Characterization of 18mm Round and 50mm Square MCP-PMTs

Transcription

1 Characterization of 18mm Round and 50mm Square MCP-PMTs Paul Hink, Robert Caracciolo, John Martin, Scott Moulzolf, Charlie Tomasetti, Joseph Wright BURLE INDUSTRIES, INC. 3 rd Beaune Conference New Developments in Photodetection June 18, 2002

2 MCP-PMT Developments! 18mm GaAs MCP-PMT " Very high, broad spectral response with excellent red sensitivity. " Very good photon counting properties. " Applications include Lidar, flourescence, chemiluminescence,! 2 Square Planacon " Large area MCP-PMT with good photon counting properties. " Ideal for tiling applications and good platform for multi-anode configurations.

3 MCP-PMT Operation photon Faceplate Photocathode Dual MCP Photoelectron V ~ 300V V ~ 3000V Gain ~ 10 6 V ~ 300V Anode

4 85104 MCP-PMT! 18 mm dual MCP.! Very high cathode sensitivity (>1200 µa/lm).! Excellent red response (>20% QE at 850nm).! Excellent photon counting properties (peak-valley > 2:1).

5 Spectral Response! Very high cathode response, >1200 µa/lm luminous sensitivity, 1500 µa/lm typical.! Excellent QE " ~30% at 600nm " > 20% at 850nm " > 20% at 370nm Cathode Sensitivity (ma/w) Typical Spectral Response Wavelength (nm) Quantum Efficiency (%)

6 Gain Curve! High gain devices, typically > 4x e+7 Gain Curve! Gating the photocathode results in > 10 7 reduction in sensitivity for white light. Gain 1e+6 1e+5 1e+4 1e Voltage (V)

7 Single Electron Spectrum! Peak:Valley > 2:1 with gain > 5x10 5 and dark counts < 200 cps.! Typical SER < 150% FWHM at gains > 1x10 6.! At higher gains ability to distinguish 1pe and 2pe peaks. Counts Single Electron Spectrum Gain vs Dark Counts Gain vs Signal e+6 1.0e+7 1.5e+7 Gain

8 Single Electron Spectrum 1000 Single Electron Spectrum (3400V) 2000 Single Electron Spectrum (3300V) Counts Counts e+6 1e+7 2e+7 2e+7 Charge (e) 0 0 5e+6 1e+7 2e+7 2e+7 Charge (e)

9 Dark Counts! < 200 cps at 30 C for operating voltage that gives > 2:1 peak-valley and gain of > 5x10 5.! Currently limited by front-end noise, not the cathode.! Slight increase in noise with increasing voltage. Count Rate (cps) Dark Count Rate vs Temperature Temperature (C)

10 Anode Pulse Response! Anode rise-time for single electrons is < 200ps.! Anode fall-time, currently limited by anode design, ~ 1ns.! Re-design of anode is in progress.

11 Pulse Linearity! Very good pulse linearity, ~ 400mA peak pulse current for < 5% linearity! Average anode current is limited to ~1µA maximum. Actual Current (ma) Pulse Linearity Estimated Current (ma)

12 Count Rate Linearity! Good count rate linearity.! Within 20% for 10 6 cps at gain of 10 6, counting pulses> 1/3 pe as defined at low count rates. Measured Count Rate (cps) Count Rate Linearity (1x10 6 Gain) 1e+7 1e+6 1e+5 1e+4 1e+4 1e+5 1e+6 1e+7 Photoelectron Rate (cps)

13 InGaAs Spectral Response 100 GaAs & InGaAs Cathodes Quantum Efficiency (%) InGaAs GaAs S Wavelength (nm)

14 Future Directions!Improved anode response.!integral gating circuit and drive module in development to allow fast gating of the PMT.!Expanded photocathode offering, including InGaAs, Bi-alkali, and Multi-alkali.!Custom anode designs will be considered.

15 Planacon MCP-PMTs! Two inch square flat PMT with dual MCP multiplier.! Four anodes, 2x2 configuration. Additional configurations will be available.! Bi-alkali cathode on quartz faceplate.! Easily tiled, low profile, photon counting, good time resolution, multianode.

16 Single Electron Spectrum! Good photon counting properties at gains of x Currently working on increasing gain by ~2X.! Peak:Valley typically > 2:1 with uniform illumination of faceplate.! DQE for single photoelectrons ~ 65%. Counts Single Electron Spectrum 0 0 5e+5 1e+6 2e+6 2e+6 Charge (e) 2270V 2400V

17 Uniformity! Cathode uniformity within 10% over full active area.! Anode uniformity ~ 1.5:1 over the 2 active area in analog mode.! Cross-talk < 1%. Counts Anode Uniformity Pulse Height (channel)

18 Pulse Height Resolution! Pulse height resolution is acceptable for many applications.! 10.5% FWHM, 2 NaI crystal, 662keV.! ~22% FWHM, LSO, 3mm x 3mm x 10mm, 511keV. Counts Pulse Height Resolution Channel #

19 Future Directions! 8x8 anode in development, first prototypes in process.! Expanded photocathode offerings.! Additional anode designs, including high speed anode.