TJG 22/6/2001
Slits
The adjustable slit
SL240 has the effect of reducing the ion source emittance,
at the cost of beam loss. At the moment resolution is limited by 2nd-order
distortion in the magnets, so this slit does not achieve anything useful.
SL470 on the same piston as WG470 works
like the equivalent slit on the GPS. It has a fixed width, and serves only
to block beams 1 mass unit or more from the beam of interest.
SL675 (after the fixed-needle beam scanner)
is adjustable, like SL240. It is used to block unwanted beams
which pass SL470.