Tomography technique as one method of visualizing internal conditions has been developed in the medical tools. Over the last view years, this technique is implemented in the industrial application for inspecting tools, such as in the geothermal industry. The design of the tomography system has been continuously improved from generation to generation by considering the reliability of the system in field. Fan beam tomography system is designed to measure various types of pipe, including geothermal pipe. The aim of this research is to design a fan beam tomography measurement system that adapts to mechanical structure condition and neighborhood. Hereafter to visualize the cross-section of a scaling pipe which varies in material density and geometry. The system is designed to represent 128 detectors that form a fan arc, with the gamma emitter positioned in the center system. Scanning was performed using gamma radiation source of Sc-46 with $15 \times$ 10-3 Curie (15 mCi) activity. The system is driven by using two motors assisted by Arduino and Labview software based for automation and data acquisition. Fan projection angle 100 degrees and fan rotation increment of the scan is 5.625 degrees. The results shows that the system design is successful in visualizing cross-section of scaling pipe, as well as distinguish the density and geometry of the material. Scale or foreign materials are identified in geothermal pipe image, and brings harms in reducing performance during operation. Image reconstruction using the MATLAB application with measurement error analysis obtained values below 5%. It can be concluded that the fan beam tomography system prototype design is successful in displaying cross-sectional images and evaluating the performance of geothermal pipes.