silicon preshower for the cms: barc participation anita topkar barc
TRANSCRIPT
Silicon Preshower for the CMS: BARC Participation
Anita TopkarBARC
CMS Preshower Detector
End caps of CMS detector has ~4300 silicon strip detectors covering area of~17 m2
BARC has delivered 1100 detector modules forthe CMS preshower
Production of additional detectors (~400 wafers) was carried out to meet the shortfall
The Preshower Silicon Detector
Preshower silicon strip detector is being
used for 0/ rejection in the ECAL, CMS
• Strips of 1.80 mm width with a pitch of 1.9 mm• Area - 63mm x 63mm
Detector specifications are very stringent as they are to be operated in a high radiation background of neutrons ( 2x10 14 /cm2) & gamma ( 10Mrad) for a long period often years
Technology development and production of detectors• Technology developed by BARC in eight batches using BEL
facility. Knowhow for fabrication of detectors was provided to BEL
• Detectors were designed during various phases (prototype, preproduction, production)
• Characterization setups and probe jigs developed and quality control facility setup at BEL during production
• Quality control of detectors was carried out (BARC and Delhi university)
• Micromodule production facility was setup at BEL
There was lot of support from CERN Preshower Group during production of silicon detectors and modules in India)
Strip Detectors for CMS Experiment at LHC, CERN
Silicon detectors produced by BARC cover an area of 40,000 cm2 in the CMS detector of LHC
Wafers designed and fabricated during various stages of development
1 2 3
Detector module
Front end hybrid developed by CERN
Detector Specifications
Electrical
High breakdown voltage Breakdown voltage for all strips >= 300V/500VLow leakage:Total current of all strips <= 10 μA at 300VUniformity of all strips: Maximum 1 strip with leakagecurrent> 5 μA at 300V
Geometrical
Tight control over dimensionsLength 63.0 +- 0.1 mmWidth 63.0 +0.0, -0.1 mm
Detector Design
Design for improving breakdown voltage & reducing the leakage current
Floating field guard rings Rounded cornersField plates
Fabrication Process High resistivity <111>, FZ wafers Ion implanted junctions with oxide
passivation P+ guard rings Gettering to reduce leakage currents Aluminum metallization PSG passivation on the top
Fabrication process optimized in eight batches to achieve desired specifications
Quality control of the strip detector
Leakage current of strips, capacitance of strips, full depletion voltage, breakdown voltage, mechanical tolerances on geometry
• Probe-jigs to make contact to the 32 strips simultaneously• Simulaneous measurement of strip current of 32 strips ( IV)• Simulaneous measurement of strip capacitance of 32 strips
( CV)
Probe-jigs, measurement setups required for qualification of detectors and modules were developed. Test facility was setup at BEL for qualification of detectors as per the CERN specifications
0
100
200
300
400
500
600
0.1 2.1 4.1 6.1 8.1 10.1
No
of S
enso
rs
I300 (Microamps)
0
200
400
600
800
1000
No
of S
enso
rs
VBD (Volts)
Performance of detectors supplied to CERN
Breakdown voltage Total current at 300V
0.0E+00
1.0E-10
2.0E-10
3.0E-10
4.0E-10
5.0E-10
0 100 200 300
Voltage (Volts)
Cap
acit
ance
(F
arad
s) prerad
postrad
Radiation hardness of sensors
Change of full depletion voltage due to a neutron dose of 2x1014 n/cm2
Production of sensor micromodules
12
Detector Ceramic tile
Detector aligned and glued to ceramic tile
Aluminum tile
Complete micromodule with readout hybrid assembled on ladder
Fully assembled Preshower Dee plane
The assembled end cap with micromodules – Assembly, Installation and Commissioning by CERN
Participation in CMS : Benefits
• Technology development for large area silicon strip detectors was Initiated
• Capability for large scale production for detectors using industry facilities is developed
• This also resulted in the development of a wide range of silicon detectors for applications in BARC and for international Experiments
Large area PIN diodes Pad detectors for physics experiments and radiation monitoring
PIN photodiodes for scintillators & X-ray imaging
Silicon microstrip detectors for PHENIX Experiment at RHIC, BNL
Silicon pad detectors for experiments at GANIL, France
Silicon detectors developed by BARC
Thanks you