Status of the Cylindrical GEM ‐Status of the Cylindrical GEM ‐project for theproject for the

KLOE 2 Inner Tracker‐KLOE 2 Inner Tracker‐

Danilo Domenici (INFN-LNF)Danilo Domenici (INFN-LNF)on behalf of the KLOE-2 collaborationon behalf of the KLOE-2 collaboration

Villa Olmo, Como – 6Villa Olmo, Como – 6thth October 2009 October 2009

KLOE-2 Highlights

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KLOE-2 is going to continue and improve the KLOE physics program at the upgraded DaΦne machine with a focus on KS η and η’ rare decays, neutral kaon interferometry, lepton universality test and γγ physics

End of 2009: roll-in of KLOE for 1 year of data-taking

Spring 2011: upgrade of KLOE with new Calorimeters (QCALT, CCAL, HET) and a new Inner Tracker based on the GEM technology for a 2-3 years of data-taking

The project has been approved and funded by INFN

Other 4 talks presented in this Conference (Gonnella, Schioppa, Miscetti, Martini)

The KLOE Detector

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Multi-purpose detector optimized for KL physics

Huge, transparent Drift Chamber

in 5.2 kGauss field of a SC coil

Carbon fiber walls, 55000 stereo wires,

2 m radius, 4 m long, He/CO2 gas mixture

Momentum resolution: σ(pT)/pT ~ 0.4%

Pb-Scintillating Fiber Calorimeter with excellent timing performance

24 barrel modules, 4 m long and C-shaped End-Caps for 98% solid angle coverage

Time resolution: σT = 54 ps / √E(GeV) 50 ps⊕

Energy resolution: σE/E = 5.7% / √E(GeV)

Drift ChamberDrift Chamber CalorimeterCalorimeter

Need for an Inner Tracker

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Simulation results for a π track from KS → ππSimulation results for a π track from KS → ππ

Δx @pca

Δz @pca

Δpx @pca

Δx @vertex

IT 0.6 mm 0.9 mm 1.2 MeV/c 1.9 mm

No IT 1.7 mm 2.2 mm 1.6

MeV/c 4.9 mm

Sensitivity on CPT violation parameters on K0 interference

(αβγ)

Sensitivity on CPT violation parameters on K0 interference

(αβγ)

KLOE measurement (σΔt = τs)

KLOE-2 prevision (σΔt = 0.25 τs)

Factor of 10 improvement of present error feasible with 20 fb-1

(100 fb-1 needed witout IT)

The Inner Tracker

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IT to be inserted inside KLOE Inner radius 127 mm (20 τs) to

preserve KL-Ks interference region Outer radius 215 mm to safely

install inside the DC

IT to be inserted inside KLOE Inner radius 127 mm (20 τs) to

preserve KL-Ks interference region Outer radius 215 mm to safely

install inside the DC

Inner Tracker Numbers

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5 independent tracking layers

σrφ = 200 µm and σZ = 500 µm spatial resolutions with XV strips-pads readout

700 mm active length

1.5% X0 total radiation length in the active region with Carbon Fiber supports

Realized with fully Cylindrical-GEM

detectors

Realized with fully Cylindrical-GEM

detectors

The Cylindrical-GEM

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Conversion & Drift

Transfer 1

Transfer 2

Induction

Cathode

GEM 1

GEM 2

GEM 3

Anode

Read-out

3 mm

2 mm

2 mm

2 mm

Gas Electron Multiplier (F. Sauli, CERN, 1997)Thin (50 μm) metal coated kapton foil, perforated by a high

density of holes (70 μm diameter, 140 μm pitch)With 400 V between the two copper sides, a 100 kV/cm electric field is produced into the holes acting as multiplication channels

for electrons produced in the gas by a ionizing particle

Triple-GEM

3 mm

2 mm

2 mm

2 mm

Cathode

GEM 1

GEM 2

GEM 3

Anode

Read-out

Cylindrical Triple-GEM

C-GEM Prototype150 mm radius (Layer 1) x 352 mm active length

1538 strips with 650 µm pitch only along Z

C-GEM Prototype150 mm radius (Layer 1) x 352 mm active length

1538 strips with 650 µm pitch only along Z

Manufacturing the Prototype

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1

352 mm

960 mm

Full sensitiveUltra-light detector

Full sensitiveUltra-light detector

Large GEM foilLarge GEM foil Vacuum bagVacuum bag

Cylindrical GEMCylindrical GEM

Cylindrical cathodeCylindrical cathode

The GASTONE ASIC

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Dedicated FEE chip for the KLOE-2 Inner Tracker Low power consumption and high integration requirements 4 different blocks:

