within an SP chain Allows alternate SP shunt circuits Excellent performances demonstrated on SP stavelet SPP ASIC submitted Aug 2011 DC-DC powering: buck DC-DC converter Custom low-mass inductor and shield[4] AMIS 4 ASIC: Over current, over temperature, input under-voltage, and soft start state machine for reliable start-up procedure[5] New prototype circuits underway 39x6 mm2 All hybrids on V = 22.7 V, I = 5.09 A Slow control disables odd hybrids V = 12.7 V, I = 5.09 A AMIS4 13x28 mm2 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Stave modules production and tools Scalability for large scale production even at prototyping stage Panelization of laminated hybrids Designed for machine placement of passives and solder reflow Tools developed for controlled gluing and wire bonding of ABCNs Conservative design rules for high yield and volume, and low cost Final hybrids testable on panels, ready for module assembly Diverse tools developed for uniform gluing of hybrids to sensors Numerous options investigated: glue spread on sensor or hybrid backplane, different glue stencils,… Optimized glue thickness for best module performances: ~ 120 μm Automated wire bonding of ASICs to sensor and hybrids to test frames Fully testable modules, ready for stave assembly 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

S. Díez Cornell, HSTD-8, Taipei (Taiwan) Stave module testing PCB test frames: cheap and flexible test benches for testing Different power configurations, G&S, added circuitry … DAQ system for stave modules and stavelets: HSIO Generic DAQ board (ATCA form factor) with single (large) Virtex-4 FPGA for data processing & connection to controller PC Interface board: connectors & buffers for connectivity to FEE Currently supports up to 64 streams (>64 streams with larger FX100 FPGA in future) Upgraded sctdaq software Allows standard 3ptGain, Response Curve, Noise Occupancy, DT Noise,… on ABCN-250 modules Expected noise performances for parallel, serial, and DC-DC powered modules Similar ENC noise performances obtained at the different sites Liverpool Berkeley, serial Freiburg, serial 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Stave module construction and test Numerous institutes involved in the construction and test of stave modules and stavelets[6] Up to 31 modules built so far (Nov 2011) 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Proton irradiations of stave modules Irradiated at CERN-PS 24 GeV proton beam scanned over inclined modules Module biased, powered, and clocked during irradiation Up to 2x1015 cm-2 reached Sensor and module behave as expected Noise increase consistent with shot noise expectations Slide borrowed from T. Affolder, TIPP2011, June 2011 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

S. Díez Cornell, HSTD-8, Taipei (Taiwan) Stavelets Stave prototypes with 4 modules per side Sensors directly glued to bus tape with “soft” glue for easy module replacement or removal Key test bed for electrical testing Powering, protection, G&S, … Single-sided serial and DC-DC powered stavelets built and tested so far SP stavelet tested with custom constant current source (0-6A, OVP), excellent performances[7] Power and PPBs SP stavelet EOS board Custom Cu bus tape BCCs Power and Buck DC-DC converters DC-DC stavelet EOS board Custom Cu bus tape BCCs 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Stavelet bus tape layout SP shield Layer (Al) SP Trace Layer (Cu) HV SP Current Return LVDS Clock/Command/Data & NTC 100μm track/gap over 40cm (1.2m) 11 For DC-DC, the power section of the SP tape is cut off and replaced by a custom section Slide borrowed from P. Phillips, TWEPP2011,Sept2011 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Electrical tests on stavelets ENC noise close to noise on individual modules for both stavelets Approximately ~ 20e higher in both cases SP stavelet: PPB and bypassing hybrids does not affect noise performances Double Trigger Noise clean at 1 and 0.75fC with appropriate current routing Slightly better DT Noise performances at 0.5fC for DC-DC stavelet Still work in progress[1] Serially powered stavelet H0 H1 H2 H3 H4 H5 H6 H7 Column 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ENC 661 623 628 675 650 636 697 760 687 646 640 666 680 624 656 DTN @1.0fC DTN @0.75fC DTN @0.5fC 130 40 58 255 1181 32 56 102 50 26 237 DC-DC powered stavelet H0 H1 H2 H3 H4 H5 H6 H7 Column 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 dENC 27 26 17 -10 -9 28 31 -26 -23 -2 DTN @1.0fC DTN @0.75fC DTN @0.5fC 36 18 38 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Stave material estimates Stave material estimates for 130 nm stave[8, 9]: Based on as-built stavelets Titanium cooling tube: 2.2mm OD x 0.14mm wall Tapes contribution could be significantly reduced (~50%) by removing Al screen + one glue layer: under investigation Sensor dominates module material (~ 63%) Power components will add 0.03 - 0.15 %X0, depending on power scheme (first approximation: changes in bus tape not considered) Modules 54% Stave core 28% Tapes 15% Adhesives 3% %X0 Stave core 0.55% Bus tapes 0.30% Modules 1.07% Module to stave adhesives 0.06% TOTAL 1.98% 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Endcap petals: Petalet program The endcap petal follows closely the barrel stave design First petal cores already been produced First endcap hybrids (ABCN-250 ASICs) produced and tested Petalet prototype underway Combines innermost radius sensors and region where petal splits in 2 sensor columns[10] Endcap hybrid “Petalet” 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

