New TRLFS Laboratory at the CTU in Prague

Time-resolved laser-induced fluorescence spectroscopy (TRLFS) is a unique method for direct actinide and lanthanide speciation at low concentrations that is increasingly used for the study of various chemical aspects of actinides and lanthanides in solutions, suspensions or on solid surfaces namely in the framework of environmental studies or problems related to nuclear fuel reprocessing and waste disposals. Early in this year, construction and equipment of a new TRLFS laboratory was finished at the Czech Technical University in Prague, Czech Republic, in collaboration and under the support of Institute of Radiochemistry, Forschungszentrum Rossendorf, Germany. The new set-up comprises:

− Vibrant 355 II (Opotec) tunable laser with optical parametric oscillator, basic range 410 2400 nm, pumped at 355 nm with a Brilliant Nd:YAG pulse laser with SHG 532 nm and THG-355 nm modules and an additional FHG 266 nm module. Independent outlets for 355 nm and 266 nm laser beams. A UV 3 module extends the range down to 355 nm. Variable repetition frequency up to 10 Hz with the lengths of the laser pulse 6-8 ns.
− Cuvette Holder Flash 200 with Temperature Controller TC 101 (Quantum Northwest) and the necessary optical elements for signal collection and focussing.
− MS257 (Oriel) monochromator/spectrograph with 4 gratings (150 l/mm 190 800 nm, blaze 300 nm; 300 l/mm 250-1150 nm, blaze 500 nm; 600 l/mm 280 1200 nm, blaze 500 nm; 1200 l/mm 280-1600 nm, blaze 500 nm), with micrometrically adjustable aperture and optical fibre outlet. The main parameters are: outlet focal length 257,4 mm, resolution 0,1 nm, precision ± 0,1 nm, repeatability ± 0,028 nm.
− iStar 720 (Andor) DH720i-18F-03 intensified CCD camera designed for low-light spectroscopy applications requiring fast gating. The CCD sensor has spectral range of 180-850 nm and it includes a digital delay generator built into the head - the minimum optical gate is 1.6 ns.
Results of the first measurements obtained in the new laboratory for a standard UO22+ – SO42– system will be presented. The future research plans include:
− study of uranium complexation with humic substances,
− study of actinides bonding onto solid surfaces,
− actinides and lanthanides complexation with novel extraction and/or complexing agents relevant for spent nuclear fuel reprocessing or operational decontamination, respectively.