JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 1 Concepts and Status of the GEM trackers Evaristo Cisbani / INFN-Rome Sanità Group SBS - Review JLab : 22/Jan/2010

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 2 Outline Requirements for tracking Conceptual design –GEM technology –Modular approach GEM design details –Mechanics –Service components Electronics Beam tests –Very preliminary results

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 3 Different (e,e’h) experimental configurations ExperimentsLuminosity (s·cm 2 ) -1 Tracking Area (cm 2 ) Resolution Angular (mrad) Vertex (mm) Momentum (%) GMn - GEnup to 7· x150 and 50x200 < 1<20.5% GEp(5) up to 8· x120, 50x200 and 80x300 <0.7 ~1.5 ~ 10.5% SIDISup to 2· x120, 40x150 and 50x200 ~ 0.5~1~1<1% Maximum reusability: same trackers in different setups Most demanding HighRatesLargeArea Down to ~ 70  m spatial resolution

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 4 Choice of the technology System Requirements Tracking Technology DriftMPGDSilicon High Background Rate (up to): (low energy  and e) 1 MHz/cm 2 NOMHz/mm 2 High Resolution (down to): 70  m Achievable 50  m30  m Large Area: from 40×150 to 80×300 cm 2 YESDoable Very Expensive … and modular: reuse in different geometrical configuration Flexibility in readout geometry and lower spark rate GEM  Ms

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 5 GEM working principle Ionization Multiplication Readout Multiplication Readout independent from ionization and multiplication stages Recent technology: F. Sauli, Nucl. Instrum. Methods A386(1997)531 GEM foil: 50  m Kapton + few  m copper on both sides with 70  m holes, 140  m pitch Strong electrostatic field in the GEM holes

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 6 Rate capability Hit rate not an issue Ar/CO 2 /CF 4 (60/20/20) Triple GEM Poli Lener, PhD Thesis - Rome 2005

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 7 Aging in COMPASS and LHCb Altunbas et al. NIMA 515 (2003) 249 Expected max. collected charge in GEp: 0.5 mC/mm 2 /y Ar/CO 2 (70/30) X-ray 8.9 keV  -ray 1.25 MeV Ar/CO 2 /CF 4 (45/15/40) Alfonsi et al. Nucl. Phys. B 150 (2006) kHz/mm 2 25 kHz/mm 2 Use of not-outgassing epoxy Change in HV No significant aging expected

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 8 Spatial Resolution in COMPASS: 70  m COMPASS readout plane (33x33 cm 2 ) and results (analog readout) C. Altunbas et al. NIMA 490 (2002)  m resolution achieved by strips centroid  Analog readout required

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 9 Approach: 40x50 cm 2 Module Use the same “basic” module for all trackers types –Size: 40x50 cm 2 active area + 8 mm frame width FEM study: –3 x GEM foils (double mask technology) –2D strip readout (a la COMPASS) mm pitch –x/y and u/v coordinates Two exceptions in readout foil: 1.Front Tracker last 2 chambers: Double segmented readout to reduce occupancy (Pentchev talk) 2.Coordinate Detector: 1D strip readout 1 mm pitch

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 10 Material Budget Based on the COMPASS GEM single honeycomb smaller copper thickness Minimise material to reduce background (Pentchev talk) and multiple scattering

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 11 Single Module Mechanical Structure 3D di Francesco gas in/out-let detail cover drift 3 x transfer+induction honeycomb Service frame

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 12 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 Rui De Oliveira design based on our preliminary drawing x/y In production

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 13 ± 45° u/v readout plane and fan-out configuration u v 1.25% dead area in v plane (in simpler configuration) Conceptual design Detailed design in progress

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 14 Detail of the HV distribution SMD resistor pads GEM active area 20 5×20 cm 2 HV sectors Use the HV modules developed by Corradi/Murtas at LNF 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 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 15 Assembling tools: GEM foil stretcher Francesco Noto; inspired by al. (LNF) In production Uniform and controlled stretching of the foil (30 kg on the load cells) Load cells

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 16 SBS Tracker Chambers configuration 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 Front Tracker Geometry x6 Back Trackers Geometry X(4+4) GEp(5) SBS

