Low level determination of (226)Ra in water using a micro-precipitate track method for large-scale environmental monitoring.
In the present paper a method has been developed for the determination of (226)Ra in water by the detection, using a solid-state nuclear track detector (SSNTD), of alpha particles from (226)Ra in equilibrium with (222)Rn in micro-precipitates collected on a filter. The micro-precipitates were prepared from environmental water samples by collection of radium with lead as Pb/RaSO(4). Several factors affect the (226)Ra precipitation on the filter and its recovery, in particular the filter pore size. Therefore in this experiment Whatman #42 and Millipore filters with different pore sizes were used. Using a 0.45 microm Millipore filter, the recovery efficiency was increased up to 96%, and the alpha self-absorption and scattering decreased remarkably. For efficient detection of alphas from (226)Ra/(222)Rn in equilibrium, three types of SSNTD were used-polycarbonate (PC) electrochemically etched (ECE), CR-39 and LR-115 chemically etched (CE). By preparing a standard micro-precipitate on a filter with known (226)Ra/(222)Rn characteristics, the calibration response of each detector and its minimum detection limit (MDL) were determined.
Taheri
M
M
National Radiation Protection Department, Iranian Nuclear Regulatory Authority, PO Box 14155-1339, Tehran, Iran. mtaheri@aeoi.org.ir
Sohrabi
M
M
Jaleh
B
B
Hosseini
T
T
Montazer Rahmati
M M
MM
D004867:Equipment Design; D019544:Equipment Failure Analysis; D005590:Fractional Precipitation / Q000295:instrumentation* / Q000379:methods; D008832:Microchemistry / Q000295:instrumentation*; D011834:Radiation Monitoring / Q000295:instrumentation*; D011886:Radon / Q000032:analysis*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D014867:Water; D011886:Radon