Study of the MPPC performance R

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Study of the MPPC performance- RD status for
the GLD calorimeter readout http//ppwww.phys.sc
i.kobe-u.ac.jp/kawagoe/gldcal/index.php?MPPC
Satoru Uozumi Shinshu University, Japan for the
GLD Calorimeter group and KEK Detector
Technology Project / Photon Sensor Group

• Nov 6-10 2006
• International Linear Collider Workshop Valencia

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The Multi Pixel Photon Counter (MPPC)- A novel
semiconductor photon sensor -

• High Gain (105106)
• Good Photon Detection
• Efficiency (2565)
• Compact
• (package size a few mm)
• Low Cost
• Magnetic-field tolerant
• High dark noise
• (order of 100-1000 kHz)
• Response against input
• light yield is non-linear

1 mm
Depletion region 2 mm
Substrate
Si Resistor
Vbias
Guard ring n-
p
n
Al conductor
p-
The MPPC is a still developing, but promising
device !
substrate p
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The MPPC is drastically evolving

• Sometime in future
• Larger sensor area
• More number of pixels
• And perhaps more

• Jan. 2006
• 100/400/1600 pixels
• Smaller pixel size results in more number of
  pixels

• Oct. 2006
• 100/400/1600 pixels commercialized
• Improved Gain and dark noise

• Mar. 2005
• 100/400 pixels
• First sample from Hamamatsu

?
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The New MPPC Sample
4 mm

• Latest 1600 pixel MPPC
• 20 samples arrived in October.
• Very compact plastic package suitable for
  attaching to scintillator strips.
• (this package is customized for our ECAL
  module, and not going to be commercialized)
• 500 more for ECAL beam test will be arrived in
  this month.

1.3 mm
3 mm
Front
Side
Scintillator strip
WLS fiber
MPPC
1 x 1 mm
Side view
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Excellent photon counting ability
New 1600 pixel sample
0,1,2,3,4,5,6,7, . . . Photoelectrons !
Old 1600pixel sample
25 mm
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• Performance of the
• latest 1600 pixel MPPC

• Gain, Noise Rate, Cross-Talk
• Device-by-device variation
• Temperature dependence
• All results are yet preliminary

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Variation of the Gain over 20 samples
Mean 23.82 fF Variation 3.1
20 samples _at_ 25 oC
Mean 75.55 V Variation 0.22 V
Gain C (Vbias-V0) / e C Pixel capacity V0
Breakdown voltage
Good Uniformity !
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Temperature dependence of the Gain

• 30 oC
• 25 oC
• 20 oC
• 15 oC
• 10 oC
• 0 oC
• -20 oC

• Breakdown voltage is linear to temperature.
• Thus the temperature change affects to the
  over-voltage ( Vbias-V0(T)).
• g eventually affects to all the MPPC properties.

DV0/DT (57.3 0.1) (mV/oC)
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Variation of the Noise Rate
Cross-talk

• Dark counting rate with threshold of 0.5 and 1.5
  photoelectron.
• Test 20 samples _at_ 25 oC

20 samples _at_ 25 oC
gt 0.5 p.e.
gt 1.5 p.e.
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Temperature dependence of theNoise Rate /
Cross-talk
gt 0.5 p.e.

• 30 oC
• 25 oC
• 20 oC
• 15 oC
• 10 oC
• 0 oC
• -20 oC

• 30 oC
• 25 oC
• 20 oC
• 15 oC
• 10 oC
• 0 oC
• -20 oC

• Lower temperature g lower dark noise
• Cross-talk is not affected by temperature change.

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KEK Detector Technology ProjectPhoton Sensor
Group(http//rd.kek.jp/)(KEK, Kobe, Kyoto,
Nagoya, Nara-WU, NDA, Shinshu, Tokyo/ICEPP,
Tsukuba)

• Develop and study the MPPC with Hamamatsu
• Aiming to have satisfactory performance to use at
  
• GLD calorimeter
• T2K near detector
• Belle Aerogel Cerenkov Counter
• Provide important feedbacks to Hamamatsu for
  improvement of fundamental properties

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News The MPPCs are finally on catalog !
(Numbers from HPK catalog)

• Hamamastu will start to deliver the MPPC in early
  2007.
• See following page for more information
• http//jp.hamamatsu.com/en/hamamatsu/press/2006/20
  06_10_26.html

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Summary

• We now have the new 1600 pixel MPPCs for the GLD
  EMCAL test module.
• Performance of the new MPPC is sufficient for
  EMCAL beam test.
• Gain (2-8)x105, Noise Rate 50-300kHz, Cross-talk
  prob. lt 2-20
• However properties are sensitive to temperature
  change.
• g Need temperature control / monitoring at
  practical use.
• The MPPC is being commercialized soon !
• Measure properties of 500 samples used for the
  scintillator-W EMCAL module (will arrive in this
  month).
• Practical use for the calorimeter readout at the
  coming beam test ( g next talk )
• The MPPC RD will be continued until we achieve
  the necessary performance for the GLD calorimeter
  readout.
• Improvement of the dynamic range (num. of pixels)
  is especially important!
• Also need to measure non-linearity, stability,
  robustness to have deeper understanding of the
  device.

Plans
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Backups
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Photon Detection Efficiency by Hamamatsu
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• Measurement with Microscopic Laser System

• Introduced by KEK-Detector Technology Project
• YAG Laser, ? 532 nm (green)
• Pulse width 2 nsec, rate 8 kHz
• Spot size 1 ?m
• Light yield 0.5 p.e. (not calibrated)
• Can perform precise pinpoint scan with the
  well-focused laser

Laser spot
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The MPPC performance
The MPPC looks feasible for theGLD Calorimeter
readout!
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Required performance for the GLD Calorimeter

• Gain Best to have 106 , at least 105
• Dynamic range can measure 1000 p.e.
• satisfactory to measure EM shower maximum
• need gt 2500 pixels
• Photon Detection Efficiency 30
• to distinguish MIP signal
• Noise rate 1 MHz (threshold 0.5 p.e.,
• threshold 1.5 p.e is also
  acceptable)
• good uniformity, small cross-talk
• Timing Resolution 1 nsec
• Necessary for bunch ID, slow neutron separation
• Sensor area 1.5 x 1.5 mm
• suitable for 1.5 mmf fiber
• Should be stable against bias voltage /
  temperature / time

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RD Status _at_ GLD Calorimeter

• The MPPC performance looks feasible for the GLD
  calorimeter readout, but still not sufficient.
• Need study and improvement of the fundamental
  property to achieve our goal.
• Now we are measuring performance of latest 400 /
  1600 pixel MPPC prototypes provided by Hamamatsu.
• Based on its results, we provide feedback to
  Hamamatsu to have improved sample.

Evaluate performance of the MPPC
prototypes Provide feedback to HPK Improved
samples from HPK
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Setup
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Response / Correction curves ( with small
cross-talk )
R (pNpe)
R-1(pNfired) p0.1
p0.1
p0
(no cross-talk)
Response curve
Correction curve