We have all seen the cop shows where the suspect denies he has ever been to the scene of the crime, only to have the CSI laboratory analyze grit from his tires or his shoes, identify a match, and his alibi falls apart.
Great viewing – but how does that help us in business?
Well, the technology that the labs used to place the suspect at the scene would have been x-ray diffraction, a way of looking at the crystalline structure of the soil and all its component parts. In the crime scene scenario, it would have involved matching two samples but the applications of the technology go much further than this.
How does it work?
It’s a bit like the light from a torch hitting a prism and creating an iridescent pattern on the wall.
Simply put, an X-ray beam is directed at a sample, and the pattern of diffraction – the way the x-ray spreads out when it hits the sample – is analyzed. Crystalline elements have defined patterns of diffraction so during analysis the exact makeup of the tiniest sample – including how many different elements there may be in that sample – can be established.
In the pharmaceutical industry, xray diffraction can be used to measure the purity of a sample. Critical when monitoring the effects of a drug trial for example would be in understanding the purity and therefore strength of the elements of a new product. Similarly when moving into production then monitoring the purity of the elements making up that drug, and building that into any quality analysis will ensure consistency and therefore market safety in the mass-produced product.
The technology naturally lends itself to geological studies – understanding from small core samples the makeup of soil beneath the surface; looking for the presence of chemical elements under thousands of years of ice; checking sea bed samples to investigate sand drift between two points. Significant decisions in any number of industries including mining and conversely conservation might be informed by X-ray diffraction analysis.
And then there’s space exploration! It is many years since soil samples were taken from the moon, but with spacecraft trailing comets and collecting dust from their tails, and NASA’s Mars exploration rover looking for signs of water, all these will be subject to X-ray diffraction analysis just to understand what elements that we know of are out there and what new elements may be found.
One advantage of X-ray diffraction is that it is a non-destructive process, meaning the sample itself is not damaged during the analysis. When you are looking at comet dust or lunar samples where the cost of gathering a sample is so high and the sample returned is so small, this is a critical factor when considering how best to investigate what we have.
Other industries are less concerned with identifying what elements may be present in a sample – they know because they put them there. Their interest in the technology is in measuring the size of certain crystals. Industrial applications where perhaps a film is to be laminated over another X-ray diffraction can inform the ideal thickness of the film to have the desired effect, whilst minimizing unnecessary and potentially costly additional thickness.
Finally, again in the manufacturing sector, X-ray diffraction can be used to determine the effects of stress on certain elements. With its ability to examine crystalline makeup at a molecular level, the diffraction patterns can change if the links between the atoms that make up the sample – the connecting lattice – are subjected to stress. So if manufacturing a product that has to withstand extremes in temperature, pressure, or forces of opposition (stretching) close monitoring of the connecting lattice will give an idea of the stress that can be absorbed before breaking. Those calculations than in turn inform the capability of those products to perform.
Whether it be in determining the elements that make up a sample and what that tells us about its location; whether it be in ascertaining the purity of a given sample and what that tells us about the amount to use and its effects, or whether it be in looking at the lattice of connectivity between atoms and how them behave under stresses, the science of Xray diffraction can shed light on all of these investigations.
So consider the questions that can be answered by analyzing that one grain of sand – the truths if you will, to be determined from the smallest of samples, that can inform the biggest of decisions.
