Microchannel Plate (MCP) Detectors with Medipix/Timepix Readout

Source: Tremsin, A.S., & Vallerga, J.V. (2020). Unique capabilities and applications of Microchannel Plate (MCP) detectors with Medipix/Timepix readout. Radiation Measurements, 130, 106228.

Date: 11 December 2019

This review paper describes a novel, hybrid type of detector that combines Microchannel Plate (MCP) amplifiers with Medipix/Timepix readout technology to enable high spatial and temporal resolution detection of low-energy particles. These hybrid detectors offer unique capabilities compared to traditional MCP or solid-state Medipix/Timepix detectors, making them suitable for diverse applications, including:

Neutron imaging: MCP/Timepix detectors have enabled a new class of energy-resolved neutron imaging experiments at spallation neutron sources. Advantages for neutron imaging include:

  • High counting rates exceeding 500 MHz in event counting mode
  • High detection efficiency of ~50% for thermal and 70% for cold neutrons
  • High spatial resolution imaging with sub-15 μm resolution
  • High temporal resolution, enabling time-resolved imaging with sub-μs timing resolution

 

  • Photon counting: MCP/Timepix detectors offer advantages for applications that require:

    • Low noise photon counting
    • High spatial resolution
    • Time-resolved imaging capabilities with nanosecond timing resolution

 

  • Mass spectroscopy: MCP/Timepix detectors have been successfully implemented in time-of-flight mass spectrometry imaging, enabling the acquisition of time-resolved images of various m/z species in a single measurement.

  • Coincidence velocity map imaging: Experiments using MCP amplifiers coupled with Timepix-based readout have been used for coincidence velocity map imaging.

  • Ion-ion coincidence measurements: A directly coupled MCP amplifier with quad Timepix readout has been used in experimental setups for ion-ion coincidence measurements.

  • Phosphorescence lifetime imaging: Timepix-based photon counting systems have shown potential in measuring lifetime curves in a large number of pixels simultaneously.

The paper also highlights the advantages and disadvantages of these hybrid detectors.

Advantages:

  • Increased counting rate capability (up to GHz rates) due to each pixel acting as an independent counter
  • Reduced MCP gain requirement due to low noise levels in Timepix readout, leading to increased local count rate capabilities and longer MCP lifetime
  • Ability to encode multiple simultaneous events

Disadvantages:

  • Operation in vacuum and high voltage requirements, posing challenges for heat dissipation
  • Dead area in the gap between MCP and readout chip
  • Loss of information about incoming particle energy due to event amplification in MCP
  • High power consumption compared to conventional anodes

The authors conclude by discussing future improvements, including the development of:

  • MCP detectors coupled with Timepix3 readout for enhanced neutron counting capabilities
  • Larger area detectors by tiling Timepix4 chips, beneficial for neutron imaging and telescope applications
  • Timepix4-based detectors with ~0.2 ns timing resolution for fluorescence lifetime imaging and other applications requiring high temporal resolution

The authors are optimistic about the future development and application of these detectors.

Origin: https://www.sciencedirect.com/science/article/am/pii/S1350448719305141

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