![]() "Hopefully what we discover will enhance understanding of the basic building blocks of our Universe. “The new caesium fountain is essential to our continuing effort to determine if hydrogen and antihydrogen behave in the same way. Professor Stefan Eriksson of Swansea University, who is leading ALPHA’s caesium fountain project, says: "Providing superior accuracy to measure the frequency of light absorbed by antimatter, the atomic fountain clock demonstrates the importance of investment in world class facilities and the role they play in underpinning breakthrough discoveries and is an excellent example of academic and public sector research establishment collaboration.” ![]() “This exciting device will further cement the UK’s role as a leading nation in the community of researchers studying the properties of antimatter. Jane Nicholson, Executive Director for Research Base at EPSRC said: ![]() The UK is a key partner in ALPHA and the capability provided by the caesium fountain reinforces the UK’s status as a global leader in the field of low-energy antimatter research. This could shed light on why there seems to be very little antimatter in the Universe today, even though it is generally held that equal amounts of matter and antimatter were created in the Big Bang 13.8 billion years ago. The results will show whether, in-line with conventional theory, hydrogen and antihydrogen have exactly the same (though mirror-image) properties. Integrating the instrument with the experiment onsite avoids ALPHA having to access this kind of capability via satellite link, minimising inaccuracies in measurements taken. One of just a few of its kind in the world, this caesium fountain is unique in its reliability and robustness, crucial to withstanding the demands ALPHA will place on it. It is anticipated that this will be achieved within the next few years. The goal is to achieve a level of precision that represents a thousand-times increase compared with current knowledge. This will provide an ultra-accurate reference against which ALPHA can measure antihydrogen atoms’ interaction with laser light, enabling the frequency of light that antihydrogen absorbs to be determined. Microwave radiation measures the frequency with which these atoms oscillate, to the fifteenth decimal place. ![]() Laser-cooled caesium atoms held in a vacuum chamber are launched up into a magnetically controlled tube before falling back down again. The caesium fountain is enclosed in a case around two metres tall. The caesium fountain was designed and built at the National Physical Laboratory (NPL), the UK’s national metrology institute in Teddington, Middlesex. This is vital to understanding the extent of the symmetry between matter and antimatter, a big question at the heart of how the Universe works. The caesium fountain will help ALPHA determine the frequency of light absorbed by antihydrogen (hydrogen’s antimatter counterpart) with the same accuracy as has already been achieved for hydrogen. Denmark’s Aarhus University has provided additional support, with funding from the Carlsberg Foundation. Swansea University has led UK involvement in ALPHA, funded by EPSRC. Parents and Guardians Guide to Universityīuilt in the UK with support from the Engineering and Physical Sciences Research Council (EPSRC), it has now been installed at the iconic CERN facility to support the pioneering Antihydrogen Laser Physics Apparatus (ALPHA) antimatter experiment.This locked frequency is then divided by 9,192,631,770 to give the familiar one pulse per second required by the real world. This peak is then used to make the slight correction necessary to bring the crystal oscillator and hence the microwave field exactly on frequency. A detector at the end of the tube gives an output proportional to the number of cesium atoms striking it, and therefore peaks in output when the microwave frequency is exactly correct. When a cesium atom receives microwave energy at exactly the right frequency, it changes its energy state.Īt the far end of the tube, another magnetic field separates out the atoms that have changed their energy state if the microwave field was at exactly the correct frequency. The range of the microwave generator is already close to this exact frequency, as it comes from an accurate crystal oscillator. The frequency of the microwave energy sweeps backward and forward within a narrow range of frequencies, so that at some point in each cycle it crosses the frequency of exactly 9,192,631,770 Hertz (Hz, or cycles per second). First they pass through a magnetic field that selects atoms of the right energy state then they pass through an intense microwave field. To create a clock, cesium is first heated so that atoms boil off and pass down a tube maintained at a high vacuum. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |