Youth Month 2021: Edward Nkadimeng

June is Youth Month, and this year the NRF is celebrating the Youth of the NRF who are Advancing Knowledge, Transforming Lives and Inspiring a Nation. We thank all participants for sharing their stories with us and we hope that you are inspired by the young dreamers and achievers who are affiliated with the NRF through their work or studies.

Mr Edward Nkadimeng is a third-year PhD Physics student at the University of the Witwatersrand

Mr Nkadimeng received NRF funding for his MSc Physics in 2019 for work in Reliability Testing and the Upgrade of a Switch-Mode Power Supply Design for Front-End Electronics. In 2020/2021, he received a prestigious Fellowship under the Southern African Institute for Nuclear Technology and Sciences (SAINTS) programme (a Human Capacity Development Programme at NRF-iThemba LABS) for his outstanding work in developing and commissioning test benches that will test the next generation of upgraded hardware for the Large Hadron Collider. Furthermore, he received an NRF Internship in 2018 and received training under the South African Agency for Science and Technology Advancement (NRF-SAASTA).

This is his story…

I am a PhD Physics student at the University of the Witwatersrand, conducting my research at one of the largest scientific centres for nuclear research at CERN. I was born in the small town of Emalahleni, Mpumalanga.

From as early as I can remember, I have always been fascinated by the physical world around us. I have always dreamed of making a grand and lasting contribution to science, but I had little idea what this contribution would be like or how to achieve it. I pursued the STEM fields from as early as Grade 9 and would continue with these subjects during my undergraduate BSc (Physics and Chemistry) up to now, a PhD in Physics.

After reading stories about all the famous physicists (such as Richard Feynman and Albert Einstein) as well as philosophers, I decided I’d like to also assist in any way I could in finding out more about what constitutes the physical realm we live in. I remember I’d always borrow a Physics World magazine from the university library and read this during my spare time to keep up with all the amazing things physicists and other scientists were doing all over the world.

On 23 July 2012, when Time Magazine released an article declaring that the elusive Higgs boson had been found at last, I knew then that this would be a field of study I really wanted to contribute to. I remember at some point the Higgs boson being referred to as the “God” particle and the celebrations that followed it. Being an avid follower of the nature of the particles that constitute matter and radiation, I joined the Wits University ATLAS group as a member of the ATLAS Collaboration after completing my BSc in Physics in 2017 – not only because of its fundamental research but also because it is a place where people from all over the world and many different backgrounds come together to work towards a common goal. Being from a developing country myself and a non-member state in South Africa, I thought it would be a great challenge for me to work there.

Ever since the discovery of the Higgs boson in 2012, it has posed more questions as to whether or not there is new physics beyond the standard model. It has been short of two years since I started working on the detector operations for the ATLAS Tile Calorimeter based at my home institution. We regularly perform tests and calibration measurements for the Tile Calorimeter sub-detector, using real size spare modules or prototypes produced in South Africa, and other replicas of the calibration systems used in the ATLAS experiment.

Did you have to overcome any obstacles to be where you are today, and what did you learn from it?

There were plenty of distractions and obstacles that I had to overcome during my undergraduate and postgraduate journey. Although research has examined personal and social factors that help African students succeed academically, less attention has been given to the coping responses that they use to overcome challenges. Some challenges included overcoming a very stressful situation during an academic semester and the various coping responses that were at my disposal to manage these stressful situations. One of the strategies I used was to seek out a proactive approach which included steps and activities that are designed to solve my own problems. Secondly, I sought support from my immediate family and friends and the Centre for Mental Health and Awareness office.

What is your research and your area of expertise?

I am involved with the Tile Calorimeter, which is the sub-detector of ATLAS, and I mainly contribute to the Phase-II upgrade activities and efforts of the detector, in particular the low voltage power distribution system that provides power to the front-end electronics that reside on-detector. My interests lie in the development and optimisation of high-performance algorithms. My project with them involves the use of cutting-edge technologies, real-time data acquisition, and electronics. I am proficient in circuit designs, programming in multiple languages, and developing low-cost test systems used in experimental physics.

Over the past several years, a paradigm shift has occurred in advanced detector systems and instrumentation. In the past, improvements in silicon manufacturing technology had enabled steady increases in transistor density, processor clock frequency, and processing speed. Industry projections indicate that transistor density will continue increasing for at least another decade. Unfortunately, power and thermal constraints have slowed the march of clock speed. Moreover, design complexities, verification efforts, as well as scalability issues in centralised structures have impeded performance improvements in monolithic designs and thus have deigned a radiation-hardened power supply purely from commercial “off the shelf” components.

