Status of KLOE-2 Inner Tracker 

JOINT-GEM meeting

Helsinki

15 July 2010

G.Bencivenni

The Inner Tracker group

G. De Robertis, N. Lacalamita, R. Liuzzi, F. Loddo, M. Mongelli, A. Ranieri, V. Valentino

INFN Bari, Bari, Italy

G. Morello, M. Schioppa INFN Cosenza, gruppo collegato LNF, Cosenza, Italy

A. Balla, G. Bencivenni, S. Cerioni, P. Ciambrone, E. De Lucia,D. Domenici, J.Dong, G. Felici, M. Gatta, M. Jacewicz, S. Lauciani,

V. Patera, M. Pistilli, L. Quintieri, E. Tshadadze Laboratori Nazionali di Frascati - INFN, Frascati, Italy

A. Di Domenico, M. Capodiferro, A. Pelosi INFN Roma, Roma, Italy

Inner Tracker Project

still a factor 2.5÷3 improvement on KS → vertex resolution

• 4 tracking layers with radii from 13 to 23cm (1 layer removed for a safe insertion)• 700 mm active length • XV strips-pads readout (40o stereo angle)

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

3 mm

2 mm2 mm

2 mm

Cathode

GEM 1GEM 2

GEM 3

Anode

Read-out

Cylindrical Triple GEMCylindrical GEM technology

Cylindrical GEM technology

# layersdx@vtx (mm)

dz@vtx(mm)

5 1.6 1.1

4 1.7 1.18

NO IT 4.2 3.1

R&D step by step

1. 2008. C-GEM prototype using 3 (354x330 mm2) GEM foils spliced together with simplified readout. No final readout. No final GEM

2. 2009. 100x100 mm2 planar chambers with XV readout pattern for study in magnetic field. Final readout. No final GEM

3. 2010. Two large (300x700 mm2) planar chambers with the new single-mask GEM foils and XV readout. Final readout and final GEM

Cylindrical-GEM prototype

352 mm

960 mm

Ø=300mm, L=350mmØ=300mm, L=350mm1538 1538 axial stripsaxial strips 650 650

µm pitchµm pitch

Very light detector: no frames in the

active area

Very light detector: no frames in the

active area

3 spliced foils vacuum bag

GASTONE: the IT FEE chip

• Mixed analog-digital circuit• Low input equivalent noise, low power consumption and high integrated chip;• 4 blocks:

Sensitivity (pF) 20 mV/fC

ZIN 400 Ω (low frequency)

CDET 1 – 50 pF

Peaking time 90 – 200 ns (1-50 pF)

Noise (erms) 800 e- + 40 e-/pF

Channels/chip 64*

Readout LVDS/Serial

Power consum. ≈ 0.6 mA/ch

GASTONE 64 chGASTONE 64 ch

0.35 CMOS - no Radhard0.35 CMOS - no Radhard

charge sensitive preamplifier shaper leading-edge discriminator (prog. thr.) monostable (stretch digital signal for trigger)

C-GEM prototype: test beam

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

Gas: Ar/CO2 = 70/30Gain: ~2·104

FEE: 16-channels GASTONETracking: 2x8-MDT stations

10 GeV pion beamCERN-PS T9 area

MDTs MDTs

Efficiency ε = 99.6%

XV readout stuides

40° X

pitch 650 µm

V

pitc

h

650

µm

10x10 cm2 planar GEM for readout study in magnetic fieldReadout is a multilayer kapton circuit with XV pattern of copper strips and pads: • X-view will provide r-φ coordinate in CGEM• V-view made of pads connected by internal vias and with ~40°stereo angle• XV crossing will provide z coordinate in CGEM

Garfield simulatio

n of B field

XV

Test beam in magnetic field

Gas: Ar/CO2 = 70/30Gain: ~2·104

FEE: GEMs partially equipped with 22 GASTONE boards

Trigger: 6 scintillators with SiPM (3 upstream, 3 downstream)

External Trackers: 4 planar GEMs w/650 µm pitch XY strips

• H4 beam-line at CERN-SPS: 150 GeV pions• Goliath Magnet: dipole field up to 1.5T in a ~3x3x1m3

