ENHANCING STEEL RADIOGRAPHY TESTING: A NEW X-RAY EXPOSURE CHART WITH PHOSPHORUS-BASED IMAGING PLATES

PENINGKATAN UJIAN RADIOGRAFI KELULI: CARTA DEDAHAN SINAR-X DENGAN PLAT PENGIMEJAN BERASAKAN FOSFOR

Abstract

An exposure chart serves as a critical tool for correlating exposure time with the strength of the radiation source and the thickness of the material being tested. It aims to ensure consistent image quality across various examinations and imaging systems. Traditionally, exposure charts were designed for X-ray machines that utilized film as the imaging medium. However, with the advent of digital imaging, imaging plates (such as those used in Computed Radiography systems) have replaced films, allowing for the creation of digital images. These digital images can be electronically stored, eliminating the need for physical film storage and streamlining image retrieval processes. While digital imaging has significantly advanced the field, comprehensive exposure charts specifically tailored for phosphor imaging plates in industrial applications are still lacking. This study addresses this gap by creating an exposure chart using a steel step wedge and a white imaging plate (equivalent to D7 film) for the Isovolt Titan E x-ray machine. To calibrate the system, we determine the minimum gray value (GVmin) and energy using a copper step wedge at a focal-detector distance of 100 cm and an energy level of 180 kV. Each step wedge is exposed to varying energy levels and constant current until the desired gray value is achieved. Subsequently, we construct an exposure chart based on steel thickness (measured in millimeters). By comparing the film and developed exposure charts, we evaluate their performance using welded plates. The results demonstrate that an exposure chart can indeed be developed for phosphor imaging plates. Furthermore, the computed radiography system significantly reduces exposure time (by approximately 80%), making it quantitatively comparable to conventional film radiography.