This beamline will provide beam diameters from 20 microns to 2 mm in an RBS target chamber. The beamline contains principal components such as a double slit, an object aperture box with four apertures ranging in size from 200 microns to 6 mm in diameter, an electrostatic quadrupole triplet lens and analysis system and an electrostatic quadrupole quadruplet lens. The quadrupole quadruplet lens gives a 10 to 1 demagnification at the target for an object distance of 4.22 meters and an image distance of 150 mm beyond the lens.
The system operates in three different modes to cover the beam diameter range specified. From 20 microns to about 200 microns diameter, the aperture box and the quadruplet lens will be used. From about 200 microns to about 0.6 mm diameter, the double slit, the triplet, and the quadruplet are all used to define and focus the beam. Above 0.6 mm diameter, the double slit and the quadrupole triplet are needed.
| Distance A | Guaranteed Beam Spot size at Target | Target Beam Current (2MeV He+) |
| 4.2 m | 20 um | 3 nA |
| 3.1 m | 25 um | 3 nA |
Microprobe Beamline:
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