ASTM E543:2006 pdf free download – Standard Specification for Agencies Performing Nondestructive Testing.
A1.3 X- and Gamma-ray Radiographic Equipment
Al .3. 1 Radiation Source—The radiation source shall be capable of producing sufficient energy and intensity to examine materials in accordance with required specifications. Either X-rays or gamma rays may be used unless otherwise specified by the contract. specification, or purchase order.
A1.3.1.l X-ray equipment should contain voltage and amperage controls (when applicable) and meters, a timer to time the length of the exposure, or other approved controls, and provisions for positioning the tube head and the part being X-rayed (when applicable). The voltage and amperage range of the equipment must be adequate to penetrate the thickness of the material to be evaluated and produce acceptable film densities.
Al .3.1.2 Gamma rays arc produced by radioactive materials, such as cobalt-60 and iridium-192. Different isotopes emit gamma rays in a specific energy range. The isotope (size, energy level, and strength) should he selected in view of the application (material, thickness, required image quality indicator, sensitivity) and a reasonable exposure time.
A 1 .3.2 Safety and Monitoring Equipment consistent with good practice and curren regulations should be available and normally includes safety switches, survey meters, film badges, dosimeters. signs, ropes, lead-lined room, and so forth, as applicable. Also, lead sheet, shot, or leaded rubber should be available to control or reduce scattered radiation.
A 1.3.3 Radiographic Quality Lei’el and identification Equipment. Image Quality Indicators (IQI’s) are used to evaluate the sensitivity of both setup and processing techniques. They must be made from material that is radiographically similar to, and that represents the specified percentage thickness of the material to be evaluated. The IQI’s must be clean and properly identified. Blocks shall he available on which the IQI can be placed during the exposure, if required. The thickness of the blocks should he approximately equal to the thickness of the sections being radiographed and radio- graphically similar. When exposing nonhomogeneous specimens such as electronic components or other complex structured devices, IQI’s shall he selected to produce similar image densities to that of the area of interest of the device being radiographed. Lead numbers and letters of adequate size and thickness should be available for film identification puiposes. There should be a sufficient number of each letter and number to put all required identification on the film. However, alternative methods of permanent film identification are permitted. Examples are light box exposures and permanent white ink.