Image plate detector.

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Image plate detector.


Both the X31 and X11 beam lines are equipped with image plate detectors. The X31 beam line uses the prototype (RED) model of the MAR-Research scanner which was built in-house at EMBL. X11 on the other hand is equipped with the newer commercial MAR scanner. Both detectors operate in a similar fashion and are based on the same design principles.

The major components of the scanners are the image plates themselves which are fixed to a circular platter mounted normal to the incident X-ray beam, a He-Ne laser/photomultiplier scanning head configuration which may be translated radially along the active surface of the image plate, and an amplifier/ADC unit which converts the analogue photomultiplier signal into a digital one ready for storage on hard disk and immediate use by image display software.

The image plate scanner is used as an integrating detector much in the same way as photographic film was used. When the plate is exposed to X-rays the image is temporarily stored in the phosphor coating. After exposure the image is read out by the laser head which scans across the plate radially as the plate rotates. The plate may be immediately erased and re-used.

Gwyndaf Evans
Fri Oct 7 15:42:16 MET 1994