Researchers from the University of Ljubljana’s Department of Physics, including S. Korpar, R. Dolenec, F. Grijalva, A. Lozar, A. Kodrič, P. Križan, S. Parashari, R. Pestotnik, A. Seljak, and D. Žontar, have conducted a comprehensive study on the Large Area Picosecond Photodetector (LAPPD), a type of photomultiplier tube designed for high-precision timing and imaging applications. Their work was published in the journal “Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.”
The LAPPD Gen-II is a large-area microchannel-plate photomultiplier tube (MCP-PMT) that uses a capacitively coupled sensing electrode for readout. The researchers investigated two variants of this detector, each with different geometries and materials, using a picosecond pulsed laser system. They measured the detector’s single-photon timing response and spatial charge distribution on segmented readout electrodes.
The study found that the prompt timing peak of the LAPPD exhibits a resolution of approximately 30 picoseconds. The overall timing structure is influenced by the propagation of photoelectrons and back-scattering effects from the MCP input surface. To better understand these phenomena, the researchers developed analytical models that describe the propagation of photoelectrons and the induced charge spread on the sensing electrodes, including secondary electron backscattering from the resistive anode.
These models accurately reproduce the measured device properties and can be used to predict performance for various detector geometries and dielectric properties. The results provide a valuable framework for optimizing MCP-PMTs for applications that require precise timing and imaging capabilities.
In the energy sector, high-precision timing and imaging detectors like the LAPPD could have potential applications in nuclear power plants and other facilities where monitoring and detecting radiation is crucial. For instance, they could be used in radiation monitoring systems to ensure safety and efficiency. Additionally, the advanced imaging capabilities could be beneficial in research and development areas, such as studying plasma behavior in fusion reactors or monitoring the structural integrity of materials in extreme environments. The models developed in this study can help tailor these detectors to specific needs, making them more versatile and effective in various energy-related applications.
This article is based on research available at arXiv.