HIGH SCIENCE and cinematic thrills join forces in a film that opens today. Angels and Demons,which is on general release tomorrow, tells the story of a plot to blow up the Vatican using "antimatter" stolen from Cern, the European Organisation for Nuclear Research. While it is currently impossible to build such a bomb, antimatter is very real and is a hot research topic for physicists working at Cern, writes DICK AHLSTROM
Irish scientists are deeply involved in the production and analysis of antimatter at Cern, which is located on the French-Swiss border near Geneva.
NUI Maynooth PhD graduate Dr Paul Bowe leads the group producing antimatter on Cern’s Alpha experiment. One of his team members is an Irish PhD student, Eoin Butler.
Meanwhile, University College Dublin’s Dr Ronan McNulty, who leads the only experimental particle physics research group in the Republic, is involved in Cern’s LHCb antimatter experiment. It is one of the major experiments attached to the Large Hadron Collider (LHC), the 27km-long atom smasher that can also produce antimatter particles.
Antimatter is easy to understand but very difficult to handle, says Dr Bowe. Our universe apparently consists of nothing but “ordinary” matter, the stuff that we, the things around us, the planets and the stars, are made of. The atoms in matter have a positively charged nucleus surrounded by negatively charged electrons.
Antimatter is the reverse of this. Its atoms have a negatively charged nucleus, called an “antiproton” and positively charged electrons called “positrons”.
BOTH FORMS OFmatter adhere to the laws of physics and equal amounts should have been formed when the energy released by the Big Bang began to condense into matter. Yet we don't see antimatter today, only ordinary matter in our universe, and this has become a major question in physics, according to Dr Bowe. "We hope to understand a little bit more why we are living in a matter universe and not in an antimatter universe."
He makes “antihydrogen” – antimatter hydrogen – on Cern’s Alpha experiment. The team separately produces antiprotons and positrons and then puts them together. Some particles will join to form atoms of antihydrogen. Alpha can produce tens of thousands of atoms in a matter of minutes.
Forcing them to sit still is another matter, “We have to keep the particles at a very low velocity. The real key is that the particles are moving very slowly when they form. If the antihydrogen is slow enough it will stay in the trap,” says Dr Bowe.
The “trap” is a combined electrical and magnetic field that holds the antihydrogen in place without allowing it to touch anything, but the space has to be extremely cold to make the antiatoms move slowly. They are trying to bring this down to just one degree Kelvin, or -272 degrees.
Dr Bowe believes that in time they will be able to hold antihydrogen for some hours or even days. The longer they can hold it in place the more they can learn from it, he says.
Alpha can make antiatoms, but so far can't trap them long enough to provide the Angels and Demonsvillains with a workable bomb. But what of the other main source of antimatter particles being produced at Cern, the LHC? Could this help them make a bomb? Definitely not, according to Dr McNulty.
The LHC accelerates particles to near the speed of light and then smashes them together to release huge amounts of energy, he explains. Some converts back to antimatter particles. He studies a tiny fragment of an atom known as a “beauty antiquark”.
The antiquark “lives for a very, very short period of time”, travelling almost at light speed for about a centimetre before it decays, says Dr McNulty. The LHCb, which his team helped build, is a remarkable detector that can track the antiquarks as they interact with matter.
“With the LHC we try to recreate the conditions of the early universe,” he explains.
It tells them what the universe was like 10 billionths of a second after the Big Bang. “We create matter and antimatter and then see what happens, how they balance out.”
Dr McNulty says it is a shame Ireland is not a formal member of Cern. He gains access via his links with the University of Liverpool and Dr Bowe via the University of Aarhus. “I think it is a shame because we are missing out on a great worldwide opportunity.” Commercial opportunities are also being missed, he says. The Government makes much of the need to develop a knowledge economy. “We have to put our money where our mouth is. We have to make a commitment.”
Dr Bowe agrees. “Modern society is based on science and this is one of the great collaborative scientific efforts,” he says.
A free public discussion about antimatter and its importance titled
Angels, Demons and Anti-matter
, takes place at the Royal Irish Academy, Dame Street, Dublin, on Tuesday June 2nd at 6 pm. Organised by The Royal Irish Academy and
The Irish Times
, speakers include Paul Bowe, Tara Shears, Ronan McNulty and UCD emeritus professor Alex Montwill. The talk will be chaired by
Irish Times
Science Editor, Dick Ahlstrom. Admission is free. Booking is required. See ria.ie
Angels and Demonsis reviewed in The Ticket tomorrow