Computed Tomography Buyers Guide

Source: By Dr Cameron Chai, Peter Airey and Dr Kamran Khajehpour from AXT PTY LTD

In Australia, the advanced manufacturing sector is booming. With the increasing implementation of additive manufacturing techniques, the need for nondestructive testing of complex components has become even more important. Not surprisingly then, computed tomography (CT) is now the go-to solution for nondestructive testing. Similar trends for CT are being seen in research, where there is a growing need to examine components non-destructively in 3D to optimise designs, as well as the fabrication processes. There are currently a large number of CT solutions available, depending on your requirements. With so many options, choosing the right solution for your needs can be confusing. We look at the various factors you should consider in your decision making process.

Sample and System Size

Benchtop systems are perfect for smaller samples, while larger systems cater to samples in the meter plus range. It is also important to consider the availability of space in your laboratory or workspace.

Materials to be Examined

CT uses x-rays that are attenuated as a function of density and thickness. The penetrating power of a CT is dictated by its power. For example, kV systems are available up to 600kV for the largest, densest components.

Imaging Modes

Often, the component being examined is comprised of different phases. Depending on what these phases are (such as differences in density), you may need to rely on different imaging modes to reveal any flaws or defects. These modes might include quantitative phase contrast, bright field, dark field or phase retrieval.

Spatial Resolution

Depending on the size of the features and defects you are looking for, systems are available with sub-micron resolution using nano-focus x-ray sources and high resolution detectors.

Speed and Temporal Resolution

CT scans generate large datasets, with higher spatial resolutions, generating even larger datasets. Faster detectors and computers now allow for 360° scans in less than 10 seconds, opening the door for higher throughputs and true dynamic (4D) scanning.

2D, 3D and 4D

CT is—by definition—3D imaging. The ability to perform simpler 2D scans can also be a useful capability, acting as a rapid quality control checking technique akin to radiography. There is also a growing trend towards performing in-situ studies within a CT. To do this successfully requires two things: • The ability to incorporate a testing rig into the instrument (such as

mechanical, thermal, environmental) that does not interfere with the imaging hardware • The ability to perform multiple scans, ideally on a continuous, uninterrupted basis, generating real-time, 4D or dynamic imaging, ensuring no instantaneous event (such as fracture) is missed

System Flexibility

For the ultimate in flexibility, systems are available with different x-ray sources and detectors (sometimes with multiple detectors installed side-by-side) that can be easily swapped over depending on specific requirements.

Investing for the Future

A CT system is a significant capital expense. As such, it is important to factor in future demands. This provides added flexibility and extends or increases the useful service life of your instrument.

After Sales Support

Like any instrument, preventative maintenance should be performed periodically to ensure optimal performance. Make sure your supplier has a support network to facilitate both preventative maintenance and emergency servicing if required. Your supplier should also stock a ready supply of spare parts and consumable items (such as filaments) that are essential to the operation of your CT.

Summary

AXT has Australia’s widest range of CT solutions from manufacturers such as Yxlon, TESCAN, Rigaku and Sigray. AXT also has access to the components and software needed to design and build custom solutions where the need arises. If CT technology is on your roadmap, please contact AXT to discuss your requirements.

AXT Australia Units 1-2 / 3 Vuko Place, Warriewood NSW 2102 Australia Phone + 61 (0)2 9450 1359 www.axt.com.au