In situ luminescence
In situ photoluminescence under electron irradiation
We developed an in-situ photoluminescence experiment in order to study:
Transient species created during irradiation Environnent evolution of luminescent dopant element under irradiation
In-situ photoluminescence measurements were performed thanks to a homemade set up (Images 1-3). In particular, to avoid a too strong gamma-rays exposition, the different devices must be separated from the irradiation cell containing the glass sample (Image 1 and 2). The fluorescence and cathodoluminescence signals were then collected by an association of 3 optical fibers connected via SMA/SMA connectors on a total length of 17 m. The first collecting fiber is mounted on a lens and is placed at 90° from the sample edge. A special fiber support allows X and Y motions without breaking the irradiation cell vacuum.
The 532 nm pulsed laser beam is transported via 2 mirrors, 2 lenses and 3 diaphragms to the sample center with a final diameter of 2 mm (Images 1 and 3). The collected light is analysed by a spectrograph SHAMROCK combined with an ICCD Camera (Image 2).
Image 1 : Nd Yag spectra physics Laser
Image 2 : Shamrock spectrometer with ICCD camera
Image 3 : In situ experiment on accelerator line
First application dedicated to the study of Sm-doped glasses (2007)
We obtained new significant results in the understanding of reduction process of rare earth element under irradiation . We showed that reduction process of Sm3+ into Sm2+ was not a direct process and evidence the presence of some intermediate transient species. Indeed, after the cut off the electron beam, a relaxation of the Sm3+ and Sm2+ emission signal was evidenced (Fig. 1).
Figure 1 : emission specta of Sm-doped glasses recorded during electron irradiation
 N. Ollier, B. Boizot, P. L'henoret, S. Guillous, G. Petite. Evidence of transient species occuring in the reduction process of trivalent lanthanides under 2.5 MeV electron irradiation by in situ cathodoluminescence and time-resolved photoluminescence. J. Appl. Phys. 105 (2009) 113515.