Third-Order Apochromatic Drift-Quadrupole Beamline
  In this paper we present the design of a straight drift-quadrupole system which can transport certain beam ellipses (apochromatic beam ellipses) without influence of the second and of the third order chromatic and geometric aberrations of the beamline transfer map. 
V. Balandin, R. Brinkmann, W. Decking, N. Golubeva
physics.acc-ph