Application of cadmium sulfide photoresistor and open-source software for X-ray detection in mammography

The extensive use of ionizing radiation in several applications, specially X-rays in medicine, necessitates reliable detection systems for accurate measurement and control. The development of low-cost detectors is crucial to expanding access to these technologies. In this context, some approaches have been developed aiming to construct X-ray detection mechanisms utilizing cadmium sulfide (CdS), a photoconductive semiconductor, as a key material. This study investigates the feasibility of using a low-cost Light Dependent Resistor (LDR) sensor, made of CdS, integrated with a custom-made electronic system, for X-ray detection. The sensor was evaluated under various X-ray beam production parameters, such as tube voltage and exposure time, to assess its responsivity with both industrial and mammography X-ray devices. The detection system monitors variations in the electrical signal by detecting changes in the voltage drop across the LDR when exposed to X-rays. The results demonstrated a linear response at low voltages (up to 55 kVp) and an exponential response at higher voltages. Additionally, the system accurately measured exposure times, with deviations from the reference values of less than 2 %. Despite some experimental limitations, the detection system based on an LDR and Arduino has proven to be an effective tool and could contribute to the advancement of accessible radiation detection technologies.