Academic literature on the topic 'Surface alpha radioactivity'

Fission-track dating, one of the more recent techniques involving the use of radioactivity, has developed one of the widest ranges of applications. Dates of objects have been obtained ranging from 6 months to 109 years BP. Volcanic tephra, obsidian, man-made and basaltic glass, meteorites, and mica have been dated. A more apt term is nuclear-track dating because fissionable elements do not have to be present in the material. Fission, which produces one form of nuclear track, is a rare mode of radioactive decay. A more common decay is alpha decay, which produces a different type of track. Uranium 238 fissions spontaneously and has a well-defined half-life. It also fissions in the presence of neutrons such as are produced by reactors, accelerators, or neutron "howitzers." About 99.27% of all uranium is uranium 238. Robert L. Fleischer, Paul B. Price, and Robert M. Walker, who have done most of the original work in this field, have determined that most minerals contain this isotope in amounts from a few parts per billion (ppb) to many parts per million (ppm). These researchers devised a chart which characterizes the ease of use of this technique as a function of the uranium concentration. A high uranium concentration allows an "easily measured" age where the observer spends an hour at the microscope counting chemically etched fission tracks. For "considerable labor," 40 hours of such work is assumed. Ancient synthetic glass typically contains 1-2 ppm of uranium, so most glasses older than 8,000 years are datable. Most pottery clay contains about 5 ppm of uranium in either the clay itself or other minerals that occur as inclusions. It is very probable that some pottery clays or the mineral inclusions, such as zircon, might contain higher concentrations than this, which would make the age measurement lie between "easily" and "with considerable labor." It is important to point out that mineral inclusions such as zircons or micas act as solid-state detectors in that they register fissions as a track on the surface in contact with the pottery clay. Both fission and alpha events can do this.

We present an ionized air transportation type alpha radioactivity monitor to efficiently perform the clearance level inspection for large size uranium waste and its detection performance. In previous work, we developed a prototype monitor with an about 1000 mm cubic measurement chamber to measure the cut waste. However, in a survey of target waste, we found that it is desired to measure not only the cut waste but also the lengthy waste such as uncut cylinders. Therefore, we developed an alpha radioactivity monitor with a long and large measurement chamber (effective sizes: 500 mm x900 mm x3200

The National Institute of Ionizing Radiation Metrology of ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) (ENEA-INMRI) organized 7 national Inter- Laboratory Comparisons (ILC) on the measurement of the environmental radioactivity and of radionuclides of medical interest. In this paper, the ILC N°6, on surface contamination measurements, will be described. The objectives of this ILC were to test, at the national level, the participant capability of measuring the surface emission rate of two Wide Area Sources (WAS) of 241Am (alpha emitter) and of

In the nuclear power industry, many techniques are used to confirm that items are suitable for free-release. These techniques usually involve monitoring of the items with at least one type of radiometric instrument, to ensure that no significant quantity of man-made radioactivity is present. These monitoring techniques depend on the stage in the clearance process, the application and the size of the article being monitored. The UK Radioactive Substances Act has a Substances of Low Activity (SoLA) exemption which allows for articles and waste that have a man-made radioactive content less than 0

Since the mid-1960s the VNIINM has been developing decontamination techniques for a variety of materials and contaminants for Russian nuclear engineering needs. 1. Early in the development, chemical decontamination was the most commonly used method. According to the nature of contaminants and contaminated material, mineral acids, alkali, mineral and organic oxidants and reductants were used. For best results, complex forming agents were sometimes added. However, in spite of widespread use of chemical decontamination at the USSR nuclear facilities, this technique has a drawback of producing a g

Abstract Starting in 2002, Belgoprocess will proceed with the treatment and conditioning of some 200 m3 of widely varying high- and medium-level wastes from earlier research and development work, to meet standard acceptance criteria for later disposal. The gross volume of primary and secondary packages amounts to 2,600 m3. The wastes have been kept in decay storage for up to 30 years. The project was started in 1998. Operation of the various processing facilities will take 7–8 years. The overall volume of conditioned waste will be of the order of 800 m3. All conditioned waste will be stored in