title: The ENEA-IRP thoron calibration facility.
abstract: To check the consistency of a (220)Rn measurement, performed by passive alpha track detector (ATD), the use of an accurate (220)Rn exposure calibration facility is mandatory. The ENEA Radon Service developed a new CR-39 ATD-Tn, coupled to the radon ATD-Rn and, to assess its sensitivity, had to design a small calibration facility, which has been recently modified to improve the spatial homogeneity exposure conditions inside the chamber, to get a continuous monitoring of the (220)Rn concentration and to reduce radon contamination. A better knowledge of the circuit response allowed selecting the best-operating conditions and how to regulate the thoron concentration. The active thoron monitor has been changed to serve as a continuous sampling and measuring device rather than a grab one; particular care has been devoted to assess the (216)Po losses on the device's inner surfaces and to evaluate the chamber transit time correction factor.
authors.affiliation: ENEA-IRP, Montecuccolino, Via dei Colli, Bologna, Italy. massimo.calamosca@enea.it
authors.forename: M
authors.initials: M
authors.lastname: Calamosca
authors.forename: S
authors.initials: S
authors.lastname: Penzo
mesh_terms: D000396:Air Pollutants, Radioactive; D016902:Air Pollution, Indoor / Q000032:analysis*; D002138:Calibration; D004781:Environmental Exposure; D004867:Equipment Design; D005740:Gases; D015233:Models, Statistical; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000592:standards*; D011874:Radiometry; D011886:Radon / Q000032:analysis*; D017687:Radon Daughters / Q000032:analysis*; D012306:Risk
chemical_list: D000396:Air Pollutants, Radioactive; D005740:Gases; D017687:Radon Daughters; D011886:Radon