About a week ago, the Cern nuclear team working on the Large Hadron Collider (LHC) restarted the machine, hoping to revolutionise our understanding of the universe.

Young Maltese scientist Nicholas J. Sammut is one of the scientists working on the machine at Cern (the European Organisation for Nuclear Research).

“We are really pushing the machine to the limit of mankind’s current technology,” he told The Malta Independent.

The LHC is a gigantic scientific instrument near Geneva, spanning the border between Switzerland and France about 100 metres underground.

It is a particle accelerator by means of which physicists are studying the smallest known particles – the fundamental building blocks of all things. It will revolutionise our understanding, from the minuscule world deep within atoms to the vastness of the universe.

The machine had been shut down for two-and-a-half months, during which the team worked on the machine to optimise all the systems, Dr Sammut told this newspaper.

“When the LHC ramps up, the magnetic field of the magnets that guide the particles around the machine varies quickly in a nonlinear manner.

“If these nonlinearities are not corrected, the particles oscillate out of their trajectory and the beam is lost. I have developed a system that corrects this and at the moment I am optimising it even more so that the tolerances under these new stringent conditions are maintained. I am currently writing a paper on this optimisation technique I found.”

Cern hosts about 6,500 scientists per day and 10,000 scientists per year. The performance of all the complex engineering systems has to be perfected, said Dr Sammut.

He explained that the machine is now being ramped up slowly and steadily, in the hope of reaching maximum energy in 18 to 24 months.

The plan is to reach a lower energy level to conduct some critical tests on the instrumentation and detectors. Then, once the team is confident that all systems are performing well and are fully optimised, it will go for full energy collisions at seven tetraelectronvolt (TeV).

“That is when we may start seeing new physical phenomena emerging. It is a long arduous road and we are being careful to make sure that the machine is optimised at each energy increase.

“We are already performing particle collisions at low energy and testing these events in our detectors. We do not exclude finding new physical phenomena at these relatively lower energies, but we expect to find most of the interesting things at full energy in 18 to 24 months.”  

The world record in particle acceleration – a record previously held by the American Tevatron machine – has already been broken.

He said these are exciting times for the researchers; naturally it is very rewarding for him to be part of this scientific journey.

“I have optimised the performance of the magnetic field during the energy increase. The machine is very complex and has many parts, but without this optimisation, it would have been very difficult, almost impossible, to even break the world record of particle acceleration, let alone supersede it to three times that energy. I am glad that my system is working the way I designed it to work.”

Asked to comment on his experience since the experiment started way back in September 2008, Dr Sammut said: “It has been a really fantastic experience – a dream come true in my case”.

Since he was a child, he always used to say he wanted to give a substantial contribution to science.

“I reached that aim and it gives me tremendous satisfaction. I would say September 2008 was the peak of the excitement. We had a grand success in the first beam injection.”

It was Dr Sammut himself who saw to the settings of the magnets to guide the particles around the machine, the first injection was a direct test of his project… “And my goodness it was being done in front of the world press!” he recalled.

“It was a very exciting day for me and for all of us there. Being in the control room with all my fellow scientists in front of the world press and successfully commissioning the machine is a feeling I will never forget. Science history was being written and I was part of it.”

This was of course followed by a let-down after we suffered a leak due to a cable fault only a few days after the experiment started, he said, although he was not involved in this fault.

The team managed to break the world record in particle acceleration after they got the machine running again.

“This was another exciting moment. Now we are continuing the journey towards reaching maximum energy. It is still an incredibly exciting time and the prospects are looking good. I can’t wait to start seeing the first new particle signatures coming out of full energy collisions!”