Strain measurements in rock samples using neutron diffraction

Abe, Jun; Sekine, Kotaro*; Harjo, S.   ; Ito, Takayoshi*; Arima, Hiroshi; Aizawa, Kazuya  

Strain measurements using neutron diffraction are based on Bragg's law. Tensile or compressive stress causes change in lattice spacing, which results in peak shift of Bragg peak. Strain value can be derived from this peak shift value. Since neutron penetrate materials more than X-rays, the strain inside the material could be obtained nondestructively using neutron diffraction technique. While the stress measurements using diffraction technique has been focused mostly on metals, the application to geological materials was examined. The aim of this study is to develop neutron diffraction technique applicable to the geological materials. In situ strain measurement on specimens under uniaxial compression have been performed at "TAKUMI". Sufficient neutron diffraction patterns could be obtained. This indicates that the strain distribution in rocks is nondestructively measurable using "TAKUMI".