Measurements with a 35-psec gate time microchannel plate camera

Measurements with a 35-psec gate time microchannel plate camera

Citation

The document provided is a preprint of an article intended for publication in a journal or proceeding. It was written in July 1990 by P.E. Bell, J.D. Kilkenny, R. Hanks, and O. Landen of the Lawrence Livermore National Laboratory, University of California. The authors state that the preprint is being made available with the understanding that it will not be cited or reproduced without permission.

Keywords

  • microchannel plate
  • x-ray detector
  • gate time
  • electron transit time
  • aspect ratio
  • L/D
  • voltage pulse
  • gain
  • modeling
  • measurements

Brief

The document describes the process and results of an experiment measuring the gate times possible for microchannel plate x-ray detectors. 

Summary

This article, which was written in July 1990 by P.E. Bell, J.D. Kilkenny, R Hanks, and O. Landen, describes how reducing the thickness and aspect ratio of microchannel plates (MCPs) can produce significantly faster x-ray gate times for use in detectors. The authors present a combination of modeling and experimental measurements to support their findings, achieving gate times as low as 34 picoseconds.

The need for faster x-ray detectors arises from the study of laser-produced plasmas, which evolve rapidly and possess fine spatial structures. Traditional MCP detectors, with a thickness of 0.5 mm, typically have gate times of around 100 picoseconds.

Key findings of the article include:

  • Measurements using a 0.2 mm thick MCP with an aspect ratio of 20 demonstrated x-ray gate times of 35 picoseconds.
  • The authors developed a time-dependent model that showed good agreement with the experimental results, validating their approach to understanding and predicting MCP gate times.
  • They found that the minimum gate time is primarily determined by the transit time of electrons through the MCP.
  • Reducing the MCP thickness and aspect ratio, and increasing the applied voltage, can further shorten the transit time and therefore the gate time.

The article also highlights the importance of minimizing electrical pulse dispersion and losses in the microstrip used to deliver the gating voltage to the MCP. The authors achieved a rise time of 48 picoseconds for the electrical pulse using a specialized microstrip design.

Origin: https://digital.library.unt.edu/ark:/67531/metadc1213030/m2/1/high_res_d/6311220.pdf

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