Kristallfilter für kalte und thermische Neutronenstrahlen

Polycristalline and single crystal neutron filters have proved as useful tools for improving the quality of cold and thermal reactor neutron beams for elastic and inelastic scatterinq work. After a short introduction to theory the nuclear, chemical and physical properties are discussed, which have to be required from appropriate filtermaterials. A comparison is made between theoretical and experimental neutron transmissions and a compilation of the most interesting data is given for the commonly used filtermaterials: bismuth, lead, beryllium, berylliumoxide, quartz, magnesiumoxide and pyrolytic graphite, which may be of practical use for the filter designer. A few experimental facilities are also shown