A Dosimetric Discussion Based on Measurements of Radon Daughter Equilibrium and Unattached Fraction in Different Atmospheres

1986 ◽  
Vol 16 (4) ◽  
pp. 313-318 ◽  
Author(s):  
E. Stranden ◽  
T. Strand
Keyword(s):  
Radon Daughter ◽  
Unattached Fraction

Measurements of the Total and Unattached Radon Daughters in a House

1988 ◽  
Vol 24 (1-4) ◽  
pp. 241-244 ◽  
Author(s):  
H. Kojima ◽  
S. Abe
Keyword(s):  
Simultaneous Measurement ◽  
Natural Ventilation ◽  
Ventilation Rate ◽  
Air Filtration ◽  
Gross Alpha ◽  
Aerosol Generation ◽  
House Construction ◽  
Radon Daughters ◽  
Radon Daughter ◽  
Unattached Fraction

Abstract Continual and simultaneous measurement of unattached radon daughters (RaA, RaB and RaC) and the total radon daughters was performed in a house under normal living conditions which include ordinary living habits, the style of house construction and the normal natural ventilation rate in Japan. The hourly concentrations of three radon daughters were obtained separately and simultaneously with a radon daughter monitor, which has air filtration and gross alpha counting systems. The instrument was automatically operated (and maintenance free) over a period of two months. The unattached atoms of radon daughters were measured with another radon daughter monitor with wire screens substituting for the filter. From the measurements for seven months from Nov. 1986 to May 1987, it can be stated that: (1) the concentration of unattached RaA is the most predominant of these daughters, and the unattached RaB is always detectable; (2) the median value of the unattached fraction, fp indicated by potential alpha energy, is around 0.04, the RaB makes a contribution of more than 30% to the overall fp; (3) the data for the unattached fraction show a typical diurnal variation, having a low level in intervals of 7 to 9 and 20 to 22 local hours. It corresponds to aerosol generation from the use of gas ranges in the house.

Radon Daughter Equilibrium and Unattached Fraction in Mine Atmospheres

1982 ◽  
Vol 42 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Erling Stranden ◽  
Leiv Berteig
Keyword(s):  
Radon Daughter ◽  
Unattached Fraction

scholarly journals Erosion and Subsequent Transport State of Escherichia coli from Cowpats

2005 ◽  
Vol 71 (6) ◽  
pp. 2875-2879 ◽  
Author(s):  
Richard William Muirhead ◽  
Robert Peter Collins ◽  
Philip James Bremer
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Overland Flow ◽  
Single Cells ◽  
Rainfall Event ◽  
Buffer Strips ◽  
Simulated Rainfall ◽  
E Coli ◽  
Unattached Fraction ◽  
Over Time

ABSTRACT Processes by which fecal bacteria enter overland flow and their transportation state to surface waters are poorly understood, making the effectiveness of measures designed to intercept this pathway, such as vegetated buffer strips, difficult to predict. Freshly made and aged (up to 30 days) cowpats were exposed to simulated rainfall, and samples of the cowpat material and runoff were collected. Escherichia coli in the runoff samples were separated into attached (to particles) and unattached fractions, and the unattached fraction was analyzed to determine if the cells were clumped. Within cowpats, E. coli grew for 6 to 14 days, rather than following a typical logarithmic die-off curve. E. coli numbers in the runoff correlated with numbers inside the cowpat. Most of the E. coli organisms eroded from the cowpats were transported as single cells, and only a small percentage (about 8%) attached to particles. The erosion of E. coli from cowpats and the state in which the cells were transported did not vary with time within a single rainfall event or over time as the cowpats aged and dried out. These findings indicate that cowpats can remain a significant source of E. coli in overland flow for more than 30 days. As well, most of the E. coli organisms eroded from cowpats will occur as readily transportable single cells.

scholarly journals Radon daughter removal from PTFE surfaces and its application in liquid xenon detectors

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
S. Bruenner ◽  
D. Cichon ◽  
G. Eurin ◽  
P. Herrero Gómez ◽  
F. Jörg ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Lead Isotopes ◽  
Ambient Air ◽  
Low Energy ◽  
Small Scale ◽  
Liquid Xenon ◽  
Radon Daughters ◽  
Radon Daughter ◽  
Cleaning Procedures ◽  
The Impact

AbstractLong-lived radon daughters are a critical background source in experiments searching for low-energy rare events. Originating from radon in ambient air, radioactive polonium, bismuth and lead isotopes plate-out on materials that are later employed in the experiment. In this paper, we examine cleaning procedures for their capability to remove radon daughters from PTFE surfaces, a material often used in liquid xenon TPCs. We find a large difference between the removal efficiency obtained for the decay chains of $$^{222}$$ 222 Rn and $$^{220}$$ 220 Rn. This indicates that the plate-out mechanism has an effect on the cleaning success. While the long-lived $$^{222}$$ 222 Rn daughters can be reduced by a factor of  2, the removal of $$^{220}$$ 220 Rn daughters is up to 10 times more efficient depending on the treatment. Furthermore, the impact of a nitric acid based PTFE cleaning on the liquid xenon purity is investigated in a small-scale liquid xenon TPC.

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