Isis keeps beaming

When physicists at ISIS, the world's leading pulsed neutron and muon source, at the

in Oxfordshire, began planning a second target station for neutron production in April 2003, they knew they faced a big challenge.

They also knew that building the new target station would give them an opportunity to improve construction of some of the major components of neutron production — the most fundamental being the hardware for the proton beam.

To make the improvements, ISIS called on

(MAC) to provide highly specialist metallised ceramic components for new monitoring equipment to be installed inside the proton beam apparatus. The ceramic vacuum tubes in the first target station were sealed with indium wire, but experience showed these could become unreliable if disturbed.

'Wires are a perfectly good vacuum seal, but the difficulty is that they are not very robust,' said Eamonn Quinn, senior project manager at Rutherford Appleton. 'If you move the [proton beam] instrument or if you put loading on its flanges, there is a risk that the indium seal will fail and you have to remake it or at least retighten that seal.'