UWC PhD Scholars Drive Innovation: Collaboration on Groundbreaking Coulomb-Excitation Experiment in China

In May 2021, a milestone was achieved at China’s largest heavy ion research facility, the Lanzhou Heavy Ion Accelerator, with the successful execution of the first Coulomb-excitation measurement.

Dr Kumar Raju (then Institute of Modern Physics, Chinese Academy of Sciences), an ex-postdoctoral fellow at the University of the Western Cape (UWC), built together with Chinese colleagues a similar experimental set-up to the one originally developed by Prof Nico Orce at iThemba LABS (Somerset West). But building the experimental pipeline wasn’t enough. The complicated particle-gamma coincidence data had to be analysed and results extracted.

Craig Mehl (white helmet) and Cebo Ngwetsheni (yellow helmet) at CERN running one of UWC’s leading experiments.

Seeking guidance, colleagues at the University of Shandong in Weihai, China, turned to Prof Orce for expertise. They were willing to pay for all the expenses, but Prof Orce couldn’t visit China for family reasons, so they agreed to send his PhD students Craig Mehl and Cebo Ngwetsheni to accomplish the mission.

“It was definitely a great opportunity for them to act independently and under the pressure of being out of their comfort zone,” Prof Orce recalls. “But Craig and Cebo had been trained in world-class research facilities (CERN in Switzerland, TRIUMF in Canada, York in the UK, or iThemba LABS) and they were about to submit their PhDs, so I did not doubt that they’d perform well.”

They did better than that.

After a whole month in China, the best way to describe their accomplishment is by stating what leading researcher at Shandong University, Dr Chen Liu, wrote about them: “I am writing to express our sincere appreciation for the outstanding contributions made by your students, Craig and Cebo, in assisting us with processing Coulomb-excitation data and learning the corresponding software. They have consistently demonstrated good talent and professionalism within our team. Their profound knowledge and excellent skills provided invaluable support in our successful implementation of the work.

“With our joint efforts, we have also successfully ran the minimisation and obtained preliminary results. In addition, they also assisted us in understanding the theoretical knowledge related to Coulomb excitation. Previously, our understanding of theoretical knowledge was not deep enough. Through this period of communication, we have gained knowledge about the semi-classical approximations and giant dipole resonances (GDR), which provide support for us to further understand the experimental method of Coulomb excitation. They also helped us modify the Doppler correction code, and we obtained better results compared to before.”

Dr Liu concluded: “Starting with, Craig and Cebo consistently maintained a high level of professionalism, approaching academic research and collaborative work with rigour and accountability. They provided us with great assistance in completing the processing of the experimental data, allowing us to gain a deeper understanding of the method of Coulomb excitation experiments.”

She finished by saying, “Thank you for providing us with this valuable learning experience. We look forward to future opportunities for collaboration and mutual advancement in academic research.”

Left to right: Cebo Ngwetsheni, Guangyu Li and Craig Mehl

Craig and Cebo have now opened the exciting prospect of working with such an excellent, large and dynamic group at Shandong University. “We’ll definitely propose joint experiments at both national facilities: Lanzhou and iThemba LABS. But most importantly, our young South African researchers made everyone proud by reaching the high standards required to support top science in China,”  concluded Prof Orce.

Cebo and Craig have just submitted their PhD thesis and are working on leading manuscripts. UWC is extremely proud of them for flying the SA flag very high – a flag waving with the wind of change.