High energy photon reference radiation beam for radiation protection based on medical LINAC facility
Faisceau de référence en photons de haute énergie pour la radioprotection produit à partir d'un LINAC médical
Résumé
The range of photon energies used for type testing of radiation protection dosimeter extends from a few keV to 10 MeV. Most National Metrological Institutes have X-ray generators for energies up to about 300 keV and then rely on isotopic sources of 137Cs and 60Co to reach 1.33 MeV. The high energy range up to 10 MeV requires dedicated facilities such as particle accelerators or nuclear reactors. The CEA LIST LNE LNHB, has proposed to mutualize the use of a medical LINAC dedicated to national references for radiotherapy by adding a target/filter/attenuator system on the radiotherapy electron beam to obtain a radiation protection beam of photons of average energy between 6 and 7 MeV. The proposed poster describes the design of the target/filter/attenuator assembly and the steps to achieve a primary reference in terms of air kerma by means of ionization chambers specially adapted to these energies and then the conversion of this reference in terms of ambient dose equivalent H*(10).