1. Front Tracker: main technical solutions 40x50 cm 2 module Front Tracker Chamber: 40x150 cm 2  Use COMPASS approach: 3xGEM, 2D readout - one significant difference: new single mask GEM foil (instead of double mask) – cheaper and faster production  Modular design: chambers consists of 3 independent GEM modules (40x50 cm 2 ) 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 SBS Front Tracker1 Requirements: Hit spatial resolution ~ 70  m Stand large background (  ~ 250 MHz/cm 2, e/  160 kHz/cm 2 ) Transverse area > 40x120 cm 2 Event rate ~ 20 kevents/s Reuse: SBS/GEp5, BigBite/Gen, BigBite/A1n …

2. Gluing Finalization (solder resistor, check HV) Stretching Electronics integration Test and characterization by rad. source and cosmics Permaglas Frames Visual Inspection Ultrasound bath cleaning GEM Foils HV curing and quality test Put together (align on reference pins) Glue Curing in vacuum (>24 h) Assembling gas lines Electronics Test SBS Front Tracker2 Clean room Module production fully established in Catania Module characterization in Rome Production speed 1 module/month FT: GEM Module construction process

3. Front Tracker: Readout Systems Based on APV25 chip (from CMS) Topology: Chamber Strips  FE (APV25)  Backplane  MPD (VME)  DAQ Custom design, compliant to JLab DAQ environment; reviewed October/2012 by fast electronics and DAQ experts; First version succesfully used in the OLYMPUS experiment in 2012. SBS Front Tracker3 VME crate 128 analog ch / ASIC 3.4  s trigger latency (analog pipeline) Capable of sampling signal at 40 MHz Radiation tolerant Multiplexed analog output Configurable / Calibration circuit

4. Real Experiment: Olympus, 2012 From Jürgen Diefenbach The APV electronics has been installed on the Olympus 3xGEM tracker made of 6 10x10 chambers with 2D readout (pad/strip – about 2500 chs), operating in a magnetic field at the level of few kG. Two events with opposite magnet polarity; particles bend left o right in the x-histogram (Red triangles show hit candidates) SBS Front Tracker Use of the INFN readout electronics 4