Multiple source exposure technique: a new method in industrial radiography

Radiographic examination of objects having large subject contrast is conventionally carried out by adopting either a multiple exposure technique or a multifilm technique. This report presents an original concept and detailed modalities of a new latitude technique that can be used in radiographic examination. This new technique also provides good radiographic sensitivity. Based on the results of the experiments conducted using x-rays and gamma rays by simulating the conditions of radiographic examination, the radiographic 'radiation quality' has been defined for the first time and is expressed in terms of a radiation quality factor (RQF) as well as the radiation quality index (RQI). The concept of spectral superimposition has been newly introduced in radiographic examination. A new latitude technique called Multiple Source Exposure (MSE) technique has been developed from the concept of spectral superimposition. The MSE technique is applicable to both x-ray and gamma ray radiography. It can be readily employed using the available commercial industrial x-ray units. However, to facilitate the MSE with gamma rays, some modifications and standardisation of the existing radiography cameras and accessories are necessary. (author)