SBS Coll. Meeting - Front Tracker GEM BB / SBS Front-Tracker GEM & Electronics E. Cisbani / INFN-RM-Sanità P. Musico / INFN-GE and the other JLab12 members of Catania, Bari, Genova ed Rome-Sanità involved in the Front-Tracker GEM Project SBS Collaboration Meeting 7-8/July/2014 - JLab 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM Overview Production, latest improvements Analysis of DESY test beam data Tracking algorithm and first simulated results Project status MPD Electronics status

SuperBigbite Spectrometer in Hall A Large luminosity Moderate acceptance Forward angles Reconfigurable detectors Background: photon (250-500 MHz/cm2) charged (160-200 kHz/cm2) Physics: Nucleon Form Factors SIDIS – TMD’s ... Nucleon structure Front tracker reused in BigBite 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS Coll. Meeting - Front Tracker GEM Workforce and funding INFN Group Researcher (Unit / FTE) Tech. Role Bari 2 / 0.5 Gas system and beam test Catania 3* / 1.5 3 / 2 GEM module assembling, mechanics, beam test, analysis Genova 1** / 0.5 Electronics design and test Rome/Sanità 1 / 0.5 Coordination, design, test, chamber integration, analysis, DAQ and reconstruction Total 7 / 3.0 6 / 4 Other support: CERN / UVa / JLab *) one mechanical engineer **) electronic engineer INFN/Funding: Prototyping and Production (2008-2014): 800 kUSD Production and Maintainance (2015-2017): ~50 kUSD/year 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Front Tracker Chamber: 40x150 cm2 Main Technical solutions Use the COMPASS approach: 3xGEM, 2D readout - one significant difference: use new single mask GEM foil (instead of double mask) – cheaper and faster production Modular design: chambers consists of 3 independent GEM modules (40x50 cm2) with thin dead area Electronics around the module, direct connection; 90 degree bending between modules External support frame in carbon fiber (long bars) to minimize thermal deformation 40x50 cm2 module Front Tracker Chamber: 40x150 cm2 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Module construction process Module production fully established in INFN-Catania Electronics preliminary QA in Genoa Module integration and characterization in INFN-Sanità GEM Foils HV curing and quality test Permaglas Frames Visual Inspection Ultrasound bath cleaning Production rate 2 module in 3 months Stretching Gluing Assembling gas lines Put together (align on reference pins) Electronics Test Clean room Glue Curing (>24 h) Finalization (solder resistor, check HV) Electronics integration Test and characterization by rad. source and cosmics 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Assembling Improvements in Catania Several small but effective impromevents during last 2 years; one of the most relevent is the compression system during glue curing --- From Lead to vacuum --- Current System based on vacuum bag Very uniform pressure for glue degassing Old System based on Lead Bricks Original idea from LNF- Bencivenni Group 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

