Design and Status of the SBS Front tracker SBS Meeting JLab : 19/March/2010 JLab 19/Mar/2010 III SBS Meeting Design and Status of the SBS Front tracker E. Cisbani / SBS Trackers Evaristo Cisbani / INFN-Rome Sanità Group (largely based on the SBS Review Meeting)

E. Cisbani / SBS Trackers Outline Requirements for tracking Conceptual design GEM technology Modular approach GEM design details Mechanics Service components Electronics MC Beam tests JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers

Different (e,e’h) experimental configurations Experiments Luminosity (s·cm2)-1 Tracking Area (cm2) Resolution Angular (mrad) Vertex (mm) Momentum (%) GMn - GEn up to 7·1037 40x150 and 50x200 < 1 <2 0.5% GEp(5) up to 8·1038 40x120, 50x200 and 80x300 <0.7 ~1.5 ~ 1 SIDIS up to 2·1037 40x120, 40x150 and 50x200 ~ 0.5 ~1 <1% JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers Most demanding High Rates Large Area Down to ~ 70 mm spatial resolution Maximum reusability: same trackers in different setups

Choice of the technology System Requirements Tracking Technology Drift MPGD Silicon High Background Rate (up to): (low energy g and e) 1 MHz/cm2 NO MHz/mm2 High Resolution (down to): 70 mm Achievable 50 mm 30 mm Large Area: from 40×150 to 80×300 cm2 YES Doable Very Expensive JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers … and modular: reuse in different geometrical configuration GEM mMs Flexibility in readout geometry and lower spark rate

E. Cisbani / SBS Trackers GEM working principle Ionization Multiplication Readout GEM foil: 50 mm Kapton + few mm copper on both sides with 70 mm holes, 140 mm pitch JLab 19/Mar/2010 III SBS Meeting Strong electrostatic field in the GEM holes E. Cisbani / SBS Trackers Recent technology: F. Sauli, Nucl. Instrum. Methods A386(1997)531 Readout independent from ionization and multiplication stages

E. Cisbani / SBS Trackers Rate capability JLab 19/Mar/2010 III SBS Meeting Ar/CO2/CF4 (60/20/20) E. Cisbani / SBS Trackers Triple GEM Poli Lener, PhD Thesis - Rome 2005  Hit rate not an issue

Aging in COMPASS and LHCb Altunbas et al. NIMA 515 (2003) 249 X-ray 8.9 keV Ar/CO2 (70/30) JLab 19/Mar/2010 III SBS Meeting Use of not-outgassing epoxy Change in HV 6.3 kHz/mm2 25 kHz/mm2 E. Cisbani / SBS Trackers g-ray 1.25 MeV Ar/CO2/CF4 (45/15/40) Expected max. collected charge in GEp: 0.5 mC/mm2/y No significant aging expected Alfonsi et al. Nucl. Phys. B 150 (2006) 159

Spatial Resolution in COMPASS: 70 mm JLab 19/Mar/2010 III SBS Meeting COMPASS readout plane (33x33 cm2) and results (analog readout) E. Cisbani / SBS Trackers C. Altunbas et al. NIMA 490 (2002) 177 70 mm resolution achieved by strips centroid  Analog readout required

E. Cisbani / SBS Trackers Approach: 40x50 cm2 Module Use the same “basic” module for all trackers types Size: 40x50 cm2 active area + 8 mm frame width FEM study: 3 x GEM foils (double mask technology) 2D strip readout (a la COMPASS) - 0.4 mm pitch x/y and u/v coordinates JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers Two exceptions in readout foil: Front Tracker last 2 chambers: Double segmented readout to reduce occupancy (Pentchev talk) Coordinate Detector: 1D strip readout 1 mm pitch

E. Cisbani / SBS Trackers Material Budget Based on the COMPASS GEM single honeycomb smaller copper thickness JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers Minimise material to reduce background and multiple scattering

Single Module Mechanical Structure 3D di Francesco cover drift JLab 19/Mar/2010 III SBS Meeting 3 x transfer+induction honeycomb gas in/out-let detail Service frame E. Cisbani / SBS Trackers

Readout Plane and ZIF extension Readout along all sides not strictly required in x/y unless additional segmentation of the readout plane weight balance unavoidable in diagonal u/v Extension feeds into ZIF connectors: no soldering on the readout foil permit safer bending Small frame width (8 mm); minimize dead area Require precise cutting around the ZIF terminals JLab 19/Mar/2010 III SBS Meeting x/y E. Cisbani / SBS Trackers Rui De Oliveira final design based on our drawing In production