• Semi-permanent setup for RD51 users

BEAM

X-Y GEMs

X-V GEM

dipole magnet

Testbeam in magnetic field

KLOE B - field

CGEM r-φ resolution(bending plane)

x = 200 m

working pointIncrease of B field requires a higher

gain

Increase of B field requires a higher

gain

CGEM z resolution

Large area GEM

Very large GEM: 0.21 m2

Very large GEM: 0.21 m2

• GEM foils up to 350x700 mm2 are needed for the IT (3 are spliced together for 1 electrode)

• After a change in the GEM manufacturing technique and >1 year R&D by CERN TS/DEM we received the first large GEM foils in April

• Two planar prototypes built with the final dimensions of IT foil for pre-production test

hole section

Large planar prototype300mm

700m

mGEM are stretched on a custom-made machine with a tension of ~1kg/cm measured by load-cells

FR4 frame is glued on the GEM with a vacuum-bag.The result is a planar foil (20 µm sag) with no need of frames inside the active area.

XV readout• The prototype has been assembled with the final KLOE-2 readout: XV strips with 650 μm pitch (~220k vias)• It will be equipped with GASTONE-64 and tested CERN-T9 in october 2010

first GEM framed and placed on

the readoutXV

Final assembly

Closing of the chamber

A heavy Al plate is placed to distribute the

pressurefinal gluing w/gas vacuum

Preliminary tests

The detector has been flushed with Ar/CO2 (70/30) and tested in current-mode with a 137Cs source (660 keV photons). Cosmic ray test is starting soon.

137Cs gamma source cosmic ray

Optimization of the fields

Only slight difference

between the two GEM (due to different hole

shapes?)

Only slight difference

between the two GEM (due to different hole

shapes?)Final operating fields values:1.0 – 3.0 – 3.5 – 6.5 kV/cm(Drift – Transf1 – Transf2 –

Induction)

Equal charge sharing occurs at higher induction field in the single-mask

4.8 6.5

Gain measurement• The different shape of the hole affects the gain of the GEM

• Gain ~25% lower in single-mask GEM• Only ~20 V increase in the operating voltage of a Triple-GEM to reach

same gain• NO discharge observed up to 40000 gain

Very stable operationVery stable operation

Inner Tracker project

Technical Design Report of the Inner

Tracker for the KLOE-2 experiment

[arXiv:1002.2572]

Technical Design Report of the Inner

Tracker for the KLOE-2 experiment

[arXiv:1002.2572]

KLOE-2 beam pipe with the IT

IT sketch

CF load test

Time ScheduleTooling and Components

• Cylindrical moulds to make electrodes: end of June (L1) – end of July (L2)• Detector mechanics (fiberglass rings): mid of july• Quality control system (microscope + HV test box): nearly ready• GEM foils: G1 (23 July), G2,G3 (20 Aug) • Readout anode circuits: 20 Aug• Vertical assembling machine (mechanics + electronics): mid of September

Production

• July: test of G1 foils and production of a fake layer (w/mylar)• end Aug: test of G2,G3, connector soldering on anode foils• September: start of Layer1 construction• October: Integration and test of vertical assembling machine• November: Layer1 assembling• December: Layer1 test

Conclusion• The Cylindrical-GEM Inner Tracker project has been finalized

• In the last 3 years an extensive R&D program has been accomplished

• full-scale Cylindrical-GEM prototype successfully tested• XV readout designed and characterized in magnetic field• new single-mask GEM tested

• Two planar prototypes with 300x700 mm2 foils (same dimensions for the cylindrical Inner Tracker) have been built

• current mode test showed good stability, uniformity and gain• cosmic ray test with final FEE and DAQ under preparation (oct. 2010)

• The first two Layers of the IT have been funded : • L2 completed by the end Nov. • then L1 production without dead time

Large Area: Gain Uniformity

15500

15600

15800

16300

15700

15700

15000

15200

15500

15000

14800

14800

12 positions scanned with gamma source (~100 mm2 spot)

Maximum difference (~1000) is of the same order of magnitude of the estimated single error (~800)

Further test needed with more collimated source