title: The LNE-LNHB water calorimeter for primary measurement of absorbed dose at low depth in water: application to medium-energy x-rays.
abstract: Water calorimeters are used to establish absorbed dose standards in several national metrology laboratories involved in ionizing radiation dosimetry. These calorimeters have been first used in high-energy photons of (60)Co or accelerator beams, where the depth of measurement in water is large (5 or 10 cm). The LNE-LNHB laboratory has developed a specific calorimeter which makes measurements at low depth in water (down to 0.5 cm) easier, in order to fulfil the reference conditions required by the international dosimetry protocols for medium-energy x-rays. This new calorimeter was first used to measure the absorbed dose rate in water at a depth of 2 cm for six medium-energy x-ray reference beams with a tube potential from 80 to 300 kV. The relative combined standard uncertainty obtained on the absorbed dose rate to water is lower than 0.8%. An overview of the design of the calorimeter is given, followed by a detailed description of the calculation of the correction factors and the calorimetric measurements.
authors.affiliation: CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), F-91191 Gif-sur-Yvette, France. benjamin.rapp@cea.fr
authors.forename: B
authors.initials: B
authors.lastname: Rapp
authors.forename: N
authors.initials: N
authors.lastname: Perichon
authors.forename: M
authors.initials: M
authors.lastname: Denoziere
authors.forename: J
authors.initials: J
authors.lastname: Daures
authors.forename: A
authors.initials: A
authors.lastname: Ostrowsky
authors.forename: J-M
authors.initials: JM
authors.lastname: Bordy
mesh_terms: D002151:Calorimetry / Q000295:instrumentation*; D006358:Hot Temperature; D009010:Monte Carlo Method; D011829:Radiation Dosage; D014867:Water; D014965:X-Rays
chemical_list: D014867:Water