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10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
10 Picosecond Timing Workshop 28 April 2006
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10 Picosecond Timing Workshop 28 April 2006

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  • 1. 10 Picosecond Timing Workshop 1 PLANACON MCP-PMT for use in Ultra-High Speed Applications
  • 2. 10 Picosecond Timing Workshop 2 Planacon™ MCP-PMTs • Two inch square flat PMT with dual MCP multiplier. • Anodes, 2x2, 8x8 and 32 x 32 configurations. • Improved Open Area Ratio device now available • Bi-alkali cathode on quartz faceplate. • Easily tiled, low profile, excellent time resolution, excellent uniformity.
  • 3. 10 Picosecond Timing Workshop 3 • 50mm Square family of MCP based PMTs – 8500X – 4 anode – 8501X – 64 anode – 8502X – 1024 anode • New improved Active Area Variants available with 86% active area, 85002/85012/85022 • 64 anode PMT available with integrated Anger- logic readout • Gated High Voltage Power Supply available PLANACON Family
  • 4. 10 Picosecond Timing Workshop 4 MCP-PMT Operation Faceplate Photocathode Dual MCP Anode Gain ~ 106 Photoelectron ∆V ~ 200V ∆V ~ 200V ∆V ~ 2000V photon
  • 5. 10 Picosecond Timing Workshop 5 MCP-PMT Construction Faceplate Anode & Pins Indium Seal Dual MCP MCP Retainer Ceramic Insulators •Spacing between faceplate and MCP and MCP and anode can be varied for different applications •Anode can be easily modified
  • 6. 10 Picosecond Timing Workshop 6 Timing Limitations – Detected Quantum Efficiency (DQE) • Photocathode QE • Collection efficiency • Secondary emission factor of first strike – Electron optics and amplification • Cathode – MCP Gap and Voltage • Pore-size, L:D, and voltage of MCP • MCP-Anode Gap and Voltage – Signal extraction
  • 7. 10 Picosecond Timing Workshop 7 Detected Quantum Efficiency DQE Component Current Next Gen Limit QE @ 420nm 20% 28% 32% Open Area of MCP 50% 70% 80% First Strike 85% 90% 95% DQE for Timing 8.5% 17.6% 24.3% Multi-photon TTS improvement 1.0 .69 .59
  • 8. 10 Picosecond Timing Workshop 8 DQE Efforts – Photocathode QE • Developing new cathode recipe for transfer system based on nuclear medicine bi-alkali which has 35% QE – Collection efficiency • 10 micron pore improves open area to ~60% • Over-etching of glass can increase this to 70% • Funneled pores can increase this to > 80% – Secondary yield • Current yield is 2.3 – 3.0 • Deposition of enhancement films such as MgO2 can improve this to 5.0 or higher
  • 9. 10 Picosecond Timing Workshop 9 Cathode-MCP Gap – Limitations • Recoil electrons (cause long TT shoulder) – Decreased DQE for leading edge timing measurements – Decrease imaging capabilities • Transit time (Variations in p.e. velocity) – Dominated by transverse momentum of the photoelectrons – Becomes worse at higher photon energies – Counter-measures • Reduce physical gap – Significant reduction in transit time, reducing effects of transverse momentum • Increase voltage – Higher acceleration reduces transit time and effects of transverse momentum
  • 10. 10 Picosecond Timing Workshop 10 Recoil Electrons MCP Faceplate pe Recoil Electron •Scattered electrons can travel a maximum of 2L from initial strike •Produces a TTS shoulder •Reduces the DQE for direct detection L
  • 11. 10 Picosecond Timing Workshop 11 85011 430 Drop Faceplate •Cathode – MCP gap is decreased from to ~0.85mm •Photocathode active area is reduced to 47mm from 50mm
  • 12. 10 Picosecond Timing Workshop 12 Effect of Reduced PC-MCP Gap 11/30/2004-12/5/2004, Playa del Carmen, Mexico5th International workshop on Ring Imaging Cherenkov Counters (RICH 2004), Development of Photon Detectors for a Fast Focusing DIRC C. Field, T. Hadig, David W.G.S. Leith, G. Mazaheri, B. Ratcliff J. Schwiening, J. Uher,+ and J. Va’vra*
  • 13. 10 Picosecond Timing Workshop 13 Cathode – MCP Transit Time • Increased voltage or decreased gap can drastically reduce the transit time, and therefore transit time spread 0.010 0.100 1.000 10.000 0 200 400 600 800 1000 1200 Cathode - MCP (V) Transittime(ns) 6.1mm 0.86mm 4.4mm 0.25mm
  • 14. 10 Picosecond Timing Workshop 14 MCP Contributions – MCP amplification is responsible for anode rise- time • Secondary electron trajectories result in variations in time between strikes. – Pore-size • Reduced pore size decreases thickness for the same amplification, reducing transit time • L:D sets the gain assuming same applied field • Want small pore size, minimum L:D and high field • Bias angle increases transit time and amplification, can reduce L:D and increase bias to keep timing properties the same but improve lifetime
  • 15. 10 Picosecond Timing Workshop 15 Amplification in Pore • Typical secondary yield is 2 • For 40:1 L:D there are typically 10 strikes (210 ~ 103 gain single plate) • Number of strikes depends on velocity of individual secondary electrons
  • 16. 10 Picosecond Timing Workshop 16 MCP Transit Time • Transit time assumes 10 strike in 40:1 L:D with 1000V applied per plate, Chevron configuration, cold secondary electrons 0.00E+00 1.00E-01 2.00E-01 3.00E-01 4.00E-01 5.00E-01 6.00E-01 0 5 10 15 20 25 30 Pore size (um) Chevrontranisttime(ns) 40:1, 1000V 60:1, 1500V
  • 17. 10 Picosecond Timing Workshop 17 Anode-MCP Gap – Limitations • Transit time (Variations in secondary electron velocities) – Dominated by location of origination in MCP – Also affected by transverse momentum • Capacitance and Inductance between the two electrodes – Can effect signal quality at the anode – Counter-measures • Reduce physical gap – Significant reduction in transit time, reducing effects of transverse momentum • Increase voltage – Higher acceleration reduces transit time and effects of transverse momentum • Provide a ground plane or pattern on the anode • Reduce resistance of MCP-Out electrode
  • 18. 10 Picosecond Timing Workshop 18 Other Considerations • Current limitations – Have received MCPs with 300uA strip current, achieve 30uA linear operation – Can increase to 60uA with electrode change • Lifetime – Capital investment in better electron scrub system – Recent modifications to the process which increases lifetime, measurements in process – Increased bias angle up to 19 degrees – Gating of Cathode during periods of no data collection • Anode configuration – Can modify electrode pattern on anodes to include ground plane or ground pattern for improved signal extraction
  • 19. 10 Picosecond Timing Workshop 19 Future Directions • Improved DQE • Improved average anode current (50 – 100 uA) • Improved lifetime • Step faceplate to optimize timing • Reduce anode-MCP gap to investigate effect on signal integrity and TTS • MCP input treatment to optimize DQE and reduce recoiling effect (increased Open Area and high yield coating) • New anode configurations with integral ground plane or ground pattern to improve

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