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High resolution imaging with MCP detectors using delay line anodes

High resolution imaging with MCP detectors using delay line anodes. Ottmar Jagutzki, Uwe Spillmann, Achim Czasch. Horst Schmidt-Böcking, Reinhard Dörner, …. In collaboration with Volker Dangendorf from PTB Braunschweig, Neutron Radiography group . The helical wire delay-line anode.

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High resolution imaging with MCP detectors using delay line anodes

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  1. High resolution imaging with MCP detectors using delay line anodes Ottmar Jagutzki, Uwe Spillmann, Achim Czasch Horst Schmidt-Böcking, Reinhard Dörner, … In collaboration with Volker Dangendorf from PTB Braunschweig, Neutron Radiography group

  2. The helical wire delay-line anode DLD40 Sobottka and Williams 1988 Fast timing electronicshigh rate, multi-hit 5(7) electronic channels only easy read-out Center-of-mass averaging high position resolutiontime resolution: < 1 ns Our typical resolution: 40-50 μm rms 80 mm “Hexanode” delay-line detector (patented)

  3. Electronic readout:

  4. Time-to-Digital-Converter: - (old)Wilkinson-type analog-digital conversion (like a TAC): high resolution but a slow digital conversion - “counter”-type fast (no!) conversion:resolution limited by clock rate Pretty high resolution and fast read-out TDC8HP:PC-controlled multi-hit TDC with 8 channels, 25 psec LSB, stableread-out speed: 400 kHz now, up to 2 MHz planned (< 10 ns dead-time between hits) “TDCHP” chip developed by CERN

  5. How to detect visible/near-UV photons with that ?

  6. Photek 75 mm image intensifier with RoentDek DL80 anode NASA test mask 0.15 mm FWHM 0.075 mm pixel (rms) Now: < 40 micron rms 5 mm grid constant, 1 mm obstacle

  7. Counting/Imaging near-UV and visiblephotons with delay-line read-out DL40-PMT Quartz windowPhoto cathode MCP stackDL40 anode(or bigger) works fine, but- difficult to build- not very robust (?) - size up to 150 mm possible?

  8. Counting/Imaging near-UV and visible photons with delay-line read-out via image charge pick-up: theRS-PMT Quartz windowPhoto cathode MCP stack Resistive screenpickup electrode(e.g. delay-line) • easy, robust design of detector head- size up to 40 mm, may be bigger- standard (multi-layer) PCB pickup electrodes Image charge read-out: Battistoni et al. 1982 Patented technique

  9. Counting/Imaging near-UV and visible photons with reconfigurable read-out Quartz windowPhoto cathode MCP stack Resistive screenotherpickup electrodes:Wedge&Strip, Pixel,… Read-out technique can easily be reconfigured using the same detector head. Patented technique

  10. Counting/Imaging VUV photons or particles with reconfigurable read-out “open RS-PMT” MCP stack Resistive screenpickup electrodes:Delay-line, Wedge&Strip, Pixel,… Image charge read-out has some advantages over charge collection for some anodes: Beneficial even for open-face detectors Patented technique

  11. Delay-line read-out of RS-PMT: Multilayer PCB Front and rear side “antennas” (Eland 1994) connected to delay-line: (Berkeley group) LC-delay-line

  12. LC-DL50 on open RS-PMT40, irradiated with α – particles, mesh obstacle 80 micron

  13. LC-DL50 on open RS-PMT40, irradiated by ions with 500 kHz, mesh obstacle 80 micron

  14. LC-DL50 on open RS-PMT40, irradiated by ions with 500 kHz, mesh obstacle 80 micron 8 x 8 mm linear scalelog scale

  15. y = (w - v)/√3 v w u x = u • Hexanode for RS-PMT: • multi-hit (simultaneous photon pair detection is possible): Compton telescope?- intrinsic linearity correction (no test mask necessary):3 combination for determining x- and y-coordinates from u, v, w coordinate system • Example for x-layer: x = u = - (v + w) (over-determination) (vector addition) But how can this help correcting non-linearity ? 50 mm LC Hex-DL on a 4-layer PCB

  16. 2,0 mm Linearity correction of LC-delay-line: (no mask needed) of RS-PMT:

  17. Summary: • Large (open-face) MCP delay-line detector with up to 3000x3000 pixel • Resistive screen PMT or open MCP detector for counting photons (might qualify for space) • redundant triple-layer delay-line anode read-out with intrinsic linearity correction • read-out anodes can easily by swapped • work to be done: • position resolution needs to be improved for the 40 mm and 25 mm formats • no experience with flight mission • not much experience with photon counting at all !

  18. Applications: - FLIM (fluorescence life-time microscopy) - NEURRAD (element sensitive neutron radiography) in cooperation with Volker Dangendorf, PTB Braunschweig Object Thanks to Jürgen Barnstedt from Tübingen for borrowing us his RS-PMT!

  19. Results of Barnstedt et al. (1998)25mm RS-PMT (Proxitronic) - bi-alkali photo-cathode - 4-jaw Wedge&Strip anode Projection of grid mask 70/600micron, resolution 35 micron (1:700)

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