Detail of the HV distribution 7 independent HV channels for each chamber (TBC) 3 HV identical doublets + 1 for drift (same on all GEM foils); each doublet serves one GEM foil, unused will be cut. SMD protection resistors, under the thin frame JLab 19/Mar/2010 III SBS Meeting 20 5×20 cm2 HV sectors SMD resistor pads GEM active area E. Cisbani / SBS Trackers Use the HV modules developed by Corradi/Murtas at LNF

SBS Tracker Chambers configuration GEp(5) SBS Front Tracker Geometry JLab 19/Mar/2010 III SBS Meeting x6 Modules are composed to form larger chambers with different sizes Electronics along the borders and behind the frame (at 90°) – cyan and blue in drawing Aluminum support frame around the chamber (cyan in drawing); dedicated to each chamber configuration Back Trackers Geometry X(4+4) E. Cisbani / SBS Trackers

GEM Trackers Accounting Area (cm2) Number of Chambers Readout Pitch (mm) Modules/Chamber Total Modules Total Readout Channels FT 40x150 6 2D 4(x/y) 2(u/v) 0.4 1×3 18 49000 + 13500 ST TT 50x200 4 + 4 2(x/y) 2(u/v) 4×0.4 1×5 20+20 13600 CD 80x300 2 1D y+y 1.0 2×6 24 12000 JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers Total chs. 101700 Last 2 FT modules with strips split in the middle (double segmentation on each site) ST and TT readout groups 4 strips in GEp(5) with binary readout

Electronics layout and outer support Green = FE card JLab 19/Mar/2010 III SBS Meeting Cyan = Module frames Cards and modules are supported by an outer aluminum frame which runs all around the chamber. Optimization is in progress. E. Cisbani / SBS Trackers Red= Outer Support Frame

Electronics Components GEM  FEC  ADC+VME Controller  DAQ JLab 19/Mar/2010 III SBS Meeting 8 mm 2D Readout Up to 10m 49.5 mm 80 mm Main features: Use analog readout APV25 chips (wire-bonded on standard PCB, no ceramics): proven to work in COMPASS ZIF connector on the GEM side (no soldering on readout foil) Minimum electronics components (front-end + VME custom module) Copper connection between front-end and VME E. Cisbani / SBS Trackers Thanks to Michael Böhmer and Igor Konorov from TUM for very productive discussions on the design of the APV25 based FrontEnd card

Front-end prototypes tests Front-end card under control First tests on analog cable length positive JLab 19/Mar/2010 III SBS Meeting 7 m cable E. Cisbani / SBS Trackers Work is in progress (see date on screenshot) 50 cm cable 50 cm cable Paolo Musico/GE

E. Cisbani / SBS Trackers Beam Tests Dec/09: preliminary beam test at DESY-II test area (low intensity electron beam from 1 to 6 GeV) of 2 10x10 cm2 2D prototypes + Gassiplex electronics Characterize the small chamber Prepare for the full size module test March/10: GEM under installation in PREX experiment (with Gassiplex electronics, switch to APV25 in May ?) Early Summer/10: Planned test of 40x50 cm2 module at DESY Demonstrate the large module works as expected Improve design Test APV25 electronics JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers

DESY beam test in Dec/09: setup JLab 19/Mar/2010 III SBS Meeting 2x 10x10 cm2 GEM prototypes Silicon Tracker + scintillator fingers Beam E. Cisbani / SBS Trackers HV Power Supply

DESY beam test in Dec/09 - pedestals JLab 19/Mar/2010 III SBS Meeting Baseline subtracted pedestals Preliminary! E. Cisbani / SBS Trackers Gassiplex Readout (not optimized for negative charge), 700 ns shaping time

DESY beam test in Dec/09 - event example Ar/CO2 70%/30% 3 GeV Electron Beam JLab 19/Mar/2010 III SBS Meeting DGEM = 410 V Vdrift = 2.5 kV/cm VGEM = 2.5 kV/cm Vind = 3.5 kV/cm Preliminary! Single Event E. Cisbani / SBS Trackers Cumulated (Beam profile)

DESY beam test in Dec/09 – x/y correlation DGEM = 410 V Vdrift = 2.5 kV/cm VGEM = 2.5 kV/cm Vind = 3.5 kV/cm JLab 19/Mar/2010 III SBS Meeting Maximum charge in strip E. Cisbani / SBS Trackers Total Charge in cluster

E. Cisbani / SBS Trackers PREX Installation JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers

E. Cisbani / SBS Trackers MonteCarlo/Geant4 Current model includes: SiD Magnet (simple dipole model) Drift Chamber (for testing) GEMs (with some sort of electronics) JLab 19/Mar/2010 III SBS Meeting Working on: bug fixing, standardize output general improvement digitization E. Cisbani / SBS Trackers

