High Energy Physics Detectors and Instrumentation; A High Bandwidth LAPPD Anode

The development of large-area (m2) photodetectors with time resolutions of picoseconds (10-12 seconds) and submillimeter space resolutions would open new opportunities in collider detectors at the Energy Frontier, kaon and neutrino experiments at the Intensity Frontier, photon detection in detectors at the Cosmic Frontier, and applications with a large impact on societal issues such as low-dose-rate Time-Of -Flight Positron Emission Tomography (TOF-PET), and reactor/fissile material monitoring/detection for national security. The approach is by comparing sophisticated simulation to measurements of novel anode designs, validated by the similar comparison using the LAPPD baseline RF anode stripline design. Models of these anodes and the neighboring micro-channel plate structures and front-end coupling have been constructed in a proprietary 4- dimensional electromagnetic finite-difference time domain (FDTD) simulation code developed over 20 years by the small business. The simulations agree extremely well with measurements of the baseline LAPPD anodes. The overall objective is the development of: 1) anodes with bandwidths of 4-6 GHz and substantially reduced crosstalk, and 2) pad-based anodes allowing application-specific patterns. Models of the baseline LAPPD anode were created in the FDTD simulation framework, and validated by comparison to measurements. The factors governing the analog bandwidth limit and cross-talk were identified from the simulation. New designs have been proposed and simulated that show improved analog bandwidth by factors of 3 or more, with substantially reduced cross-talk. The plans for Phase II are: 1) to construct, simulate, and measure prototypes of the new designs. 2) working closely with the proponents to optimize designs for collider, PET, and high-occupancy neutrino detectors, and 3) to integrate optimized designs into the LAPPD package for commercial production. Commercial Applications and Other Benefits: The availability of large-area photodetectors with excellent time and space resolution would be transformational in scientific, medical, and security markets. If successful, the work proposed here makes application-specific optimization for lower cost much easier. A beneficial side-effect is to broaden the market for large-scale applications in the medical and security fields, lowering the unit cost for scientific applications.