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In situ luminescence

In situ photoluminescence under electron irradiation


Aims:

We developed an in-situ photoluminescence experiment in order to study:
Transient species created during irradiation Environnent evolution of luminescent dopant element under irradiation


The experiment:

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 [1]. 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

[1] 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.