BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-2157 DTSTART:20110505T210000Z DURATION:PT1H0M0S DTSTAMP:20260420T120206Z LAST-MODIFIED:20110502T174530Z LOCATION:4274 Chamberlin Hall SUMMARY:The Development of Large Area Microchannel Plate Photodetector s\, NPAC (Nuclear/Particle/Astro/Cosmo) Forum\, Bob Wagner\, Argonne DESCRIPTION:The Large Area Picosecond Photodetector Development Collab oration is comprised of groups from three national laboratories\, five U.S. universities\, and two small U.S. companies working on a three-y ear project to develop a new generation of economical\, large area (40 0 cm2) microchannel plate photomultipliers that can be tailored for a wide variety of applications in particle physics\, medical imaging\, a nd high energy astrophysics. In parallel with the development of the d etector\, a readout technology based on a switched capacitor array wav eform sampling chip with time resolution in the 10 picosecond range is being developed that would allow particle identification by time-of-f light in the multi-GeV energy range. The basic photomultiplier incorpo rates a bialkali photocathode and a glass capillary microchannel plate pair functionalized by atomic layer deposition (ALD) to produce photo electrons from incident visible light photons and produce gains of gre ater 106. Borosilicate glass capillary plates with pore size of 20-40 microns provide an inexpensive substrate compared to the standard lead -glass used in commercial microchannel plates. ALD allows the resisti ve and secondary emissive functions of the plates to be fabricated sep arately and economically. The collaboration is characterizing a variet y of candidate materials for the coatings in order to optimize the gai n and stability of the microchannel plates. Plates with gain of 50\,0 00-70\,000 at 1000V. bias have been produced on 33mm diameter substrat es. The first 20cm by 20cm square glass capillaries were recently deli vered to the project. Two alternatives for assembly and hermetic seal ing of the photodetector are being pursued in parallel: a traditional ceramic housing with a strip line anode structure with embedded pins f or signal output and high voltage connection\, and an all borosilicate glass housing with a silk-screened silver strip line anode readout. T he latter represents a potentially very inexpensive method of tube fab rication. An external printed circuit board with a matching strip line layout provides a means of transmitting the signal to the waveform sa mpling chips while maintaining a 50 ohm impedance from strip line to f ront-end input. The talk will review the history and current status of the project\, summarize potential applications of the photodetector\, and outline plans for the future development and production of the ph otomultiplier.
\n URL:https://www.physics.wisc.edu/events/?id=2157 END:VEVENT END:VCALENDAR