Transcript Study of the MPPC performance

Study of the MPPC performance
- R&D status for the GLD calorimeter readout –
http://ppwww.phys.sci.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
The Multi Pixel Photon Counter (MPPC)
- A novel semiconductor photon sensor ~ 1 mm
Depletion
region
~ 2 mm
Substrate
Si Resistor
Guard ring np+ n+
Vbias
Al conductor
• High Gain (105~106)
• Good Photon Detection
Efficiency (25~65%)
• 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
p-
substrate p+
The MPPC is a still developing,
but promising device !
The MPPC is
drastically evolving …
Mar. 2005
Jan. 2006
100/400 pixels
●First sample from
Hamamatsu
●
●
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
●
Sometime in
future
Larger sensor area
●More number of
pixels
●And perhaps more…
●
?
The New MPPC Sample
4 mm
3 mm
1.3 mm
Side
Front
• 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.
Scintillator strip
1 x 1 mm
WLS fiber
Side view
MPPC
New 1600 pixel sample
Excellent photon
counting ability
0,1,2,3,4,5,6,7, . . . Photoelectrons !
Old 1600pixel sample
~ 25 mm
Performance of the
latest 1600 pixel MPPC
• Gain, Noise Rate, Cross-Talk
– Device-by-device variation
– Temperature dependence
• All results are yet preliminary
Variation of the Gain
over 20 samples
Mean : 23.82 fF
Variation ~ 3.1 %
20 samples
@ 25 oC
Mean : 75.55 V
Variation : 0.22 V
Gain = C (Vbias-V0) / e
C : Pixel capacity
V0 : Breakdown voltage
Good Uniformity !
Temperature dependence
of the Gain
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•
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•
•
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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)
Variation of the
Noise Rate
Cross-talk
●
●
Dark counting rate with
threshold of 0.5 and 1.5
photoelectron.
Test 20 samples @ 25 oC
> 0.5 p.e.
> 1.5 p.e.
20 samples
@ 25 oC
Temperature dependence of the
Noise Rate / Cross-talk
•
•
•
•
•
•
•
30 oC
25 oC
20 oC
15 oC
10 oC
0 oC
-20 oC
> 0.5 p.e.
•
•
•
•
•
•
•
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.
KEK Detector Technology Project
Photon 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
News : The MPPCs are finally on catalog !
Number of pixels
Sensor size
100
Nominal Bias Volt.
Gain (x 105)
Noise Rate (kHz)
400
1 x 1 mm2
70 10 V
24.0
7.5
400
270
Photon Detection Efficiency
Temperature dependence (DV0/DT)
65 %
50 %
1600
77 10 V
2.75
100
25 %
50 mV / oC
(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/
2006/2006_10_26.html
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. < 2-20%
–However properties are sensitive to temperature change.
g Need temperature control / monitoring at practical use.
• The MPPC is being commercialized soon !
Plans
• 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 R&D 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.
Backups
Photon Detection Efficiency by
Hamamatsu
Measurement with
Microscopic Laser System
１６００ pixel MPPC
• Introduced by KEK-Detector Technology
Project
• YAG Laser,  = 532 nm (green)
• Pulse width ~ 2 nsec, rate ~ 8 kHz
• Spot size ~ 1 mm
• Light yield ~ 0.5 p.e. (not calibrated)
• Can perform precise pinpoint scan with
the well-focused laser
~25 mm
Laser spot
The MPPC performance
PMT
MPPC
Gain
~106
105~106
Photon Detection Eff.
0.1 ~ 0.2
0.2~ 0.7
Response
fast
fast
Photon counting
Yes
Great
Bias voltage
~ 1000 V
~ 70 V
Size
Small
Compact
B field
Sensitive
Insensitive
Cost
Expensive
Not expensive
Dynamic range
Good
Determined by # of pixels
Long-term Stability
Good
Unknown
Robustness
decent
Unknown, maybe good
Noise (fake signal by
thermions)
Quiet
Noisy (order of 100 kHz)
The MPPC looks feasible for the
GLD Calorimeter readout!
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 > 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
R&D Status @ 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
Setup
Response / Correction curves ( with small cross-talk )
R (p;Npe)
R-1(p;Nfired)
p=0.1
p=0.1
p=0
(no cross-talk)
Response curve
Correction curve