HV divider and new GEM foils HV connector «spike» signal output HV Divider and spike monitor circuit Protective SMD resistors Reasonably compact, Easy to change Include output signal for «spike» detection 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Test and characterization setup Almost finalized Use small 10x10 GEM as «reference» (in series) Large scintillation pads for cosmic Test up to 3 large GEM simultaneously 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS GEM Tracker - Test Beam / Jan 2014 Small scale final system (gas, LV, HV monitored) Main Goals: Characterize chambers in terms of charge sharing, efficiency and spatial resolution at different HV, gas mixture. Figure out the gain variation of the previous test Reference Small GEM 3 Big GEMs DESY/EUDET Pixel Telescope 1-4 GeV Electron Beam AIDA-EUDET support → Got lot's of good data with high spatial resolution information from pixel telescope → Stable performance (“all” conditions carefully monitored) 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS Coll. Meeting - Front Tracker GEM Spacers shadow Cluster distributions of 9 cumulated runs Spacer Spacer shadow of ≈ 2 mm → 2.2% of total dead area of a single GEM module (Cluster finding not optimized for spacer border) Masked channels Spacer 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS GEM Test: typical event (single module) T0+25ns (A1) T0+50ns (A2) cluster T0+125ns T0 (A0) y - Strip x - Strip Combination of T0, T0+25ns, T0+50 ns Fit of hit signal evolution Readout dual layer (x bottom and y top) strip plane 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS GEM Test: measured quantities (run 499) x y x/y cluster charge max strip beam position width max peak sample # clusters Note: beam cross-section ≈ 3x2 mm2, approx. 30% with 2 or 3 hits in beam pulse 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS GEM Test: signal evolution fit (run 499) 6 sample fit! x y x/y Integral Start time (t0) Leading Const. Trailing Const. Chi2 tau0 ≈ 20 ns, tau1 ≈ 90 ns, RMS(t0) ≈ 4-5 ns 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Beam Test / Time resolution Excellent (surprising ?) start time spread (from fit) < 5 ns expected at the level of 25/sqrt(12) ≈ 4 ns (in case of negligible contribution from electron drifting in GEM) x/y start time reasonably correlated no apparent effect of MPD clock synch time spread depends on choice of APV latency (see next slide) Time spread < 5 ns! Test beam pulse period 160 ms, multiple of APV clock period 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Simulated Start Time Reconstruction Zoom Reconstructed Start Time (t0) Use double exponential function to fit 6 samples extracted with uniform random jitter (±12.5 ns) and poissonian amplitude distribution + gaussian noise. Optimal latency setting: first sample around the beginning of the signal Error on t0 Chi2 of the fit 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Beam Test: Spatial Scan – Start Time Gas flow rate: 54.3 ccm (0.5V/h) Peak Sample Start Time (fit) Look reasonably consistent Peak Sample vs V/h: 2 V/h: 1.2 ±0.4 1 V/h: 1.2 ±0.4 0.5 V/h: 1.3 ±0.5 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Beam Test: Spatial Scan – Start Time Start time increase slightly (but within uncertienties) Start time basically constant or sligtly decreasing (opposite to y ?) 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Test Beam: spatial uniformity – Charge Sharing Charge asymmetry = 2 (Cx-Cy)/(Cx+Cy) ≈ 0.4÷0.5 HV=4100 Ar/CO2=70/30 y x → x/y Charge Sharing ≈ 1.5-1.6 NOTE: some x/y hits can be not correcly associated or have pileup due to events with 2 or 3 particles/pulse Charge asymmetry spread ≈ 0.3 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Test Beam: spatial uniformity – Hit Cahrge 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Reconstruction Efficiency vs #Event Efficiency holes in some of the runs: beam instability ? Lost synch with trigger ? Good run Analysis work in progress, recently master student from Catania joint. Several data to be analyzed 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS Coll. Meeting - Front Tracker GEM Three steps track reconstruction: Suppress accidentals and ghost with time and charge correlation Associate hits with global analysis (neural network approach) Precise track reconstruction on remaining candidate tracks by Kalman filter method Background level of: 400 MHz/cm2 photons 200 kHz/cm2 charged Signal width ≈ 250 ns → Hits/cm2/trigger ≈ 0.1 → Ghosts/cm2/trigger ≈ 10-20 ! 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS Coll. Meeting - Front Tracker GEM Sij – neuron (0 or 1) – connection between two points (to be minimized) 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Track Association by NN / Simulation Energy Vij Neuron changing rate 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Kalman Filter Reconstruction: simulation Residues 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Material Procurement Status Front Tracker Module Chamber In house Ordered 1 6 3 18 GEM Foils (CERN) Drift Foil GEM foils 9 54 51 Readout 15 Honeycomb Mechanics (RESARM) Frame 0 – Cover 20 Frame 1 – Top Frame 2 – Drift Frame 3 – GEM 2 36 40 Frame 4 – Readout External Frame (Plyform) 1* Electronics (EES) FE 324 250 100 MPD 4 24 26 Backplane 12 72 80 Patch Panel (digital + analog) 8 48 50 Electronics Cabling (LINDY) HDMI 3m cable 144 HDMI 20m cable 5 90 45 LV cable ** HV cable 7 21 126 HV Divider LV Power Supply (6Vx20 Amp) HV Power Supply Gas System Controller + Flowmeters (MKS) Connectors (Legris) 10 212 Patch Panel Gas General Patch Panel Most of the material already in house or procured Remaining parts will be procured in 2014 Assembling line operational Testing line under finalization *) Design completed, waiting first proto **) 2014 funding 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Production and Test Status Produced or Assembled Tested NOT Accepted Degradation after first test GEM foils 51 25 7 Readout+Honeycomb 15 / 18 1 GEM Module 5+ 3 2 Front End Electronics 250* 50 - VME Modules 26 Backplane 80 12+ Patch Panel many returned to company*** The very first 4 GEM foils did not pass the original quality checks, 3 recent GEM foils of the same bunch did not pass the quality check One readout + honeycomb suffered bad gluing (probably still usable) 2 of the GEM modules passed preliminary tests but then degraded significiantly (large dark current due to (? gas contamination ?); still chance to fix them. *** soldering problem, bug fixed 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS Coll. Meeting - Front Tracker GEM Schedule and Status 2009 2010 2011 2012 2013 2014 2015 Preliminary design (include MC study) Prototyping Procurement Pre-Production (1st chamber) Production Beam Test Dec DESY Sept Mainz June CERN May Jan Development phases in part affected by constraints in the flow of funding Delivery delay of the GEM foils from CERN for prototyping and pre-production (no significant impact in SBS, we started erlier) During pre-production we made some fine optimization: GEM foil, details in construction procedure; one drastic change in foil quality check. Development includes: GEM chambers, readout electronics (and related software) 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS Coll. Meeting - Front Tracker GEM Main Open Issues Long cable noise If no fix available: change cabling topology Readout plane manufacturing Test in high bck needed ! GEM modules «aging» To be investigated Data rate / VME Crates (?) Implement optical fiber and SSP communication (?) 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

