Transcript Rui De Oliveira

MPGD TECHNOLOGIES AND PRODUCTION
GEM
Micromegas
Resistive MSGC (NEW!)
Rui De Oliveira
7/12/2011
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•GEM
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GEM Foil
Present max size 1.2m x 0.6m
Future max size 2m x 0.6m (thanks to new equipments)
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Double mask Vs single Mask
•Base material : Polyimide 50um + 5um on both sides
•Double mask
•Single mask
•Base material
•Hole patterning in Cu
•Polyimide etch
•Bottom electro etch
•Second Polyimide Etch
•Limited to 40cm x 40cm due to
•Mask precision and
alignment
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•Limited to 2m x 60cm due to
•Base material
•Equipment
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Double mask Vs single Mask
•Similar patterns , similar behavior
•Same material
•Angles can be adjusted to application (High gain –> Charging up)
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GEM double mask examples
COMPASS
TOTEM GEMs, T. Hilden,V. Greco…
LHCb-Muon trigger
Support Front-End
Pad Plane SupportCooling
Window
GEM stack
& LV- Distribution
Electronic
&
Shielding Cover
Drift electrode
Media-Distribution
&
Read-out Plane
•Production quantities :
around 500 GEMs/ year in
average
B. Surrow, STAR GEM
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GEM Single mask examples
•CMS 3 GEM Detector
•KLOE – Cylindrical 3 GEM Detector
•GEM 1.1m x 500mm
•GEM 800mm x 500mm
•Present production rate : 100 Gem / year
•Expected rate for 2012 : 250 GEM/Year
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New GEM stretching method (NS2)
•No spacers in active area
•Assembly time
• ½ hour for 10cm x 10cm detector (1 technician)
•2 hours for 1m x 0.6m detector (1 technician)
•No gluing , no soldering
•Re opening possible
•GEM exchange possible
•Frame less than 10mm
•Final Gas test with detector assembled
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No spacer self stretching structure
10 to 15mm
O-ring
Readout connector
Free to slide
Drift electrode
External screws to adjust
stretching
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gluing
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GEM attaching structure
(4 pieces defining gaps)
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GEM
FRAME
Bottom
R/O Board
Screws
O-ring
HV BNC Connector
Gas connectors
Read-out connectors
Top
DRIFT BOARD
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HV DIVIDER
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30cm x 30cm
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GEM foil tests in CO2 have been done by applying HV to each GEM and measuring the
current.
Nothing suspicious has been found.
100000
10000
Gain
1000
100
10
1
320
325
330
335
340
345
350
340
345
350
355
360
365
370
380
385
390
395
400
405
410
Vg3; Vg2; Vg1 [V]
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HV
Resistor are trimmed for 2 applications:
3/2/2/2 gaps
3/1/2/1 gaps
40 CHF/piece for 1 piece
4 CHF/piece for 1000 piece
Drift
GEM1
GEM2
GEM3
GND
40mm
Trimming : 0.1% relative
1mA polarizing current @ 4KV
4W power generation
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•Micromegas
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Micromegas
PCB
lamination
Mesh deposit
lamination
development
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Atlas CSC replacement project
MPGD Vs Wire chambers
-Faster
-no need for fancy gases
-lower cost
-robust
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1.2m x 0.6m
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Resistive Bulk MicroMegas
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Resistive strip process
PCB
PCB
PCB
PCB
PCB
PCB
PCB
PCB
PCB
Full PCB technique
-Better resistor uniformity
-Easy to clean
-Thermally robust
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Photoimageable coverlay technique
-less accurate , lower homogeneity
-cracks between coverlay and resistive
material trapping chemistry
-Resistor adhesion problems
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Spark signal
15us
V on 50Ohms
0.35V
Time
No protections needed
for the amplifiers
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Atlas CSC replacement project
Double sided Board
Closing
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Bulking
Res strip depositing
Test before closing
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Test
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Atlas CSC replacement project
5 Bulks have been produced
-1Standard Bulk (S1)
-No production problems
-Detector works
-3 Resistive Bulk R1 to R3 (coverlay)
-1 good piece (R2) Leakage current  20nA @850V
-2 are bad due to high leakage current
-1 Resistive Bulk R4 (full PCB)
-Immediately good at HV test
-under test
We have removed the meshes for expertise of R1 and R3
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Resistor
coverlay
R1
Micro grooves between Resistor and
Coverlay , Probably trapping some
Residues of chemistry
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Dark color due to
KmnO4 Cleaning
Perfect strips
No visible grooves
Absolutely flat
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R3
Correct strips
No visible problem
But the strips are not flat
Due to over cleaning
Clear resistor delamination due to
Coverlay preparation and shorter
Thermal treatment
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X/Y read-out
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U/V/W read-out
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Grounded Mesh
Embedded resistor
GND
PCB
+500V
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Resistive Strip
1MOhms for 1cm
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Copper Strip isolated
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Embedded resistive protection
Resistive material (pads
down to 2mm x 0.3mm )
50 to 75um
Embedded Resistor
Read-out strip
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•Resistive MSGC
•work done in collaboration with Vladimir Peskov
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drift
-600v
0V
Coverlay
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Readout lines
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Resistive lines
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Microdot detector manufacturing steps
a)
v
Multilayer PCB with a Cu
layer on the top and
one layer of readout strips
on the bottom, 1mm pitch
v
v
b)
Upper Cu layer etching
v
c)
1mm
The grooves were then
filled with resistive paste
(ELECTRA Polymers
0.1mm
d)
Removal of the Cu
Resistive cathode strips
Resistive anode dots 0.1mm diameter
Filling with
Coverlay
e)
Readout strips
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0.7mm
Anode
Dots
0.5mm
0.1mm
0.3mm
Resistive
cathode
strips
1mm
A magnified photo of Microdot detector
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Gain plots
1000000
Ne+1.5%CO 2
100000
10000
Gain
Ne
1000
100
10
1
0
200
400
600
800
0.1
Volateg (V)
Gas gain vs. the voltage of R-Microdot measured in Ne and Ne+1.5%CH4 with alpha particles
(filled triangles and squares) and with 55Fe (empty triangles and squares).
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SQ streamers
1000000
100000
Gain
10000
Ar+1.6%CO2
1000
100
Ar
10
Ar+9%CO2
1
0
200
400
600
800
1000
0.1
Voltage (V)
Gain (triangles) dependence on voltage applied to R-Microdot
measured in Ar (blue symbols) and Ar+1.6%CH4 (red symbols) and
in Ar+9%CO2.
Filled triangles and squares -measurements performed with alpha
particles, open symbols - 55Fe.
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Conclusions and next steps
•GEM single mask process is stable
•Ramp up the production
•Increase the size to 2m x 0.6m
•Reduce the prices
•Large Protected Micromegas seems OK
•Produce 4 2D detector end of January
•Resistive MSGC seems attractive but:
•Needs more measurements
•Needs more understanding
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Thank you
GEM: double or single mask
1 to 4 GEMS
Read-out: 1D , 2D ,3D ,Pads, Pixels
Compatible whith SRS electronics
Gas connection
Options:
Honey-comb structure
Built in Resistive protections
HV divider
Kit or assembled
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Bulk Micromegas
Read-out: 1D , 2D ,3D,Pads, Pixels
Compatible whith SRS electronics
Gas connection
Options:
Honey-comb structure
Resitive protection
Resitive sharing layers
Kit or assembled
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Voltage-Current Characteristic of the
DC Electrical Discharge
Gas Discharge Physics, Yuri P. Raizer