Search results for "Induced radioactivity"
showing 4 items of 4 documents
Measurements of neutron radiation and induced radioactivity for the new medical linear accelerator, the Varian TrueBeam
2016
Abstract Contemporary linear accelerators applied in radiotherapy generate X-ray and electron beams with energies up to 20 MeV. Such high-energy therapeutic beams induce undesirable photonuclear (γ,n) and electronuclear (e,e'n) reactions in which neutrons and radioisotopes are produced. The originated neutron can also induce reactions such as simple capture, (n,γ), reactions that produce radioisotopes. In this work measurements of the non-therapeutic neutrons and the induced gamma radiation were carried out in the vicinity of a new medical accelerator, namely the Varian TrueBeam. The TrueBeam is a new generation Varian medical linac making it possible to generate the X-ray beams with a dose…
Measurements of Thermal and Resonance Neutron Fluence and Induced Radioactivity Inside Bunkers of Medical Linear Accelerators in the Center of Oncolo…
2016
Emission of high-energy X-ray and electron therapeutic beams from medical linear accelerators is related to undesirable neutron production and to induction of radioactivity. In this work, measurements of thermal and resonance neutron fluence and induced radioactivity were performed inside two bunkers with medical linacs — Elekta in the Center of Oncology in Opole (Poland). The bunkers differ with a construction of their walls. The neutron measurements were performed by means of the induced activity method during emission of the 18 MV X-ray beam. The investigation of radioactivity induced by neutrons was based on the method of off-line gammaray spectroscopy measurements. This work has shown …
Recent evolution of the multi-isotopic radioactive content in ice of Livingston Island, Antarctica.
1999
The temporal arrangement of the ice layers that are produced in ecosystems with perpetual snows form situations that greatly favour the study of the temporal evolution of the radioactive fallout that occurs in the said zones, whether this fallout is natural or artificial in origin. This allows one to investigate the causes of the fallout and the mechanisms transporting the radionuclides involved from their source point to the study zone, as well as their subsequent behaviour in that zone. There are special difficulties involved in this type of study in Antarctica. Some are of a general character deriving from the conditions of extreme climate and isolation which complicate the processes of …
Natural and artificial radioactivity levels in Livingston Island (Antarctic regions).
1994
Radioactive contamination of the sea and land is due, on the one hand, to fallout from atmospheric atomic explosions since 1945, and, on the other, to emissions produced by nuclear and radioactive facilities. Given its geographic position far distant from the aforementioned main sources of radioactive contamination, Antarctica should have the lowest levels that can be measured on the Earth of artificial radionuclides in the various receptor media which are characteristic of the trophic chain. In the case of Antarctica, these are melt-water, sea-water, mosses, algae, and lichens. With the aim of contributing basic information on the radiation levels present in the Antarctic ecosystem, we hav…