About

Henry J. Frisch is a professor affiliated with the Enrico Fermi Institute at the University of Chicago, specializing in experimental particle physics with a focus on precision measurements and instrumentation development. His research prominently features the development of large-area picosecond-resolution time-of-flight detectors, including the Large-Area Picosecond Photodetector (LAPPD) project, which aims to advance fast timing and high-resolution photodetection technologies. Frisch has contributed extensively to the design and commercialization of micro-channel plate (MCP)-based photodetectors, emphasizing applications in high-energy physics experiments and neutrino detection. His work includes pioneering efforts in pico-second timing instrumentation, optical time projection chambers, and waveform sampling electronics, which have significant implications for particle tracking and timing resolution in collider and neutrino experiments. Throughout his career, Frisch has delivered numerous talks and presentations on these topics at international conferences and workshops, reflecting his leadership in the field of fast timing detector development and precision experimental techniques.

Research topics

• Optics
• Computer Science
• Physics
• Optoelectronics
• Atomic physics
• Engineering
• Electrical engineering
• Materials science
• Computational physics
• Nuclear physics
• Telecommunications

Selected publications

• Physical Testing of The PSEC5 ASIC

  2025-07-28

  reportOpen access

  The PSEC5 ASIC is a high-speed waveform sampling chip designed for ultra-fast timing detectors, offering up to 40 GSPS sampling with 10-bit resolution. This makes it well-suited for applications requiring fine time resolution, such as MCPs and LGADs. This work focuses on the physical testing and validation of the chip s internal clocking and SPI-controlled registers. Testing began with inspection of schematics and the prototype to identify and resolve design issues. Then, custom firmware was developed for an Arduino controller to interface with the chip via SPI, enabling read and write access to key control registers. Results confirm that the VCO operates between ~3.2 4.0 GHz and remains stable under non-VCOVDD fluctuations. The Division Ratio register enables frequency division by known factors (256, 128, 64, etc.), indicating a pre-division frequency of 3.2 GHz when the digital band is unmodified. While most registers responded correctly, some issues were observed, including unexpected current draw and unstable discriminator behavior. Overall, the chip shows promising functionality, but further work is needed to understand the state of the read only registers and address the existing issues. Continued testing and firmware development will be critical to ensuring reliable integration into detector systems.

  PublisherOA PDFDOI

• Design of an 8-channel 40 GS/s 20 mW/Ch waveform sampling ASIC in 65 nm CMOS

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2025-01-01 · 1 citations

  articleOpen access
  PublisherOA PDFDOI

• Simulation of a Compton-based detector for low-dose high-resolution time-of-flight positron emission tomography.

  PubMed · 2024-01-03

  preprintOpen access

  Two major challenges in time-of-flight positron emission tomography (TOF-PET) are low spatial resolution and high radioactive dose to the patient, both of which result from limitations in detection technology rather than fundamental physics. A new type of TOF-PET detector employing low-atomic number (low-Z) scintillation media and large-area, high-resolution photodetectors to record Compton scattering locations in the detector has been proposed as a promising alternative, but the minimum technical requirements for such a system have not yet been established. Here we present a simulation study evaluating the potential of a proposed low-Z detection medium, linear alkylbenzene (LAB) doped with a switchable molecular recorder, for next-generation TOF-PET detection. We developed a custom Monte Carlo simulation of full-body TOF-PET using the TOPAS Geant4 software package. By quantifying contributions and tradeoffs for energy, spatial, and timing resolution of the detector, we show that at reasonable combination of specifications, our likelihood-based identification of pairs of first interaction locations in the simulated detector identifies 87.1% of pairs with zero or negligible error, and correctly rejects 90% of all in-patient scatters. The same specifications give TOF-PET sensitivity of ~66.7% and PSF width 4.6 mm with clear contrast. A detector with these specifications provides a clear image of a brain phantom simulated at less than 1% of a standard radiotracer dose.

  PublisherOA PDF

• Low-dose TOF-PET based on surface electron production in dielectric laminar MCPs

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2023-09-27 · 1 citations

  articleOpen accessCorresponding

  We present simulations of whole-body low-dose time-of-flight positron emission tomography (TOF-PET) based on the direct surface production (Domurat-Sousa et al., 0000) by 511 keV gamma rays of energetic electrons via the Photo-electric and Compton Effects, eliminating the scintillator and photodetector sub-systems in PET scanners. In Ref. Domurat-Sousa et al. (0000) we described Microchannel Plates (MCP) constructed from thin dielectric laminae containing heavy nuclei such as lead or tungsten (LMCPTM ). The laminae surfaces are micro-patterned to form channels, which can then be functionalized to support secondary electron emission in the manner of conventional MCPs. After assembly of the laminae, the channels form the pores of the conversion LMCP. This conversion stage is then followed by a high-gain MCP-based amplification stage, which also can be constructed using the laminar technique, but with pores typical of currently-available large-area MCPs . We have simulated direct conversion using modifications to the TOPAS Geant4-based tool kit. A 20 × 20 × 2.54 cm3 LMCP, composed of 150-micron thick lead-glass laminae, is predicted to have a ≥30% conversion efficiency to a primary electron that penetrates an interior wall of a pore. The subsequent secondary electron shower is largely confined to one pore and can provide high space and time resolutions. In whole-body PET scanners the technique eliminates the scintillator and photodetector subsystems. The consequent absence of a photocathode allows assembly of large arrays at atmospheric pressure and less stringent vacuum requirements, including use of pumped and cycled systems. TOPAS simulations of the Derenzo and XCAT-brain phantoms are presented with dose reductions of factors of 100 and 1000 from a literature benchmark. New applications of PET at a significantly lower radiation dose include routine screening for early detection of pathologies, the use in diagnostics in previously unserved patient populations such as children, and a larger installed facility base in rural and under-served populations, where simpler gamma detectors and lower radiation doses may enable small low-cost portable PET scanners.