• charge sensitive preamplifier• shaper• leading-edge discriminator (with programmable thr.)• monostable to stretch the digital signal for trigger

Sensitivity (pF) 20 mV/fC

ZIN 400 Ω (low frequency)

CDET 1 – 50 pF

Peaking time 90 – 200 ns (1 -50 pF)

Noise (erms) 974 e- + 59 e-/pF

Baseline restorer yes*

Channels/chip 64*

Readout LVDS/Serial

Power consum. ≈ 0.6 mA/ch

GASTONE board ver.1GASTONE board ver.1

C-GEM Prototype Performance

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Performance measured at PS testbeam with GASTONE digital Readout Electronics and external Drift Tubes Tracking System

Spatial Resolution(GEM) =(250µm)2 – (140µm)2 200µm

Spatial Resolution(GEM) =(250µm)2 – (140µm)2 200µm

Efficiency ε = 99.6%Efficiency ε = 99.6%

XV Strips-Pads Readout

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X pitch 650 µm V

pit

ch

650

µm

1000

µm

40°

Peculiar XV readout designed for the cylindrical geometry

X Strips for rφ coordinate V Strips at 40° formed by Pads connected

by internal vias Crossing of X and V gives Z coordinate

Readout extensively studied in Magnetic Field in a TB at SPS

Readout extensively studied in Magnetic Field in a TB at SPS

Simulation of Magnetic Field Effect

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Ar/CO2=70/30B=0.5 T

Lorentz angle αL = 9°

700 μm

Electron avalanche in a Triple-GEM (3/2/2/1 mm) with 0.5 T field.

The result is both a displacement (Lorentz angle) and a spread of the

charge8 m

m

Dedicated 10x10 cm2 planar chambers built to study the readout

Dedicated 10x10 cm2 planar chambers built to study the readout

Test Beam at SPS with Goliath

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Test Beam ParametersGas: Ar-CO2 70-30GEM Gain: 2x104

FEE: 22 GASTONE boardsTrigger: 6 scintillators with SiPM

SPS H4 beam π+ 150 GeV/c SPS H4 beam

π+ 150 GeV/c

beam

GOLIATH Dipole (up to 1.5 T)

5 planar GEMs

Magnetic Field Measurements

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1: Displacement of the charge

2: Spread of the charge

KLOE fieldKLOE field

Since we have a digital readout the spread of the charge also

affects the efficiency, which can be recovered increasing the gain

B = 0 valueB = 0 value

Large GEM Prototype

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1.5x2.5 cm2

pad readout PCB

70x30 cm2 Triple-GEM planar prototype for quality and

uniformity test

70x30 cm2 Triple-GEM planar prototype for quality and

uniformity test

Cathode PCB

GEM3

GEM2

GEM1

Large GEM Prototype

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A very large tensioning tool has been designed.The frame gluing will be performed by using the

“vacuum bag” technique, tested in the construction of the CGEM

With the usual 1 kg/cm, finite element simulation (ANSYS)

indicates a maximum gravitational+electrostatic sag

of the order of 20 μm

Meters

Load Cells

Jaws

Detector Parts

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FR4 support for FEE

QCAL

Kapton readout circuit with connectors

Gastone Boards and HV connectors

Carbon-fiber support for readout circuit

Gas in/out

Conclusions

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The KLOE experiment has been approved for a new run starting at end-2009

In 2011 a new Inner tracker will be inserted for a fine vertex reconstruction

The IT is realized with the innovative technique of fully Cylindrical GEM detectors

A (almost) full-size prototype has been built and successfully tested under different conditions (X-rays, Cosmic-rays, Beam-test)

The peculiar XV readout has been tested in Magnetic Field with dedicated 10x10 cm2 chambers

A large (70x30 cm2) planar chamber is under construction to test the uniformity over a large area

The design of the final detector and the integration with the beam-pipe and the calorimeters has started