Distance from radioactive source

Interpreting Graphs Some people, such as X-ray technicians, must work near radioactive sources. They know the importance of keeping a safe distance from the source. The graph shows the intensity of a radioactive source versus the distance from the source. 

Radiation intensity varies inversely with the square of the distance from the source. Doubling the distance from the source decreases the intensity by a factor of four (2 ). Again, the use of robot manipulators is advantageous, allowing a greater distance between the operator and the radioactive source. 

The main interest in the analysis of uranium in environmental samples is its effect as radioactive toxic heavy metal on the flora and fauna and assessment of the potential risk to human life directly or through the food chain. Natural uranium is present in practically all types of environmental samples—plants, soil, water bodies, and even air. In addition, anthropogenic activities related mainly to releases and discharges from the uranium fuel cycle may contaminate nearby areas, and that pollution may spread by wind and water action to considerable distances from the source. In order to assess the uranium content in the environment, representative samples need to be gathered (see Frame 3.2)—a task that is much more complicated than generally expected due to the variability of the sampled media. 

Thus, according to this theory, polarity of transport is produced by an asymmetry in cellular permeability to the auxin anions (see also Sect. 3.2.3.3), but polar transport is basically an asymmetric diffusion (Goldsmith 1977, p 457). Therefore, the theory requires that profiles of the distribution of radioactivity in plant parts which had been supplied with a constant concentration of labeled auxin should fit to a solution of Pick s second law of diffusion, which relates the concentration to both the time of transport and the distance from the source, namely to error function curves. Such curves are constructed from... 

A point source of radioactivity measuring 80 mR/hr at one meter has been detected. At what distance from the source will the radiation be reduced to 20 mR/hr ... 

The presence of radiation in the workplace - which is an inevitable consequence of the radioactivity of uranium - requires that additional safety precautions be taken over and above those observed in other similar workplaces. There are generally three sources from which radiation exposure may occur (i) radiation emitted from uranium ore in-situ and/or during handling (ii) airborne radiation resulting from the decay of radon gas released from the ore and uranium dust and (iii) contamination by ore dust or concentrate. Radiation levels around uranium mining and milling facilities are quite low - for the most part only a few times the natural background levels - and they decrease rapidly as the distance from... 

High-radiation areas must be secured carefully (i.e., level greater than 500 rad, radiation absorbed dose in 1 h at a distance of 1 m from the source) by providing proper ventilation and respiratory equipment, which monitors air contamination. It is also recommended that the radioactive material be properly stored with the required control along with posting signs such as ... 

Although uranium is weakly radioactive, most of the radiation it gives off cannot travel far from its source. If the uranium is outside your body, such as in soil, most of its radiation cannot penetrate your skin and enter your body. To be exposed to radiation from uranium, you have to eat, drink, or breathe it, or get it on your skin. If uranium transformation products are also present, you can be exposed to their radiation at a distance. For more information about how uranium can leave your body, see Chapter 2. 

The detector response is measured by placing a radioactive iron-source ( Fe) in front of the detector and accumulating for several hours. If the source is placed at a short distance of the detector, the varying distance of each pixel from the source must be considered. Actual pre-evaluated detector response images should be available from the local staff. Detector response is corrected by multiplying the pre-evaluated detector response image and the raw data accumulated during the experiment. 

Safety considerations are based on the magnitude of the half-life, shielding, distance from the radioactive source, time of exposure, and type of radiation emitted. We are never entirely free of the effects of radioactivity. Background radiation is normal radiation attributable to our surroundings. 

The geometry effect of the detection system concerns the size and shape of the radioactive source and the detector, and the distance between them. For the fluidized-bed configuration, these factors can be accounted for completely by the solid angle W of the detector with respect to the point source. The solid angle represents the fraction of photons emitted from the source that reaches the detector. 

Assume that the following experiment is performed (Fig. 5.2). A radioactive source of constant intensity is placed at a fixed distance from a gas counter. The high voltage (HV) applied to the counter may be varied with the help of a potentiometer. An appropriate meter measures the charge collected per unit time. If the HV applied to the counter is steadily increased, the charge collected per unit time changes as shown in Fig. 5.3. The curve of Fig. 5.3 is divided into five regions, which are explained as follows. 

Figure 24.34 shows the position of two workers near a radioactive gamma source. The worker at Position A is standing 2.5 m from the source and receives an exposure of 0.98 mrem/s m. The worker at Position B receives an exposure of 0.50 mrem/s m. What is the distance of the worker at Position B from the source ... 

Safe Exposure The intensity of a radioactive source is 1.15 mrem/s m at a distance of 0.50 m. What is the minimum distance a person could be from the source to have a maximum exposure of 0.65 mrem/s m ... 

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