Centre of Radiation Research and Technology

(based on the 10 MeV electron linear accelerator LAE 10)

The Linear Electron accelerator LAE10 has been constructed at the Institute of Nuclear Chemistry and Technology (INCT) and was installed in 1999. The LAE 10 has been solely dedicated to pulse radiolysis experiments and related work in the field of radiation chemistry with the following nominal parameters: electron energy 10 MeV, pulse duration 4-10 ns and 100 ns, peak current 1A, beam power 0.2 kW and repetition rate 1, 12.5, 25 Hz and single pulse mode.

Pulse radiolysis is an invaluable tool for studying the kinetics and spectra of transient chemical species. It has found a broad range of important applications in chemistry and biochemistry, extending far beyond the scope of radiation chemistry to which it was first applied.

With the advent of microprocessors, all aspects of the generalized experiment are susceptible to computer control. On this page we describe a computer-controlled pulse radiolysis system based on a fast digital storage oscilloscope (DSO). The oscilloscope produces a sufficient number of time points that multiple time scales can be generated by the computer from a single kinetic trace originating from DSO. Thus, one can in principle, with a single kinetic trace, resolve time constants from a few nanoseconds to tens, or even hundreds of microseconds. The simultaneous recording transient absorption data on multiple time scales is valuable for saving both experimental time and the amount of valuable samples.

The INCT laser flash photolysis system is based on the Nd:YAG SURLITE II laser (Continuum). The time duration of a laser pulse is 6 ns (FWHM). Currently, the system is capable of operating on the four lines: basic line 1064 nm with energy 670 mJ and three harmonic generated lines 532, 355 and 266nm with energies 315, 101, 83 mJ, respectively.
Low noise, high power Hamamatsu L2273 lamp is used as a source of analyzing light. Wavelength selection is performed by SpectraPro 275 monochromator (Acton Reserch Corporation, 200 – 1000 nm) or bandpass filters. Optical signal is monitored by photomultiplier (Hamamatsu, R-955), silicon diode (PDA10A ,ThorLabs), or InGaAs diode (PDA10CF , ThorLabs) depending on needs and spectral range of measurement. LeCroy WR6051A digitizer is used for data acquisition. System is fully controlled by written in Delphi TSFF software.
The system is equipped with temperature controlled cell-holder Flash 300 (Probis-Scientific).
If necessary, small sample volume, flowing system based on syringe pump (KDS-270-CE, KD Scientific) can be used. Optionally flash laser photolysis at INCT can work with iCCD camera commonly used in our pulse radiolysis facility.