Long-range alpha detector
- Los Alamos National Lab., NM (United States)
Historically, alpha-particle and alpha-contamination detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity even if the particles are intercepted. Alpha detectors have had to be operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. Alpha particles interact with the ambient air, producing ionization in the air at the rate of {approximately}30,000 ion pairs per mega-electron-volt of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The long-range alpha detector (LRAD) offers several advantages over more traditional alpha detectors. First and foremost, it can operate efficiently even if the contamination is not easily accessible. Second, ions generated by contamination in crevices and other unmonitorable locations can be detected if the airflow penetrates those areas. Third, all of the contamination on a large surface will generate ions that can be detected in a single detector; hence, the detector's sensitivity to distributed sources is not limited by the size of the probe. Finally, a simple ion chamber can detect very small electric currents, making this technique potentially quite sensitive.
- OSTI ID:
- 7074146
- Report Number(s):
- CONF-911107-; CODEN: TANSA; TRN: 92-030890
- Journal Information:
- Transactions of the American Nuclear Society; (United States), Vol. 63; Conference: 1991 Winter meeting of the American Nuclear Society (ANS) session on fundamentals of fusion reactor thermal hydraulics, San Francisco, CA (United States), 10-15 Nov 1991; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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