Isotope Separation Online (ISOL), is an isotope production technique looking at short-lived isotopes, down to millisecond half-lives. Having significantly contributed to our understanding of the atomic nucleus over the past 50 years, ISOL physicists nowadays also aim to apply this scientific tool to other domains in science and society, for example in the field of medical science and cancer treatment.
The ISOL technique actually does not simply produce isotopes, it produces them in almost pure Radioactive Ion Beams (RIBs). Through bombardement of a target material with high-energy particles, a whole series of radioactive isotopes is produced. Aided by a properly heated target, many of these isotopes first diffuse out of the material and then effuse towards an ion source, where the actual RIB formation takes place. At the ion source the incoming atoms are deliberately and if possible selectively ionized, after which they are extracted into an ion beam by a strong electrical field. Further purification, and sometimes the only purification towards a specific chosen isotope, comes from mass separation in the homogeneous magnetic field of a dipole magnet. The residual pure ion beam is then available for any application. For example, for medical use this pure, carrier-free beam of a chosen isotope can be planted into or onto any desired material. The resulting sharp reduction in post-processing effort, opens a whole new spectrum of potential radioisotopes in nuclear medicines , with half-lives ranging from 1 hour up to several days. This, however, on the single condition that the ISOL-technique can reliably provide batches large enough for actual application.
With the governement decision in 2018 to fund the construction of a 100 MeV proton accelerator and a receiving target facility as a first phase of the MYRRHA-project, SCK•CEN has embarked on a voyage to develop, build and operate one of the most, if not the most intensely irradiated ISOL targets worldwide, ISOL@MYRRHA. A key step into valorizing the resulting increase of in-target isotope production, is an efficient ionization process that can actually handle these influxes, as the efficiency of today's ISOL ion sources already shows significant drops under high load. Tinkering on the side won't be enough to bridge this gap. Only a thorough understanding of the mechanisms at hand, and a creative design process can lead to an ion source that lives up to the established expectations. As first PhD-student on this topic, through literature study, interaction with the community, computational modeling and actually designing and testing of ion sources, you will have a large hand to play in the future development route to a high intensity ISOL ion source.