 NDTnetWCNDT '96 - New Delhi Table of Contents |  |
  | Full Paper Not Received |  |
| NDTnet WCNDT '96 - New Delhi Table of Contents | |
| | Full Paper Not Received | |
2.2 proposed in this paper for the density or thickness measurement of materials with the minimum relative deviation, where µ is the mass attenuation coefficient of the materials, is the material density, and is the thickness of the materials along the path of the transmitted beam. For high explosive materials and 60 KeV gamma-rays, µ is 0.18 cm/g or so, and for the cylinders tested, is about 1.8 g/cc and is from 3 cm to 11 cm. The radioisotope also has a 3000 mCi activity and a 31 mm active diameter to provide a wide well- distributed beam profile across a collimator with a high intensity of gamma-rays. A sodium iodide crystal gamma-ray detector is used in conjunction with a single channel analysis system which has a 2.5 µ s fixed dead time to allow the high count- rate measurements can be done. A motorized translation stage is designed to move the specimens in two dimensions for scanning different locations with a positioning precision of 0.5 mm and a translation length of 400 mm. This system is controlled by a 486/66 personal computer which handles parameter setup, device control, data acquisition and analysis, data reporting and user's database functions. In this paper, a brief introduction is additionally given to some important experimental and deductive methods, such as do-cycle testing method and substitution for the bulk density of a high explosive cylinder with the average one of the locations tested by gamma-rays, etc. | | Full Paper Not Received | |