Want to learn more about one of science's heroes from history, Henry Moseley? Moseley solved one of chemistry's greatest puzzles - determining what distinguishes elements from one another and developed a means of identifying elements based on their atomic characteristics. Sadly he lost his life fighting at Gallipoli in WWI.
Learn more about his life and legacy by watching our online film here.
The noble gases are so named because they rarely react with other elements. Helium, neon, argon, krypton, xenon and radon atoms all have a full outer valence shell of electrons, which makes them quite unreactive. They are the only chemical elements that are stable single atom molecules at standard temperature and pressure, and are usually colourless and odourless.
Noble gases have important industrial applications, including lighting, welding, and space exploration, and blimps and balloons switched to helium after accidents involving flammable hydrogen. At Diamond, liquid helium is used on some of the beamlines, to cool samples to below 10 K (-263°C).
The second most abundant element in the universe, helium, is most often associated with party balloons and squeaky voices. But with a boiling point −270 °C (about 4 K), liquid helium also makes the world’s best coolant. The world uses around 30,000 tonnes of helium every year, most of which is a by-product of the natural gas industry.
At Diamond, an electron’s journey from source to storage ring is a tale of high power, split-second timing and frankly terrifying voltages. Only once the electrons have been accelerated by the equivalent of three billion volts in the booster ring can they be transferred to the storage ring, where they can release their energy as light to the beamlines. In the storage ring, their orbit is maintained by transmitters providing over 400 kilowatts of radiofrequency (RF) power to replace the energy lost to the beamlines. Electric fields accelerate the electrons in two cavities operating at a combined voltage of two and a half million volts. With such enormous electric fields in the cavities, huge currents are induced in the cavity walls: in a normal metal the cavity would heat up and waste energy, but Diamond’s storage ring cavities are made of niobium, a material that becomes superconducting at temperatures near absolute zero (-269°C), losing all electrical resistance. A closed circuit of liquid helium cryogenic coolant keeps the cavity cold and superconducting, maximising the efficiency of the storage ring. Read more here.
Diamond’s Surface and Interfaces group is home to six beamlines with a range of techniques for investigating structural, magnetic and electronic properties of surfaces and interfaces. Many of those beamlines rely on a Sample Manipulator to hold samples securely in an X-ray beam less than a tenth of a millimetre across, whilst also enabling them to move and rotate around multiple axes and rotate around each axis. The differing requirements of each beamline mean that the basic design of the Sample Manipulator is customised for each one.
For some experiments the Sample Manipulator is required to ‘clean’ the sample by heating to over 1200 K (1000°C). In others, investigation of magnetic properties requires cooling the sample to below 10 K (-263°C) using liquid helium. Fast cooling, good thermal stability at cryogenic temperatures and low liquid helium usage during long experiments are all critical requirements.
I10 is Diamond’s beamline for Advanced Dichroism Experiments (BLADE), and is equipped with a superconducting magnet 300,000 times the strength of the Earth’s magnetic field. BLADE also records the lowest temperature at Diamond: 300 mK – a chilling -272.85 °C. The superconducting magnet system was supplied by Oxford Instruments to challenging specifications. It is able to sweep from -14T to +14T in less than an hour, and all of the cooling liquid helium used during magnet sweeping is recondensed for reuse. BLADE’s RASOR end station is a soft X-ray diffractomer, equipped with a liquid helium cryostat that enables samples to be cooled to 12 K. Read more here.
Scientists working at Diamond’s Extreme Conditions beamline (I15) carried out experiments looking at the properties of unusual compounds of the noble gas xenon. Because conditions of extreme pressure prevail deep inside both the Terrestrial and Giant planets, their work improved our understanding of the chemistry of inaccessible planetary interiors and, ultimately, the properties of warm dense matter.
Simple, ‘inert’ gas atoms can solidify, alloy or bond under extreme pressures, and the researchers loaded xenon-helium and xenon-hydrogen mixtures into a diamond anvil cell (DAC). They brought the DAC to Diamond to look at the gas structures with an intense and collimated X-ray beam. In the case of the xenon-helium mix, the studies found that the xenon behaves just as it does when pure. For the xenon-hydrogen mix, the story was more complicated. Two distinct H2-Xe solids were identified depending on the initial concentration of xenon in hydrogen. Read more here.
In 2017, British adventurer Tom Morgan flew over South African countryside, carried aloft in a chair attached to 100 helium balloons. He flew 15 miles (24km) in two hours, reaching an altitude of 8,300 feet (2,530 metres), and later remarked that “It was a fairly indescribable feeling, wafting across Africa on a cheap camping chair dangling from a load of balloons.”
Diamond Light Source is the UK's national synchrotron science facility, located at the Harwell Science and Innovation Campus in Oxfordshire.
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