| Zugriffsnummer | 23151 |
| Dokumenttyp | Zeitschriftenartikel |
| Sprache | Englisch |
| Titel | Secondary charged particle equilibrium in 137-Cs and 60-Co reference radiation fields |
| Autor(in); Institution |
Behrens, Rolf; 6.3, Strahlenschutzdosimetrie, PTB-Braunschweig
Kowatari, Munehiko; Japan Atomic Energy Agency, Tokai, Naka, Ibaraki, JAPAN
Hupe, Oliver; 6.3, Strahlenschutzdosimetrie, PTB-Braunschweig
|
| Quelle/Jahr | Radiation Protection Dosimetry: 136 (2009), 3, 168 - 175 |
| ISSN | 0144-8420 |
| DOI | |
| Verlag | Oxford: OUP |
| Zusammenfassung | During the calibration or irradiation of dosemeters, typical irradiation geometries (collimated beams) and source-to-detector distances (1 to 5 m) lead to the fact that for photon energies above a few hundred keV, the secondary charged particle equilibrium us usually not ensured. The reason is that the radius of the radiation field at the detector position is smaller than the range of the secondary electrons produced in air whose maximum particle energy is as large as the maximum photon energy. Therefore, the International Organization for Standardization (ISO) recommends putting a build-up plate made of polymethyl methacrylate (PMMA) in front of the dosemeter to be calibrated in ISO 4037-3 In this paper, the effect of the thickness of the build-up plate and its distance from the dosemeter at different source-to-dosemeter distances were investigated by means of measurement and calculation. It turned out that the geometrical arrangement for the source, dosemeter, and build-up plate recommended by ISO mostly does not ensure secondary charged particle equilibrium. The consequence is to always place the build-up plate directly in front of the dosemeter to be calibrated or irradiated. |
