Speaker
Dr
Aleksey Arakcheev
(Budker INP SB RAS)
Description
The residual mechanical deformation and stress were measured in the preliminary experiments carried out at synchrotron radiation (SR) scattering stations on VEPP-3 in the Siberian Center of Synchrotron and Terahertz Radiation. The deformation and stress were calculated on the base of the dependence of the scattering angle on the inclination of the tungsten sample. Significant changes in the SR diffraction are found as the result of material recrystallization or irradiation of the material by plasma. It implies that the SR scattering diagnostics may be an informative instrument for in-situ observations of the state of the plasma facing components.
The next stage of the SR scattering diagnostics development at the novel scattering station “Plasma” is the dynamic measurements during pulsed heat loads. Currently a 1J YAG laser is used for the 0.2ms heat load simulation and a 100J laser is under development. The parameters of the heating are sufficient for simulation of the expected pulsed heat load in ITER. The destructive effect of pulsed heat loads is caused by mechanical stresses that occur in highly non-uniformly heated materials. The main aim of the current development of diagnostics based on SR scattering is the dynamic measurements of the mechanical deformation and stress dependences on the depth below the surface. It looks like the rotation of crystallographic planes due to mechanical deformations is the dominant effect in the SR scattering. So the deformation and stress distributions may be calculated using measurements of the diffraction peak parameters of SR passed through the sample. The set of requirements (the pass through material, dynamical measurements of pulsed processes) determines restrictions on SR brightness and energy. The SR from VEPP-4 with energy 69keV will be used for experiments with tungsten. Also a single crystal samples are necessary for increasing of the diffraction peak brightness. Currently the one-dimensional gas X-ray detector DIMEX is used for measurements. The development of the silicon detector for increasing of the sensitivity and to decrease of the instrumental diffraction peak width is in progress.
The diffraction peak parameters for SR reflected by germanium single crystal were observed in the first dynamic experiments. The changes of intensity and position of the diffraction peak were measured during the pulsed laser irradiation of material. The result demonstrated possibility of the dynamic experiments. The recent experiments were aimed at measurements of the diffraction peaks passed through the single crystal tungsten sample. The X-ray patterns were observed at phosphor plate for sample thickness of 200µm and 500µm with crystallographic orientation [111]. One of the diffraction peaks was measured by one-dimensional X-ray detector with exposure 10µs. The measurements of the diffraction peak dynamic during the pulsed laser irradiation of material and during the cooling stage will be the next step. It will give data on the dynamics of the spatial distributions of the mechanical deformation and stress.
Primary author
Dr
Aleksey Arakcheev
(Budker INP SB RAS)
Co-authors
Dr
Aleksandr Burdakov
(Budker INP SB RAS)
Mr
Aleksandr Kosov
(Budker INP SB RAS)
Mr
Alexander Chernyakin
(Budker INP SBRAS)
Dr
Alexander Shmakov
(Boreskov Institute of Catalysis SD RAS)
Alexander Vasilyev
(Budker INP SB RAS, Novosibirsk State University)
Mr
Alexandr Kasatov
(Budker INP SB RAS)
Mr
Alexey Ancharov
(Institute of Solid State Chemistry and Mechanochemistry SB RAS)
Prof.
Boris Tolochko
(Institute of solid state chemistry and mechanochemistry)
Dr
Dmitry Skovorodin
(Budker INP SB RAS)
Mr
Igor Kandaurov
(Budker INP SB RAS)
Dr
Leonid Vyacheslavov
(Budker INP SB RAS)
Mr
Lev Shekhtman
(Budker INP SB RAS)
Mr
Marat Sharafutdinov
(ISSCM SB RAS, Budker INP SB RAS)
Mr
Oleg Evdokov
(Institute of Solid State Chemistry and Mechanochemistry SB RAS)
Mr
Sergey Bugaev
(Budker INP SB RAS)
Dr
Sergey Polosatkin
(Budker INP SB RAS)
Mr
Sergey Popov
(Budker INP SB RAS)
Mr
Victor Kurkuchekov
(Budker INP SB RAS)
Mr
Vladimir Aulchenko
(BINP)
Mr
Vladimir Popov
(Budker INP SB RAS)
Dr
Vladimir Zhulanov
(Budker INP)
Mr
Yuriy Trunev
(Budker INP SB RAS)
