Building the Polaris instrument at ISIS
14 Mar 2012



Steve Hull, Jon Randall and Ron Smith talk about the Polaris instrument at ISIS, one of the most advanced neutron instruments in the world.




Steve Hull: “I’m Steve Hull and this is Polaris. The Polaris diffractometer will use neutrons from the ISIS source. Those neutrons will be used to perform diffraction experiments on materials. Polaris will be used primarily for chemistry and physics.

So when the instrument is finally operational, there will be another plate on the end here with detectors in, another plate on the far end with more detectors in, and this whole chamber here will be pumped out to a reasonable vacuum,  to stop any air scattering of the neutrons as they pass from the samples to the detectors.

This project has been running for around four years, with costs of around £4 million in total. We can start looking at chemical reactions as they occur within reaction vessels. We can look at how products are made from their starting materials, using cells such as this. Scattered neutrons will then go off into these detectors here. In there, when a neutron hits a scintillator, it gives a little flash of light. That flash of light then goes off as a signal into the electronics. From that we can build up a diffraction pattern and from that diffraction pattern we get information about the structure of the atomic arrangement of the material which is inside the cell.

The new Polaris instrument has a whole range of detectors covering a wide range of angles. Using those large detectors, we can collect diffraction data very quickly. A typical experiment on Polaris would last one or two days and during that time we would expect to do measurements on a dozen or so samples. At the fasted, we would be able to collect data perhaps in a second. But if we want to do more detailed measurements, we would want to collect data for up to an hour ".

Jon Randall: “The process of bringing the actual finished item across involves a lot of people. We have had to clear pathways, make sure that there is a safe route to come down and that the route is big enough to take the tank.

All of the work and the effort that everybody has put in on every section and to finally get it installed is such a big achievement ”.

Ron Smith: “We have got almost a thousand photomultipliers here which need to have cables connected to them. We have a team of electricians and it will take them probably two or three weeks to get all the cables routed in and connected up to all the ends.  We have got groups from UK and overseas universities waiting to do their experiments. It will be good to get them back here, get them on the beamline, and get them collecting their data. There’s a lot of science waiting to be done”.​