Rapid and precise measurements of radon in water using a pulsed ionization chamber
Junhyeong Seo, Guebuem Kim
Abstract
Abstract Radon‐in‐air monitor (RAD7, Durridge Co.) has been widely used to measure 222 Rn in water samples. RAD7 measures 222 Rn via 218 Po + ( t 1/2 = 3.1 min), which is electrically attracted to a silicon alpha detector. In this study, a new method was developed for measuring 222 Rn in water samples by modifying a commercially available pulsed ionization chamber (PIC, FT‐Lab Co.). The PIC detects and amplifies the electric pulses generated by microspace charges produced by 222 Rn decay. Two passive PICs (volume: 2 × 400 mL) were combined and modified to form an active system (named Rn‐SNU) that continuously circulates air (~ 1 L min −1 ). Rn‐SNU is approximately seven to nine times more efficient than RAD7 and does not necessitate a delay of ~ 15 min to reach radioactive equilibrium between 222 Rn and 218 Po + . However, RAD7 is more accurate in discriminating 222 Rn daughters, 218 Po + and 214 Po + . In this study, 222 Rn was successfully measured in coastal seawater samples using Rn‐SNU connected to a grab bottle. Our results suggest that 222 Rn measurements in water samples can be conducted more efficiently and rapidly with an Rn‐SNU than with other widely used instruments and methods.