Transcript Slide 1

Villa Olmo, Como – 6th October 2009
Status of the Cylindrical‐GEM
project for the
KLOE‐2 Inner Tracker
Danilo Domenici (INFN-LNF)
on behalf of the KLOE-2 collaboration
KLOE-2 Highlights
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)
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
2
The KLOE Detector
Drift Chamber
Calorimeter
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%
18/07/2015 Villa Olmo, Como
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)
D. Domenici - LNF
3
Need for an Inner Tracker
Simulation 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)
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)
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
4
The Inner Tracker
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
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
5
Inner Tracker Numbers
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
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
6
The Cylindrical-GEM
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
Cylindrical Triple-GEM
Triple-GEM
Read-out
Cathode
Conversion & Drift
3 mm
GEM 1
Anode
2 mm
Transfer 1
GEM 2
2 mm
2GEM
mm 3
2 mm
Anode
3 mm
Transfer 2
Induction
Read-out
18/07/2015 Villa Olmo, Como
GEM
3
2 mm
GEM 2
2 mm
GEM 1
Cathode
C-GEM Prototype
150 mm radius (Layer 1) x 352 mm active length
1538 strips with 650 µm pitch only along Z
D. Domenici - LNF
7
Manufacturing the Prototype
Large GEM foil
Vacuum bag
1
Cylindrical GEM
Cylindrical cathode
Full sensitive
Ultra-light detector
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
8
The GASTONE ASIC
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
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
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
GASTONE board ver.1
9
C-GEM Prototype Performance
Efficiency ε = 99.6%
Performance measured at PS testbeam
with GASTONE digital Readout Electronics
and external Drift Tubes Tracking System
Spatial Resolution
(GEM) =(250µm)2 – (140µm)2  200µm
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
10
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
X pitch
650 µm
1000 µm
XV Strips-Pads Readout
40°
Readout extensively
studied in Magnetic
Field in a TB at SPS
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
11
Simulation of Magnetic Field Effect
8 mm
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
charge
700 μm
Ar/CO2=70/30
B=0.5 T
Lorentz angle αL = 9°
18/07/2015 Villa Olmo, Como
Dedicated 10x10 cm2 planar
chambers built to study the readout
D. Domenici - LNF
12
Test Beam at SPS with Goliath
SPS H4 beam
π+ 150 GeV/c
GOLIATH Dipole (up to 1.5 T)
5 planar GEMs
Test Beam Parameters
Gas: Ar-CO2 70-30
GEM Gain: 2x104
FEE: 22 GASTONE boards
Trigger: 6 scintillators with SiPM
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
13
Magnetic Field Measurements
B = 0 value
KLOE field
2: Spread of
the charge
1: Displacement
of the charge
Since we have a digital readout
the spread of the charge also
affects the efficiency, which can
be recovered increasing the gain
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
14
Large GEM Prototype
70x30 cm2 Triple-GEM planar
prototype for quality and
uniformity test
Cathode PCB
GEM1
GEM2
GEM3
1.5x2.5 cm2
pad readout PCB
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
15
Large GEM Prototype
Meters
With the usual 1 kg/cm, finite
element simulation (ANSYS)
indicates a maximum
gravitational+electrostatic sag
of the order of 20 μm
Jaws
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
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
16
Detector Parts
Kapton readout circuit
with connectors
Gastone Boards
and HV connectors
FR4 support for FEE
Gas
in/out
18/07/2015 Villa Olmo, Como
Carbon-fiber support for
readout circuit
QCAL
D. Domenici - LNF
17
Conclusions
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
18/07/2015 Villa Olmo, Como
D. Domenici - LNF
18