Effect of Voltage Variation on Dose Rate and Operating Range of Industrial X-ray Equipment

PENGARUH VARIASI TEGANGAN TERHADAP LAJU DOSIS DAN DAERAH OPERASI PESAWAT SINAR-X INDUSTRI

Abstract

Industrial X-ray equipment is widely used in non-destructive testing (NDT) to inspect defects in metal materials such as weld joints, pipes, and steel structures. Operation of this equipment produces ionizing radiation that may endanger radiation workers and the public around the facility, making the determination of work zones (controlled area, supervised area, and public area) based on the radiation dose rate an important part of the radiation protection and safety program. This study aims to determine the effect of the operating voltage of industrial X-ray equipment on the radiation dose rate and the extent of the operating zones around the facility. Dose rate measurements were carried out at three operating voltage variations (110 kV, 135 kV, and 150 kV) at four measurement points (A, C, D, and E) using a calibrated surveymeter, recording the distance from the source to the point where the dose rate reached the controlled-area boundary value (3 μSv/h) and the public-area boundary value (0.5 μSv/h). The results show that an increase in operating voltage is generally followed by an increase in the distance required to reach both boundary values. The most significant increase occurred at Point A, where the controlled-area and public-area boundary distances increased by 96.7% and 97.0%, respectively, when the voltage was raised from 110 kV to 150 kV, while Point E showed a more moderate increase of about 39.6% and 39.1%, likely related to shielding effects around that point. This indicates that the higher the operating voltage, the wider the controlled and supervised areas that must be established around the X-ray equipment. Therefore, the selection of operating voltage in industrial radiography activities needs to consider the available working area so that radiation protection remains consistent with the ALARA (As Low As Reasonably Achievable) principle.