  PublisherDOI

• Methods of fabricating vacuum housings with hermetic solder seals using capillary solder wicks

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23

  articleOpen access1st authorCorresponding

  Hermetically sealed electronic devices and methods for fabricating the hermetically sealed electronic devices are provided. The devices include a solder sealed vacuum housing. The solder seal is formed using a solder wick having an external solder reservoir. When the reservoir is filled with molten solder, the solder is drawn via capillary action into a precisely defined narrow gap between two components of the housing where it forms an airtight and vacuum-tight seal.

  PublisherOA PDF

• Positron-emission tomography detector systems based on low-density liquid scintillators and precise time-resolving photodetectors

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23 · 2 citations

  articleOpen access1st authorCorresponding

  TOF-PET detector systems, and methods for imaging photon-emitting samples using the detector systems, are provided. The TOF-PET detector systems use large-area photodetectors with extremely high time-resolution and an approach to data collection and analysis that allows for the use of inexpensive low-density scintillator materials. The TOF-PET detector systems are characterized by their ability to identify, on a statistical basis, the transverse and depth location of the first of the series of energy deposition events that are generated when a gamma photon enters the low-density scintillator material.

  PublisherOA PDF

• Surface direct conversion of 511 keV gamma rays in large-area laminated multichannel-plate electron multipliers

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2023-07-16 · 1 citations

  articleCorresponding
  PublisherDOI

• Use of flat panel microchannel photomultipliers in sampling calorimeters with timing

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23 · 1 citations

  articleOpen access1st authorCorresponding

  Large-area, flat-panel photo-detectors with sub-nanosecond time resolution based on microchannel plates are provided. The large-area, flat-panel photo-detectors enable the economic construction of sampling calorimeters with, for example, enhanced capability to measure local energy deposition, depth-of-interaction, time-of-flight, and/or directionality of showers. In certain embodiments, sub-nanosecond timing resolution supplies correlated position and time measurements over large areas. The use of thin flat-panel viewing radiators on both sides of a radiation-creating medium allows simultaneous measurement of Cherenkov and scintillation radiation in each layer of the calorimeter. The detectors may be used in a variety of applications including, for example, medical imaging, security, and particle and nuclear physics.

  PublisherOA PDF

• Surface Direct Conversion of 511 keV Gamma Rays in Large-Area Laminated Multichannel-Plate Electron Multipliers

  arXiv (Cornell University) · 2023-06-20

  preprintOpen access

  We have used the TOPAS simulation framework to model the direct conversion of 511 keV gamma rays to electrons in a micro-channel plate (MCP) constructed from thin laminae of a heavy-metal-loaded dielectric such as lead-glass, patterned with micro-channels (LMCP). The laminae serve as the converter of the gamma ray to a primary electron within a depth from a channel-forming surface such that the electron penetrates the channel surface (`surface direct conversion'). The channels are coated with a secondary-emitting material to produce electron multiplication in the channels. The laminae are stacked on edge with the channels running from the top of the resulting `slab' to the bottom; after assembly the slab is metalized top and bottom to form the finished LMCP. The shape of the perimeter of a lamina determines the dimensions of the slab at the lamina location in the slab, allowing non-uniform cross-sections in slab thickness, width, and length. The slab also can be non-planar, allowing curved surfaces in both lateral dimensions. The laminar construction allows incorporating structural elements in the LMCP for modular assembly in large-area arrays. The channels can be patterned on the laminae surfaces with internal shapes and structure, texture, and coatings optimized for specific applications and performance. The channels can be non-uniform across the LMCP and need not be parallel in either transverse direction. Surface direct conversion of the gamma ray to an electron eliminates the common two-step conversion of the gamma ray into an optical photon in a scintillator followed by the conversion of the photon into an electron in a photodetector. The simulations predict an efficiency for conversion of 511 keV gamma rays of $\gtrapprox$ 30\% for a 2.54 cm-thick lead-glass LMCP. The elimination of the photocathode allows assembly at atmospheric pressure.

  PublisherOA PDFDOI

• Batch production of microchannel plate photo-multipliers

  OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2023-01-23 · 1 citations

  articleOpen access1st authorCorresponding

  In-situ methods for the batch fabrication of flat-panel micro-channel plate (MCP) photomultiplier tube (PMT) detectors (MCP-PMTs), without transporting either the window or the detector assembly inside a vacuum vessel are provided. The method allows for the synthesis of a reflection-mode photocathode on the entrance to the pores of a first MCP or the synthesis of a transmission-mode photocathode on the vacuum side of a photodetector entrance window.

  PublisherOA PDF

Frequent coauthors

• A. Elagin

  65 shared

• Bernhard W. Adams

  56 shared

• E. Angelico

  Stanford University

  52 shared

• E. Oberla

  40 shared

• Eric Spieglan

  39 shared

• M. J. Shochet

  35 shared

• M. Wetstein

  Iowa State University

  34 shared

• Anil U. Mane

  Argonne National Laboratory

  33 shared

Education

• BA, College

  Harvard University

  1966