Gamma versus alpha sensors for Rn-222 long-term monitoring in geological environments

Zafrir, Hovav; Haquin, G.; Malik, U.; Barbosa, Susana; Piatibratova, Oksana; Steinitz, G.

doi:10.1016/j.radmeas.2011.04.027

Cited by 33 publications

(20 citation statements)

References 23 publications

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“…The count rate of both γ-sensors is similar, and the systematic difference among them can be attributed to a slight difference in sensitivity and/or owing to their slightly differing positions. The higher count rate of the γ-sensor, relative to the α-detector, reflects the large difference of the sampled volume (owing to the different range of α-and γ-radiation in air; see also [24]). The high correspondence of the radiation pattern recorded by the two γ-sensors allows referring to them as a single detector by summing the two count rates, thus improving the signal-to-noise ratio.…”

Section: Resultsmentioning

confidence: 99%

“…Two 2 × 2 NaI detectors fitted with a single channel analyser in the range of 50-3000 keV (PM-11 detector; ROTEM Inc., Israel) are placed in parallel and horizontally at the monitoring site to record the γ-radiation emitted from the walls and from radon in the air of the room. The advantages of using these detectors for monitoring of radiation from radon are given by Zafrir et al [24]. Varying radon levels are recorded by the count rate of the γ -detectors, connected to a datalogger.…”

Section: Experimental Set-upmentioning

confidence: 99%

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Influence of a component of solar irradiance on radon signals at 1 km depth, Gran Sasso, Italy

2013

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Exploratory monitoring of radon is conducted at one location in the deep underground Gran Sasso National Laboratory (LNGS). Measurements (15-min resolution) are performed over a time span of ca 600 days in the air of the surrounding calcareous country rock. Using both α - and γ -ray detectors, systematic and recurring radon signals are recorded. Two primary signal types are determined: (i) non-periodic multi-day (MD) signals lasting 2–10 days and (ii) daily radon (DR) signals—which are of a periodic nature exhibiting a primary 24-h cycle ( θ =0.48). The local ancillary environmental conditions (pressure, temperature) seem not to affect radon in air monitored at the site. Long-term patterns of daytime measurements are different from the pattern of night-time measurements indicating a day–night modulation of γ -radiation from radon in air. The phenomenology of the MD and DR signals is similar to situations encountered at other locations where radon is monitored with a high time resolution in geogas at upper crustal levels. In accordance with recent field and experimental results, it is suggested that a component of solar irradiance is affecting the radiation from radon in air, and this influence is further modulated by the diurnal rotation of the Earth. The occurrence of these radon signals in the 1 km deep low-radiation underground geological environment of LNGS provides new information on the time variation of the local radiation environment. The observations and results place the LNGS facility as a high-priority location for performing advanced investigations of these geophysical phenomena.

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Section: Resultsmentioning

confidence: 99%

Section: Experimental Set-upmentioning

confidence: 99%

Influence of a component of solar irradiance on radon signals at 1 km depth, Gran Sasso, Italy

2013

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“…Continuous monitoring of atmospheric radon would be also extremely valuable, since significant disequilibrium between Rn-222 and its progeny is expected to occur on all time scales, including sub-synoptic time scales (Zahorowski et al 2012). Further insight is expected to be gained by extending the monitoring set-up to include additional alpha particle sensors, given the advantages of the combination of the two types of measurements (Zafrir et al 2011(Zafrir et al , 2013 for the understanding of the temporal variability of radon and its progeny. Figure 1: Geographical location of the ARM-ENA facility at the Graciosa island, Azores archipelago.…”

Section: Discussionmentioning

confidence: 99%

“…Continuous radon monitoring, particularly in the case of very low concentrations such as typically found in the atmosphere, is much more challenging than the continuous monitoring of radon progeny, fostering the measurement of the gamma radiation from the radioactive decay of radon progeny as an alternative to the direct measurement of radon. Crystal scintillators for gamma rays have higher relative sensitivity in comparison to solid-state alpha detectors and ionization chambers, allowing for a more detailed characterization of the temporal variability of environmental radioactivity, particularly in the case of fast changes (Zafrir et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Short-term variability of gamma radiation at the ARM Eastern North Atlantic facility (Azores)

