Science & Technology, Singapore (Commonwealth Union) – A significant discovery set to play a significant role in medicine and industry with experimental findings have indicated that the recoil causes X-rays to lose energy, possibly impacting practical applications.
For the 1st time since it was suggested more than 80 years ago, scientists from Nanyang Technological University, (NTU) have indicated the phenomenon of “quantum recoil”, defining how the particle nature of light has a significant effect on electrons moving through materials.
Turning quantum recoil into a practical possibility will pave the way for businesses to more precisely form X-rays of specific energy levels, that can bring greater accuracy in healthcare and manufacturing applications like medical imaging and flaw detection in semiconductor chips.
Quantum recoil theory was forwarded by Russian physicist and astrophysicist Nobel laureate Vitaly Ginzburg in 1940 which precisely accounted for radiation emitted while charged particles such as electrons move via a medium, like water, or materials having repeated patterns on the surface.
This radiation is formed when electrons in motion disturb atoms in the medium or the material. When the atoms return to an undisturbed state, they transmit radiation, that include X-rays.
As electrons are meant to eliminate energy and reduce speed when this happens, the classical theory forecasts that its effects on the emitted radiation is insignificant.
But, Ginzburg forwarded that this conclusion breaks down while exploring the quantum electrodynamics theory dealing with the way charged particles engage with an electromagnetic field, and how light engages with matter.
The theory indicates, that when electron movement slows down after disturbing atoms close to it, the energy and momentum these electrons lose must be transferred to the transmitted radiation. This occurs due to light existing as particles containing energy and momentum, moving in a wave as radiation.
The transfer leads to the energies of the radiation emitted to shift from classical predictions and also impact the reduced speed of electrons making them deviate from their traveling path.
This phenomenon is referred to as quantum recoil. But it was unable to be proven till the present.
The Singapore scientists, led by Nanyang Assistant Professor Wong Liang Jie from the NTU, School of Electrical and Electronic Engineering, showed the phenomenon via separate experiments that bombarded electrons from a scanning electron microscope onto 2 very thin materials, around 1,000 times thinner than a strand of hair.
The 2 materials were boron nitride in a hexagonal form regularly utilized as lubricants for paints, and graphite used in rechargeable battery terminals as well as pencil lead.
Dr Edward Morton, the Chief Technology Officer of Singapore medical diagnostics equipment manufacturer CTmetrix a non-participant of the research says “Quantum recoil is key to optimising the X-ray source energy and cannot be ignored.”
CTmetrix has applied for the utilization of the NTU patent to produce more compact and precise tuneable X-ray machines to be used in the biomedical imaging of human tissue samples. The company hopes to have a prototype ready by the end of this year.
“We see the market for tuneable X-ray sources to be in medical diagnostics of tissue samples taken from patients, for the rapid analysis of a tumour or other biological materials. In this way, tuneable X-ray sources can help medical diagnosis be more accurate, with immediate analysis even within the operating theatre,” said Dr Morton, in referance to the small size of the X-ray machines capable of being achieved via the exploitation of the NTU patent.
“This has great potential for improving clinical diagnosis and patient outcomes,” he added.
Another Singapore company that was not part of the research looking to use the patent is Component Technology, supplying visual inspection solutions for the semiconductor industry. The firm hopes to produce tuneable X-ray inspection machines for the verification of various layers of semiconductor chips for defects, such as voids.
