A nearly mono-energetic 6-7 MeV photon calibration source

Area of Science:

• Nuclear Physics
• Radiation Detection and Measurement

Background:

• High-energy photon sources are crucial for various scientific applications.
• Characterizing and calibrating photon fields is essential for accurate experiments.
• Contamination by secondary particles can affect experimental outcomes.

Purpose of the Study:

• To develop and characterize a novel photon source.
• To investigate the energy spectrum and dose equivalent rate of the produced photons.
• To assess and understand the impact of contaminants like electrons and scattered photons.

Main Methods:

• Utilized the 19F(p, alpha gamma)16O nuclear reaction with a CaF2 target.
• Employed 2.7 MeV protons and measured photon dose equivalent rates up to 6 mSv/h at 100 cm.
• Performed calibration of photon fluence to within +/- 5%.
• Conducted experiments with filter materials and Monte Carlo simulations (EGS code) to analyze contaminants.

Main Results:

• Developed a photon source emitting 85% of dose equivalent from 6.1, 6.9, and 7.1 MeV photons.
• Achieved a high dose equivalent rate of up to 6 mSv/h over a large area.
• Quantified photon fluence calibration accuracy to +/- 5%.
• Identified significant contamination from knock-on electrons and scattered photons.

Conclusions:

• The developed photon source provides a well-calibrated, high-energy photon field.
• Further investigation and mitigation strategies are necessary to address electron and scattered photon contamination for precise applications.