Dosimetry and Calorimetry Performance of a Scientific CMOS Camera for Environmental Monitoring

Area of Science:

• Applied Physics
• Environmental Science
• Sensor Technology

Background:

• Lead (Pb) contamination in drinking water is a significant public health concern.
• Radioisotopes such as 210Pb emit gamma (γ)-rays detectable by silicon sensors.
• Current detection methods may lack the sensitivity or accessibility for widespread water quality monitoring.

Purpose of the Study:

• To evaluate the performance of a CMOS camera (OXFORD INSTRUMENTS Neo 5.5) as a detector for X-rays and low-energy γ-rays.
• To assess the sensitivity of the CMOS sensor for detecting 210Pb, a radioisotope associated with lead contamination.
• To determine if the CMOS device can assay lead in drinking water at levels relevant to World Health Organization guidelines.

Main Methods:

• Testing the CMOS camera's response to X-rays and γ-rays across a 6 keV to 60 keV energy range.
• Measuring the camera's energy resolution and sensitivity to incident radiation.
• Utilizing calorimetric information and Monte Carlo simulations (Geant4) to refine detection limits.

Main Results:

• The CMOS camera exhibited a linear energy response and energy resolution better than 2% for X-rays and γ-rays above ~10 keV.
• A minimum detectable rate of 40 ± 3 mHz was achieved, corresponding to an incident activity of 7 ± 4 Bq.
• With calorimetric data, the minimum detectable rate improved to 4 ± 1 mHz for 26.3 keV γ-rays, indicating suitability for detecting 210Pb at the few to 100 ppb level.

Conclusions:

• The tested CMOS sensor demonstrates excellent performance as a γ- and X-ray detector.
• This technology shows significant potential for sensitive, in-situ monitoring of lead contamination in drinking water.
• Further development could lead to cost-effective and accessible tools for water quality assessment.