Meet the scientists!

The ISIS facility is a neutron source – visiting scientists come to experiment on samples using the neutrons we produce.  A particle accelerator is required to make these neutrons.  Protons are accelerated to 84% the speed of light and then smashed into a target which produces neutrons.  My job as an accelerator physicist involves helping to operate the particle accelerators at ISIS – essentially making sure the protons get up to speed!  I also help with development of our current accelerator technology and help to design potential future accelerators.

The entire acceleration process at ISIS starts with a H- ion source (a Hydrogen with an extra electron) and these are accelerated in a linear accelerator (linac) up to 34% the speed of light.  The H- ions then pass through a thin foil which removes the two electrons, leaving just a bare proton.  This is good – it’s the protons we accelerate next!  These protons then get further accelerated to 84% the speed of light.  This happens in a circular accelerator called a synchrotron.  Protons are positively charged.  What’s cool about charged particles is that they are accelerated by electric fields and will change direction (be deflected) in the prescence of magnetic fields.  As the particles speed up (as they are accelerated by electric fields) they are bent around on a circular orbit by magnets.  The strength of these magnets needs to increase as the protons speed up to keep the protons on a cirular orbit – it’s all synchronised, hence the name synchrotron!  The ring is 163 m in circumference and it takes 10,000 revolutions for a proton to reach 84% speed of light.  Those 10,000 revolutions take only 10 ms!  And the whole process is run at 50 Hz which means it does this 50 times per second, or alternatively you could say the process runs once every 20 ms…  When I talk about protons, I don’t mean 1 or 2 protons, I mean a lot of protons – roughly 2E13, so that’s 20000000000000 protons whizzing around getting up to 84% the speed of light 50 times per second!  Don’t worry if these numbers seem crazy to you – they seem crazy to everyone!  Once they reach this speed they are extracted from the ring and taken towards one of two target stations, where they smash into the target to produce neutrons!

And that’s where my knowledge of ISIS really stops I’m afraid…  I help make the neutrons and then other scientists (like some in this zone, Natalia and Andrew go and do some cool science with them)!

I joined ISIS two years ago as part of the STFC Graduate Scheme, I came straight from University.  During the initial two years there was plenty of training on all aspects of accelerator physics as well as many other work-related skills (including a week-long sailing trip with other graduates as a team building exercise)!   There’s also loads that I get to do working at the lab besides science – there’s lunchtime football leagues, rounders leagues, tennis ladders, music clubs, all-sorts and with over 1500 people working on-site there’s never a dull moment!

I’m currently working on numerous accelerator physics projects, all of which are vastly different.  A few to highlight are:

• an individual research project looking at making a proposal for a new experiment I’d like to do
• a software (computational simulation) project working in a small team of two other accelerator physicists to try and predict the physical phenomena observed with beams of high energy particles
• a much larger project, working closely with both physicists and engineers, looking at how we could design and build potential future accelerator upgrades for ISIS.  By improving the accelerators we will be able to accelerate more protons to higher speeds – which would be great!

It’s really important to tell people about the science you do, so all this work is documented, reports are written and results/conclusions are presented to my peers.  This year I was also able to display my work at a major international conference in Spain.  Conferences are a great opportunity to meet others in your field of work – and it means you get to travel to some awesome places too!

Alongside the main projects I’ve also been able to work in various “Graduate Scheme” projects which are less technically focused, such as producing recruitment material, organising “inset” days for new starters and being a representative on decision making boards within the organisation.  I’m also responsible for updating content on our group website.  Most of the work is computer based but I do find myself still doing simple calculations and planning by hand.  On a typical day I would tend to focus on one or two projects, as well as replying to emails, attending meetings and occasionally giving tours of the facility.

I have a couple of options floating around my head, nothing solid as yet…

1)      Last year I made a model to demonstrate the ISIS accelerators and it seemed to go down quite well.  People could come and “accelerate protons” themselves and witness some of the challenges involved.  It was made of off-cuts of hardboard, a stripped down power drill, a remote control car wheel, a lazy-susan base with bearings, some acrylic tubing, plant pots, nasty grey paint and chocolate footballs for protons.  It did the job quite well but I reckon with £500 I could make an even better model, made out of better materials, make it more professional and more portable.  This could then be taken by any ISIS folk into schools when they do talks or to any science fairs STFC is involved in. 

2)      There are loads (>100) of accelerators all over the world that are used for particle physics experiments and then many more that are used in medical physics or for industrial applications.   They come mainly in 2 varieties, linear and circular.  There are then subdivisions of those classes depending on the exact way particles are accelerated.  But I only ever learnt about accelerators for approximately 2 lessons of A-Level science and not at all at University.  With £500 I could set up a website and spend some time creating simple applets that demonstrate the basic properties of accelerators so people may understand why they are expensive to build and complicated to design, operate and maintain.  There are a few existing applets but I think they could be better (!) and I could put them all in one place for a very basic introduction to the field.  Maybe even develop accelerator apps for phones (as people seem to be into that nowadays (I don’t have a smart-phone so can’t comment…!))

What do you reckon?