Difference between revisions of "Tagger Magnetic Field Mapping"
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(→Some preliminary ideas about mapping requirements) |
(→Some preliminary ideas about mapping requirements) |
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#** 1" by 1" from 30 cm to 15 cm outside, | #** 1" by 1" from 30 cm to 15 cm outside, | ||
#** 1" by 0.25" transverse from 15 cm outside to 10 cm inside | #** 1" by 0.25" transverse from 15 cm outside to 10 cm inside | ||
− | :: A step of 0.25" near the field boundary means that the maximum field variation per step (which occurs just inside the nominal field boundary) is about 15%. This should be acceptable. | + | :: A step of 0.25" near the field boundary means that the maximum field variation per step (which occurs just inside the nominal field boundary) is about 15%. This should be acceptable. If the time required for the above is excessive, we could take 2" steps parallel to the long field edge instead of 1". |
− | + | ||
===Fields at which maps should be taken=== | ===Fields at which maps should be taken=== | ||
* [http://zeus.phys.uconn.edu/halld/tagger/fieldmap-6-2013/ Study of saturation effects in the dipole at various excitation currents] - ''Dan Sober'' | * [http://zeus.phys.uconn.edu/halld/tagger/fieldmap-6-2013/ Study of saturation effects in the dipole at various excitation currents] - ''Dan Sober'' |
Revision as of 10:17, 14 June 2013
Some preliminary ideas about mapping requirements
- We need to map every region of the field where electrons are transported, but can omit corners where no trajectories go. I attach a crude picture of electron orbits. Maybe Sascha has a better one.
- By my previous experience ray-tracing in the Hall B tagger magnet (6 cm gap), I would propose the following.
- Uniform field region inside gap (at least 10 cm or 4" away from a field boundary:
- 1" by 1" grid
- In the vicinity of the long field boundary:
- 1" (parallel to edge) by 0.25" transverse from -10 cm inside to +15 cm outside
- 1" (parallel to edge) by 1" transverse from +15 cm to +30 cm outside
- In the vicinity of the entry face and the full-energy beam exit, cover a region at least 6" (i.e. +/- 3") wide around the trajectories:
- 1" by 1" from 30 cm to 15 cm outside,
- 1" by 0.25" transverse from 15 cm outside to 10 cm inside
- Uniform field region inside gap (at least 10 cm or 4" away from a field boundary:
- A step of 0.25" near the field boundary means that the maximum field variation per step (which occurs just inside the nominal field boundary) is about 15%. This should be acceptable. If the time required for the above is excessive, we could take 2" steps parallel to the long field edge instead of 1".