First Test of The Imperial College Gabor (Plasma) Lens prototype at the Surrey Ion Beam centre

The first plasma (Gabor) lens prototype operating at high electron density was built by the Imperial College London in 2015. In November 2015 the lens was tested at the Ion Beam Centre of the University of Surrey with a 1 MeV proton beam. Over 500 snapshots of the beam hitting a scintillator screen installed 0.5 m downstream of the lens were taken for a wide range of settings. Unexpectedly, instead of over- or underfocusing the incoming particles, the lens converted pencil beams into rings. In addition to the dependence of their radius on the lens settings, periodic features appeared along the circumference, suggesting that the electron plasma was exited into a coherent off-axis rotation. The cause of this phenomenon is under investigation