Photonis Microchannelplate Selection Guide
To select your microchannelplate based detector solution you need to consider the following questions amongst others:
What am I aiming to detect?
Microchannelplate detectors can be used for dectection of electrons, neutrals, ions and photons (xray and UV). Where detection of photons is required special surface coatings may be employed improve the conversion efficiency to electrons at the front of the detector.
Will I be imaging or not?
If imaging is required then "Imaging" quality or even "Premium" quality plates will be required. The specifications for these plates include tolerances on variation in gain across the plate and patterning. The image resolution required may also affect the channel spacing required.
What gain/dynamic range do I require?
Particle counting applications require high gain and may also require well defined pulse height distributions. In these cases a 'Chevron' pair of plates is most commonly used (sometimes even 3 plates in a 'Z' stack). Where very high count rates are anticipated the extended dynamic range plates (EDR) may be needed; their higher bias currents allow individual channels to recover faster.
For analogue amplification of a few thousand a single plate may suffice. The dynamic range is then limited by the largest current that may be drawn from the rear of the plate. As a rough guide, to stay in the linear region of operation, the current drawn from the output should be less than one tenth of the bias current. For a typical standard 25mm plate the bias current is 4 - 16ľAmp whereas for an extended dynamic range plate it would be 30 - 128ľAmp.
What active area do I need?
This determines the size of plate required. All sized are quoted by reference to the nominal active area. Not surprisingly, larger plates are more expensive. 25mm active area plates are probably the most commonly used and offer the greatest choice of options.
There are a very large number of posibilities and we would be happy to discuss any special requirements and supply a quote. However, where possible, it is usually best to pick from one of the standard plate specifications or assemblies. We have tried to give an indication of the wide range of standard configurations in the table below below:
| Working area | Pore Size in microns | 40:1/46:1 Length to pore diameter ratio | 60:1 Length to pore diameter ratio | Standard | EDR |
|---|---|---|---|---|---|
| 8mm diameter | 25 | yes | - | yes | - |
| 11.5mm diameter | 10 | yes | - | yes | - |
| 18mm diameter | 5 | - | yes | yes | - |
| 10 | yes | yes | yes | yes | |
| 25mm diameter | 5 | yes | yes | yes | yes |
| 10 | yes | yes | yes | yes | |
| 25 | yes | yes | yes | yes | |
| 40mm diameter | 10 | yes | yes | yes | yes |
| 25 | yes | yes | yes | yes | |
| 50mm x 8mm | 25 | yes | - | yes | - |
| 75mm diameter | 10 | yes | - | yes | yes |
| 25 | yes | yes | yes | - | |
| 80mm x 100mm | 25 | yes | - | yes | yes |
| 84mm diameter | 25 | yes | - | yes | - |
| 90mm x 110mm | 25 | yes | - | - | yes |
| 100mm x 15mm | 25 | yes | yes | yes | - |
| 120mm diameter | 25 | - | yes | yes | - |
| 150mm diameter | 25 | yes | yes | yes | - |
Micro Channel plate Options
Plates are available as :
- Single plate
- Two plates matched to within 10%
- Two plates matched to within 10% and tested as a chevron
- Three plates matched to within 10% and tested as a stack
- Cesium Iodide
- Copper Iodide
- Magnesium Fluoride
- Potassium Bromide
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Last updated:24 October 2009 16:21
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