The external beam microprobe facility in Florence:: Set-up and performance

An external beam microprobe facility, based on a quadrupole doublet supplied by Oxford Microbeam Ltd, has been installed on a new beamline at the 3 MV single-ended Van de Graaff accelerator in Florence. The goal was to obtain a beam with a spot size on target of 10-20 mum and a current in the order of at least 1 nA, in order to allow PIXE, PIGE and RBS elemental analysis in air or in a helium atmosphere. The beam was extracted from the vacuum lines through a 0.1 mum thick Si3N4 window to minimise lateral straggling. The design goals have been Successfully achieved the measurements of the beam spot characteristics in vacuum as well as in air and in helium atmosphere. are here reported. (C) 2002 Published by Elsevier Science B.V.