Multianode Photomultiplier Tube Studies for Imaging Applications Rachel Montgomery NPE Seminar 15/09/11 r.montgomery.glasgow@gmail.com
Outline 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
Multianode Photomultiplier Tubes (MAPMTs) Window Photon Crosstalk mechanisms (which may compromise http://www.hamamatsu.com position sensitivity): Modified from: Optical Charge spill over Electro - magnetic Position Sensitive Readout R. Montgomery, NPE Seminar, Slide 3
Hamamatsu H8500, H9500 and H7546 MAPMTs Active Number Pixel Packing MAPMT Area Of Size Fraction Photocathode (mm) Pixels (mm) (%) 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 H9500 H8500 H7546 http://www.hamamatsu.com R. Montgomery, NPE Seminar, Slide 4
Applications Contalbrigo, M. et al (2010), doi:10.1016/j.nima.2010.10.047 - Particle identification - Medical imaging devices , detectors , e.g. RICH e.g. SPECT, PET, counters (CLAS12 radionuclide imaging Proximity RICH) R. Montgomery, NPE Seminar, Slide 5
Applications – CLAS12 RICH Requirements: • Efficient single photon detection capabilities • Pixel size < 1cm x 1cm • High packing fraction and minimal deadspace Tested MAPMTs at Glasgow: • H8500 • H7546 plus light catcher R. Montgomery, NPE Seminar, Slide 6
CLAS12 Tests - Experimental Setup Light-tight box X-Y Stage High Voltage MAPMT Neutral Laser Under Density λ = 633nm Test Filters Trigger Out Signals Ready Gate QDC Trigger Generator Modules Computer Data R. Montgomery, NPE Seminar, Slide 7
H8500 Single Photoelectron Scans, 1mm Beam Diameter Noise Single photoelectron R. Montgomery, NPE Seminar, Slide 8
H8500 Single Photoelectron Scans, 1mm Beam Diameter, 0.5mm Steps 0 ° 10 ° 20 ° 30 ° R. Montgomery, NPE Seminar, Slide 9
Studying the fine structures of the MAPMTs... R. Montgomery, NPE Seminar, Slide 10
Sub-millimetre Precision Laser Scans • H8500 – 11 dynode chains/pixel Support • H9500 – 6 dynode chains/pixel Structure • H7546 – 2 dynode chains/pixel One • 0.1mm laser beam diameter used Pixel to scan such sub-structures at a H9500 Face sub-millimetre precision arXiv:physics/0701153v1 [physics.ins-det] H7546 Face R. Montgomery, NPE Seminar, Slide 11
H9500 Pixel Responses 20 Photoelectrons Single Photoelectron • 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 530 Photoelectrons R. Montgomery, NPE Seminar, Slide 12
H9500 Pixel Responses 20 Photoelectrons Single Photoelectron • 0.04mm step scans of single pixel • Several light levels X-slice • Segmentation of dynode chains from 20pe • Effects begin to wash out, but still response present, with increasing light level R. Montgomery, NPE Seminar, Slide 13
H9500 Pixel Responses 20 Photoelectrons Single Photoelectron • 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 530 Photoelectrons R. Montgomery, NPE Seminar, Slide 14
H9500 Pixel Responses 20 Photoelectrons Single Photoelectron • 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 15
H9500 Crosstalk Single Photoelectron 20 Photoelectrons • Crosstalk patterns show dependencies upon dynode mesh arrangement • Constructional features are further revealed with increasing photon levels 530 Photoelectrons R. Montgomery, NPE Seminar, Slide 16
H8500 Pixel Responses 20 Photoelectrons Single Photoelectron • 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 260 Photoelectrons R. Montgomery, NPE Seminar, Slide 17
H8500 Pixel Responses 20 Photoelectrons Single Photoelectron • 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 X-slice from 260pe response R. Montgomery, NPE Seminar, Slide 18
H8500 Pixel Responses 20 Photoelectrons Single Photoelectron • 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 Y-slice from 260pe response R. Montgomery, NPE Seminar, Slide 19
H8500 Crosstalk Single 20 Photoelectron Photoelectrons X-slice 260 Photoelectrons R. Montgomery, NPE Seminar, Slide 20
H8500 Crosstalk Single Photoelectron Single Photoelectron 20 Photoelectrons 0.05mm Steps 0.05mm Steps 20 Photoelectrons 20 Photoelectrons Crosstalk from constructional support structures 0.10mm Steps 0.10mm Steps R. Montgomery, NPE Seminar, Slide 21
H8500 Common Last Dynode (D12) Studies • Charge and timing of dynode 12 (common last dynode) signals included into setup • Useful for self-triggering R. Montgomery, NPE Seminar, Slide 22
H8500 Common Last Dynode (D12) Studies Timing and charge spectra of H8500 common last dynode signals: Timing - 100fC/bin Double Gaussian fit Single added with photoelectron quadratic dynode 12 background charge Va’vra , J. (2003), doi: 35ps/bin 10.1016/S0168- spectrum 9002(03)00270-5 Centre pitch scans show efficiencies, gains and timing mimic relative differences between pixels. Average σ 1 time resolutions for: • 20 photoelectrons = 67.5ps • Single photoelectron = 154.4ps R. Montgomery, NPE Seminar, Slide 23
H8500 Common Last Dynode (D12) Studies Single 20 Photoelectron, Photoelectrons, Efficiency, Efficiency, Single Pixel Single Pixel 0.06mm Steps 0.05mm Steps Single 20 Photoelectron, Photoelectrons, Timing Timing 0.06mm Steps 0.05mm Steps R. Montgomery, NPE Seminar, Slide 24
H7546 Pixel Responses Single Photoelectron 20 Photoelectrons • 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 300 Photoelectrons region R. Montgomery, NPE Seminar, Slide 25
H7546 Pixel Responses Single Photoelectron 20 Photoelectrons arXiv:physics/0701153v1 [physics.ins-det] 300 Photoelectrons R. Montgomery, NPE Seminar, Slide 26
H7546 Crosstalk 20 Photoelectrons Single Photoelectron 300 Photoelectrons 300 Photoelectrons R. Montgomery, NPE Seminar, Slide 27
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 R. Montgomery, NPE Seminar, Slide 28
Recommend
More recommend
