New standards of absorbed dose to water under reference conditions by graphite calorimetry for $^{60}$Co and high-energy x-rays at LNE-LNHB

Abstract : The LNE-LNHB has developed two primary standards to determine the absorbed dose to water under reference conditions (for 10 cm × 10 cm) in $^{60}$Co, 6 MV, 12 MV and 20 MV photon beams: a new graphite calorimeter and a water calorimeter. This first paper presents the results obtained with the graphite calorimeter and the new associated methodology. The associated relative standard uncertainty ($k$ = 1) of absorbed dose to water is 0.25% for $^{60}$Co and lies between 0.32% to 0.35% for MV x-ray beams.