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Photon-Absorption Enhancement Factor

Photon-Absorption Enhancement Factor. Daniel Ferenc, Andrew Chang Eckart Lorenz Physics Department, University of California Davis, Max Planck Insitute, Munich. Work supported by National Nuclear Security Administration (NNSA), Office of Nonproliferation Research and Engineering, DOE, and

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Photon-Absorption Enhancement Factor

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  1. Photon-Absorption Enhancement Factor Daniel Ferenc, Andrew Chang Eckart Lorenz Physics Department, University of California Davis, Max Planck Insitute, Munich Work supported by National Nuclear Security Administration (NNSA), Office of Nonproliferation Research and Engineering, DOE, and two Advanced Detector Awards, Office of Science, DOE

  2. ENCLOSURE: FLAT-PANEL TV 3 existing mass-production technologies ELECTRON DETECTION: SEMICONDUCTOR Scintillator + Geiger-MODE AVALANCHE DIODE ‘Light Amplifier’ PHOTONELECTRON CONVERSION: CLASSICAL PHOTOCATHODE

  3. MAJOR MODIFICATIONS (will show tomorrow) ENCLOSURE: FLAT-PANEL TV 3 existing mass-production technologies ELECTRON DETECTION: SEMICONDUCTOR Scintillator + Geiger-MODE AVALANCHE DIODE ‘Light Amplifier’ PHOTONELECTRON CONVERSION: CLASSICAL PHOTOCATHODE ALREADY VERY GOOD

  4. MAJOR MODIFICATIONS (will show tomorrow) ENCLOSURE: FLAT-PANEL TV LOOKIN FORWARD FOR IMPROVEMENTS 3 existing mass-production technologies ELECTRON DETECTION: SEMICONDUCTOR Scintillator + Geiger-MODE AVALANCHE DIODE ‘Light Amplifier’ PHOTONELECTRON CONVERSION: CLASSICAL PHOTOCATHODE ALREADY VERY GOOD

  5. DIAGNOSTIC TOOL – NOT USED (YET)

  6. 7-pixel 5-inch ReFerence Flat-Panel Prototype • UHV Transfer System : • Photocathode deposition • Indium/Au/Cr deposition • Vacuum sealing

  7. Lasers for Active Mirror Control

  8. SUPER-EFFICIENT CAMERA

  9. Maximizing Double-Hits in a PMT Not yet optimized for the milky PMT coating  Significant additional improvements to come PMT

  10. Photon Absorption (Electron ‘Creation’) e.g. in S-20 40% ph. (400 nm) are absorbed in a 30 nm thick photocathode Probability for an electron to reach the vacuum surface Random Walk - mainly electron-imperfection scattering (less e-e and e-phonon) e.g. scattering length in S-20 ~25 nm Photon Photo-Electron Therefore: QE ~ 10-20% Glass Window Photocathode Vacuum

  11. Probability for an Electron to Reach the Vacuum Surface (Random Walk) Photon Absorption (Electron Creation) (e.g. Substrate, Reflector,…) Photon Photo-Electron & LOWER PRODUCTION COST ! Vacuum Photocathode

  12. Probability for an Electron to Reach the Vacuum Surface (Random Walk) UV Photon Absorption (Electron Creation) Mostly @ Surface Thin Photocathode on a Reflector, Interference, Multi-layer Systems UV Photon Photo-Electron Westinghouse, RCA, ITT ~1963-1975 Vacuum Photocathode

  13. Reflection Mode vs. Transmission Mode ~30-43 % QE bialkali ~190-450 nm (Hamamatsu side-on PMT R7517) Extension into “blue & UV” Quantum Efficiency Wavelength

  14. TRANSMISSION PC REFLECTION PC Source: Silvano Donati, Phosotosensors

  15. H2O REFLECTION-MODE PHOTOCATHODES WORSE – dense media for larger incidence angles GOOD - air AIR • Water Cheenkov – neutrinos etc. • Liquid scintillator • Plastic, crystal scintillator Gamma-ray astronmy – Atmospheric Cherenkov Telescopes

  16. & Mr. Mrs. Mass production High performance

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