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Spectrometer Optics. John J. LeRose. a. The Basics. Charged particles moving through static magnetic fields. Magnetic Rigidity. Local radius of curvature. Bend Angle. Arbitrary Trajectory. Reference Trajectory. y. x. r 0. Magnetic Midplane. TRANSPORT formalism. References:
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Spectrometer Optics John J. LeRose
a The Basics Charged particles moving through static magnetic fields. Magnetic Rigidity Local radius of curvature Bend Angle
Arbitrary Trajectory Reference Trajectory y x r0 Magnetic Midplane TRANSPORT formalism References: K.L. Brown, D.C. Carey, C. Iselin and F. Rothacker, Designing Charged Particle Beam Transport Systems, CERN 80-04 (1980) K.L. Brown, SLAC Report-75 (http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-r-075.pdf) …...
x x x z x z y z l = length difference between trajectory and the reference trajectory All trajectories are characterizedby their difference from a reference trajectory* *”The Central Trajectory”
General Solution of the equation of motion: Each component can be expressed as a Taylor series around the Central Ray:
The first order transfer matrix: For static magnetic systems with midplane symmetry:
Calibrations for normal running • In general one wants to determine the tensor elements, Dijkl, Tijkl, Pijkl, Yijkl • Start from the last best known values • Previous run • Calculated from SNAKE output (new tunes) • Use your favorite polynomial fitting routine • Collect calibration data: • The extent of the calibration data taken depends on how well you need to measure things • Elastic scattering with and without sieve • Delta scans • “Optics” target (segmented in y0) • Optimize the tensors • Pointing survey is also a good idea
12C(e,e’) @ 6° and 2 GeV 10-4 (FWHM) all peaks
The End Thanks!