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 17 GEM Trackers Accounting TrackerArea (cm 2 ) Number of Chambers ReadoutPitch (mm) Modules/ Chamber Total Modules Total Readout Channels FT40x15062D 4(x/y) 2(u/v) 0.41×31× ST + TT 50x D 2(x/y) 2(u/v) 4×0.41× CD80x30021D y+y 1.02× 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 Total chs

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 18 Electronics layout and outer support Cards and modules are supported by an outer aluminum frame which runs all around the chamber. Optimization is in progress. Green = FE card Cyan = Module frames Red= Outer Support Frame

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 19 Electronics Components GEM  FEC  ADC+VME Controller  DAQ 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 2D Readout Thanks to Michael Böhmer and Igor Konorov from TUM for very productive discussions on the design of the APV25 based FrontEnd card Up to 10 m 80 mm 49.5 mm 8 mm

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 20 Front End Card 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 ANALOG OUT Digital IN/OUT + LV to the next card First front-end prototypes under test

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 21 Prototype Design completed VME64x Custom Controller  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 From the VXS backplane: 1.Trigger L1/L2 2.Synch 3.Clock 4.Busy (OUT) (duplicated on front panel) More on DAQ  Hansen Talk

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 22 Beam Tests Dec/09: preliminary beam test at DESY-II test area (low intensity electron beam from 1 to 6 GeV) of 2 10x10 cm 2 2D prototypes + Gassiplex electronics –Characterize the small chamber –Prepare for the full size module test March/10: Expected next test/data taking in high lumi at JLab/PREX experiment (with new electronics) Late Spring/10: Planned test of 40x50 cm 2 module at DESY –Demonstrate the large module works as expected –Improve design

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 23 DESY beam test in Dec/09: setup Silicon Tracker + scintillator fingers 2x 10x10 cm2 GEM prototypes HV Power Supply Beam

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 24 DESY beam test in Dec/09 - pedestals Preliminary! Gassiplex Readout (not optimized for negative charge), 700 ns shaping time Baseline subtracted pedestals

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 25 DESY beam test in Dec/09 - event example Single Event Cumulated (Beam profile) Ar/CO2 70%/30% 3 GeV Electron Beam Preliminary!  GEM = 410 V Vdrift = 2.5 kV/cm VGEM = 2.5 kV/cm Vind = 3.5 kV/cm

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 26 DESY beam test in Dec/09 – x/y correlation Total Charge in cluster Maximum charge in strip  GEM = 410 V Vdrift = 2.5 kV/cm VGEM = 2.5 kV/cm Vind = 3.5 kV/cm

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 27 SBS Front Tracker Project INFN groups involved in the front tracker development + electronics BA: Gas system CA: Mechanics + Test + MC + Slow Control GE: Electronics ISS/RM: Prototyping, Test, Digitization + Reconstruction, SiD, Coordination Collaboration and funding  Liyanage Talk

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 28 Conclusions 3 different trackers required in the SBS experiments; –support high rate, –down to ~70  m spatial resolution –large areas 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 Detail design almost completed, first 40x50 cm 2 module in production, test in late Spring/10 Electronics based on APV25; first prototypes under test

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 29 Backup slides

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 30 Choice of the frame width - FEM Foil stretched with 30 kg weight Electrostatic field of 10x5 kV/cm (1 Pa) Permaglass frame <40  m distorsion assumed safe

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 31 GEM: Prototype 0 and 1 First 10x10 prototypes under cosmic test Using 70/30 Ar/CO 2 gas mixture 7 Independent HV levels up to ~ 4000 V Assembling the GEM chambers parts require a careful quality control at several check points and specific tools for gluing, heating, testing, cleaning Final 40x50 cm 2 module finalized; GEM foils and readout ordered

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 32 Clean Room Tools and Facilities HV single foil testing station Visual inspection back-light board Assembling the GEM chambers parts require a careful quality control at several check points and specific tools for gluing, heating, testing, cleaning

JLab 22/Jan/2010 SBS - Review E. Cisbani / SBS Trackers 33 Slow Control HV management is not trivial! 7 HV levels must rump up/down coherently Low pass filters