Identification of scaling thickness on 48 inches pipe line using gamma scanning technique

Gas pipeline suspected consist of scale inside the wall. A cracking gas flowed from furnish to gasoline fractionation tower has a diameter 48 inches and length 20 meters. Gamma scanning technique performed to diagnose scaling profile and thickness inside the pipe. A gamma source Cs-137 has an activity 80 mCi and other equipment such as a gamma rate meter, Nal(TI) scintillation detector, induction motor, and two gamma collimators which has a radius 5 mm and a deep 30 mm, a computer designed for measuring objects with a radius of 150 cm. The measurement method was scanned the pipe vertically and horizontally. Experiment result observed scale thickness is 32-57 cm in range. This experiment report is guide to maintain schedule for continuous productivity. (author)