Monolithic integration of high-efficiency UV photocathodes on large-area microchannel plates for high spatial and temporal resolution particle detection

Reliable, high-sensitivity and high-resolution photon detectors, which can alleviate major limitations imposed by photomultiplier tubes (PMTs), for future high energy physics (HEP) and nuclear physics (NP) experiments, are of great interest to DOE- Other fields that could greatly benefit from these detectors include Cherenkov telescopes in astrophysics, positron emission tomography (PET) in medical imaging, space and planetary explorations, solar-blind UV missile tracking, and other scientific, industrial and military applications- For many of these applications, a photocathodes (PC) in conjunctions with a micro- channel plate (MCP) have been considered as a lower cost, less bulky and more robust alternative to PMTs- However, for detection of low level or fast transient signals, thestandardgeometry phototube with a separate semi-transparent PC positioned above a MCP stack does not have the required efficiency and/or spatial and temporal resolutions- This proposal is directed toward the application of an innovative metallic buffer for deposition of high- quality III-nitride based photocathode structures directly on operational MCPs- If successfully developed, the close proximity of the PC and MCP in addition to the operation in opaque (reflection) mode, will result in significant improvements in both detection efficiency and spatial and temporal resolution- The proposed metallic buffer for high quality deposition of III-N PCs on MCPs will also act as a mirror to reflect the unabsorbed light back into the PC layer to increase efficiency, as well as providing an effective backside metal contact to avoid charging effects, especially in large diameter detectors-