Development of a lyoluminescence dosimetry system to measure high radiation doses

The paper presents the results of studying the dosimetric characteristics of the lyoluminescence (LL) system constituted by tris (hydroxymethyl) amino methane, as lyoluminescent material, and a solution (7 x 10-4 mol.mL-1 of luminol (5-amino-2,3 dihydro 1,4-phtalazinedione)), as solvent. Optimum parameters determined were: The phosphor weight used in each reading, the grain size of the phosphor powder and the solvent temperature. The dosimetric characteristics studied were: The response as a function of dose, reproducibility and fading. Readings were performed in a thermoluminescent (TL) analyser which was modified to be used as LL reader. This modification consisted in removing the heating pan, putting in its place an interchangeable dissolution cells system. This arrangement allows one to inject the solvent into the LL phosphor previously placed in the dissolution cell. The results are compared with those obtained for the lyoluminescence dosimetry (LLD) system constituted by commercial sugar and a solution of luminol, as well as with measurements effectuated by means of electron spin resonance (ESR). The LLD system tris-luminol allows the determination of absorbed doses in the range from 5 Gy to 1 kGy with an uncertainty of 3%. For this reason this system represents an appropriate dosimetric system to be used in radiation processing. (author). 5 refs, 5 figs, 2 tabs