Demonstration of single-shot picosecond time-resolved MeV electron   imaging using a compact permanent magnet quadrupole based lens
  We present the results of an experiment where a short focal length (~ 1.3 cm) permanent magnet electron lens is used to image micron-size features of a metal sample in a single shot, using an ultra- high brightness ps-long 4 MeV electron beam from a radiofrequency photoinjector. Magnifcation ratios in excess of 30x were obtained using a triplet of compact, small gap (3.5 mm), Halbach-style permanent magnet quadrupoles with nearly 600 T/m field gradients. These results pave the way to- wards single shot time-resolved electron microscopy and open new opportunities in the applications of high brightness electron beams. 
D.Cesar, J.Maxson, P.Musumeci, Y.Sun, J.Harrison, P.Frigola,   F.H.O'Shea, H.To, D.Alesini, R.K.Li
physics.acc-ph