GEM Tracker for high luminosity experiments at JLab Hall A

Evaristo Cisbani (8), V. Bellini (5), M. Capogni (2), S. Colilli (8), R. De Leo (4), R. De Oliveira (1), V. De Smet (3,5), R. Fratoni (8), S. Frullani (8), F. Giuliani (8), M. Gricia (8), F. Librizzi (5),

M. Lucentini (8), F. Mammoliti (5), S. Minutoli (6), P. Musico (6), F. Noto (5), R. Perrino (7), F. Santavenere (8), C. Sutera

(1) CERN, Geneva, Swiss(2) ENEA Casaccia, Italy(3) Haute Ecole Paul Henri Spaak, ISIB-Brussels, Belgium(4) INFN Bari and University of Bari, Bari, Italy(5) INFN Catania and Catania University, Catania, Italy(6) INFN Genova, Genova, Italy(7) INFN Lecce, Lecce, Italy(8) INFN Roma Sanità group and Italian National Institute of Health, Rome, Italy

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1

Energy Upgrade of CEBAF accelerator @ JLab

CHL-2CHL-2

Upgrade magnets Upgrade magnets and power and power suppliessupplies

add Hall D (and beam line)6 GeV CEBAF (< 2013)

Max Current: 200 AMax Energy: 0.8 - 5.7 GeVLong. Polarization: 75-85%

12 GeV CEBAF

(>2013)Max Current: 90 AMax Energy Hall A,B,C: 10.9 GeVMax Energy Hall D: 12 GeVLong. Polarization: 75-85%

$ 310M

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Hall A Hall B/CLAS Hall C

Two High Momentum Resolution + one large angular acceptance spectrometers

Dedicated neutron and gamma detectors

Large acceptanceHigh multiplicity

reconstructionSix coils Toroidal field

Two Asymmetric spectrometers

High momentum range and high resolution

Dedicated detectors

High beam currents (>100 A), lumi 1037 cm-2 s-1

Tagged real photons beam

High beam currents (>100 A), lumi 1037 cm-2 s-1

3He T/L Polarized target, high flexibility unpol. from H to Pb

NH3/ND3 Polarized long. target

NH3/ND3 Polarized long. target, high flexibility unpol. from H to Pb

Large and flexible installations

Fixed 4pi detector Large and flexible installations

Experimental Halls Today MP

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Hall A Hall B/CLAS12 Hall C Hall D/GLUEX

+ 1 large angular and momentum, high lumi spectrometer with hadron ID

+ large acceptance solenoid detector

New beam line

New large acceptance detector with recoil detector (possibly extended hadron ID by large RICH detector)

+ “super high” momentum spectrometer

Excellent hermetic coverage,

Solenoid field

High multiplicity reconstruction

+ lumi 1038 cm-2 s-1 + improved tagger for real photons

108 linearly polarized (coherent

Bremstrahlung), up to 12 GeV, real photons/s

+ higher thickness target+ polarized proton target

+ trans. polarized H/D target www.jlab.org/Hall-D

hallaweb.jlab.org www.jlab.org/Hall-B www.jlab.org/Hall-C www.gluex.org

Experimental Halls after 2013 MP

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JLab physics investigations

1. Origin of quark and gluon confinement (non-perturbative QCD)

– Gluonic excitations, existence and properties of exotic mesons (and baryons)

– Mesons and baryons spectroscopyMesons and baryons spectroscopy

2. Dynamics of the quarks/gluons in the nucleons

– Parton Distributions Functions (and Fragmentation Functions)

– New view of nucleon structure via the Generalized Parton Distributions (GPDs) accessed in Exclusive Reactions

– Form Factors at high Q2, improve knowledge of charge and current in the nucleons – constraints on the GPDs

3. Dynamics of the nucleons in the nuclei

– The Quark Structure of Nuclei (resolving the EMC effect)

– The Short-Range Behavior of the N-N Interaction and Its QCD Basis

– Quark propagation through Nuclear Matter (hadronization)

4. Standard model limits

– High Precision Tests of the Standard Model via Parity-Violating Electron Scattering Experiments (low energy but very high luminosity)

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Some challenging experiments in Hall A

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 0.5%

SIDIS up to 2·1037 40x120,

40x150 and 50x200

~ 0.5 ~1 <1%

Maximum reusability: same trackers in different experimental configuration

Most demandingMost demanding

HighHighRatesRates LargeLarge

AreaArea

Down to Down to ~ 70 ~ 70 mmspatial resolutionspatial resolution

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SuperBigbite Spectrometer in Hall ALarge luminosity

Moderate acceptance

Forward angles

Reconfigurable detectors

Electronics for:• Front GEM tracker• Large backward GEM trackers >100k channels

High photon up to 250 MHz/cm2 and electron 160 kHz/cm2 background

Use VME64x

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Tracker 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 (moving to single mask tech.)

– 2D strip readout (a la COMPASS) - 0.4 mm pitch

– x/y 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

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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

Carbon fiber support frame around the

chamber (cyan in drawing); dedicated

to each chamber configuration

Front TrackerGeometry

x6

Back Trackers Geometry

X(4+4)

GEp(5) SBS

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Drfit, GEM and Readout foils

20 HV sectors on one side of the GEM

Reference holes

Gas In/Out

HV Terminals

ZIF terminals (0.3 mm pitch)

Protection resistors on each HV sectors

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Gas Flow / COMSOL MultiPhysics Simulation

V. De Smet + F. Noto

COMSOL/Thin-Film Flow Model

Maximize uniformity and steady fluxMinimize spacer apertures

Final design

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MonteCarlo + Digitazation + Tracking

High+ e background hitsMHz/cm2

(Signal is red)

Bogdan Wojtsekhowski + Ole Hansen+ Vahe Mamyan et al.

