CERN employment and training opportunities - STFC

Contents

CERN doctoral student programme

CERN offers placements for postgraduate students to study towards a doctorate in a technical field for member states. The placement gives you the chance to work on your thesis while spending six to 36 months at the forefront of science. The programme is open to students from a range of specialisations from engineering, material science, mathematics and applied physics. Particle physics students are not eligible for this scheme.

You can find out more on the CERN recruitment website.

Case study

Lorraine Bobb is coming to the end of her PhD with RHUL in collaboration with the John Adams Institute (JAI), CERN and Cornell University. She has been developing a non-invasive, micron scale, transverse beam size monitor. The prototype that she has designed aims to measure the vertical size of the main beam to within one micron. Existing techniques used at other particle accelerators including the LHC are typically based on measurements taken when the beam passes through a thin screen or wire. The problem with these methods is that the interaction of the beam with the screen or wire can damage the integrity of the beam. For the high luminosities that CLIC aims to achieve, the charge density and high energy of the beam would simply destroy the beam measurement instrumentation and therefore a non-invasive technique is required.

“A non-invasive technique (the laser wire scanner) already exists,” explains Lorraine, “but it’s expensive and technically quite demanding. CLIC needs a cheaper and easier solution.”

Lorraine, with the help of her research group, designed the new instrument, chose the materials that would be used to make it and oversaw the manufacture of the prototype. “Finding a company capable of meeting the precision machining tolerances was a challenge; the instrument, which uses a target like a tuning fork, has two prongs that must have a coplanarity (or flatness) to within tens of nanometres [a human hair is approximately 100,000 nm wide].”

Lorraine installed her prototype at CesrTA, the test accelerator at Cornell University and as she approaches the end of her PhD, she is now analysing the data.

“Early indications suggest that there is a lot of background noise caused by synchrotron radiation when observing shorter wavelengths, and that possibly the instrument needs to be positioned differently to minimise this background. But the project has enabled me to develop a new process for the practicalities of measuring beams non-invasively – getting the beam through the 1mm target aperture on a circular machine, without it hitting the sides, was a challenge.”

This article was taken from issue 38 of the UK News from CERN newsletter.

Last updated: 15 November 2021

NOTE Council web content is being transitioned to this website – let us know if you have feedback or would like to help us test new developments.