How can your research/work advance knowledge, transform lives and inspire a nation?

Our approach and goals would be to illustrate the techniques that we can employ in thinking about the reliability of an electronic circuit. We have done a rigorous analysis using sophisticated software packages. This allowed us to approach this problem at a very basic level, to develop an intuitive feel for how reliability calculations work, what factors influence reliability, and how to incorporate actual performance experience from an existing large system. Often, there is one or a few components in a design that are the weakest in terms of reliability.

Being able to identify these and mitigate their impact can make substantial improvements in the reliability of a system. There are several benefits to this type of analysis. The first is to increase the awareness on the part of the designer of the reliability of components used in a design, as part of component selection. This requires research to find the failure data for individual components, which is not always readily available for commercial parts. Generally, there is a trade-off between high-reliability parts, i.e. for space and military applications, and cost, which makes this a significant factor in the initial selection of components for an application. Furthermore, this would give the experiment a prediction or indicator of what failure rate to expect on the detector and, in future, assist in the development of a similar system in South Africa at NRF-iThemba LABS. This will also assist with planning for basic systems, as well as the resources that might be needed. We, as the designers, hope to assess our design choices by comparing the theoretical failure rate with the actual rate that will be measured in the coming years. This will assist with the design of future front-end systems. There is much that can be learned from critical evaluation of the performance of an existing system.

The research positions South African science in the national and global arenas through greater awareness of cutting-edge science and its contributions, and enhanced competitiveness in science and innovation. Also, it contributes to the national research strategies by the transfer of technology from CERN to South Africa which is supported by the Department of Science and Innovation for the next four years.

What are some of your proudest achievements?

I have participated in various international and local conferences/workshops presenting my work on developing test benches, which validate results of the latest switch-mode power supplies by both looking into the test parameters and assumptions of the data from component manufacturers, as well as comparing with the available failure data from the current operation.

• My talk for the 5th International Conference on Particle Physics and Astrophysics from 05-09 October 2020 can be found here.
• My talk for the ACES 2020 – Seventh Common ATLAS CMS Electronics Workshop for LHC Upgrades from 26-28 May 2020 can be found here.

I was also invited to deliver a plenary talk for the entire community during ATLAS Week 2020. This event takes place once a year, where the work of thousands of scientists are summarised and showcased.

In February 2020, I was invited to co-convene the official CERN TileCal Phase-2 Low Voltage and Detector Control System Working Group, which includes a large community of scientists and Engineers from 46 institutions around the world. This was covered by Wits University news, NRF news, and the ATLAS Tile calorimeter.

I also led the LVPS team, which consisted of experts from the University of Texas at Arlington and Prague University, where we conditionally passed the final design review with follow-up action items. This was a huge milestone for African science as a critical product and prototype would thus be delivered on South African soil.

Did the COVID-19 pandemic (and national lockdown) change the way you work/study? How did you adapt to the “new normal”?

I was lucky enough that our work was transnational and we had already started using an application called “vidyo-connect” (an open-source video conference application) to present and discuss the Tile Calorimeter Phase-II challenges before the COVID-19 pandemic hit us. I was already able to work from home and on campus before the COVID-19 pandemic disturbed everyone and everything. We continued working partially from home, and in some instances, in the High Throughput Laboratory when needed to.

What is the best advice you have ever received (and from whom)?

The best advice came from my mother, Albertina Nkadimeng, when I had just turned 21. She mentioned that I should narrow my focus and that doing so would bring big results. The number one reason people give up so fast is because they tend to look at how far they still have to go instead of how far they have come. But it’s a series of small wins that can give us the most significant success.

What, in your opinion, are some of the best ways to get youngsters interested in science-related careers?

It really is platforms provided by entities of the NRF, such as career exhibitions from NRF-SAASTA, as well as entities such as SANSA, the CSIR etc. that provide hands-on activities outside the classroom. Every time we were out doing an outreach program, you’d find so much interest related to the science fields.

What are your career aspirations for the future?

Short term: after completing my PhD, I plan to pursue a dual postdoctoral internship at Wits University and abroad. I am driven by a lifelong interest in the understanding of and appreciation for physics, and by finding physics concepts and principles within the familiar objects of everyday experience. I am keen to continue my education in this subject and to perform my own research which can contribute to the knowledge of the field.