中子散射及其原理简介_储祥蔷.pdf

中子散射及其原理简介 储祥蔷 xqchu@ 中国工程物理研究院 研究生院 2019年7月23日 中子散射高研班，绵阳 chux@ 1 7/30/19 Summer Schools… chux@ 2 2019/7/30 The Discovery of the Neutron by James Chadwick in 1932 Neutron Polonium chamber Source Beryllium target Ionization chamber Original neutron chamber xqchu@ 3 7/30/19 Internal Structure of the Neutron xqchu@ 4 7/30/19 Neutron Categories According to Energy Distribution Slow neutrons: E < 1000eV Fast neutrons: E > 1000eV Thermal neutrons: E ~ 0.025 eV Epithermal neutrons: 0.025 eV < E < ~ 1000 eV Very cold neutrons: Ultracold neutrons: Cold neutrons: E < 0.005eV ~ 8 µeV < E < 800 µeV E < 8 µeV The calculated neutron spectrum from a spallation source (IPNS). xqchu@ 5 7/30/19 Why Neutron Scattering? 1994 Nobel