S. Díez Cornell, HSTD-8, Taipei (Taiwan) Conclusions Stave program has shown significant progress Module prototypes built and shown to work after irradiation at higher fluences than expected on the Si tracker Both LV powering architectures being studied in detail with stavelet prototypes Up to 20 groups involved in the module/stave/petal construction and test Up to 31 modules and 2 single-sided stavelets, with both powering schemes implemented, have been built and tested so far, more underway: Double-sided stavelets at RAL Stavelets at other construction sites Petalets Full-size, next generation stave prototypes will be designed and built as soon as ABCN-130 ASIC is ready (6 months from now?) 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

S. Díez Cornell, HSTD-8, Taipei (Taiwan) Thank you! References [1] P. Phillips, Stavelet status, ATLAS Upgrade week, CERN, Nov 2011 [2] D. Lynn, Possible Approaches to HV Distribution to Atlas Strip Staves, ATLAS Upgrade week, CERN, Nov 2011 [3] D. Lynn et al., Serial power protection for ATLAS silicon strip staves, NIM-A 633, pp. 51-60 (2011) [4] G. Blanchott, DC-DC converters: gained experience, ATLAS Upgrade Week, CERN, Nov 2011 [5] S. Michelis, DC-DC powering ASICs, ATLAS Upgrade week, CERN, Nov 2011 [6] S. Wonsak, Stave module status, ATLAS Upgrade week, CERN, Nov 2011 [7] J. Matheson, Progress and advances in Serial Powering of silicon modules for the ATLAS Tracker Upgrade, JINST 6 C01019, 2010 [8] T. Jones, Strip stave radiation lengths, Local Support Working Group (LSWG) – Mechanics, Berkeley, Sept 2011 [9] A. Affolder, Material study , ATLAS Upgrade Week, Oxford, March 2011 [10] I. Gregor and C. Lacasta, The petalet, ATLAS Upgrade week, CERN, Nov 2011 Backup slides: Radiation hard n-in-p short strip sensors Thermo-mechanical stave demonstrator Short strip module Stavelets 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Radiation-hard short strip sensors Slide borrowed from T. Affolder, TIPP2011, June 2011 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

Thermo-mechanical stave demonstrator Slide borrowed from T. Affolder, TIPP2011, June 2011 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

S. Díez Cornell, HSTD-8, Taipei (Taiwan) Short strip module 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)

S. Díez Cornell, HSTD-8, Taipei (Taiwan) Stavelets Serial power: DC-DC power: 06/12/2011 S. Díez Cornell, HSTD-8, Taipei (Taiwan)