Study of the performance and time response of the RadonEye Plus2 continuous radon monitor
Abstract
The availability of afordable continuous radon monitors opens new opportunities
for studying the dynamics of indoor radon and for more precise
estimates of the exposure based on the actual occupancy of homes and workplaces.
These new applications require tests of the monitors characteristics,
including their response time. A study of a promising electronic radon monitor
with high sensitivity, the RadonEye Plus2, was conducted. By exposure
of 36 RadonEye monitors it was found that they have excellent linearity up
to 3500 Bq/m3. A slight deviation from linearity within 12% was observed in
the range 3500{7000 Bq/m3. The reproducibility of the monitors was within
7%, estimated in the range of linearity.
A dedicated procedure for studying the time response was developed
based on exposure to rectangular activity concentration pulses (spikes). It
was applied to the RadonEye and three other commercial monitors. The determined
characteristic response times of the RadonEye monitor are about
40 minutes for reaching 50% of the plateau of a rectangular pulse and 90 minutes
for reaching 90%. They are somewhat higher than the corresponding
response times of the AlphaE monitor, which are 20 and 60 minutes respectively.
The response times of the RAD7 monitor in snif mode are about 3
minutes for reaching 50% of the plateau and 10 minutes for reaching 90%.
The AlphaGUARD monitor in
ow-through mode has the fastest response { reaches 95% of the plateau in less than 2 minutes. The monitor Alpha-
GUARD PQ2000 Pro Rn/Tn is therefore recommended for follow-up of the
activity concentration in time response studies of other monitors.
Overall, the RadonEye's response is suffciently fast to follow the diurnal
variations even in buildings with active ventilation. The presented methodology
can be applied to other monitors for continuous radon measurements.
It is demonstrated that it can be expanded to obtain the response function
of a monitor and to model its response to variable concentrations.