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Unique X-ray system gives Department of Physics a competitive advantage

27 July 2021 | Story Leonie Bolleurs | Photo UFS Photo Archive

Hendrik_web read more — Prof Hendrik Swart played a key role in the Department of Physics acquiring the PHI Quantes XPS system, the first in Africa and one of only 20 in the world.

The state-of-the-art equipment in the Department of Physics at the University of the Free State (UFS) differentiates this department from its competitors. Availability of the equipment makes it possible for researchers as well as students to deliver work that receives national and international recognition.

Recently, the department acquired a PHI Quantes XPS system, the first in Africa and one of only 20 in the world.

Creating better phosphor

“The Quantes XPS system uses X-rays to determine the chemical composition of molecules on the surface of a sample. The system is unique in the sense that it also has an extra X-ray source that can determine the chemical state below the surface, which was not possible in the past. This will help us to dictate the position of defects in our phosphor materials that will consequently enable us to create better phosphor for solid state lighting as well as solar cell applications,” explains Prof Hendrik Swart, Senior Professor in the Department of Physics, who also holds the SARChI Chair in Solid State Luminescent and Advanced Materials.

After he had the opportunity to observe the system in the factory in Chigasaki, Kanagawa, Japan, where he attended a conference, Prof Swart was very impressed by its performance. He discussed it with Prof Koos Terblans, Head of the department, and other colleagues, and started making plans to buy the system.

When the department first bought the X-ray photoelectron spectroscopy (XPS) system in 2007/2008, it became the national facility on XPS measurements. Not only is this an upgrade of the XPS system bought 14 years ago, but the new system will enable the department to do more measurements. “The number of samples that we have to handle has just become too much for one system. The new system’s increased capacity for making measurements addresses this challenge and it also gives UFS scientists and postgraduate students more time to spend on fundamental measurements to develop research of a higher level,” says Prof Swart.

(The Quantes XPS system. Photo:Supplied)

Explaining about the measurements, Prof Swart says: “This advanced X-ray photoelectron spectroscopy (XPS) instrument has the capability to analyse the very small area that the user is interested in and a large area of the uniform sample surface. The two different types of X-ray sources – the hard X-ray source and the more conventional soft X-ray source – can be switched automatically, allowing users to analyse the same area and/or points of a sample. The PHI Quantes XPS system ensures the availability of superior features such as automatic analysis, automatic sample transfer, turnkey charge neutralisation, and advanced data processing.”

“This XPS instrument is designed to pioneer new methods and applications transcending conventional ideas of what is possible.”

Optimising efficiency of materials

Prof Swart says the Department of Physics, especially the Research Chair in Advanced and Luminescent Materials, is developing new high-technology materials on a daily basis. “It is very important to know the chemical composition and defect distribution of the materials in order to add value to the fabrication of these materials,” he adds.

“The distribution of these defects is vital for the efficiency of the phosphor materials. If we know where these defects are located, we can determine the mechanisms of the light output coming from these phosphors,” describes Prof Swart.

Research conducted as part of the Research Chair in Solid State Luminescent and Advanced Materials will benefit significantly from this new system.

(Prof Koos Terblans, Head of the Department of Physics next to the Quantes XPS system. Photo:Supplied)

“We are currently concentrating on phosphors as sensors (temperature), light-emitting diodes (LEDs), and solar cells, where we optimise the efficiency and durability of these materials. Any new knowledge, which I believe the PHI Quantes XPS system will provide us, will help us to reach our goal much quicker,” he says.

Apart from the positive impact on research, the PHI Quantes XPS system will also be a benefit to society in the long term. Improved LEDs can be used to save electricity, and better solar cells can help to generate electricity, to mention but two examples.

News Archive

Researchers international leaders in satellite tracking in the wildlife environment

2015-05-29

Ground-breaking research has attracted international media attention to Francois Deacon, lecturer and researcher in the Department Animal, Wildlife and Grassland Sciences at the UFS, and Prof Nico Smit, from the same department. They are the first researchers in the world to equip giraffes with GPS collars, and to conduct research on this initiative. Recently, they have been joined by Hennie Butler from the Department of Zoology as well as Free State Nature Conservation to further this research.

“Satellite tracking is proving to be extremely valuable in the wildlife environment. The unit is based on a mobile global two-way communication platform, utilising two-way data satellite communication, complete with GPS systems.

“It allows us to track animals day and night, while we monitor their movements remotely from the computer. These systems make possible the efficient control and monitoring of wildlife in all weather conditions and in near-to-real time. We can even communicate with the animals, calling up their positions or changing the tracking schedules.

“The satellite collar allows us to use the extremely accurate data to conduct research with the best technology available. The volume of data received allows us to publish the data in scientific journals and research-related articles.

“Scientific institutions and the public sector have both shown great interest in satellite tracking, which opens up new ground for scientific research for this university. Data management can be done, using Africa Wildlife Tracking (AWT) equipment where we can access our data personally, store it, and make visual presentations. The AWT system and software architecture provide the researcher with asset tracking, GPS location reports, geo-fencing, highly-detailed custom mapping, history reports and playback, polling on demand, history plotting on maps, and a range of reporting types and functions,” Francois said.

Data can be analysed to determine home range, dispersal, or habitat preference for any specific species.

Francois has been involved in multiple research projects over the last 12 years on wildlife species and domesticated animals, including the collaring of species such as Black-backed Jackal, Caracal, African Wild Dog, Hyena, Lion, Cheetah, Cattle, Kudu, Giraffe, and Black Rhino: “Giraffe definitely being the most challenging of all,” he said.

In 2010, he started working on his PhD, entitled The spatial ecology, habitat preferences and diet selection of giraffe (Giraffa camelopardalis giraffa) in the Kalahari region of South Africa.

Since then, his work has resulted not only in more research work (supervising four Masters students) but also in a number of national and international projects. These include work in the:

Kalahari region (e.g. Khamab Nature Reserve and Kgalagadi Transfrontier Park)
Kuruman region (Collared 18 cattle to identify spatial patterns in relation to the qualities of vegetation and soil-types available. This project took place in collaboration with Born University in Germany)
Woodland Hills Wildlife Estate and Kolomella Iron Ore – ecological monitoring
A number of Free State nature reserves (e.g. Distribution of herbivores (kudu and giraffe) and predators (camera traps)

Francois is also involved with species breeding programmes and management (giraffe, buffalo, sable, roan, and rhino) in Korrannaberg, Rustenburg, Hertzogville, Douglas, and Bethlehem as well as animal and ecological monitoring in Kolomella and Beesthoek iron ore.

Besides the collaring of giraffes, Francois and his colleagues are involved in national projects, where they collect milk from lactating giraffes and DNA material, blood samples, and ecto/endo parasites from giraffes in Southern Africa.

With international projects, Francois is working to collect DNA material for the classification of the nine sub-species of giraffe in Africa. He is also involved in projects focusing on the spatial ecology and adaptation of giraffe in Uganda (Murchison Falls), and to save the last 30 giraffe in the DRC- Garamba National Park.

This project has attracted a good deal of international interest. In June 2014, a US film crew (freelancing for Discovery Channel) filmed a documentary on Francois’ research (trailer of documentary). Early in 2015, a second crew, filming for National Geographic, also visited Francois to document his work.

More information about Francois’ work is available at the GCF website.

Read Francois Deacon's PhD abstract

Direct enquiries to news@ufs.ac.za.

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