How an MCP Works
For over thirty years, Photonis (formerly Philips Photonics, Galileo and Burle) has consistently set the standard in electron multipliers and related products. Today, an extensive R&D program coupled with unsurpassed expertise in microchannel plate (MCP) technology continues to deliver a succession of product and process improvements that push aside previous technology limits. This expertise is used to mass-produce MCPs for Photonis’s image intensifier tubes as well as for a variety of custom scientific applications. This, plus the ability to meet your product requirements, makes Photonis the preferred choice of professionals the world over.
A microchannel plate (MCP) is an electron multiplier for detecting X-rays, ultraviolet radiation and charged particles. The output is a two-dimensional electron image which preserves the spatial resolution of the original input radiation, but with a linear gain up to 1000. This output can excite a phosphor screen placed close to the output, giving a visual representation of the radiation pattern. Alternatively, the electron image can be read out by, for example, a wedge-and-strip or fast delay-line anode array.
Important features of MCPs are:
- high electronic gain
- immunity from magnetic fields
- fast response
- low noise
- low power consumption
- high spatial resolution
- small size and ruggedness
Each plate consists of an array of tiny glass tubes fused together to form a thin disc. Both faces of the disc are metal coated to provide parallel electrical connections to all channels. In a vacuum, and with a potential difference (usually 800 to 1400 V) across the plate, each channel becomes a continuous dynode electron multiplier, operating on the same principle (electron avalanche) as its cousin, the single-channel electron multiplier.
Photonis developed the first-ever square-pore, radially-packed X-ray focusing MCP optics and is currently refining the technology with continued support by ESA. For special projects, options are available, such as square-pore squarepacked X-ray optics with pore sizes of 10 to 100 µm. These plates with a thickness of several millimeters, formed with a spherical radius or with metal-coated pore walls for optimum reflectivity, can be developed and supplied.
The curved-channel MCP was invented by the Philips LEP laboratory in 1973 and produced in Photonis’s factory in Brive in 25 µm pore, 25 mm diameter for some time. It was seen as a new way to prevent ion feedback at high gain with preserved spatial resolution. The major application was the invention of the Multi-Anode Multi-Array (MAMA) tube by Timothy et al. at the time. Today, improved MCP readout arrangements in the form of “wedge & strip” anodes, fast delay-lines or Vernier anodes offer equal or better spatial resolution with the MCP stacks mentioned above. As the curved-channel MCPs were very difficult and costly to make in large formats, they are only used for a few MAMA tubes, offered by competitors who copied the process after Photonis’s patents expired.
To request more information or a quotation for MCP or other Photonis products, contact IL Photonics.