Speaker
Prof.
Boris Tolochko
(Institute of solid state chemistry and mechanochemistry SB RAS)
Description
The technique of X-ray diffraction with time resolution has shown tremendous progress recent years. This is due to the development of the accelerator technology, methods of generation of synchrotron radiation (SR), and fast X-ray detectors. The report reviews the main principles of time-resolved X-ray diffractometry and requirements to the object, equipment and detectors. Considered are the basic parameters of the diffraction installations at BINP, SLAC, and EuXFEL.
To obtain the best experimental parameters it is necessary to minimize the duration of the SR flash and the divergence of the primary beam, as well as increasing its intensity and monochromaticity. Unfortunately, currently it is impossible to improve all the parameters simultaneously, so the experimenters have to compromise. For example, they increase the flux of photons at the expense of deterioration of the monochromaticity (BINP and APS/ANL) and carry out experiments in the "pink" spectrum. Or they increase the exposure time at the expense of summation of photons from a few bunches. This mode was applied to investigation into the dynamics of nucleation and growth of nanodiamonds in a shock-wave impact on hydrocarbons. Possible options of development of time-resolved X-ray diffractometry installations at BINP are considered.
Now we are preparing an experiment to study the behavior of the crystal lattice of the material of the fusion reactor first wall in a plasma discharge on the diverter. A fast one-coordinate X-ray detector was developed for this experiment. The detector enables fast recording of 100 diffraction frames with an exposure time of 73 ps and a periodicity of 100 ns. Thus, we can record X-ray "movies" with high time resolution, which store information about the dynamics of plasma interaction with the structure of the crystal surface in a plasma discharge (100 μs in the ITER).
To solve this problem we are developing an installation to work on beams of synchrotron radiation of VEPP4(BINP SB RAS). The installation will enable obtaining information about what is happening to the crystal lattice when the plasma of the ITER reactor interacts with the wall for a short period of time. The plasma discharge parameters in the ITER are as follows: an energy of 100 J for 100 μs on an area of 1 mm2. We conducted first successful test experiments, having recorded changes in the crystal lattice W, using a laser with a power of 1 J and a pulse width of 100 μm. Now diffraction patterns with a time resolution of 73 ps can be recorded.
The same method will be used for investigation into the behavior of the crystal lattice of space materials under the impact of shock waves and meteorites, flying with speeds of up to 11 km/sec. For this experiment, a gun launching small pellets with such speeds has been designed.
Primary author
Prof.
Boris Tolochko
(Institute of solid state chemistry and mechanochemistry SB RAS)
Co-authors
Mr
Aleksandr Kosov
(Budker INP SB RAS)
Dr
Aleksey Arakcheev
(Budker INP)
Konstantin Ten
(LIH SB RAS)
Dr
Konstantin Zolotarev
(Budker Institute of Nuclear Physics)
Mr
Lev Shekhtman
(Budker Institute of Nuclear Physics)
Mr
Oleg Evdokov
(Institute of solid state chemistry and mechanochemestry SB RAS)
Mr
Vladimir Aulchenko
(BINP)
Dr
Vladimir Zhulanov
(Budker INP)
