Bragg diffraction optics for energy-dispersive neutron transmission diffraction

2000 ◽  
Vol 283 (4) ◽  
pp. 403-405 ◽  
Author(s):  
P Mikula ◽  
M Vrána ◽  
V Wagner
1997 ◽  
Vol 234-236 ◽  
pp. 1058-1060 ◽  
Author(s):  
P. Mikula ◽  
P. Lukás̆ ◽  
M. Vrána

2005 ◽  
Vol 490-491 ◽  
pp. 234-238 ◽  
Author(s):  
Miroslav Vrána ◽  
Pavol Mikula

Using our long experience in Bragg diffraction optics we successfully used focusing principles for substantial increasing both luminosity and resolution of the strain scanners with respect to the conventional devices. Monochromatic neutrons are selected by the cylindrically bent monochromator from the reactor spectrum. There is a strong correlation between divergences of incoming and outgoing beams with respect to the polycrystalline sample, which can be easily manipulated by changing the monochromator bending radius. By setting a proper value of the radius, a narrow, quasiparallel and highly luminous output beam can by adjusted. The strong correlation between wavelength and direction of incoming and outgoing beams depending on the monochromator bending radius can be as well used for suppression of surface effect in residual strain scanning. In scanning near a sample surface aberration peak shifts arise due to the fact that the gauge volume defined by input and output slits is partially out of the sample and its value can be of the same order as the residual strain effects. In this work we demonstrate that by changing of the bending radius of monochromator, this surface effect can be suppressed to values smaller then experimental errors in residual strain scanning.


2006 ◽  
Vol 3-4 ◽  
pp. 331-336
Author(s):  
Pavol Mikula ◽  
Petr Lukáš ◽  
Miroslav Vrána

The performance of an unconventional high-resolution neutron diffractometer using Bragg diffraction optics that can be efficiently employed in strain/stress diffractometers are reported. Presented results demonstrate their experimental abilities for powder diffraction, namely for residual strain/stress measurements. In addition to the macrostrain scanning capability, the device can also be used for microstrain/stress studies by suitable analysis of the diffraction profiles. Two examples of the strain measurements are presented.


Author(s):  
Pavol Mikula ◽  
Miroslav Vra´na ◽  
Lubos Mra´z ◽  
Leif Karlsson

The present paper deals with an efficient use of high-resolution neutron diffraction for material research studies, namely for studies of internal stresses. It is demonstrated that a conventional neutron diffractometer equipped with focusing elements can be used as neutron strain/stress scanner with medium power neutron sources. Principles of this enhanced technique are introduced and an example of internal strain/stress measurements in the vicinity of welds is presented.


1997 ◽  
Author(s):  
Volker Wagner ◽  
Z. Kouril ◽  
Petr Lukas ◽  
Pavel Mikula ◽  
Jan Saroun ◽  
...  

2000 ◽  
Vol 283 (4) ◽  
pp. 289-294 ◽  
Author(s):  
P Mikula ◽  
J Kulda ◽  
P Lukáš ◽  
M Ono ◽  
J Šaroun ◽  
...  

1997 ◽  
Author(s):  
Pavel Mikula ◽  
Petr Lukas ◽  
Jan Saroun ◽  
Pavel Strunz ◽  
Miroslav Vrana ◽  
...  

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