Barbosa

Miranda

Azevedo

2017

Journal of Environmental Radioactivity

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This work addresses the short-term variability of gamma radiation measured continuously at the Eastern North Atlantic (ENA) facility located in the Graciosa island (Azores, 39N; 28W), a fixed site of the Atmospheric Radiation Measurement programme (ARM). The temporal variability of gamma radiation is characterized by occasional anomalies over a slowly-varying signal. Sharp peaks lasting typically 2-4 h are coincident with heavy precipitation and result from the scavenging effect of precipitation bringing radon progeny from the upper levels to the ground surface. However the connection between gamma variability and precipitation is not straightforward as a result of the complex interplay of factors such as the precipitation intensity, the PBL height, the cloud's base height and thickness, or the air mass origin and atmospheric concentration of sub-micron aerosols, which influence the scavenging processes and therefore the concentration of radon progeny. Convective precipitation associated with cumuliform clouds forming under conditions of warming of the ground relative to the air does not produce enhancements in gamma radiation, since the drop growing process is dominated by the fast accretion of liquid water, resulting in the reduction of the concentration of radionuclides by dilution. Events of convective precipitation further contribute to a reduction in gamma counts by inhibiting radon release from the soil surface and by attenuating gamma rays from all gamma-emitting elements on the ground. Anomalies occurring in the absence of precipitation are found to be associated with a diurnal cycle of maximum gamma counts before sunrise decreasing to a minimum in the evening, which are observed in conditions of thermal stability and very weak winds enabling the build-up of near surface radon progeny during the night.

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“…The radon sensitivity of the Barasol alpha system—Barasol, BT45N, of Algade Inc., France, based on the manufacturer's specifications, is about 50 Bq/m3 per 1 count in 1 h, and the equivalent radon sensitivity of the narrow gamma system in use—1.5 inches × 3 inches BGO crystal scintillators of Scionix, Netherlands, is about 0.02 Bq/m3 per 1 count per 1 h. based on the comparison under equilibrium conditions, with a calibrated alpha ionization chamber device—AlphaGUARD, Saphymo GmbH, Germany [ Zafrir et al , ].…”

Section: Introductionmentioning

confidence: 99%

Novel determination of radon‐222 velocity in deep subsurface rocks and the feasibility to using radon as an earthquake precursor

et al. 2016

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A novel technique utilizing simultaneous radon monitoring by gamma and alpha detectors to differentiate between the radon climatic driving forces and others has been improved and used for deep subsurface investigation. Detailed long‐term monitoring served as a proxy for studying radon movement within the shallow and deep subsurface, as well as for analyzing the effect of various parameters of the radon transport pattern. The main achievements of the investigation are (a) determination, for the first time, of the radon movement velocity within rock layers at depths of several tens of meters, namely, 25 m/h on average; (b) distinguishing between the diurnal periodical effect of the ambient temperature and the semidiurnal effect of the ambient pressure on the radon temporal spectrum; and (c) identification of a radon random preseismic anomaly preceding the Nuweiba, M 5.5 earthquake of 27 June 2015 that occurred within Dead Sea Fault Zone.

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Gamma versus alpha sensors for Rn-222 long-term monitoring in geological environments

Cited by 33 publications

References 23 publications

Influence of a component of solar irradiance on radon signals at 1 km depth, Gran Sasso, Italy

Influence of a component of solar irradiance on radon signals at 1 km depth, Gran Sasso, Italy

Short-term variability of gamma radiation at the ARM Eastern North Atlantic facility (Azores)

Novel determination of radon‐222 velocity in deep subsurface rocks and the feasibility to using radon as an earthquake precursor

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