title: Estimating back to front ratio of wire screen for measurement of thoron decay products.
abstract: Wire screens are widely used for measuring the fine fraction of radon/thoron decay products. Their capture efficiencies are generally defined at low aerosol concentration conditions as well as at low sampling flow rates. Effect of changes in sampling flow rate and aerosol concentration on wire screen capture efficiencies and counting correction factor has been studied in this work. Controlled experiments have been conducted using two different mesh sizes at two different aerosol concentration conditions. Experimental results were compared with the existing theories for capture efficiencies of wire screens given by Cheng and Yeh (1980) and Alonso et al. (2001); and semi empirical relation for the front to total ratio given by Solomon and Ren (1992). Theoretical predictions have been found to be relatively close to the experimental findings for moderate aerosol conditions but disagreement was observed in case of high aerosol concentration. The possible reasons for these differences have been discussed in this work.
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.forename: Amruta
authors.initials: A
authors.lastname: Koli
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Khandare
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Joshi
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.lastname: Mariam
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.forename: Arshad
authors.initials: A
authors.lastname: Khan
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India. Electronic address: bsapra@barc.gov.in.
authors.forename: B K
authors.initials: BK
authors.lastname: Sapra
mesh_terms: D000336:Aerosols / Q000032:analysis; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D011834:Radiation Monitoring / Q000379:methods*; D011886:Radon / Q000032:analysis*
chemical_list: D000336:Aerosols; D000396:Air Pollutants, Radioactive; D011886:Radon
keywords: Aerosols; Back to front ratio; Capture efficiency; Thoron decay products; Wire screen