A novel ultra-short scanning nuclear microprobe: Design and preliminary results

The paper describes an optimized scanning nuclear microprobe (MP) with a ne w ultra-short (total length of 1.85 m) probe forming system based on a divi ded Russian quadruplet (DRQ) of magnetic quadrupole lenses. Modern electros tatic accelerators have a comparatively high beam brightness of about 10-25 pA/mum(2)/mrad(2)/MeV. This allows the MP proposed to provide a high later al resolution even with large (1%) parasitic (sextupole and octupole) pole tip field components in all lenses, The features of the design permit the M P operation in the high current and low current modes with a short working distance and inexpensive quadrupole lenses. A new quadrupole doublet design has been developed for the MP. In the present work the calculated features of the new MP are compared with preliminary experimental results obtained with a similar system (total length of 2.3 m) at the INP in Cracow. The new MP is prom ising for studies of solids or biological samples with high res olutions (0.08-2 mum) in both modes under ambient conditions. A vertical ve rsion of the ultra-short MP can be very useful for single ion bombardments of living cells. (C) 2001 Elsevier Science B.V. All rights reserved.