X-ray Induced Electric Currents in Anodized Ta₂O₅: Towards a Large-Area Thin-Film Sensor

Area of Science:

• Materials Science
• Radiation Physics
• Sensor Technology

Background:

• Tantalum (Ta) and its oxide (Ta2O5) are known for their unique electrical and physical properties.
• Development of efficient radiation detection systems is crucial for various high-tech applications.

Purpose of the Study:

• Investigate radiation-induced current characteristics in anodized tantalum for potential sensor development.
• Explore the feasibility of large-area (≫cm2) thin-film radiation sensors for medical, national security, and space applications.

Main Methods:

• Anodization of micro-thin tantalum foils and coating with conductive polymer counter electrodes.
• Assembly and irradiation of porous tantalum capacitors and flat tantalum foil capacitors with kVp X-ray beams.
• Measurement of dark current and transient radiation-induced currents under varying external voltage biases.

Main Results:

• Measured transient currents up to 50 nA under X-ray irradiation (approx. 3 cGy/s) in Ta2O5 capacitors.
• Similar current-voltage characteristics observed in nano-porous and flat tantalum foil capacitors, influenced by X-ray attenuation.
• Signal intensity correlates with capacitor oxide thickness; a non-negligible signal at zero bias is attributed to fast electron production in tantalum.

Conclusions:

• Anodized tantalum demonstrates potential as a material for large-area, self-powered radiation sensors.
• The material is suitable for X-ray detection and energy harvesting applications.
• Further development could lead to advanced sensors for critical fields.