The Large Hadron Collider, a £1.5 billion particle accelerator, will need a £2 billion machine to examine the discoveries it makes, the head of the European Committee on Future Accelerators will say next week.
Brian Foster, chair of the committee and professor of physics at the University of Bristol, will tell the European Physical Society's high-energy physics meeting in Aachen, Germany, that plans for a linear accelerator are gaining political support. This will be completely different in design from the circular LHC, which is due to enter service in 2007, He said: "It seems very likely that there will be only one machine in the world in this class. That means it has to have worldwide support, and it has already got backing from the Organisation for Economic Cooperation and Development's Global Science Forum."
Professor Foster said: "The LHC is going to be a very good discovery machine because it will work by colliding comparatively large particles such as protons at very high energy. When they collide, you get a huge spread of energy that maximises the chances that you will see something new from the collision."
First among its targets will be the Higgs boson, a particle associated with one of the most basic properties of matter - its mass.
Professor Foster said: "The new machine we are looking at will be a linear collider, a long, straight machine that will be used to collide electrons and positrons (particles identical to electrons but with the opposite electrical charge). As far as we can tell, these are simple, point-sized objects, and when they collide they do so with maximum energy every time.
"That means that under any possible result we can envisage from the LHC, this machine will tell us in detail what we have discovered. If there is a Higgs boson, for example, the LHC will find it but the collider will tell us its size, mass and other properties exactly.
"In the past, we have had big advantages from having a hadron collider and an electron one running at the same time. We hope to get started on this machine soon to get the same benefits."
The UK invested in the collider's development phase in the last round of the spending review, but it has yet to make a formal commitment to the full project.
Exactly who would build the collider and where is a tricky issue because Cern, the Swiss laboratory where the LHC is under construction, has been blamed for cost overruns on the project.
Professor Foster said that this aspect of the plan was likely to be discussed at a meeting of world science ministers in 2004.