| Zugriffsnummer | 40180 |
| Dokumenttyp | Konferenzartikel |
| Sprache | Englisch |
| Titel | The problems of a consistent assessment of the individual dose in mixed neutron-photon radiation fields |
| Autor(in); Institution |
Wagner, Siegfried R.; 6, Atomphysik, PTB-Braunschweig
|
| Quelle/Jahr | Radiation protection: proceedings - fifth Symposium on Neutron Dosimetry : radiation protection aspects: 1 (1985), 87 - 94 |
| Schriftenreihe | EUR: 9762 EN |
| Herausgeber(in) |
Schraube, H.
|
| ISBN | 92-825-5617-4 (Vol 1) ; 92-825-5619-0 (Vol 1 and Vol 2) |
| Verlag | Luxembourg: Commission of the European Communities |
| Konferenzangaben | Fifth Symposium on Neutron Dosimetry, Munich, Neuherberg, 17-21 September 1984, Germany |
| Zusammenfassung | The system of dose limitation as set by ICRP refers to two categories of quantities, effective dose equivalent, and mean dose equivalents in particular tissues or organs. As both categories of quantities cannot be measured easily, operational quantities of the dimension of dose equivalent are introduced, which can be assessed by practical instruments. In area monitoring for neutrons this has to be a quantity defined in an anthropoid phantom. With most area monitors for neutrons the quantity dose equivalent ceiling is used, which is the sum of the dose equivalent maxima produced by all components of the incident neutron radiation (according to incident energy and direction of incidence) irradiating a specified phantom. Another quantity serving the same purpose is the dose equivalent as produced at a specified depth in a 30 cm dia soft tissue sphere (ICRU sphere). Such area monitors are calibrated by exposing them to a well defined neutron field of known neutron flux density using fluence to dose equivalent conversion factors as given by ICRP, which take into account the dose equivalent contribution of the heavy charged particles produced by the neutrons as well as the contribution by the neutron capture gamma radiation arising in the phantom. The photon radiation present in a mixed radiation environment in absence of the phantom is assessed separately by an instrument which ideally does not respond to neutrons. On the other hand, individual monitoring in mixed radiation fields is generally performed separately by photon responding and by neutron responding individual monitors worn on the trunk of the exposed individual. In this case, the photon monitor senses the contribution from the incoming photon radiation (including the backscattering from the body) and the contribution by photons from neutron capture in the body. Hence it would not be consistent to calibrate the individual neutron monitor by using the same neutron fluence to dose equivalent conversion factors as with the area monitor. However, ICRP gives only the neutron fluence-to total dose equivalent conversion factors. The quantitative inferences from this inconsistency are presented and the question raised whether it would be more expedient to use fluence to dose equivalent conversion factor corrected for this effect when calibrating individual neutron monitors on phantoms. |