SBS Front Tracker Project JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers INFN groups involved in the front tracker development + electronics BA/LE: Gas system + HV CA: Mechanics + Test + MC + Slow Control GE: Electronics ISS/RM: Prototyping, Test, Digitization + Reconstruction, SiD, Coordination Collaboration and funding  Liyanage Talk

E. Cisbani / SBS Trackers Conclusions GEM technology adopted high rate and spatial resolution proven in real experiments Modular approach to get large area detectors, and at the same time to guarantee the already achieved performance Work in progress: Production of the first 40x50 cm2 modules Finalize design of the mechanics Test Electronics prototypes Improve MonteCarlo and Digitization and analyze data Lab/Beam tests of GEM prototype Setup Infrastructure and tools (clean room, stretcher, quality checls protocol …) JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers

E. Cisbani / SBS Trackers JLab 19/Mar/2010 III SBS Meeting Backup slides E. Cisbani / SBS Trackers

E. Cisbani / SBS Trackers First front-end prototypes under test Front End Card Digital IN/OUT + LV Front End card based on COMPASS original design The APV25 chip (originally developed for SiD in CMS) Bus like digital lines (CLOCK, trigger and I2C) & Low Voltages Single differential line for the ANALOG out ZIF connectors on the GEM side (no soldering on readout foil); minimize thickness 800 front-end cards needed JLab 19/Mar/2010 III SBS Meeting ANALOG OUT E. Cisbani / SBS Trackers to the next card Analog frame coming out from the card First front-end prototypes under test

VME64x Custom Controller JLab 19/Mar/2010 III SBS Meeting From the VXS backplane: Trigger L1/L2 Synch Clock Busy (OUT) (duplicated on front panel) VME controller hosts the digitization of the analog signals coming from the front-end card. Handle all control signals required by the front end cards (trigger/clock/I2C) Compliant to the JLab/12 VME64x VITA 41 (VXS) standard Designed with the possibility to detach the ADC subcomponent to extend FEC-VME64x distance (expected to be ~7 m) 50 modules required E. Cisbani / SBS Trackers First 2 prototypes expected next week

Choice of the frame width - FEM Foil stretched with 30 kg weight Electrostatic field of 10x5 kV/cm (1 Pa) Permaglass frame <40 mm distorsion assumed safe JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers

E. Cisbani / SBS Trackers GEM: Prototype 0 and 1 First 10x10 prototypes under cosmic test Using 70/30 Ar/CO2 gas mixture 7 Independent HV levels up to ~ 4000 V JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers Assembling the GEM chambers parts require a careful quality control at several check points and specific tools for gluing, heating, testing, cleaning Final 40x50 cm2 module finalized; GEM foils and readout ordered

E. Cisbani / SBS Trackers Slow Control HV management is not trivial! 7 HV levels must rump up/down coherently Low pass filters JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers

Clean Room Tools and Facilities JLab 19/Mar/2010 III SBS Meeting Visual inspection back-light board E. Cisbani / SBS Trackers HV single foil testing station Assembling the GEM chambers parts require a careful quality control at several check points and specific tools for gluing, heating, testing, cleaning

Assembling tools: GEM foil stretcher Load cells Uniform and controlled stretching of the foil (30 kg on the load cells) JLab 19/Mar/2010 III SBS Meeting Load cells E. Cisbani / SBS Trackers In production Francesco Noto; inspired by Bencivenni @ al. (LNF)

± 45° u/v readout plane and fan-out configuration Conceptual design JLab 19/Mar/2010 III SBS Meeting u v E. Cisbani / SBS Trackers 1.25% dead area in v plane (in simpler configuration) Detailed design in progress

E. Cisbani / SBS Trackers Digitization MC gives track and energy lost (E) in drift region Extract number of primary electron-ion pairs from poissonian with mean=ni=E/W Each of the above pair originate from points uniformly distributed along the primary track in drift region Electrons drift toward the readout at speed vd~5-6 cm/us Electrons spread (diffuse) on the perpendicular direction with distribution defined by sigma_s=sqrt(2Dt) The total charge collected from each original pair is gaussanian distributed around the mean gain G=8000 (20x3) with sigma = G*f and gaussian spatially distributed with sigma = sqrt(2Dvd/L), L=drift-readout distance, around the projection of the origin into the readout plane JLab 19/Mar/2010 III SBS Meeting E. Cisbani / SBS Trackers