Nuclear data for neutron-induced reactions in the intermediate energy range of 20 to 200 MeV are of great importance for the development of nuclear reaction codes since little data exist in that range. Also several different applications benefit from
such data, notably accelerator-driven incineration of nuclear waste. The Medley setup was used for a series of measurements of p, d, t, $^3$He and $alpha$-particle production by 175 MeV quasi-mono-energetic neutrons on various target nuclei. The measurements were performed at the The Svedberg Laboratory in Uppsala, Sweden. Eight detector telescopes placed at angles between 20$^circ$ and 160$^circ$ were used. Medley uses the $Delta E$-$Delta E$-$E$ technique to discriminate among the particle types and is able to measure double-differential cross sections over a wide range of particle energies. This paper briefly describes the experimental setup, summarizes the data analysis and reports on recent changes in the previously reported preliminary data set on bismuth. Experimental data are compared with INCL4.5-Abla07, MCNP6 using CEM03.03, TALYS and PHITS model calculations as well as with nuclear data evaluations. The models agree fairly well overall but in some cases systematic differences are found.
At the IGISOL-JYFLTRAP facility, fission mass yields can be studied at high precision. Fission fragments from a U target are passing through a Ni foil and entering a gas filled chamber. The collected fragments are guided through a mass separator to a
Penning trap where their masses are identified. This simulation work focuses on how different fission fragment properties (mass, charge and energy) affect the stopping efficiency in the gas cell. In addition, different experimental parameters are varied (e. g. U and Ni thickness and He gas pressure) to study their impact on the stopping efficiency. The simulations were performed using the Geant4 package and the SRIM code. The main results suggest a small variation in the stopping efficiency as a function of mass, charge and kinetic energy. It is predicted that heavy fragments are stopped about 9% less efficiently than the light fragments. However it was found that the properties of the U, Ni and the He gas influences this behavior. Hence it could be possible to optimize the efficiency.
The Medley setup is planned to be moved to and used at the new neutron facility NFS where measurements of light-ion production and fission cross-sections are planned at 1-40 MeV. Medley has eight detector telescopes providing Delta E-Delta E-E data,
each consisting of two silicon detectors and a CsI(Tl) detector at the back. The telescope setup is rotatable and can be made to cover any angle. Medley has previously been used in many measurements at The Svedberg Laboratory (TSL) in Uppsala mainly with a quasi-mono-energetic neutron beam at 96 and 175 MeV. To be able to do measurements at NFS, which will have a white neutron beam, Medley needs to detect the reaction products with a high temporal resolution providing the ToF of the primary neutron. In this paper we discuss the design of the Medley upgrade along with simulations of the setup. We explore the use of Parallel Plate Avalanche Counters (PPACs) which work very well for detecting fission fragments but require more consideration for detecting deeply penetrating particles.
We have measured double-differential cross sections in the interaction of 175 MeV quasimonoenergetic neutrons with O, Si, Fe and Bi. We have compared these results with model calculations with INCL4.5-Abla07, MCNP6 and TALYS-1.2. We have also compare
d our data with PHITS calculations, where the pre-equilibrium stage of the reaction was accounted respectively using the JENDL/HE-2007 evaluated data library, the quantum molecular dynamics model (QMD) and a modified version of QMD (MQMD) to include a surface coalescence model. The most crucial aspect is the formation and emission of composite particles in the pre-equilibrium stage.
