| ATTRIBUTE | ALANINE DOSIMETRY SYSTEM | RED 4034 DOSIMETRY SYSTEM |
|---|---|---|
| Instrumentation | Electron paramagnetic resonance (EPR) spectrometer | SpectrophotometerMicrometer |
| Dosimeter Description | Alanine substrate pressed into pellet shape with wax for binding material. Pellet is placed into a film package with a bar code that cannot be separated from the film package. | Polymethylmethacrylate (PMMA) molded sheets cut into ~ 3.0×1.1×0.55 mm pieces. Hermetically sealed in a film package. |
| Dosimeter Response (per ASTM) |
Dosimeter contains crystalline alanine and registers the absorbed dose by the formation of alanine-derived free radicals. Identification and measurement of the alanine-derived free radicals are performed by EPR spectroscopy.ISO/ASTM 51607 Standard Practice for Use of an Alanine-EPR Dosimetry System | Induction of chemical reactions resulting from irradiation, which create absorption bands in the visible and/or UV regions of the spectrum. Optical absorbance is determined at appropriate wavelengths within these radiation-induced absorption bands and is quantitatively related to absorbed dose.ISO/ASTM 51276 Standard Practice for Use of a Polymethylmethacrylate Dosimetry System |
| Dosimeter Measurement Process | Insert alanine dosimeter into spectrometer, system automatically transfers dosimeter bar code into software and begins taking measurementDose calculated | Users remove dosimeter from packetPlace dosimeters into holder that holds 8 dosimeters
Place holder into spectrophotometer and absorbance transferred into software Remove dosimeters from holder and read thickness of dosimeters, one at a time Thickness automatically transferred into software Dose calculated |
| Influence Quantities (per ASTM)1 |
Temperature, pellet massISO/ASTM 51607 Standard Practice for Use of an Alanine-EPR Dosimetry System | Temperature, humidity, dose rate, post-irradiation responseISO/ASTM 51276 Standard Practice for Use of a Polymethylmethacrylate Dosimetry System |
| Typical Dosimeter System Uncertainty (per ASTM) |
± 4%ISO/ASTM 51607 Standard Practice for Use of an Alanine-EPR Dosimetry System | ± 6%ISO/ASTM 51276 Standard Practice for Use of a Polymethylmethacrylate Dosimetry System |
| Typical Dose Range | 0.5-150 kGy | 5-50 kGy |
1 Influence quantities are compensated for by either the user or the dosimeter manufacturer.