Efficiency optimization of microchannel plate (MCP) neutron imaging detectors. I. Square channels with 10B doping

Efficiency optimization of microchannel plate (MCP) neutron imaging detectors. I. Square channels with 10B doping


Tremsin, A. S., Feller, W. B., & Downing, R. G. (2005). Efficiency optimization of microchannel plate (MCP) neutron imaging detectors: I. Square channels with 10B doping. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 539(1–2), 278–311. 


  • Neutron detection
  • Detection efficiency
  • Neutron imaging


Microchannel plates (MCPs) with high concentrations of 10B atoms incorporated in the glass can achieve neutron detection efficiencies up to 78% because the microscopic structure allows thin channel walls that maximize the escape of neutron capture reaction products into the channels to produce detectable electron avalanches. 


This article explores how to maximize the efficiency of neutron detection using microchannel plates (MCPs) doped with ¹⁰B. The study focuses on MCPs with square channels due to their superior efficiency compared to circular or hexagonal designs.

  • The key to enhancing neutron detection lies in optimizing two probabilities: the probability of neutron absorption (P1) and the probability of the reaction products escaping into an open channel (P2).
  • The overall neutron detection efficiency is the product of P1, P2, and the probability of generating an electron avalanche (P3, assumed to be close to unity).

Maximizing Neutron Absorption (P1)

  • Achieving a P1 close to 1 involves using a sufficiently thick MCP with a high density of ¹⁰B atoms.
  • Practical limitations on single MCP thickness make stacking multiple MCPs in a chevron or Z-stack arrangement an attractive solution.
  • This stacked configuration allows for increased neutron absorption without compromising the electron multiplication process.
  • A stack of just three 1 mm thick MCPs with 8 µm pores can increase P1 from 0.52 to 0.9.

Optimizing Reaction Product Escape (P2)

  • P2 is maximized by minimizing the MCP wall thickness (W) while choosing an appropriate channel width (d).
  • The study simulates P2 for an MCP with 8 µm pores and 2 µm walls, demonstrating a dependence on the neutron capture point within the wall.
  • Results indicate that for this specific MCP geometry, P2 can be as high as ~78%.

Model Predictions and Conclusion

The model predicts that by combining a stacked MCP configuration for high P1 and optimized channel dimensions for high P2, it is possible to achieve very efficient neutron counting. These MCP-based detectors would have high spatial resolution (~10 µm) and sub-nanosecond timing capabilities, making them suitable for a variety of neutron detection applications.

Origin: https://escholarship.org/content/qt7v17n03g/qt7v17n03g.pdf?t=lnqz51

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