Difference between revisions of "Ion Optics"
From CASE
(New page: Herein should be a general intro to ion optics. A set of links should include one to courses taught by CASE faculty. ===The NSL Facility=== <li> Negative ions sputter from the source sam...) |
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===The NSL Facility=== | ===The NSL Facility=== | ||
| − | + | * Negative ions sputter from the source sample holder (often called "cone" locally). Details of the electric field lines, production of a conical divot and material all contribute to the emittance of the ions as they leave the sample holder. Typical units are tens of MeV-mm/mradian | |
| − | + | * The electric field created by the extraction electrode "extracts" the negative ions. | |
| − | + | * A gridded Einzel Lens focuses the beam to the object point of the inflection magnet. An aperture is placed where the beam is large to allow for reduced currents. | |
| − | + | * The 90 degree inflection magnet has a natural focal length of R (radius= ?? meters). This matched in the vertical plane by shaped pole pieces. | |
| − | + | * An aperture at the entrance to the injector accelerator tube reduces the electron load to the tube and provides an image to the lens of the tube. This lens is weak. | |
| − | + | * An electrostatic triplet and electrostatic steerer at Ground Station create a beam waist just in front of the Tandem, matching to the bulge lens effect of the Tandem accelerator tubes. | |
| − | + | * The first 20 planes of the Low Energy column have reduced value (gradually decreasing from full to half value) to weaken the bulge lens effect. | |
| − | + | * There are no active optical elements in the Tandem Van de Graaff, only gently focusing via the spiral inclined electrodes in the tubes | |
| − | + | * The High Energy AG Lens is the first magnetic focusing element. It works with the HE Magnetic Steerer to create a beam waist at the object point of the Analyzing Magnet. We create this with a circular aperture ~ 1.5 meters in front of the magnet. | |
| − | + | * Image #2 is the image point of the Analyzer. It is closer to the magnet than the object point, therefore we have magnification of less than one. | |
| − | + | * The Tunnel Triplet has its object point at Image 2. Along with the Tunnel vertical steerer and the Switching Magnet is creates an image on whatever beamline is selected. | |
| − | + | * The Beamline Quadrupole creates a focus at the target. If steering is required there are horizontal and vertical steerers on each beamline | |
| − | + | ||
| − | + | ||
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Return to [[Lab Manuals]] | Return to [[Lab Manuals]] | ||
Revision as of 15:16, 12 August 2010
Herein should be a general intro to ion optics. A set of links should include one to courses taught by CASE faculty.
The NSL Facility
- Negative ions sputter from the source sample holder (often called "cone" locally). Details of the electric field lines, production of a conical divot and material all contribute to the emittance of the ions as they leave the sample holder. Typical units are tens of MeV-mm/mradian
- The electric field created by the extraction electrode "extracts" the negative ions.
- A gridded Einzel Lens focuses the beam to the object point of the inflection magnet. An aperture is placed where the beam is large to allow for reduced currents.
- The 90 degree inflection magnet has a natural focal length of R (radius= ?? meters). This matched in the vertical plane by shaped pole pieces.
- An aperture at the entrance to the injector accelerator tube reduces the electron load to the tube and provides an image to the lens of the tube. This lens is weak.
- An electrostatic triplet and electrostatic steerer at Ground Station create a beam waist just in front of the Tandem, matching to the bulge lens effect of the Tandem accelerator tubes.
- The first 20 planes of the Low Energy column have reduced value (gradually decreasing from full to half value) to weaken the bulge lens effect.
- There are no active optical elements in the Tandem Van de Graaff, only gently focusing via the spiral inclined electrodes in the tubes
- The High Energy AG Lens is the first magnetic focusing element. It works with the HE Magnetic Steerer to create a beam waist at the object point of the Analyzing Magnet. We create this with a circular aperture ~ 1.5 meters in front of the magnet.
- Image #2 is the image point of the Analyzer. It is closer to the magnet than the object point, therefore we have magnification of less than one.
- The Tunnel Triplet has its object point at Image 2. Along with the Tunnel vertical steerer and the Switching Magnet is creates an image on whatever beamline is selected.
- The Beamline Quadrupole creates a focus at the target. If steering is required there are horizontal and vertical steerers on each beamline
Return to Lab Manuals
