T. Kirchner

A facility for measurements of nuclear cross sections for fast neutron cancer therapy

A facility for measurements of neutron-induced double-differential light-ion production cross-sections, for application within, e.g., fast neutron cancer therapy, is described. The central detectio ...

Cross Section Data and Kerma Coefficients at 95 MeV Neutrons for Medical Applications

Motivated by the need of data on neutron-induced reactions with biologically relevant materials, e.g., carbon and oxygen, we have constructed and installed the MEDLEY detector array at the neutron beam facility of the The Svedberg Laboratory in Uppsala. The central detection elements of MEDLEY are three-detector telescopes, consisting of two silicon detectors and a Csl crystal. To cover wide energy and angle ranges, we have mounted eight such telescopes at 20° intervals. We have used ΔE − ΔE − E techniques to obtain good particle identification for protons, deuterons, tritons, 3He and α particles over an energy range from a few MeV up to 100 MeV. To define the detector solid angle, plastic scintillators were employed to serve as active collimators. We have up to now measured double-differential cross sections of inclusive light-ion production induced by 95 MeV neutrons on carbon and oxygen. From these data production cross sections, as well as partial kerma coefficients, are being determined. We have found that especially the proton kerma coefficient for carbon is substantially larger than that of a recent evaluation, leading to a larger total kerma coefficient. The obtained data supports a trend observed for similar data at lower energies.

SCANDAL - A Facility for Elastic Neutron Scattering Studies in the 50–130 MeV Range

Recently, a large number of applications involving high-energy (> 20 MeV) neutrons have become important. Examples are development of spallation sources, transmutation of nuclear waste, fast-neutron cancer therapy, as well as dose effects for airflight personnel and electronics failures due to cosmic-ray neutrons. Elastic neutron scattering plays a key role for the understanding of all these areas. The most important reason is that it allows a determination of the optical potential, which plays a decisive role in every microscopic calculation including neutrons in either the entrance or exit channel. In addition, the elastic cross section is also the largest of the individual partial cross sections contributing to the total cross section. A facility for detection of scattered neutrons in the energy interval 50–130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20–180 MeV neutron beam facility of the The Svedberg Laboratory, Uppsala. It is primarily intended for studies of elastic neutron scattering, but can be used for the (n,p) t and (n,d) reaction experiments as well. The performance of the spectrometer is illustrated in measurements of the (n,p) and (n,n) reactions on 1H and 12 C at 96 MeV.