title: Radiation surveillance using an unmanned aerial vehicle.
abstract: Radiation surveillance equipment was mounted in a small unmanned aerial vehicle. The equipment consists of a commercial CsI detector for count rate measurement and a specially designed sampling unit for airborne radioactive particles. Field and flight tests were performed for the CsI detector in the area where (137)Cs fallout from the Chernobyl accident is 23-45 kBq m(-2). A 3-GBq (137)Cs point source could be detected at the altitude of 50 m using a flight speed of 70 km h(-1) and data acquisition interval of 1s. Respective response for (192)Ir point source is 1 GBq. During the flight, the detector reacts fast to ambient external dose rate rise of 0.1 microSv h(-1), which gives for the activity concentration of (131)I less than 1 kB qm(-3). Operation of the sampler equipped with different type of filters was investigated using wind-tunnel experiments and field tests with the aid of radon progeny. Air flow rate through the sampler is 0.2-0.7 m(3)h(-1) at a flight speed of 70 km h(-1) depending on the filter type in question. The tests showed that the sampler is able to collect airborne radioactive particles. Minimum detectable concentration for transuranium nuclides, such as (239)Pu, is of the order of 0.2 Bq m(-3) or less when alpha spectrometry with no radiochemical sample processing is used for activity determination immediately after the flight. When a gamma-ray spectrometer is used, minimum detectable concentrations for several fission products such as (137)Cs and (131)I are of the order of 1 Bq m(-3).
authors.affiliation: STUK-Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881, Finland. roy.pollanen@stuk.fi
authors.forename: Roy
authors.initials: R
authors.lastname: Pöllänen
authors.forename: Harri
authors.initials: H
authors.lastname: Toivonen
authors.forename: Kari
authors.initials: K
authors.lastname: Peräjärvi
authors.forename: Tero
authors.initials: T
authors.lastname: Karhunen
authors.forename: Tarja
authors.initials: T
authors.lastname: Ilander
authors.forename: Jukka
authors.initials: J
authors.lastname: Lehtinen
authors.forename: Kimmo
authors.initials: K
authors.lastname: Rintala
authors.forename: Tuure
authors.initials: T
authors.lastname: Katajainen
authors.forename: Jarkko
authors.initials: J
authors.lastname: Niemelä
authors.forename: Marko
authors.initials: M
authors.lastname: Juusela
mesh_terms: D000396:Air Pollutants, Radioactive; D000401:Aircraft; D004867:Equipment Design; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods; D013057:Spectrum Analysis
chemical_list: D000396:Air Pollutants, Radioactive