Abstract
Abstract
Neutron radiation is widely used for investigation of matter
at research reactors and spallation sources. One undesired
side-effect is the production of radioactive nuclides in structure
materials of the instruments (e.g. mounting structures and
radiation shieldings) due to neutron capture reactions. Hence the
structure materials themselves become radiation sources. The
knowledge of the activities after a certain time of operation is
essential for determination of the accessibility, for modifications
of the instrument, for reusing the material and for waste
management. It is desirable to have these data in the design phase
of the instrument. One possibility to obtain the data is a
combination of simulation and calculation. In this paper the
simulations/calculations for the LaDiff cold triple-axis neutron
spectrometer project at FRM-II (research reactor Munich) are
presented. The activities in the shielding house around the
experimental area of the instrument made from stainless steel and
lead are considered for the cases with and without boron-carbide
cover and for different Sb-contents of the lead layer. The influence
of the skyshine is also considered.