Accelerator-driven photon reference field for replacement of 137Cs γ-ray

A transition to a mechanical source for x-ray reference field is desired to replace high-activity Co-60 and Cs-137 gamma-ray sources for enhancing nuclear security and safety management. The National Metrology Institute of Japan (NMIJ) developed a new photon reference field using an electron beam from a linac with energy less than 1 MeV. The effective energy of the photon field is comparable with Cs-137 gamma-ray. The air kerma rate in the reference field was validated by comparing a commercial cavity ionization chamber to the NMIJ standard reference field. The calibration constants were consistent within 0.8% for every relative extended uncertainty (k = 2).

Automated summary

A mechanical source is desired to replace high-activity gamma-ray sources in order to enhance nuclear security and safety management. NMIJ developed a new photon reference field using an electron beam, which has comparable energy to Cs-137 gamma-ray. The validation of the reference field's air kerma rate was achieved by comparing it to a commercial cavity ionization chamber.