A semi-empirical approach to estimate the parameters determining the LR-115 detector response in radon measurements. (November 2018)

• Record Type: Journal Article
• Authors: Rojas, Jhonny; Palacios, Daniel; Pereyra, Patrizia; Pérez, Bertin; Bohus, Laszlo Sajo; López, María Elena
• Is Part Of: Radiation measurements. Volume 118(2018:Nov.)
• Page Start: 36
• Page End: 42
• Publication Date: 2018-11
• Subjects: Critical angle -- Diffusion chamber -- Energy window -- LR-115 detector -- Monte Carlo simulation -- Radon; Nuclear emulsions -- Periodicals; Particle tracks (Nuclear physics) -- Periodicals; Thermoluminescence -- Periodicals; Cosmic rays -- Periodicals; Radiation -- Measurement -- Periodicals; Radiometry -- Periodicals; Radiation Monitoring -- Periodicals; Émulsions nucléaires -- Périodiques; Particules (Physique nucléaire) -- Traces -- Périodiques; Thermoluminescence -- Périodiques; Rayonnement cosmique -- Périodiques; Radiométrie -- Périodiques; 539.77
• DOI: 10.1016/j.radmeas.2018.08.005
• Languages: English
• ISSNs: 1350-4487

Abstract

Abstract: One way to estimate the calibration factor (CF) of an LR-115 detector within a diffusion chamber by Monte Carlo (MC) simulation requires as input parameters the energy window (Δ E ), the dependence of critical angle with energy [ θ c = f ( E )] or mean critical angle (< θ c >), and the air fraction of 218 Po atoms ( f 1 ). Using simulated tracks and MC techniques, it was demonstrated that < θ c > can replace θ c = f ( E ) relatively accurate. Results of numerical examples validate the correct performance of developed MC code. A semi-empirical approach to estimating the parameters E min, E max, < θ c >, and f 1 is presented. The method is based on the calculation of the CFs by means of MC simulations ( S sim ) for the range of expected input parameters values and their comparison with the experimental CF ( S exp ). Parameters that minimized the deviations between S exp and S sim were obtained through successive iterations. < θ c > was the parameter with the most marked and differentiated tendency to converge. The energy window and mean critical angle for our etching conditions, track counting method, and environmental conditions during exposure of LR-115 detectors were [1.5 ± 0.3, 4.0 ± 0.2]MeV and (56.1 ± 6.6)°, respectively. The air fraction f 1 was found to be 0.1 for most of the used diffusion chambers. The comparison of radon concentrations obtained with the reference and test monitors, using in the latters the CFs simulated with the mean values of found parameters, demonstrate that the proposed method is applicable if uncertainties around 20% are accepted. Highlights: A program based on Monte Carlo simulations for sensitivity calculation was developed. The mean critical angle reproduces with good approximation the total sensitivity. Simulated and experimental calibration factors of the LR-115 detector are compared. The parameters that determine the response of the LR-115 detector are estimated. Diffusion chambers of any geometry and size can be calibrated using found parameters.