Monolayer Graphene Radiation Sensor with Backend RF Ring Oscillator Transducer

Area of Science:

• Materials Science
• Radiation Detection
• Sensor Technology

Background:

• Ionizing radiation detection is critical for safety and industrial applications.
• Existing sensors face challenges with sensitivity, stability, and environmental interference.
• Graphene's unique electronic properties offer potential for advanced radiation sensing.

Purpose of the Study:

• To develop and characterize a novel graphene-based sensor for gamma and beta radiation.
• To integrate a radio frequency (RF) ring oscillator transducer for converting radiation-induced changes in graphene resistivity to frequency output.
• To evaluate the sensor's sensitivity, selectivity, and stability under varying radiation doses and environmental conditions.

Main Methods:

• Fabrication of a graphene sensor on a copper substrate.
• Integration with a custom RF ring oscillator readout circuit.
• Irradiation experiments using gamma and beta sources.
• Characterization using Raman spectroscopy and Scanning Electron Microscopy (SEM).

Main Results:

• Achieved high average sensitivity to gamma irradiation (3.82 kΩ/kGy) and frequency change (7.86% kGy^-1).
• Demonstrated minimal error (0.46%) from background light and temperature variations, indicating high stability and selectivity.
• Observed radiation-induced lattice defects in graphene, correlating with increased resistance and sensitivity, with distinct responses to gamma and beta radiation.

Conclusions:

• The proposed graphene RF ring oscillator sensor effectively detects gamma and beta radiation with high resolution and selectivity.
• The sensor is suitable for monitoring low-to-medium radiation doses (0-1 kGy for gamma, 0-9 kGy for beta), addressing a gap in current technology.
• This technology has significant implications for radiation safety and quality control in industries such as pharmaceuticals and food processing.