title: The UK primary standard calorimeter for photon-beam absorbed dose measurement.
abstract: A description is given of the UK primary standard graphite calorimeter system. The calorimeter measures absorbed dose to graphite for photon radiations from 60Co to 19 MV x-rays, and is the basis of the NPL therapy-level absorbed dose to water calibration service. Absorbed dose to graphite from the photon calorimeter has been compared with three other standards: an ionization chamber and cavity theory, for 60Co gamma radiation; the NPL electron calorimeter, for 12-14 MeV electron beams; and the BIPM 60Co absorbed dose standard. The three standards agreed within 0.5% which is similar to the measurement uncertainties.
authors.affiliation: National Physical Laboratory, Teddington, Middlesex, UK.
authors.forename: A R
authors.initials: AR
authors.lastname: DuSautoy
mesh_terms: D002151:Calorimetry / Q000295:instrumentation* / Q000379:methods*; D003037:Cobalt Radioisotopes; D004583:Electrons; D005720:Gamma Rays; D006108:Graphite; D006801:Humans; D008433:Mathematics; D019047:Phantoms, Imaging; D017785:Photons; D011878:Radiotherapy / Q000379:methods*; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D006113:United Kingdom
chemical_list: D003037:Cobalt Radioisotopes; D006108:Graphite