3 minute read
Hope and promise fulfilled
DOCTOR NTOMBIZONKE YVONNE KHESWA was born in the dusty squalor of Tembisa (meaning ‘hope’ or ‘promise’ in isiZulu), a poorly serviced dormitory township started when thousands of black people living on freehold land around Johannesburg were forcibly removed and dumped there.
While in high school, Dr Kheswa moved to Durban where she matriculated. A diploma in analytical chemistry at Mangosuthu Technikon (now Mangosuthu University of Technology) followed in 1999, after which she was employed as a laboratory technician by sugar giant Tongaat Hulett. She completed a BTech in Chemistry at the Durban University of Technology in 2004 and moved to the Sugar Milling Research Institute in the same year.
In 2005, her family relocated to the Western Cape where she was off ered a job as a target maker by iThemba Laboratory for
Accelerator Based Sciences (iThemba LABS), an NRFfunded multidisciplinary research facility focused on the use of particle accelerators to produce radioisotopes for medical use and the conduct of applied nuclear physics research. >>
“I had to establish the target laboratory to provide target materials to be used in experiments conducted by researchers in nuclear physics and other fi elds. This stimulated my passion to continue with my postgraduate studies,” says Dr Kheswa.
UWC, which was nearby and had a strong Physics department, was the natural choice. She completed her MSc in Physics in 2011 at UWC with a dissertation titled ‘Synthesis and Characterisation of 114Cd targets’ (cosupervised by the department’s Professor Dirk Knoesen and Dr Miroslava Topić of the Materials Research department at iThemba LABS).
Explaining the focus of her dissertation, she says: “To study nuclear reactions and nuclear structures, target materials in the form of metal fi lm or gas are bombarded with high-energy particles. The target material is designed to yield as few competing reactions under ion bombardment as possible to enable the study of certain nuclear reactions or the structure of nuclei. This requires a chemically and isotopically pure target material.”
Around the time she completed the dissertation, according to UWC Department of Physics and Astronomy Prof Nico Orce, an experiment was proposed to explore the rise of surface vibrations in nuclei. “But it couldn’t be done in South Africa at the time. The [needed particle] beams were not here and we needed to develop the technology to produce new science. We needed a dedicated PhD student capable of working on both the physics and the chemistry; someone with the patience and ability to do the job.”
That person was Dr Kheswa, who soon began the groundbreaking research that would result in her PhD in Physics in 2019 for her ‘Synthesis of the metallocenes for the production of exotic high energy ion beams’. In short, Dr Kheswa developed the new particle beams of exotic nickel isotopes needed for a range of new experiments at iThemba LABS.
“These charged particle beams are initially prepared in a dedicated ion source before they can be accelerated to the target material,” explains Dr Kheswa. “The beams (of 60Ni8+ and 62Ni8+) are directed at targets such as nuclei, which are just a few micrometres in size, for analysis.”
An excited Prof Orce says, “Her work is proof of principle that we can now study exotic stable nuclei such as 62Ni, which was accelerated for the fi rst time ever at iThemba LABS. It opens new possibilities [in South Africa] for high-impact science and for investigating the frontiers of nuclear physics through novel nuclear reactions.”
Dr Kheswa modestly insists that “Good things in life don’t just come from talent or hard work,” and says her achievements were underpinned by the “interactions, contributions and discussions with the ion source specialists from iThemba LABS, Dr Rainer Thomae and his team, organometallic specialists from the Chemistry Department (Drs Salam Titinchi and Hanna Abbo) and nuclear physics scientists from both the Physics Department (UWC) and Subatomic Physics (iThemba LABS), including Prof Orce.”
The pathfinding researcher from Tembisa now hopes to help the next generation of African nuclear scientists fulfil their promise.
