BS EN ISO 20785‑2:2020 pdf download.Dosimetry for exposures to cosmic radiation in civilian aircraft Part 2: Characterization of instrument response.
4.2? General? considerations? for? the? dosimetry? of? the? cosmic? radiation? field? in? aircraft? and requirements for the characterization of instrument response Detailed consideration of the measurements to be made and the radiation field are given in ISO 20785‑1 [8]. The radiation field at aviation altitudes is complex. Thus, its dosimetry requires specialized techniques of measurement and calculation. The preferred approach would be to use devices that have an ambient dose equivalent response that is independent of the energy and the direction of the total field, or the field component to be determined. It is generally necessary to apply corrections to the results of measurements, using data on the energy and direction characteristics of the field and the energy and angle ambient dose equivalent response of the device. The field comprises mainly photons, electrons, positrons, muons, protons and neutrons. There is not a significant contribution to dose equivalent from energetic primary heavy charged particles or fragments. The electrons, positrons and muons are directly ionizing radiation and, together with indirectly ionizing photons and secondary electrons, interact with matter via the electromagnetic force. Neutrons (together with a small contribution from pions) interact via the strong interaction, producing directly ionizing secondary particles. Protons are both directly ionizing via the electromagnetic force and indirectly via strong force interactions.
4.3 General considerations for measurements at aviation altitudes The quantity to be measured, the measurand, is the ambient dose equivalent, H*(10), or its rate. Because of the number of different particles and the wide particle energy range of the radiation field at aviation altitudes, the characterization of instruments requires an extended set of measurements under well-defined conditions. Both the energy and angle dependence of response need to be measured and a calibration or response function (more usually matrix) established. The instrument response needs to be determined by measurements in both reference fields and radiation fields representative for the atmospheric radiation field. For particles and energies of the atmospheric field where no reference fields are available, the response needs to be determined by other means such as simulations.
The single field-specific correction factor, or calibration factor or coefficient, can be applied for the assumed energy and angle distributions of the given particle type or types. In some instances, this same factor or coefficient can be applied for the range of flight altitude, geomagnetic latitude and solar modulation over which measurements are being made.BS EN ISO 20785‑2 pdf download.