Aug 19, 2011
Corporation launches microfocus X-ray machineBack
South African National Centre for Radio- graphy and Tomography (Sancrat) and Necsa chief scientist for neutron radiography/ tomography Frikkie de Beer explains that use of the facility has been reserved for postgraduate researchers until the end of the year, after which it will be available for use by other researchers.
The device is a self-contained, 225 kV microfocus X-ray computed tomography machine that has a five-axis sample mani- pulator and can be used to study samples up to about 300 mm in diameter, says Belgium-based metrology and radiation imaging specialist Nikon Metrology X-ray imaging engineer Carsten Rudolf.
The machine uses an electron beam focused, in a micrometre-range-sized spot, onto an X-ray-producing multimetal target, either tungsten, copper, molybdenum or silver, which enables researchers to produce different spectra of X-rays without breaking the vacuum chamber.
It boasts chilled-water cooling of the electron beam tube and the X-ray-producing target rod to ensure a stable temperature environment, which improves the consistency and repeatability of results between multiple tests and samples, he adds.
The conical X-ray beam is centred on a Perkin-Elmar flat panel detector about 1 m away from the X-ray source and uses geometric magnification, because X-rays are not modified by lenses, that sees the sample moved closer or further away from the X-ray focal point to produce magnification effects of the signals captured by the detector.
The captured signals are then fed to the heart of the system – a series of computers that use dedicated software to reconstruct the images taken into a three-dimensional (3D) representation of the sample (virtual image), enabling researchers to study and obtain quantitative information (such as volume and size distribution) of the varied materials and surfaces of the samples in a noninvasive and nondestructive manner.
The machine can penetrate, for example, aluminium samples up to 100 mm thick. However, for denser materials, such as carbonates in rocks, steels, titanium or uranium, the samples must be reduced in size and thickness to enable the X-ray beam to penetrate.
Further, the machine can also be fitted with a rotating reflection target. This means that the electron beam focal spot on the target moves in a circle as the target is rotated, enabling a higher energy electron beam (increasing its flux) without melting the surface of the target.
Generating X-rays is an inefficient process where a lot of heat is produced when generat- ing only a few X-ray photons. However, with better cooling, power on a rotating reflection target can be increased over a smaller focal spot or the flux increased to enable faster throughput, says Rudolf.
“Using the same electron beam, the machine can be set up to produce small focal spot sizes, such as spot sizes between 3 µm and 5 µm for reflection targets, 10 µm on rotating targets and 1 µm on transmission targets, which enables researchers to detect inclusions, voids or material properties in resolution of about the spot size if one moves the object close to the focal spot,” he adds, highlighting the machine’s versatility to serve the South African research community.
Objects larger than 300 mm in diameter can be placed in the machine and a partial image generated, but only if X-rays can penetrate the sample and if it fits into the machine. Multiple images of an object can then be combined to create one image of an object larger than 300 mm in diameter using Nikon Metrology’s software, he notes.
The machine and its software have also been designed to enable users to see the contrast between similar-density materials, such as carbon fibres present in a carbon-composite material. Both the fibres and the material are chemically carbon but, by varying the spectrum of the X-rays, the attenuation of the materials can be detected, enabling the machine to produce images from similar- density samples, notes Rudolf.
Indeed, global diamond giant De Beers’ technology division DebTech principal scientist Dr Cecil Churms, speaking at the launch of the system in July, said he had used similar microfocus X-ray technology to identify diamonds present in a core sample by using both the high-power end of the machine’s capabilities, as well as its low-power capabilities, and then used his own mathematical expertise, knowledge of geology and the system’s calculating software to combine the data sets into a 3D model that represented the positions of the diamonds in the sample.
He told the mathematically inclined members of the audience that he used a Fourier transform to Fourier space, weighted it according to the frequency and then did an inverse transform.
Churms emphasised that, by understanding the machine and understanding how variations in parameters affect the image acquired, researchers can get excellent results, even if presented by technically challenging samples, such as a diamond- bearing core sample.
South African and International Research
This system forms part of Necsa’s National Beam Line Centre, which promotes and manages the use of different forms of electro- magnetic and neutron radiation imaging to conduct tests and research.
The centre will comprise the newly launched microfocus X-ray radiography/ tomography facility (Mixrad) and the South African neutron radiography/tomography facility (Sanrad), as well as two more facilities that are being built, namely the high-energy X-ray radiography/ tomo- graphy facility and the gamma radiation radiography/tomography facility, says De Beer.
All the facilities will be operational by 2015. However, the Sanrad facility will be taken off-line in 2012 for one-and-a-half years to enable upgrades that will make it compliant with European standards and operation capabilities.
“The microfocus X-ray addition intro- duces a new era in research with X-ray imaging for South African scientists because the instrument provides a research platform from which competitive applications for beam time at advanced synchrotron facili- ties abroad can be made. Although a few microfocus X-ray instruments are in operation in South Africa, beam time will be available free for general research.
“The Sancrat team works in collaboration with visiting scientists and researchers to Necsa and advises them on the use of neutron or X-ray imaging during their research. We help researchers and clients to obtain the best 3D tomographs from the imaging systems and assist in the evaluation and analysis of the data they have obtained from the machine.”
