Micro-focus X-ray Radiography and Tomography (MIXRAD)
The Micro-focus X-ray Radiography and Tomography Facility (MIXRAD) uses X-rays to examine the internal structure of samples non-destructively at the micron scale. The facility produces two-dimensional radiographs and three-dimensional computed-tomography datasets for scientific research, industrial analysis and technology development. X-ray contrast is created by differences in attenuation as radiation passes through a sample. Dense materials and elements with higher atomic numbers generally attenuate X-rays more strongly than lighter or less dense materials, allowing internal features and material variations to be distinguished.
Capabilities
During a micro-CT scan, the sample is rotated while a series of digital X-ray projections is recorded from different angles. These projections are reconstructed into a three-dimensional virtual volume that can be visualised, measured and digitally segmented.
MIXRAD provides:
- Non-destructive imaging of internal structures
- Two-dimensional X-ray radiography
- Three-dimensional micro-computed tomography
- Micron-level spatial information
- Detection of internal defects, voids, cracks and inclusions
- Analysis of density and material variations
- Digital measurement and segmentation of reconstructed volumes
- Feasibility studies to support applications for access to synchrotron imaging facilities
Applications
MIXRAD supports investigations in areas such as:
- Materials science and engineering
- Geology and mining
- Anatomy and biomedical science
- Palaeoanthropology and heritage science
- Agriculture and biological sciences
- Chemistry
- Manufacturing and product development
- Quality assurance and non-destructive examination
Technical Specifications
|
System |
Nikon XTH 225 ST |
|
|
X-RAY SOURCE |
Voltage (kV) |
30 – 225 |
|
Current (mA) |
0 – 1 |
|
|
Spot size (µm) |
1 – 3 |
|
|
Multi targets possible |
Mo; Cu; W; Ag |
|
|
Filter kit with a range of foils |
Cu; Al; Sn; Ag |
|
|
TRANSLATION TABLE |
Axis movement (directions) |
5 |
|
Rotation accuracy |
1/1000th of a degree |
|
|
DETECTOR |
Type |
Perkin Elmer 2048 x 2048 pixels |
|
Dynamic range |
16 bit |
|
|
Physical size (mm) |
400 x 400 |
|
|
Pixel size (Micron) |
200 x 200 |
|
Scanning and Data-Acquisition Times
A typical scan takes between approximately 30 minutes and several hours. The required time depends on the sample’s size, composition and complexity, as well as the spatial resolution and contrast required. Users should consult an instrument scientist before submitting a proposal to confirm that the sample is suitable for micro-CT and to obtain an estimate of the required scanning time.
Data Reconstruction and Analysis
MIXRAD is equipped with computing resources for reconstructing two-dimensional projection data into three-dimensional virtual volumes. The reconstructed datasets can be imported into visualisation and analysis software for digital segmentation, measurement and interpretation. The time required for reconstruction and analysis depends on the number of samples, dataset size and complexity of the required information. Projects may take from several hours to several months to complete. Instrument scientists provide training and support in data reconstruction, visualisation and analysis. Commercial services can include sample scanning, reconstruction, analysis and reporting.
Calibration and Quality Assurance
The MIXRAD system is maintained and calibrated annually to support consistent data quality. Scans are performed by trained and certified instrument scientists.
Referencing MIXRAD
Users publishing results obtained with MIXRAD should reference:
J.W. Hoffman and F.C. De Beer, “Characteristics of the Micro-Focus X-ray Tomography System at the MIXRAD Facility at NECSA in South Africa,” 18th World Conference on Nondestructive Testing, Durban, South Africa, 2012. https://www.ndt.net/article/wcndt2012/papers/37_wcndtfinal00037.pdf
Instrument Scientists
Mr Jakobus Hoffman
Email: jakobus.hoffman@necsa.co.za
———————————-
Dr Lunga Bam
Email: lunga.bam@necsa.co.za
Apply for Beam Time
Prospective users should contact an instrument scientist to discuss project feasibility, sample requirements and instrument availability. The completed Beam Time Request Form must be submitted to the instrument scientist and the BLC User Office at UserOffice@necsa.co.za and to RadTom@necsa.co.za.