title: Development of a model using the MATLAB System identification toolbox to estimate (222)Rn equilibrium factor from CR-39 based passive measurements.
abstract: Can and Bare method is a widely used passive method for measuring the equilibrium factor F through the determination of the track density ratio between bare (D) and filtered (Do) detectors. The dimensions of the used diffusion chamber are altering the deposition ratios of Po-isotopes on the chamber walls as well as the ratios of the existing alpha emitters in air. Then the measured filtered track density and therefore the resultant equilibrium factor is changed according to the diffusion chamber dimensions. For this reason, high uncertainty was expected in the measured F using different diffusion chambers. In the present work, F is derived as a function of both track density ratio (D/Do) and the dimensions of the used diffusion chambers (its volume to the total internal surface area; V/A). The accuracy of the derived formula was verified using the black-box modeling technique via the MATLAB System identification toolbox. The results show that the uncertainty of the calculated F by using the derived formula of F (D/Do, V/A) is only 5%. The obtained uncertainty ensures the quality of the derived function to calculate F using diffusion chambers with wide range of dimensions.
authors.affiliation: National Institute for Standard, Ionizing Radiation Metrology Laboratory, P. O. Box 136, Giza 12211, Egypt; Medical Physics Department, Faculty of Medicine, Jazan University, Jazan, KSA, Egypt. Electronic address: mabo_elmgd@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Abo-Elmagd
authors.affiliation: National Institute for Standard, Ionizing Radiation Metrology Laboratory, P. O. Box 136, Giza 12211, Egypt.
authors.forename: A M
authors.initials: AM
authors.lastname: Sadek
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D004058:Diffusion; D008962:Models, Theoretical; D011092:Polyethylene Glycols / Q000737:chemistry; D011834:Radiation Monitoring / Q000379:methods*; D011886:Radon / Q000032:analysis*; D035501:Uncertainty
chemical_list: D000396:Air Pollutants, Radioactive; C028827:CR 39; D011092:Polyethylene Glycols; D011886:Radon
keywords: Can and bare method; Diffusion chamber; Equilibrium factor; MATLAB System identification toolbox; Radon