Further, research scientists and industrial scientists can apply online for beam line time at Sancrat’s facilities during next year, and specifically for Mixrad beam line time from October this year. Information about Necsa’s radiation imaging capabilities is also provided online for researchers to consider.
“The Mixrad facility can be applied to many fields of science, including palaeosciences, archaeology, geosciences, energy (nuclear and coal), biosciences (anatomy and food sciences), civil, mechanical and chemical engineering, as well as nondestructive testing,” he says.
Necsa’s mandate, as determined under the Nuclear Energy Act, is to perform and support research and development in the field of nuclear and radiation science and technology. For Necsa, it is important that this knowledge does not stay at Pelindaba but is used in a collaborative fashion with South African institutions, as well as international institutions, he says.
“We see ourselves as part of the South African national system of innovation and, with our capabilities and our work, aim to ensure that science and technology make a growing difference to our socioeconomic situation and, importantly, to skills development. It places South African capabilities in this regard on par with international standards. We believe this will lead to the development of high-level expertise in South Africa and we hope that we will grow within our role and participation in this.”
Industrial applications of research and development are a crucial part of Necsa’s mandate and partial funding for the machine from the National Research Foundation reflects the view that science and research can help to change South Africa’s socio- economic situation, he concludes.
Edited by: Chanel de Bruyn
Creamer Media Senior Deputy Editor Online
To subscribe email email@example.com or click here
To advertise email firstname.lastname@example.org or click here
Other ICT News
Updated 2 hours ago Cybersecurity multinational Check Point has released its latest 700-series cybersecurity systems for small businesses, which draw on its international threat intelligence to provide up-to-date cybersecurity, says Check Point South Africa country manager Doros...
Updated 2 hours ago The increasingly open nature of corporate networks and the commensurate increase in cyberattack vectors require improved collaboration and threat intelligence sharing, as well as broad, automated security systems that can winkle out and neutralise smaller threats and...
Updated 2 hours ago The memorandum of understanding (MoU) for institutionalising cooperation in radio astronomy between South Africa and the other Square Kilometre Array (SKA) African partner countries was approved at the recent Third SKA African Partner Countries Ministerial Meeting,...
Recent Research Reports
Automotive 2016: A review of South Africa's automotive sector (PDF Report)
Creamer Media’s Automotive 2016 Report provides an overview of South Africa’s automotive industry over the past 12 months. The report provides insight into local demand and production, vehicle imports and exports, investment and competitiveness in the sector, as well...
Energy Roundup – April 2016 (PDF Report)
The April 2016 roundup covers activities across South Africa for March 2016 and includes details of a North Gauteng High Court Judge’s dismissal of a court application to postpone the 9.4% electricity tariff increase, which the National Energy Regulator of South...
Electricity 2016: A review of South Africa's electricity sector (PDF Report)
Creamer Media’s Electricity 2016 report provides an overview of South Africa’s electricity sector, focusing on State-owned power utility Eskom and independent power producers, electricity planning, transmission, distribution and the theft thereof, besides other issues.
Energy Roundup – March 2016 (PDF Report)
The March 2016 roundup covers activities across South Africa for February 2016 and includes details of the Department of Energy’s plans to announce the preferred bidders for the first tranche of the coal independent power producer procurement programme; the Council...
Steel 2016: A review of South Africa's steel sector (PDF Report)
Creamer Media’s Steel 2016 Report examines South Africa’s steel industry over the past 12 months. The report provides insight into the global steel market and and particularly into South South Africa’s steel sector, including production and consumption, main...
Construction 2016: A review of South Africa's construction industry (PDF Report)
Creamer Media’s Construction 2016 Report examines South Africa’s construction industry over the past 12 months. The report provides insight into the business environment; key participants; local demand; geographic diversification; corporate activity; black economic...
This Week's Magazine
Updated 1 hour 38 minutes ago The two spent-fuel pools at Eskom’s 1 800 MW Koeberg nuclear power station, in the Western Cape, will be full by 2018, increasing the urgency on the State-owned utility to begin pursuing alternative storage options. Koeberg has, over the past 32 years, accumulated a...
Updated 1 hour 38 minutes ago South Africa lacks the skills necessary to implement the government’s plan to build 9.6 GWe of new nuclear energy capacity, warns nuclear-qualified Quality Strategies International CEO David Crawford. “Apart from the concern about the affordability of the programme,...
Updated 1 hour 38 minutes ago Cybersecurity multinational Check Point has released its latest 700-series cybersecurity systems for small businesses, which draw on its international threat intelligence to provide up-to-date cybersecurity, says Check Point South Africa country manager Doros...
Updated 1 hour 38 minutes ago Daimler Trucks and Buses Southern Africa (DTBSA) saw a marked slip in new-vehicle sales in 2015 compared with 2014, with sales dropping from 5 897 units to 5 300 units. The decline came as the South African new truck and bus market declined from 31 558 units in 2014...
Updated 1 hour 38 minutes ago Group of 20 (G-20) economies threatened to penalise havens that don’t share information on their banking clients after the leak of the Panama Papers provoked a global uproar over tax evasion. The G-20 will consider “defensive measures” against financial centers and...