6 GEM chambers with x/y readoutUse multisamples (signal shape)

for background filtering

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Electronics Components

GEM FEC MPD DAQ

Main features:• Use analog readout APV25 chips• 2 “active” components: Front-End card and VME64x custom module • Copper cables between front-end and VME• Optional backplane (user designed) acting as signal bus, electrical shielding, GND

distributor and mechanical support

2D R

eado

ut

75 mm

49.5

mm

8 mm

Up to 10mtwisted,shielded

copper cable(HDMI)

Passive backplane(optional)

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Front End Card (Proto 1 – basically final)

GEM FEC MPD DAQ

AnalogOutput

Inpu

t Pro

tecti

on d

iode

s

Panasonic FPC connectorsAnalog driver (not used)Voltage regulatorThermometer2 In/Out optionsAPV25 bonding on PCB

Digital Input +Power supplyERNI marketing changed:female connector available only wired

Analog out +Digital Input +Power supply

APV25

Improved ZIF connectors (2x77)and groundingin the final version

mainlyfor test

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Radiation Hardness Test of Voltage Regulators

Irradiated by 137Cs (0.834 Gy/min) for 3 days -> corresponding to about 4.5 JLab years of operation

Comparison of Rad. Hard LHC 4913 PDU and Standard SMD TPS736 Voltage Regulators

Power Cycle

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MultiPurposeDigitizer v1

VME64x controller hosts the

digitization of the analog signals

coming from the front-end card.

It handles all control signals required

by the front end cards (up to 16 FE)

Compliant to the JLab/12 VME64x

VITA 41 (VXS) standard

We intend to make it accessible by

standard VME/32 as well

2 HDMI-type A: digital lines + 2

analog lines (compatible with

RD51/SRS hybrids connector)

2 HDMI-type B: 16 analog lines

Added delay line for clock-convert

phase fine tuning (DELAY25 from

CERN)

DigitalOUT

(HDMI)

16 AnalogIN (HDMI) Analog

Receivers

ADCs50 MHz12 bits

USB

ETH

OpticalFiber

2x64MbyteSDRAM

Live InsertionHot-Swap

Oscillators(100 MHz, 62.5 MHz)

Flash EPROM

Thermometer

Voltage Regulators

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Electronics layout on one chamber

FE cards are connected by a passive backplane (with hard rad voltage regulators); backplane acts as a good GND connection for the cards

Front-end cards are electromagnetically shielded by backplane and external frame (with thin conductive tape)

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External Service Frame

Mechanical support of:•GEM module•Electronics•Services (Gas, Cabling ...)

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Assembling the first 40x50 cm2 module

Stretching

Gluing the nextframe with spacers

Foil Tension: T = 2 kg/cmSpacer Sector: S = 170 cm2Expected maximum pressure on foil P 10 N/m2

Maximum foil deformation:u 0.0074 * P * S / T = 6.4 m

Use stretching and spacersto keep foil flat

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Stretcher design from LNF / Bencivenni et al.

Beam test @ DESY (EUDET support) MP

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Beam test @ DESY (EUDET support)

• Fully equiped GEM

module

• 18 front-end cards

• 2304 channels

(front end cards on the

other side)

• 7 independente HV

levels

2-6 GeV low intensity electron beam / silicon tracker available

Data taking: end of 2010

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Beam test @ DESY (EUDET support)

Dec/2010On-line data: beam profile

July/2010(10x10 cm2 GEM)

Large improvement from July/2010

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Single Events @ DESY 2010 TestClear hits But still noisy events

x

y

Electronics Firmware were not fully reliable (several misaligned events and channels) which makes the analysis quite difficult.

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CERN test (magnetic field effects)

Electronics firmware consolidated but No chance to take good data:lost the 40x50 prototype (GEM 2 short) due (likely) to improper operation of the HV system.

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Magnetic field / Extrapolation from KLOE Data

Limit due toreadoutpitch

Expected fringefield at JLab

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10x10 GEM Tracker for High Intensity Test MP

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Electronics (2500 channels) @ Olympus GEM

Commissioning summer/fall 2011; data taking in 2012

The APV electronics has been installed onthe Olympus GEM tracker made of 6 10x10 chambers with 2D readout (pad/strip)

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Olympus experiment (at DESY) aims to measure the higher order effects in elastic electron – proton scattering which could explain the Form Factor measurements discrepancy.

Conclusions● Several improvements in the last 6 months:

● Bugs fixed (in electronics firmware mainly)● Mechanics and GEM design improved● Montecarlo and Track Reconstruction● Firmware largely improved

● Design of the JLab GEM Tracker is finalized● Work is still in progress in several directions:

● External service frame under finalization● Readout electronics firmware (move to external SDRAM)● DAQ Software● Data analysis● HV system - independent channels with current monitor (LNF/Corradi)

● New production of 40x50 module just requested (mechanics and foils); clean room ready; stretcher under revision

● Final electronics production will start in second half of September

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