The Large Area Picosecond PhotoDetector (LAPPD) Collaboration was formed in 2009 to develop large-area photodetectors capable of time resolutions measured in pico-seconds, with accompanying sub-millimeter spatial resolution. During the next three and one-half years the Collaboration developed the LAPPD design of 20 x 20 cm modules with gains greater than $10^7$ and non-uniformity less than $15\%$, time resolution less than 50 psec for single photons and spatial resolution of 700~microns in both lateral dimensions. We describe the R\&D performed to develop large-area micro-channel plate glass substrates, resistive and secondary-emitting coatings, large-area bialkali photocathodes, and RF-capable hermetic packaging. In addition, the Collaboration developed the necessary electronics for large systems capable of precise timing, built up from a custom low-power 15-GigaSample/sec waveform sampling 6-channel integrated circuit and supported by a two-level modular data acquisition system based on Field-Programmable Gate Arrays for local control, data-sparcification, and triggering. We discuss the formation, organization, and technical successes and short-comings of the Collaboration. The Collaboration ended in December 2012 with a transition from R\&D to commercialization.

We describe a pin-less design for the high voltage (HV) resistive divider of the all-glass LAPPDTM 8 in.-square thin photodetector module. The divider, which distributes high voltage applied to the photocathode to the two micro-channel plates (MCPs) that constitute the amplification stage, is comprised of the two MCPs and three glass mechanical spacers, each of which is coated with a resistive layer using atomic layer deposition (ALD). The three glass grid spacers and the two MCPs form a continuous resistive path between cathode and anode, with the voltages across the MCPs and the spacers determined by the resistance of each. High voltage is applied on an external tab on the top glass window that connects to the photocathode through the metal seal. The DC ground is supplied by microstrips on the bottom glass plate that form the high-bandwidth anode. The microstrips exit the package through the glass-frit seal of the anode base-plate and the package sidewall. The divider is thus completely internal, with no HV pins penetrating the low-profile flat glass package. Measurements of the performance of the divider are presented for the 8 in.-square MCP and spacer package in a custom test fixture and for an assembled externally pumped LAPPDTM prototype with an aluminum photocathode.

Planar microchannel plate-based photodetectors with a bialkali photocathode are able to achieve photon detection with very good time and position resolution. A 6×6cm2 photodetector production facility was designed and built at Argonne National Laboratory. Small form-factor MCP-based photodetectors completely constructed out of glass were designed and prototypes were successfully fabricated. Knudsen effusion cells were incorporated in the photocathode growth chamber to achieve uniform and high quantum efficiency photocathodes. The thin film uniformity was simulated and measured for an antimony film deposition, showing uniformity of better than 10%. Several prototype devices with bialkali photocathodes have been fabricated with the described system and their characteristics were evaluated in the large signal (multi-PE) limit. A typical prototype device exhibits time-of-flight resolution of ~27psec and differential time resolution of ~9psec, corresponding to spatial resolution of ~0.65mm.

A novel microelectrocrystallization (MEC) procedure (ten-fold decrease in halogenated solvent use, micromolar quantities of electron donor molecule and supporting electrolyte, and Hg free electrodes), necessitated by the very small available quantities of the novel organometallic Au(CF3)4– anion, has been developed to prepare two distinct phases of κ-(ET)2Au(CF3)4·(TCE)[ET = bis(ethylenedisulfanyl)tetrathiafulvalene, TCE = 1,1,2-trichloroethane] which exhibit ambient pressure superconductivity with onset temperatures of 2.1 and 10.5 K.

A novel microelectrocrystallization (MEC) procedure (ten-fold decrease in halogenated solvent-use, micromolar quantities of electron donor molecule and supporting electrolyte, and Hg free electrodes), necessitated by the very small available quantities of the novel organometallic AU(CF3)(4)- anion, has been developed to prepare two distinct phases of kappa-(ET)(2)Au(CF3)(4) .(TCE) [ET = bis(ethylenedisulfanyl)tetrathiafulvalene, TCE = 1,1,2-trichloroethane] which exhibit ambient pressure superconductivity with onset temperature of 2.1 and 10.5 K.