Effect of gamma radiation on potential ionising radiation detectors and dosimeters based on quantum dots
In this work, we report measured effects on the fluorescent emission spectra of commercially produced core-shell (CdSe/ZnS) quantum dots (QDs) of 2.5 nm, 3.3 nm and 6.3 nm size in toluene, following exposure to 1 MeV gamma irradiation in the range 0.1-110 Gy. We show that damage depends on the size of the QDs, an effect seen in solutions of a single type of QD as well as in a mixture, and that increasing the concentration of QDs in the toluene decreases the effect. Measurements have recently been made to investigate and shift in peak wavelength following irradiation and these are reported here. Recent work on the production of a prototype 2D imaging dosimeter, by absorbing a solution of green emitting QD in toluene into a sample of porous 'Vycor' glass, has shown that QDs absorbed in the Vycor fluoresce under several hours of continual illumination and that the system continues to show fluorescence for several days after the initial preparation. Initial results of experiments to dynamically image the Vycor during electron irradiation are presented as is progress on the development of a second prototype device for 2D radiation dosimetry. © 2012 IEEE.
