Speaker
Description
Independent fission yields in neutron-induced fission at high neutron energy is important for the understanding of the fission process, and it is also in relevant for reactor physics applications. So far, measurements of independent fission yields in proton-induced fission has been performed at the IGISOL facility at the University of Jyväskylä, using the Penning trap as a high resolving-powermass-filter. In order to also facilitate neutron-induced measurements, a dedicated ion guide and a proton-to-neutron converter was developed. However, the first measurements [1] indicate that fewer fission products than expected reach the Penning trap. To explore potential reasons and possible improvements, a simulation model was developed [2, 3] and benchmarked [4]. The benchmark showed that the model is able to reproduce the performance of the ion guide remarkably well, but that the neutron flux from the converter has been over-estimated.
Based on the benchmark, the parameters of the setup, including the geometry of neutron converter, the distance from the converter to the uranium targets, and the size of the uranium targets and volume of the ion guide, have been optimized with regards to the production of fission products. However, the collection efficiency of the ion guide still limits the intensity of extracted fission products.
To significantly improve the collecting efficiency, as well as the extraction time, an electric field guidance system, inspired by the RF-system used in the CARIBU gas catcher [5], is considered to be deployed. In the gas catcher, fission products are prevented from hitting the walls of the ion guide by the RF-structure, and are guided by a DC electric field toward an extraction nozzle. With this poster we present the design of the guiding system for the IGISOL ion guide, as well as a simulation model for estimates of the extraction yields of fission products from the ion guide.
Rferences:
[1] A. Mattera et al. Production of sn and sb isotopes in high-energy neutron-induced fission of $^{nat}$U. Eur. Phys. J. A,54:33, 2018.
[2] A. Al-Adili et al. Simulations of the fission-product stopping efficiency in IGISOL.Eur. Phys. J. A,51:59, 2015.
[3] K. Jansson et al. Simulated production rates of exotic nuclei from the ion guide for neutron-induced fission at IGISOL. Eur. Phys. J. A,53:243, 2017.
[4] Zhihao et al.Benchmark of simulation of the ion guide for neutron-induced fission products. Submitted to Eur. Phys. J. A.
[5] G. Savard, A.F. Levand, and B.J. Zabransky. The caribu gas atcher. Nucl.Inst. Meth. B,376:246–250, 2016.