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Central tracker for 12GeV upgrade in HallB
Micromégas : a new detector for CLAS12
Detector’s principle GARFIELD simulation Spatial resolution measurement
Long Micromégas prototype tests Integration to the CLAS magnet
Saclay team: S. Aune, J. Ball, M. Combet, M. El Yakoubi, P. Konczykowski,
C. Lacombe-Hamdoun, S. Procureur, F. Sabatié
P. KonczykowskiCEA Saclay06/28/08
Central Detector(Silicon and maybe Micromégas)
Forward Detector
CLAS12 - Spectrometer
Micromegas principleMicromegas principle
~100 ~100 mm
thin gapthin gap
Fast ions collectionFast ions collection
ComparisonComparison
4 x 2MM
4 x 2SI
2 x 2SI + 3 x 2MM Specs.
pT/pT (%) 2.9 2.1 1.6 5
(mrad) 1.3 15.1 1.4 <10-20
(mrad) 10.9 2.9 2.6 <10
z (μm) 212 1522 267 tbd.
(for @ 0.6 GeV/c , = 90°)
A mixed solution combines the SI and MM advantages! The « only SI » solution is never optimal…
: less material on the particle path, flexibility, cheap
: feasibility with a 5T field, worst intrinsic resolution
Micromégas advantages:
Central tracker
1000 V1500 V2000 V2500 V3000 V
Simulations in B-fieldSimulations in B-field
Regular electric field configuration :
Large Lorentz angle (~ 75o)
- higher drift field
- reduce conversion gap
1 mm!
GARFIELD code (CERN)
Experimental setup
Magnet refurbishing: Fall 2007
Tests started: February 2008
Magnetic field: 0 to 1.5 T
Laser: UV 355nm + neutral filters <50µJ/pulse, 2ns pulse, very good beam size and divergence
Detector: MM prototype V3Bulk MM detector equipped with Gassiplex Board (96 channels)
Active area 30x30 mm2, pitch 300 μm2.25mm Drift-Mesh, 128µm Mesh-StripsGas: 5% iC4H10 + 95% Ar
UV Laser
Drift electrode
Al-mylar
Micromesh
Strips
~400V
Con
vers
ion
1.88
mm
Am
plifi
catio
n
128μ
m
~1kV/cm
~40kV/cm
Experimental principle
Focusing lens
Filter
~800V
e-
Ar-iC4H10
UV Laser
Drift electrode
Micromesh
96 Strips
~400V
Con
vers
ion
1.88
mm
Am
plifi
catio
n
128μ
m
~1kV/cm
~40kV/cm
With a magnetic field
Focusing lens
Filter
~800V
B
e-
ΘLorentz
This distance is related to lorentz
Ar-iC4H10
Data acquisition & analysis
•<ADCi/ΣjADC>
•Lorentz angle mesured from the deviation of the B=0T peak
•Drift distance: 1.88mm
•The signal spreads out with the Lorentz deviation → increase the resolution
B = 0T
B = 1.5T
Labview DAQ
Lorentz angle behaviour with the magnetic field
Lorentz angle behaviour with the drift HV
this difference may be related to the uncertainty on the drift gap
Spatial resolution Sigma of the average
position calculated event by event
σ²exp=(σ2laser+σ²det)/N
When the magnetic field increases → the resolution increases
Test the detector homogeneity
B = 0T
B = 1.5T
Micromégas prototype for the central tracker
One type of Bulk:Active area; 115 mm for 288 strips, 500 mm longMaterial: 100 µm PCB, 5 µm Cu, 18µm mesh, 20µm Mylar
Two type of structure, X and Y, for Bulk integration:Cylindrical for Y: ext: 220 mmTile for X: int 180 mm
One support for up to 3 X tiles and 3 Y cylinders:Channels: 1728 read by AFTER ASIC (T2K)Active area: 0.34 m²Dead zone between detectors not optimized on the prototype !!!
Y cylinder
X tileSupport structure
Micromegas Bulk Demonstrator
Y cylinderX tile
Y connector
Y HT cable
Y joint
Interface attachment to handcart
Length: 600 mmDiameter:180 / 220 mm
Magnet interface (3 Teflon pads)
Cylindrical prototype
Cylindrical Prototype
Received friday May 23rd
Bulk made at CERN 4*72 strips 4 prototypes have been fabricated
and flat-tested, cylindrical test on the way
Detailed views During Bulk realization
Long Prototype : fabrication (Jan.-March. 2008)
Flex PCB cable tests :
Strip cables (40cm, 80cm et 80cm U-shaped)
Wire cables (40 cm, 80cm et 80 cm U-shaped)
55Fe source tests
Flex PCB cable, 80 cm
U-shaped
Acquisition made with T2K Labview DAQ Software
Detector’s electronic
(FEC +FEM)
PLV4: Long Prototype V4
Long MM experimental setup
AFTER signal on the strips
Signal
Time (x 50 ns)
ADC55Fe shaped signal
Signal - noise
Noise
Channel 71
512 time samples
Integration to the CLAS magnet
Out In
The prototype will be fixed on a mobile cart (telescopic slide rail) itself fixed on the magnet.The handcart allows full test in and out without dismounting the detector. Will be used for future test @ 5T with DVCS magnet.
