Scientists at Diamond use lots of different techniques to carry out their research. Diffraction is a natural phenomenon and an important tool that helps scientists unravel the atomic structure of our world.
What is it?
You encounter diffraction every day. In fact, you’re probably experiencing its effects right now. The murmur of background noise, the levels of heat or light in a room – all of these are related to diffraction.
Think of waves on the ocean; they behave in the same way as light and sound. When water waves hit an object like a rock or a boat, their trajectory is changed and they disperse in a different pattern.
The same is true of light and sound waves. You can have a covert natter at work or school because the sound from your conversation bounces off walls and is spread out as it hits surrounding objects. This causes the waves to become distorted so that they reach others as a murmur of blurred sound. And it’s not just sound; light and heat are also affected by diffraction. We don’t tend to install radiators or lamps behind TVs or fridges because the objects will interfere with the waves, leaving your room rather cold and dark.
Once you understand the process of diffraction, it seems quite clear. But it took a while for scientists to work out what was going on. Wave diffraction was first observed in the 17th
century, but it wasn’t until 1803, when Thomas Young performed an experiment to observe waves diffracting through two slits, that the phenomenon began to be more fully understood. Young’s nifty diagram of wave diffraction was to have vital significance; in 1952, Rosalind Franklin and Raymond Gosling used diffraction to produce the image of DNA that Watson and Crick would later use to solve the structure.
Since the 20th
century, diffraction has been cornerstone of modern science, permeating virtually every aspect of research.
If you shine a bright light at an object, it produces a diffraction pattern as it leaves the sample. This is because the light bounces off each atom inside the object, creating a unique arrangement of light and dark spots. This pattern can then be used to identify the atomic structure of the object itself.
Some samples can be tricky to study using diffraction. That’s why scientists use a technique called crystallography to freeze their samples into ice-like crystals. If it’s crystallised first, then almost anything – from virus structures to ancient fossils – can be studied using diffraction. Knowing the structure of diseases is the first step in creating better treatments. Identifying the structural composition of water samples can provide insights into pollution levels and climate change. Understanding the atomic nature of samples is vital to all areas of modern research, and that’s why diffraction is such an important scientific technique.
Diffraction at Diamond
Diamond Light Source is a valuable tool for scientists who want to determine the atomic structure of crystallised samples. The bright beams of synchrotron light can pass through objects such as DNA, viruses, industrial materials, and chemical solutions, and produce a diffraction pattern that provides a clear indication of the sample’s structure.
Our scientists use diffraction to develop stronger materials for cars and aeroplanes, to identify the impact of climate change, and to develop new and more effective drugs for disease. Diffraction is an essential technique in modern science, and its discovery has led to some of the most significant scientific advances in history. The simple practice of shining a light on samples to determine their structure has helped scientists to illuminate some of the most complex and beautiful aspects of our world.