Name: Donald Houngbo
Date: September 28, 2016
Time: 16:00 h
Room Jozef Plateau
Faculty Engineering and Architecture
Jozef Plateaustraat 22
Development of a liquid-PbBi target for ISOL@MYRRHA
Radioactive Ion Beams (RIBs) constitute a tool for physicists to study nuclei far from stability. The RIBs used in these studies are produced via different complementary techniques, among which the Isotope Separation Online (ISOL). At current ISOL facilities, part of the requested RIBs cannot be delivered because they necessitate R&D. In order to meet the requirements of certain experiments, the need to increase RIB-intensities by several orders of magnitude was identified and future facilities like ISOL@MYRRHA have been planned. A common feature of these facilities is their high-power driver beam which indicates a need for development of a new generation of targets capable of operating under this high-power condition.
A molten metal target concept, capable of addressing this need, was studied in this work. Because the target material flows in a loop equipped with a heat exchanger, this target concept is capable of handling high power primary-beams. In addition, liquid targets typically offer higher in-target production rates. Also, as in this concept the irradiated liquid is fractionated into small droplets inside a release volume, good release properties could be envisaged.
The work comprises the conceptual design and simulations of the target. Effects like pressure drop, cavitation, liquid-metal recirculation, instabilities and non-uniform flows were studied. These phenomena are most crucial inside the irradiation volume, as they can significantly affect the performance of the target. The need to optimize the release volume of the target derives from the fact that the main objective of this target is the production of RIBs of short-lived Hg isotopes with 177Hg (t1/2 = 0,118 s) as reference. In this objective, a computational approach to predict the release of nuclides out of the target and assess its efficiency was developed and validated. Besides, the energy loss profile and subsequent temperature and pressure distributions in the irradiation volume of the target were studied.
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