Front Tracker: main technical solutions

40x50 cm2

module

Front Tracker Chamber: 40x150 cm2

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 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

SBS Front Tracker 1

Requirements:

Hit spatial resolution ~ 70 m

Stand large background ( ~ 250 MHz/cm2, e/ 160 kHz/cm2)

Transverse area > 40x120 cm2

Event rate ~ 20 kevents/s

Reuse: SBS/GEp5, BigBite/Gen, BigBite/A1n …

Gluing

Finalization(solder resistor, check HV)

Stretching

Electronics integrationTest and characterization by rad.

source and cosmics

Permaglas FramesVisual InspectionUltrasound bath

cleaning

GEM FoilsHV curing and

quality test

Put together(align on reference pins)

Glue Curingin vacuum

(>24 h)

Assemblinggas lines

ElectronicsTest

SBS Front Tracker 2

Clea

n ro

om

Module production fully established in Catania

Module characterization in Rome

Production speed 1 module/month

FT: GEM Module construction process

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 Tracker 3

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

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

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