![]() ![]() The 95% confidence limits of the slopes of the regression lines included the value of one, indicating no bias. ![]() Slopes of regression equations were 1.01 for CO2 and 0.97 for N2O. In the field, soil gas fluxes measured from FluxCASEs were in agreement with manual sampling for both N2O and CO2. In laboratory measurements of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) concentrations of a standardized gas mixture, coefficients of variation associated with automated and manual sample collection were comparable, indicating no loss of precision. ![]() The FluxCASE design and operation is described, and the accuracy and precision of the FluxCASE system is evaluated. This study describes Chamber Automated Sampling Equipment (FluxCASE) to collect and store chamber headspace gas samples at assigned time points for the measurement of soil gasmore » flux. An automated system for collecting gas samples from chambers in the field would eliminate the need for personnel to return to the chamber during a flux measurement period and would allow a single technician to sample multiple chambers simultaneously. The number of chambers that can be sampled is limited by the spacing between chambers and the availability of trained research technicians. Quantification of soil gas flux using the static chamber method is labor intensive. ![]() Published by Elsevier GmbH.Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Fluxĭavis, Morgan P. This effect is negligible for PTW Roos chambers at clinical linear accelerators with 4 μ s pulse duration for pulse doses up to 120 mGy.Ĭopyright © 2010. This reduced influence of the ion recombination is interpreted by the reaction kinetics of ion recombination as a second-order reaction. For longer pulses, however, the correction factor decreases and at a pulse duration of about 200μs reaches 75% of the value valid for short pulses. In this work experimental investigations of the saturation correction factor have been made for pulses of 4 μ s up to pulse doses of about 230 mGy, and the theory of Boag, Hochhäuser and Balk was again confirmed. However, this description is only accurate when the pulse length is short compared to the collection time of the ionization chamber. The physical description of the correction factor by Boag, Hochhäuser and Balk for pulsed radiation is well established. In dosimetry this effect must be accounted for by the saturation correction factor k(S). In gas-filled ionization chambers as radiation detectors, the collection of the charge carriers is affected by the recombination effect. ![]()
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