New research from the School of Physics & Astronomy (Institute for Gravitational Research) and the School of Engineering (Electronic & Nanoscale) has led to the development of a first MEMS gravimeter, fabricated in the James Watt Nanofabrication Centre, which could revolutionise the way gravity surveys are performed.
In a new paper published in the journal Nature, researchers discuss their work which shows the first measurement of Earth Tides with a MEMS device. The earth tides are a twice daily variation in the local gravitational field of approximately 200 parts per billion, and the measurements reported show the MEMS gravimeter to have the sensitivity and long term stability necessary for gravity surveying and imaging.
Dr Giles Hammond, Reader in the School of Physics and Astronomy, who led the work on the Physics side said: “The collaboration between Physics and Engineering has developed over the last 3 years, initially starting with a Glasgow sensors studentship and Royal Society Paul Instrument funding. The research is now a main theme of the QuantIC quantum technology hub in quantum enhanced imaging, and has gained significant buy-in from industrial partners”
Mr Richard Middlemiss, PhD student on the project, stated; “There are a lot of potential industrial applications for gravimeters, but their cost and bulkiness have made them impractical in many situations. Our device opens up the possibility of making gravity measurement a much more realistic proposition for all kinds of industries, from unmanned aerial vehicles equipped with sensors to survey large areas for oil and gas quickly, all the way to navigation in small satellites known as cubesats to maintain their orbit around the Earth, the focus of a current EngD”
Prof Douglas Paul, of the James Watt Nanofabrication Centre Executive Team and EPSRC Quantum Technology Fellow said: “We have taken the silicon microfabricated MEMS technology which is used to make the accelerometers in every car airbag and smartphone but we have managed to engineer the sensitivity to be over 10,000 times better. Present gravimeters are big and therefore expensive to be stable over periods of up to a week but similar to Harrison’s approach that won the Longitude Act prize over 250 years ago, we have engineered a miniature MEMS gravimeter that drifts less.”
Prof Sheila Rowan, Head of the Institute for Gravitational Research, further stated: “The expertise of the Institute for Gravitational Research in developing precision opto-mechanical systems has been essential to develop this applied research theme. By combining the groups expertise together with the James Watt Nanofabrication Centre, we have been able to make a remarkable new sensing device”
The QuantIC team comprising, Mr Steven Bramsiepe, Dr Giles Hammond, Dr Stefan Hild, Prof James Hough, Mr Emanuelle Ghisetti, Mr Richard Middlemiss, Dr Antonio Samarelli, Prof Douglas Paul, Prof Rowan are now working on developing a field prototype unit with industry, which can be used to monitor gravity signals without the need for any mains power.
The research team's paper, titled 'Measurement of the earth tides with a MEMS gravimeter', is published in Nature. and is reported on in the BBC web pages.