Overview
ISO/ASTM 51607:2013 - Practice for use of the alanine‑EPR dosimetry system - defines materials, instrumentation and procedures for measuring absorbed dose in photon and electron radiation processing using alanine-EPR dosimetry. The standard describes the alanine dosimeter (a type I dosimeter) based on electron paramagnetic resonance (EPR) spectroscopy of alanine‑derived free radicals, and explains how to use alanine dosimeters in both reference‑standard and routine dosimetry systems. It is intended to be read with ASTM E2628 and other dosimetry guidance.
Key topics and technical requirements
- Dosimeter composition and form: crystalline α‑alanine in pellet or film forms; acceptable binders and packaging recommendations to avoid extraneous EPR signals.
- EPR measurement: use of an X‑band EPR spectrometer (typical microwave frequency ~9–10 GHz) and stable EPR intensity reference materials to derive dosimeter response.
- Influence quantities: identification and control/compensation for factors that affect response, including irradiation temperature, humidity, dose rate, radiation energy, pre‑ and post‑irradiation handling, and dose fractionation.
- Calibration and verification: procedures for system calibration, use of check standards, incoming dosimeter stock assessment and routine system verification.
- Documentation and traceability: minimum record keeping for calibration, routine readings and corrective factors.
- Measurement uncertainty: guidance for estimating and reporting uncertainty in absorbed‑dose determinations.
Practical applications
ISO/ASTM 51607:2013 is applied wherever accurate absorbed‑dose measurements are required in radiation processing, including:
- Sterilization of medical devices and pharmaceuticals
- Food irradiation and shelf‑life processing
- Polymer modification and material processing
- Radiation damage studies and research
- Calibration and transfer dosimetry between facilities
The standard supports quality assurance, regulatory compliance and process validation by providing a validated practice for alanine‑EPR dosimetry, which is nondestructive and suitable for archival dosimetry records.
Who should use this standard
- Radiation dosimetrists and metrology laboratories
- Process engineers and QA managers in radiation processing facilities
- Calibration and standards organizations implementing reference or routine dosimetry systems
- Regulatory and conformity assessment bodies assessing dosimetry practices
Related standards
- ASTM E2628 (Practice for dosimetry in radiation processing) - companion document
- ISO/ASTM 51261, 51707 - related calibration and uncertainty guidance
- ASTM E170, E2701; ICRU Reports 80 & 85a; JCGM GUM (measurement uncertainty)
Keywords: ISO/ASTM 51607:2013, alanine‑EPR dosimetry, alanine dosimeter, EPR spectroscopy, absorbed dose, radiation processing, dosimetry calibration, measurement uncertainty.