CAN Revolutionary laser system produce the next LHC

An international team of physicists has proposed a revolutionary laser system, inspired by the telecommunications technology, to produce the next generation of particle accelerators, such as the Large Hadron Collider (LHC) in CERN.

The International Coherent Amplification Network (ICAN) sets out a new laser system composed of massive arrays of thousands of fibre lasers, for both fundamental research at laboratories such as CERN and more applied tasks such as proton therapy and nuclear transmutation.

Lasers can provide, in a very short time measured in femto-seconds, bursts of energy of great power counted in peta-watts or a thousand times the power of all the power plants in the world.

Compact accelerators are also of great societal importance for applied tasks in medicine, such as a unique way to democratise proton therapy for cancer treatment, or the environment where it offers the prospect to reduce the lifetime of dangerous nuclear waste by, in some cases, from 100 thousand years to tens of years or even less.

Major Difficulties
However, there are two major hurdles that prevent the high-intensity laser from becoming a viable and widely used technology in the future.

• First, a high-intensity laser often only operates at a rate of one laser pulse per second, when for practical applications it would need to operate tens of thousands of times per second.

• The second is ultra-intense lasers are notorious for being very inefficient, producing output powers that are a fraction of a percent of the input power. As practical applications would require output powers in the range of tens of kilowatts to megawatts, it is economically not feasible to produce this power with such a poor efficiency.

Technological Consortium
To bridge this technology divide, the ICAN consortium, an EU-funded project initiated and coordinated by the Ecole polytechnique and composed of the University of Southampton Optical Research Centre (ORC), Jena and CERN, as well as 12 other prestigious laboratories around the world, aims to harness the efficiency, controllability, and high average power capability of fibre lasers to produce high energy, high repetition rate pulse sources.

The aim is to replace the conventional single monolithic rod amplifier that typically equips lasers with a network of fibre amplifiers and telecommunication components.

Gerard Mourou

Gerard Mourou of Ecole polytechnique who leads the consortium says: "One important application demonstrated has been the possibility to accelerate particles to high energy over very short distances measured in centimetres rather than kilometres as it is the case today with conventional technology."

"This feature is of paramount importance when we know that today high energy physics is limited by the prohibitive size of accelerators, of the size of tens of kilometres, and cost billions of euros."

"Reducing the size and cost by a large amount is of critical importance for the future of high energy physics."

Dr Bill Brocklesby

Dr Bill Brocklesby from the ORC adds: "A typical CAN laser for high-energy physics may use thousands of fibres, each carrying a small amount of laser energy."

"It offers the advantage of relying on well tested telecommunication elements, such as fibre lasers and other components."

"The fibre laser offers an excellent efficiency due to laser diode pumping. It also provides a much larger surface cooling area and therefore makes possible high repetition rate operation."

"The most stringent difficulty is to phase the lasers within a fraction of a wavelength."

"This difficulty seemed insurmountable but a major roadblock has in fact been solved: preliminary proof of concept suggests that thousands of fibres can be controlled to provide a laser output powerful enough to accelerate electrons to energies of several GeV at 10 kHz repetition rate - an improvement of at least ten thousand times over today's state of the art lasers."

Such a combined fibre-laser system should provide the necessary power and efficiency that could make economical the production of a large flux of relativistic protons over millimetre lengths as opposed to a few hundred metres.

Societal Application
One important societal application of such a source is to transmute the waste products of nuclear reactors, which at present have half-lives of hundreds of thousands of years, into materials with much shorter lives, on the scale of tens of years, thus transforming dramatically the problem of nuclear waste management.

CAN technology could also find important applications in areas of medicine, such as proton therapy, where reliability and robustness of fibre technology could be decisive features.

Revolutionary New Burn dressing 'lights up' to signal an infection

Scientists have developed a medical dressing that 'lights up' when a burn is infected.

It could be lifesaving in young children with serious burns in whom infections can rapidly become fatal, the Bristol researchers said. 

A prototype is available for demonstration purposes but trials in humans are still some years away.

Fast diagnosis of infection in children with burns, such as those caused by scalds from hot drinks, is a big problem for clinicians, the researchers said.

Current tests for an infected wound can take up to a couple of days but children - especially those of pre-school age - are particularly at risk from the effects of infection due to their relatively poor immunity.

They can quickly develop a condition called toxic shock syndrome, which if left untreated can be fatal in half of cases.

Fluorescent dye 
The dressing developed by scientists at the University of Bath uses nanocapsules containing a dye that burst open in the presence of disease-causing bacteria.

Using a UV light, doctors can quickly check whether there is infection by seeing if the dressing glows.

The nanocapsules are activated when they come into contact with toxins produced by harmful bacteria, so do not release the dye in response to normal bacteria that live on the skin.

So far the dressing has been tested on skin samples in the laboratory.

Dr Toby Jenkins

Dr Toby Jenkins, reader in Biophysical Chemistry at Bath, and project lead said about 5,000 children a year in England and Wales are treated in hospital for burns.

"The big problem for clinicians is the fast diagnosis of infection. Current methods take between 24 and 48 hours to get an answer as to whether the wound is infected.

"However, our burns dressing gives a simple colour change under UV light if a pathogenic, disease-causing bacteria is present in the burn, meaning clinicians can be alerted quickly to a potential infection."


Dr Amber Young, consultant paediatric anaesthetist at the South West Paediatric Burns Centre at Frenchay Hospital in Bristol and clinical adviser to the project said when a child with a small burn develops a high temperature there is no easy way of knowing if the child has a serious bacterial infection, or simply a cough or cold.

Dr Amber Young

"We currently have to remove the dressing to test for infection, which may result in slower healing and potentially life-long scarring and is very distressing for the child.

"This new dressing will mean we will be able to detect the early signs of infection so we can diagnose and treat the child quickly."

Prof Sheila MacNeil

Prof Sheila MacNeil, from Sheffield University, said the technology was based on two clever concepts - that it only reacts in the presence of life-threatening bacteria and that the florescent dye only shows up once the nanocapsules have burst.

"It has been developed for use in paediatrics but it could also be useful in lots of other contexts, such as the management of chronic ulcers in the home," she added.