SBS Coll. Meeting - Front Tracker GEM GEM Tracker Activity 2014-2015 Continue Production Test, Characterization and Calibration of GEM and electronics Fix damaged modules/material, replace if no fix possible Finalization of a rubust and efficient track reconstruction algorithm Complete and test the complex firmware of the DAQ Study (and solve) open issues 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Working Space @Jlab needed GEM chamber assembling and testing need space at JLab (layout sent in 2010) 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

GEM Electronic System Status Production status of electronic boards Firmware Update on MPD v 4.0 VME intrerface Event Builder 7-8 July 2014 Paolo Musico and Evaristo Cisbani SBS Meeting @ JLAB

Production Status APV Front-End cards 210 delivered (some used for DESY test) 140 in progress (SMD ok, to be bonded) Backplanes 74 delivered (some tested) MPD 28 delivered and tested: 2 with marginal problems (to be fixed) Patch Panels 25 Analog Patch Panels delivered 35 Digital Patch Panels delivered 7-8 July 2014 SBS Meeting @ JLAB

MPD v 4.0 firmware update Revised memory mapping D64 read only cycle implemented: MBLT, 2eVME, 2eSST 2eSST simulated peak speed: 148, 222, 296 MB/s Event builder implemented and simulated TBD Multiboard block transfer Analyze use of fiber optic protocol 7-8 July 2014 SBS Meeting @ JLAB

MPD v 4.0 VME interface testing 2eSST cycles tested with STRUCK SIS-3104 2eSST supported by new firmware release Readout speed measured by software: 100 transfer 4MB each. Data integrity checked for each block. Speed limited by SIS3104 2Gb/s fiber connection Bus speed is measured directly on VME bus 7-8 July 2014 SBS Meeting @ JLAB CYCLE DATA period Bus Speed Readout Speed 2eSST160 6 ck = 54 ns (3s/3h) 142 MB/s 117 MB/s 2eSST267 4 ck = 36 ns (2s/2h) 213 MB/s 124 MB/s 2eSST320 3 ck = 27 ns (2s/1h) 284 MB/s

Event Builder Implemented multi event block structure as suggested by DAQ people. Native data width: 24 bit, packed to 32 bit on 64 bit boundary for efficiency. Implemented 128MB FIFO data buffer using DDR2 SDRAM. Quite complicate machinery used to arbiter read and write to/from DDR2. Output can be read in 32/64 bit format in any of the supported VME cycles, including 2eSST. Performed functional simulation (FPGA + DDR2 + ADC) of quite simple events to follow all the signals. Some effort has to be put in DAQ driver to recover packed data. 7-8 July 2014 SBS Meeting @ JLAB

Next Steps Analyze a possible implementation of fiber optic data link to be connected to the SSP Implement Multi Board block transfer (some hints needed) Deep debug and test (implies rewriting of some DAQ code) 7-8 July 2014 SBS Meeting @ JLAB

Support Slides

“Residual Noise” on first APV channels Condition: 4 cards connected to chamber (one by flat adapter) Cards connected to VME by 20 m long HDMI cables Evident noise on first few (up to 8) channels of each card; This noise is somehow masked in the card with adapter (this is way we never put great attention to it in the past) Baseline noise at the level of 7 ADC channel. Pedestal Strips, physics order RMS of Pedestal Card + Flat Adapter GEM VME HDMI cable MPD 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

Electronics Misconfiguration Issue Electronics Low Voltage monitor 2 power lines for 2 groups of cards Small current drop during APV configuration; the “normal” level must restore In case of proper configuration; otherwise the electronics does not work properly Chamber appears inefficient → this likely explain the gain issue in 2013 DESY test 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM

BARI Gas System w/Humidity Sensor and Absorber < 100 ppM of H2O Series operation Series operation or GEM_50x40 or GEM_50x40 ~ 20 m long pipe ~10 m ~10 m ~ 20 m long pipe 7 July 2014 - JLab SBS Coll. Meeting - Front Tracker GEM