Target Systems at FIPPS

General ILL webinar organised by College III
Wednesday, 28 October 2020 at 14h00

https://ill.zoom.us/j/94915868083

“Target Systems at FIPPS"

Felix Kandzia

ILL, Grenoble, France

FIPPS (FIssion Product Prompt γ-ray Spectrometer) is a gamma-ray spectrometer for thermal neutron induced reactions at the ILL. It is composed of a highly collimated halo-free pencil neutron beam impinging on a stable or radioactive target surrounded by a high resolution High Purity Germanium detector array. The nuclei, which are studied, are the products of either neutron capture or nuclear fission.

Two important aspects to ensure good data quality in the experiments at FIPPS are the target and its environment. In this talk, I will briefly describe the layout of FIPPS in its standard configuration, what means have been taken to minimize background and which characteristics of the target material should be considered in the preparation of experiments. I will then give a more detailed description of two special cases, which required a dedicated development of target environments: First a setup for gaseous targets, designed to handle variable target gases at pressures up to 10 bar. Secondly, an active fission target, to suppress beta-decay related background in the study of fission fragments. The latter is achieved by dissolving the fissile isotope in a liquid scintillator, thus allowing to directly detect the recoil of the fission fragments with high efficiency and to select fission signals on an event-by-event basis in the offline data analysis. Besides the target design, I will present its performance during two experimental campaigns, its strengths and limitations as well as future perspectives.

Yung-Hee  KIM (College III Secretary)