1. Proof of feasibility of VSiPMT (Vacuum Silicon PhotoMultiplier Tube)
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Proof of feasibility of VSiPMT
(Vacuum Silicon PhotoMultiplier Tube)
D. Vivolo
Univ. Federico II and INFN Naples, Italy
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

2. D. Vivolo - Proof of feasibility of VSiPMT
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Outline
VSiPMT
Geant4 simulations
Experimental setup
Prototype test
Perspectives
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

3. A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Beyond PMTs
To date, a crucial role in astroparticle experiments has been played by PhotoMultiplier Tubes (PMTs).
However they suffer of many
drawbacks :
fluctuations in the first dynode gain make single photon counting difficult;
Moreover the next generation of experiments will require further improvements in photon detectors
the linearity is strongly related to the gain and decreases as the latter increases;
performances
New generation of photodetectors, based on inverse p–n junction:
the transit time spreads over large fluctuations;
the mechanical structure is complex and expensive;
PIN photodiodes: no gain;
sensitivity to magnetic fields;
avalanche photodiodes (APD): gain of few hundreds;
the need of voltage dividers increases failure risks, complexity in the experiments designs and power consumption.
avalanche photodiodes in linear Geiger-mode (SiPM): gain of 105 – 106.
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

4. small sensitive surface
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
SiPM technology
Attractive features
high quantum efficiency
low operation voltages
compactness
robustness
weak sensitivity to the magnetic fields ! ! !
Limit
small sensitive surface
(at present silicon wafer costs and the thermal dark current limit the dimensions of the SiPM photo detector at few mm2)
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

5. Surface increase: our purposes
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Surface increase: our purposes
Vacuum Silicon PhotoMultiplier Tube (VSiPMT)
SiPM
Photocathode
1st stage Cilindrical Focusing Electrode
2nd stage Conical Focusing Electrode
Optical Concentrators + digital noise reduction circuit
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

6. D. Vivolo - Proof of feasibility of VSiPMT
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Timeline
2007
2013
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

7. + VSiPMT: design Design Combination of SiPM with vacuum technology
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
VSiPMT: design
Combination of SiPM with vacuum technology
replacing the dynodes structure of a PMT with a SiPM (Vacuum Silicon PhotoMultiplier Tube, VSiPMT)
Design
Hemispherical vacuum glass PMT standard envelope composed by:
a photocathode for photon-electron conversion
In such a configuration, the SiPM acts both as a non-imaging concentrator and as an electron multiplier with G≈ , similar to the dynode chain of a classical PMT. +
photoelectrons
an electric field that accelerates and focuses all the photoelectrons to a small focal area covered with the SiPM
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

8. The quartz window has an anti-reflective function:
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Geant4 Simulations
Geant4-based simulation of electron backscattering over SiPM
Quantities:
Simulated device
2 sets of simulations
Backscattering coefficient
Incoming electron beam
Normally incident beam
Beam energy keV
Range in Si
Total released energy
Quartz layer
(0.15 mm)
Si substrate
(5mm)
Backscattering energy fraction
Average energy loss in Si
Variable incident angle
Beam energy 10 keV
The quartz window has an anti-reflective function:
Backscattering coefficient is 12.6% with quartz layer and 14.1% without it
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

9. Geant4 Simulations: highlights/1
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
VSiPMT
Geant4 Simulations
Exp. Setup
Experimental Setup
KF technique
KF technique
Prototype test
Perspectives
KF technique
Geant4 Simulations: highlights/1
Normally incident beam
Beam energy keV
Variable incident angle
Beam energy 10 keV
E [keV]
Range in Si [mm]
1.2 10keV
Range in Si [mm] °
Incidence angle [°]
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

10. Geant4 Simulations: highlights/2
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Geant4 Simulations: highlights/2
Normally incident beam
Beam energy keV
Variable incident angle
Beam energy 10 keV
75°
10 keV
Backscattering coefficient
Incidence angle [°]
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

11. Experimental Setup/1 Test of SiPM performances as an electron detector
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Experimental Setup/1
8 MeV 3+C beam
Backward secondary e- collected (stripping)
Energies up to 9 keV required.
Electrostatic grids system for acceleration and deflection.
High vacuum (10-6mbar)
Test of SiPM performances as an electron detector
Low-energy electron beam required
Ion beams accelerated by TTT3 Tandem Accelerator at MeV energies bombarding a thin 12C foil (30 mg/cm2)
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

12. Iin = Ibw  ASiPM/Aspot ≈ 6nA
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Experimental Setup/2
average energy loss in collisions with Carbon atomic electrons per unit length: dE/dx = 152 eV/Å
in 100Å each 3+C ion extracts ∼ 1300 e-
Measured 8 MeV 3+C beam current
Ip=400pA
Backward electron current
Ibw = Ip x 1300 = 520pA
Input electron current on SiPM
Iin = Ibw  ASiPM/Aspot ≈ 6nA
ASiPM = 1 mm2
Aspot ≈ 0.9 ± 0.1 cm2
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

13. Preliminary estimation of Electron Detection Efficiency
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Results
Evidence of the feasibility of the SiPM as an electron counter
Dark condition
Responses for multiple triggers overlaid
Peak values
hystogram
Separated
waveforms
Preliminary estimation of Electron Detection Efficiency
EDE ≈ (23 ± 9) %
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

