[PPT] - Multianode Photomultiplier Tube Studies for Imaging Applications PowerPoint Presentation

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Multianode Photomultiplier Tube Studies for Imaging Applications

Rachel Montgomery NPE Seminar 15/09/11 r.montgomery.glasgow@gmail.com

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Multianode Photomultiplier Tubes (MAPMTs):

Design, crosstalk
Hamamatsu H8500, H9500 and H7546 MAPMTs
Applications

CLAS12 RICH Tests:

Setup, method, Observations

Sub-millimetre Precision Studies:

Homogeneity of MAPMT responses and crosstalk patterns
H8500 MAPMT dynode 12 studies

Summary:

Overview of findings
R. Montgomery, NPE Seminar, Slide 2

Outline

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Multianode Photomultiplier Tubes (MAPMTs)

Photon

Modified from: http://www.hamamatsu.com

Position Sensitive Readout Crosstalk mechanisms (which may compromise position sensitivity):

Optical Charge spill over Electro - magnetic

Window

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R. Montgomery, NPE Seminar, Slide 4

Hamamatsu H8500, H9500 and H7546 MAPMTs

MAPMT Active Area (mm) Number Of Pixels Pixel Size (mm) Packing Fraction (%) Photocathode H8500 49 x 49 64 (8 x 8) 5.8 x 5.8 89 Bialkali H9500 49 x 49 256 (16 x 16) 2.8 x 2.8 89 Bialkali H7546 18.1 x 18.1 64 (8 x 8) 2.0 x 2.0 78 Super Bialkali

H8500 H9500

http://www.hamamatsu.com

H7546

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Applications

Particle identification

detectors, e.g. RICH counters (CLAS12 Proximity RICH)

Medical imaging devices,

e.g. SPECT, PET, radionuclide imaging

Contalbrigo, M. et al (2010), doi:10.1016/j.nima.2010.10.047

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Applications – CLAS12 RICH

Requirements:

Efficient single photon

detection capabilities

Pixel size < 1cm x 1cm
High packing fraction and

minimal deadspace

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Tested MAPMTs at Glasgow:

H8500
H7546 plus light catcher

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CLAS12 Tests - Experimental Setup

Ready Trigger X-Y Stage Laser λ = 633nm Neutral Density Filters MAPMT Under Test High Voltage Light-tight box Gate Generator QDC Modules Computer Trigger Out Signals Data

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H8500 Single Photoelectron Scans, 1mm Beam Diameter

Noise Single photoelectron

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0° 10° 30° 20°

H8500 Single Photoelectron Scans, 1mm Beam Diameter, 0.5mm Steps

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Studying the fine structures of the MAPMTs...

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Sub-millimetre Precision Laser Scans

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H8500 – 11 dynode chains/pixel
H9500 – 6 dynode chains/pixel
H7546 – 2 dynode chains/pixel
0.1mm laser beam diameter used

to scan such sub-structures at a sub-millimetre precision

One Pixel Support Structure H9500 Face H7546 Face

arXiv:physics/0701153v1 [physics.ins-det]

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H9500 Pixel Responses

0.04mm step scans of single pixel
Several light levels
Segmentation of dynode chains
Effects begin to wash out, but still

present, with increasing light level Single Photoelectron 20 Photoelectrons 530 Photoelectrons

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H9500 Pixel Responses

0.04mm step scans of single pixel
Several light levels
Segmentation of dynode chains
Effects begin to wash out, but still

present, with increasing light level Single Photoelectron 20 Photoelectrons

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X-slice from 20pe response

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H9500 Pixel Responses

0.04mm step scans of single pixel
Several light levels
Segmentation of dynode chains
Effects begin to wash out, but still

present, with increasing light level Single Photoelectron 20 Photoelectrons 530 Photoelectrons

R. Montgomery, NPE Seminar, Slide 14

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H9500 Pixel Responses

0.04mm step scans of single pixel
Several light levels
Segmentation of dynode chains
Effects begin to wash out, but still

present, with increasing light level Single Photoelectron 20 Photoelectrons

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H9500 Crosstalk

Crosstalk patterns show

dependencies upon dynode mesh arrangement

Constructional features are

further revealed with increasing photon levels

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Single Photoelectron 20 Photoelectrons 530 Photoelectrons

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H8500 Pixel Responses

Single Photoelectron 260 Photoelectrons 20 Photoelectrons

0.04mm step scans of single pixel
Several light levels
Segmentation of dynode chains
Effects begin to wash out, but still

present, with increasing light level

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H8500 Pixel Responses

Single Photoelectron 20 Photoelectrons

0.04mm step scans of single pixel
Several light levels
Segmentation of dynode chains
Effects begin to wash out, but still

present, with increasing light level

R. Montgomery, NPE Seminar, Slide 18

X-slice from 260pe response

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Single Photoelectron 20 Photoelectrons

0.04mm step scans of single pixel
Several light levels
Segmentation of dynode chains
Effects begin to wash out, but still

present, with increasing light level

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Y-slice from 260pe response

H8500 Pixel Responses

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H8500 Crosstalk

Single Photoelectron 20 Photoelectrons

X-slice

260 Photoelectrons

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H8500 Crosstalk

20 Photoelectrons

0.10mm Steps

20 Photoelectrons

0.05mm Steps

Single Photoelectron Single Photoelectron

0.05mm Steps

20 Photoelectrons

0.10mm Steps

Crosstalk from constructional support structures

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Charge and timing of dynode

12 (common last dynode) signals included into setup

Useful for self-triggering

H8500 Common Last Dynode (D12) Studies

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H8500 Common Last Dynode (D12) Studies

Timing and charge spectra of H8500 common last dynode signals:

Timing - Double Gaussian fit added with quadratic background Single photoelectron dynode 12 charge spectrum

Centre pitch scans show efficiencies, gains and timing mimic relative differences between pixels. Average σ1 time resolutions for:

20 photoelectrons = 67.5ps
Single photoelectron = 154.4ps

35ps/bin 100fC/bin

Va’vra, J. (2003), doi: 10.1016/S0168- 9002(03)00270-5

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Single Photoelectron, Efficiency, Single Pixel 0.06mm Steps Single Photoelectron, Timing 0.06mm Steps

H8500 Common Last Dynode (D12) Studies

20 Photoelectrons, Efficiency, Single Pixel 0.05mm Steps 20 Photoelectrons, Timing 0.05mm Steps

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H7546 Pixel Responses

Single Photoelectron 20 Photoelectrons 300 Photoelectrons

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0.04mm step scans
Several light levels
Different dynode arrangement from

H8500 and H9500 visible

At high light levels, central focussing

electrode becomes highest gain region

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H7546 Pixel Responses

Single Photoelectron 20 Photoelectrons 300 Photoelectrons

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arXiv:physics/0701153v1 [physics.ins-det]

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H7546 Crosstalk

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Single Photoelectron 20 Photoelectrons 300 Photoelectrons 300 Photoelectrons

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Summary

Position sensitive MAPMTs:

Enhancing performance of imaging detectors
Detection/surface homogeneity and crosstalk studies vital

Sub-millimetre precision laser scans of H8500, H9500 and H7546:

Reveal response and crosstalk pattern dependencies upon dynode

arrangements and mesh construction

Observed at several light intensities
Crosstalk patterns become stronger at larger light intensities (as

expected) H8500 dynode 12 studies:

Common last dynode signals are also affected by MAPMT construction

Future tests:

Dynode 12 studies for the H9500 and H7546
Sub-millimetre scans for MCPPMTs and SiPMs

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