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Del Mar Ventures manufactures a wide range of MCP Imaging Detectors using single, double and triple channel plates. These detectors can be used for imaging gamma, X-rays, EUV, VUV, UV and visible radiation, ion, electron and neutron fields using appropriate type of Radiation Converters. Schematic view of the Imaging Detector is shown on Fig.1.

Fig.1. Schematic view of the MCP Imaging Detector.

Basic principle of all MCP-based Imaging Detectors is a conversion of initial radiation into "electron image", which is amplified by microchannel plate (s), then converted to visible image registered by CCD camera (or , in some cases by eye or film).
Input radiation (the electromagnetic spectrum from visible to high energy gamma rays and different kind of particles) first converted by Radiation Converter into appropriate radiation or particles, which efficiently generate initial electrons when interacting with input surface of the first microchannel plate. The microchannel plates stack multiplies initial electrons creating electron avalanche. Electron avalanche from microchannel assembly generates luminescence from the phosphor screen. Image from the phosphor screen is coupled to CCD camera using different Optical Couplers.
Resulting resolution and detection efficiency depends on many factors and is optimized for each detector manufactured by Del Mar Ventures according to customer requirements.

Radiation Converters

Different type of Radiation Converters are used for different radiation registered. We have summarized some typical Radiation Converters used in the Table 1.

Energy Dependence of the VUV-EUV-XUV-X-ray Detection Sensitivity

10eV-1keV. Photons in this energy range are strongly attenuated by air, but can be imaged in vacuum by luminescence screens, or by open microchannel plates. The detection quantum efficiency (DQE) of a microchannel plate for photons is a function of the photon energy and the angle of incidence. Typical efficiency is 10% falling away at both low energy and high energy. Efficiency can be increased to around 20% and higher by coating such as MgF₂ and CsI, thickness of the coating should be optimized for the desired photon energy.
1-50 keV. Luminescent screen made of inorganic powder scintillators provide 20-30 visible photons per absorbed keV and can be efficiently coupled with a fiber optic block or other optical system to a microchannel plates image intensifier. With a quantum efficiency of typically 10% at the image intensifier photocathode, it can be seen that every X-ray photon will generate several photoelectrons, ensuring an almost completely efficient detection probability.
At high photon energies the thickness of the scintillator required for good absorption efficiency, increases. The spatial resolution is approximately equal to twice the thickness of the powder applied, so that, for example at 18 keV the limiting resolution will be 100 microns for a scintillator capable of absorbing 90% of available photons. For photons above this energy, it is necessary to choose between a scintillator optimized either for resolution or for counting efficiency.

Image Amplification

Depending on the customer requirements Image Intensifiers with different input window materials and photocathodes or open Microchannel Plate assembles are used.

Several examples of MCP-based imaging Detectors are described below.

Ion and Electron Beam Imaging

Ion or electron beam profile can be imaged using open MCP assembly. If the energy of incoming particles is within 0.3 - 3.0 keV range, than the input surface of the detector (input surface of first MCP) is to be connected to ground potential, the output surface will be at ~ +2 -2.5kV and the phosphor screen at about +5 kV above ground potential. Assembly of two MCP's in chevron configuration will provide a total gain 10⁶ - 10⁷ depending on output surface potential. Open MCP assemblies can operate at vacuum not less then 2*10^-5 Torr.
The same type of open MCP assemblies with a phosphor screen as an anode are used in Field Ion Microscopy. Curved Microchannel Plates may be used to obtain an ultimate resolution of the FIM systems.

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