14. p+npn+ configuration, special non-windowed series for e optimization.
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Prototype HV
SiPM Bias
Amplifier
GND pe g
p+npn+ configuration, special non-windowed series for e optimization.
Lower voltage required with respect to simulations (-2,5/3 KV expected).
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

15. Excellent photon counting capability!
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Prototype: waveforms
Peak values
hystogram
VSiPMT illuminated by a pulsed laser light at low intensity (407nm)
oscilloscope triggered in synch with the laser
Responses for multiple triggers are overlaid
Well separated
waveforms
Excellent photon counting capability!
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

16. Prototype: efficiency Preliminary results on 50mm prototype
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Prototype: efficiency
photons
photocathode
dynode
photoelectrons
photons
photocathode
-2/3 KV
-2/3 KeV
SiPM (70 V)
photoelectrons
PMT Efficiency
VSiPMT Efficiency
e = e photocathode x e 1st dynode
e = e photocathode x e SiPM (50)
0,30 ≈ 0, x ,8
0,23 ≈ 0, x ,61
e = e photocathode x e SiPM (100)
Preliminary results on 50mm prototype
0,30 ≈ 0, x ,78
e ≈ 0,2
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

17. Prototype: operating point
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Prototype: operating point
preliminary
photons
photocathode HV
2 - 5 KeV
SiPM (70 V)
photoelectrons
Efficiency is highly stable over 3200 V
No need for high voltage stabilization
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

18. Prototype: xy scan preliminary 7mm x 7mm bialkali photocathode
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Prototype: xy scan
preliminary
7mm x 7mm bialkali photocathode
1mm2 SiPM
Homogeneous efficiency
≈ 0.2 over a 9mm2 surface
Surface increase factor ≈ 9
Standard technology
Focalization optimization is possible
WORK IN PROGRESS
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

19. Prototype: gain High gain (105 – 106), linear trend preliminary
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Prototype: gain
Peak values
hystogram
preliminary
Area hystogram
Measure of the charge corresponding to 1 pe (peaks in area hystogram)
High gain (105 – 106), linear trend
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

20. Highlights on preliminary results
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Highlights on preliminary results
PMT
VSiPMT
comparison
Efficiency
Photocathode x
1st dynode (0,8)
Fill factor SiPM (vs..1)
≈ equivalent
Gain
Timing
nsec
fractions of nsec
(no spread dynodes)
+ VSiPMT
Linearity
depending on gain
-Pe spot over all SiPM surface
-dim. SiPM e n. of cells
not depending on gain
in progress
Power Consumption
Divider Dissipation
No dissipation: just
Amp. G=5-7 (50mW)
+VSiPMT
Stability H.V.
H.V. stabilization fot
stable gain
No H.V. stability
(plateau)
Single photon detection
difficult
Photon counting
Dimensions & Costs
Compactness-low cost
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

21. Perspectives Crucial features under investigation
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
VSiPMT
Geant4 Simulations
Experimental Setup
Prototype test
Perspectives
Perspectives
Preliminary results are extremely encouraging
Prototype test in progress...much work still to be done
Crucial features under investigation
Focusing system optimization
More accurate efficiency measurements in progress
Timing performances - TTS
Linearity optimization – Dynamic range
Low temperature performances
...
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

22. D. Vivolo - Proof of feasibility of VSiPMT
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Thank you
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

23. D. Vivolo - Proof of feasibility of VSiPMT
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Backup slides
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

24. D. Vivolo - Proof of feasibility of VSiPMT
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Normally incident beam
Beam energy keV
Variable incident angle
Beam energy 10 keV
Incidence angle [°]
Backscattering energy fraction q=
Einc
(Einc – Erel)
q increases with q
75°)
Backscattering energy fraction
10 keV
E [keV]
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

25. D. Vivolo - Proof of feasibility of VSiPMT
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Normally incident beam
Beam energy keV
Variable incident angle
Beam energy 10 keV
E [keV]
Total released energy [keV]
Small until 4 keV
7,8 keV at 10keV
Total released energy [keV]
3.5 75°
Incidence angle [°]
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

26. D. Vivolo - Proof of feasibility of VSiPMT
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Normally incident beam
Beam energy keV
Variable incident angle
Beam energy 10 keV
E [keV]
Average energy loss in Si [MeV/cm]
16 10keV
Average energy loss in Si [MeV/cm]
6.5 75°
Incidence angle [°]
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT

27. Laser beam characterization
A Kalman Filter approach for track reconstruction in a neutrino telescope: road to ANTARES
Laser beam characterization
High gain
2.75 x 105 at 72.8V bias
Low breakdown voltage
(70V)
Very linear output signal
Single photon sensitivity
SiPMs have better performances than PMTs
with lower power consumption
Geant4 Simulation
10 keV electron beam
50% at 75°
68% at 75°
Backscattering coefficient for a normally incident beam is12.6%
Backscattered energy fraction is 22% for normally incident beam
14.2% without anti-reflection quartz window
For small incidence angle the SiPM represents a valid solution to substitute the classical dynode chain of PMTs.
23/05/2013
D. Vivolo - Proof of feasibility of VSiPMT