400 mm
Prototype « cart »
View with interface
Electronics box
detector
HT filter
Gas distribution
DVCS magnetTelescopic slide rail
Prototype inside CLAS+DVCS magnet
Goals:•Dry test for test beam end 2008: full prototype on handcart•Lorentz angle @ 5T: one X tile with UV laser •Cosmic test @ 5T: Three X tiles.
Goals:•Beam test: full cylindrical prototype on cart•Beam test: Forward prototype if possible
2000-channel tests #1 and 2
1. During fall 2008, 5T test inside DVCS solenoid:
2. During change-out between e1-dvcs and eg1-dvcs(?), beam test:
2007 08 09 10 11 12 13 2014
Feasability Definition Development Production Experiment
A B C D EProject
Decision(Si and/or MM)
Milestones
PreliminaryDesignReview
ProductionReadiness
Review
2k-ch.v1
Prototyping ForwardB
FinalDesignReview
now
08 09
Beam test5T test1.5T test
now
Conclusion & Perspectives
B-field tests at 1.5T almost done: optimistic results
6 MM detectors to be built at CERN this summer and integrated in the mechanical structure
The whole structure with mounted detectors will be shipped to JLab end of August/beginning of September
ANNEXES
But we need to check: 1. how realistic GARFIELD simulation is2. can we reach a satisfactory voltage setup with athin cylindrical Micromegas detector.
Why we need tests in B-fieldWhy we need tests in B-field
Space resolution
Electronics schematicAMPLIFIER
ORTEC
454
QUAD DISCRIM.
LECROY
821
DUAL TIMER
N93B
50ns
SEQUENCER
V551
LEVEL
ADAPTER
8010
DUAL TIMER
N93B
50ns
IN
IN1
OUT START
OUT
OUTMESH (IN)
GATE GEN.
VETO
START
TRIGGER
E.MARKER
OUT2
BUSY
CLR CLK
IN2
GASSIPLEX
IN
CLR OUT1
STRIPS (IN)
C-RAM
V550 CLK
T/H
OUT
START
OUT
STRIPS DATA (OUT)
CLEAR
DREADY
CONV
VME
VME
Data acquisition (Labview)
Data analysis : GUI ROOT
Reads the Labview files
Substracts the pedestals
Draws the average ADC per channel, the position weighted by the ADC value, its evolution during the run, the ADC spectrum for one channel and for all the channels, etc
Single Event Viewer
Palette
DE/E
19.8% PLV1-4 23/04/2008
20.2% 2.07E-01 2.33E-01 2.02E-01 2.10E-01 2.12E-01
20.6% 2.12E-01 2.34E-01 2.15E-01 2.08E-01 2.13E-01
21.0% 2.07E-01 2.20E-01 2.01E-01 1.98E-01 2.01E-01
21.4%
21.8% Vd=520V
22.2% Vg=420V ig=27nA
22.6% d-gaz=2l/h
23.0%
23.4%
1.1% sigma
15% Delta max
Long Prototype study with 55Fe
Energy resolution
Homogeneity of the detector
Noise study: preliminary resultsPedestal for channel 71
Summary (preliminary)
0- Electro. Only
1- FEC + Det
2- Flex PCB cable 40 with Strips
3- Flex PCB cable 40 with wires
4- Flex PCB cable 80U with Strips
5- Flex PCB cable 80U with Wires
6- Flex PCB cable 40 x 2
7- Flex PCB cable 2 m
Probably not real
Without noise optimization: noise with 80cm flex cable ~6for MIP signal expected ~50.=> Flex PCB cables up to 80cm are definitely useable !
-Improved precision tests thanks to a larger drift gap
-Direct measurement of gap with the laser setup
-Precise variation of the laser intensity with neutral filter wheel
-Tests planned in the fall ’08 with e1-dvcs magnet at 5T and large-area detectors
Future plans with B-field tests (June-July + fall ’08)
PCB
Photoresist 1
Photoresist 2Mesh
UV
1) PCB (pistes, pixels,…)
2) Photoresist 1 (50 à 150 microns )
3) Grille (inox tissé de 19 microns, 500 LPI)
4) Photoresist 2 (50 à 100 microns)
5) Insolation UV
6) Développement
7) Cuisson (UV et four)
Mask2 à 4 mm 50 à 100 m
Plots: 200 à 400 microns
Mini: 4 mm
Concept du bulkConcept du bulk