Gamma radiography

Table 1 Characteristic attributes of the isotopes used in gamma radiography of weldments.

A further advantage is the Selenium halflife of 120 days, which is 60% more when compared to iridium and a factor of approx. 4 when compared to Ytterbium. These differences turn out to be an important economical aspect when comparing the different sources, as they are a direct measure of the useful life of sources. The short halflife and the very high costs for Ytterbium sources have been the main factors for the rather low importance of Ytterbium in the full range of gamma radiography. 

One of its isotopes, Am-241, is a portable source for gamma radiography also a source of ionization for smoke detectors. In the glass industry, it is used as a radioactive glass thickness gage. Other isotopes do not have much commercial application. 

Industrial utilization of amenrium has been quite limited. Uses include a portable source for gamma radiography, a radioactive glass thickness gage for the flat glass industry, and an ionization source for smoke detectors. 

The most frequent application of gamma radiography is checking the welds in pipelines. This is done most conveniently by putting the source inside the centre of the pipe and attaching the film to the outside of the weld. For checking long pipelines, sophisticated, self-propelled crawlers which travel in the pipe are used. These devices can be positioned exactly at the desired position from the outside. At a command the exposure is made. Then the crawler is instructed to move on to the next weld. Practically all new gas- or oil-pipeline systems are checked with this type of equipment. 

Use Gamma radiography, radiochemical research, diagnostic aid, electronic devices. 

Industrial gamma radiography sources High/medium dose rate brachytherapy sources 1000 > A/D > 10... 

The cause of the sodium incident was determined at the beginning of September, and the storage drum was then definitively droned on 9th September. At the beginning of October, gamma radiography examination revealed that a crack had developed at the base of a weld on a support plate of the cooling circuits (see Figure 2.21). 

At the beginning of 1988, gamma radiographies showed up that other indications of cracks existed in several zones of the main drum made of 15 D3 ferritic steel and the first assessments of a sample, which were later on confirmed, showed that cracking by hydrogen, affecting these zones, was highly intense. 

INTERNATIONAL ATOMIC ENERGY AGENCY, Practical Radiation Safety Manual on Gamma Radiography, IAEA-PRSM-1 (Rev. 1), IAEA, Vienna (1996). 

Radiation Protection Apparatus for Industrial Gamma Radiography Specifications for Performance, Design and Tests, ISO 3999, ISO, Geneva (2004). 

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