Benjamin Greenwood - Student Profile
Current research project
Compact, laser-driven ion beamlines for interdisciplinary applications
The interaction of an ultra-high intensity laser pulse with a flat foil target can accelerate ions to energies of several tens of MeV per nucleon. These ions have potential uses both in science and healthcare, for example for cancer therapy, and the use of a laser-driven ion accelerator has the potential to provide a relatively cheap and more compact source. It is therefore important to optimise these sources for applications.
The Target Normal Sheath Acceleration (TNSA) mechanism resulting from these interactions produces a proton beam with a divergence of a few tens of degrees and a quasi-exponential energy spectrum. Many applications require more collimated, mono-energetic proton beams. A helical coil target design, presented in Nature Communications by Kar et al. (2016), can be used to collimate and post-accelerate the proton beam due to the electric field generated by the charge pulse it carries away from the interaction. My research looks at the potential to increase the repetition rate of this target design and to deliver the ions produced onto secondary targets for applications.
I was educated at Wildern School and Peter Symonds College in England before moving to Belfast in 2014 to undertake my undergraduate MSci degree in physics at Queen’s University. I graduated in June 2018 with a first-class degree and won both the John Geddes Physics Prize and the Greer Prize. Having undertaken my master’s project at the STFC Rutherford Appleton Laboratory on characterising cryogenic targets for laser-driven ion acceleration experiments, I decided to stay at Queen’s to undertake a PhD in the same field.
Laser-driven ion acceleration