Shigeto Adachi

Compact nuclear microprobe system for RBS/PIXE

A compact nuclear microprobe system for RBS/PIXE with an overall size of 4.5 m (length) × 2.5 m (width) × 1.8 m (height), including an accelerator, has been created by arranging an accelerator, objective slits, an E × B filter and a quadrupole magnet doublet in order in a straight line. The beamline was designed to produce a collimated beam with a divergence of less than 0.01° for channeling measurements, as well as a microprobe with a spot size of about 1 μm for micro-RBS/PIXE measurements, by only adjusting the lens currents. A measuring chamber has a goniometer of our own original design with four axes and a revolving disk head holding 30 samples for automatic sequential measurements. The combination of two kinds of beam and two sample manipulators make the system extremely versatile. This paper describes fully the system design and details of the main components. The optical aberration caused by an E × B filter is discussed using computer simulation, and measured ion contamination due to the arrangement of the system in a straight line is evaluated.