Measurements on low level plutonium sources using Rad Elec Electret Ion Chambers
This is a technique for measuring gross alpha particle emission from interior contaminated surfaces. The technique utilizes electret ionization chambers (EICs), which consist of a charged Teflon plate (the electret) and an electrically-conductive plastic chamber of 145 ml volume. To measure very low levels of alpha contamination, the EIC is left in place on the surface to be measured for about 48 hours. The change in the surface charge of the electret is a measure of the ionization during the measurement period. The rate of change of the charge is converted into an activity using an appropriate calibration factor. This system has the ability to make accurate gross alpha contamination measurements while being subject to a high airborne radon concentration, such as might occur in certain buildings or during an atmospheric inversion. Previous studies of the effectiveness of these EIC`s focused on levels of alpha contamination much higher than is allowed for unrestricted release of material at the Rocky Flats Environmental Technology Site (RFETS). This study evaluated the performance of EIC`s at levels from 100 disintegrations per minute (dpm) per 100 cm{sup 2} to below 20 dpm per 100 cm{sup 2} (all measurements are referenced to a 4{pi} geometry). The EIC`s were found to be within 5% accuracy, as compared to a gas flow proportional counter calibrated with a NIST-traceable source. Test results indicate that the EIC, left in place for 48 hours, can detect alpha contamination as low as 6.4 {+-} 3.0 dpm/100 cm{sup 2} to a 95% confidence level.
- Research Organization:
- Rocky Flats Environmental Technology Site, Golden, CO (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC34-90RF62349
- OSTI ID:
- 677206
- Report Number(s):
- RFP-5216; CONF-980905-; ON: DE99000187; TRN: 99:002260
- Resource Relation:
- Conference: SPECTRUM `98: nuclear and hazardous waste management international topical meeting, Denver, CO (United States), 13-18 Sep 1998; Other Information: PBD: [1998]
- Country of Publication:
- United States
- Language:
- English
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