title: Study of the radioactivity induced in air by a 15-MeV proton beam.
abstract: Radioactivity induced by a 15-MeV proton beam extracted into air was studied at the beam transport line of the 18-MeV cyclotron at the Bern University Hospital (Inselspital). The produced radioactivity was calculated and measured by means of proportional counters located at the main exhaust of the laboratory. These devices were designed for precise assessment of air contamination for radiation protection purposes. The main produced isotopes were (11)C, (13)N and (14)O. Both measurements and calculations correspond to two different irradiation conditions. In the former, protons were allowed to travel for their full range in air. In the latter, they were stopped at the distance of 1.5 m by a beam dump. Radioactivity was measured continuously in the exhausted air starting from 2 min after the end of irradiation. For this reason, the short-lived (14)O isotope gave a negligible contribution to the measured activity. Good agreement was found between the measurements and the calculations within the estimated uncertainties. Currents in the range of 120-370 nA were extracted in air for 10-30 s producing activities of 9-22 MBq of (11)C and (13)N. The total activities for (11)C and (13)N per beam current and irradiation time for the former and the latter irradiation conditions were measured to be (3.60 ± 0.48) × 10(-3) MBq (nA s)(-1) and (2.89 ± 0.37) × 10(-3) MBq (nA s)(-1), respectively.
authors: Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland saverio.braccini@lhep.unibe.ch.
authors: S
authors: S
authors: Braccini
authors: Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland.
authors: A
authors: A
authors: Ereditato
authors: Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland.
authors: K P
authors: KP
authors: Nesteruk
authors: Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Napoli I-80126, Italy.
authors: P
authors: P
authors: Scampoli
authors: Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland.
authors: K
authors: K
authors: Zihlmann
mesh_terms: D000388:Air / Q000032:analysis*; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D017357:Cyclotrons; D007554:Isotopes / Q000032:analysis* / Q000138:chemical synthesis*; D011522:Protons; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000396:Air Pollutants, Radioactive; D007554:Isotopes; D011522:Protons