AUTOMATIC COUNTER
An automatic counter of alpha particle tracks recorded by a sensitive emulsion of a photographic plate is described. The counter includes a source of mcdulated dark-field illumination for developing light flashes from the recorded particle tracks as the photographic plate is automatically scanned in narrow strips. Photoelectric means convert the light flashes to proportional current pulses for application to an electronic counting circuit. Photoelectric means are further provided for developing a phase reference signal from the photographic plate in such a manner that signals arising from particle tracks not parallel to the edge of the plate are out of phase with the reference signal. The counting circuit includes provision for rejecting the out-of-phase signals resulting from unoriented tracks as well as signals resulting from spurious marks on the plate such as scratches, dust or grain clumpings, etc. The output of the circuit is hence indicative only of the tracks that would be counted by a human operator.
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-14-025741
- Assignee:
- U.S. Atomic Energy Commission
- Patent Number(s):
- US 2939633
- OSTI ID:
- 4143299
- Country of Publication:
- United States
- Language:
- English
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