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Magnetic deflectors
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Magnetic deflectors
Project details
Axial field function
The equipotentials of scalar and reduced potential
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Project detail

  • Three types of deflectors are shown that can be defined in EOD
  • Project shows the outputs for saddle deflector, toroidal deflector and radial saddle deflector
  • For saddle deflector the field depends on what multipole component is computed
  • Finally the output potential can be shown as scalar potential (zero on axis) and “reduced” potential whose value on axis gives the axial multipole function

Axial field function

The computation of the 1st,3rd, 5th and 7th harmonic component of the deflector with 54 degrees half angle – normalized (by dividing with field maximum).
1st,3rd, 5th and 7th harmonic component of the deflector

The equipotentials of scalar and reduced potential

  • Scalar magnetic potential
Scalar magnetic potential
  • Reduced magnetic potential
Reduced magnetic potential


The dipole field of saddle coil is used to calculate aberrations

Graphical plot of deflected trajectory

Graphical plot of the deflected trajectory

Aberration coefficients

Trace file: C:\Examples\defl\aberrations.EODtrc
Integration method Runge-Kutta Fehlberg 4-5 order
Max. step size  =   0.10000000     mm
Axial fields interpolation: cubic spline
Relativistic correction: off
Particle electron, charge -1e
 Aberrations calculation results
 Fields used for tracing
 1 .\dem1-20-1357.EODinp
   Magnetic deflector - field
      main deflector
      Field is symmetrical
     Interpolation Cubic spline
     Field zmin (original) -100.00000000 mm
     Field zmax (original) 100.000000000 mm
     Field magnitude       1.00000000000
     Field z shift         0.00000000000 mm
     Field rotation        0.00000000000 deg
        # of points          90
        Field maximum        0.00007 T/mm^0
        Maximum z [mm]       0.00000
        Field width [mm]    21.02499

Particle properties:
Object position zo=        -1.0000000E+02 mm
Energy=                     1.0000000E+04 eV
U=                          1.0000000E+04 eV
Delta Energy=               1.0000000E+00 eV
Aber. for aperture=         5.0000000E-03 rad
Aber. for obj. height=      1.0000000E-03 mm
Deflection X=               1.0000000E+00 mm
           Y=               1.0000000E+00 mm

Image #                           0 (asymptotic), image #  1 not found!
Image position zi=         -1.0000000E+02 mm

Beam rotation=              0.0000000E+00 rad
                            0.0000000E+00 deg
Image magnification=        1.0000000E+00 times

Aberration coefficients related to image

-------------- Main deflection -----------------
Deflection x=               0.0000000E+00 mm
           y=              -3.8856614E-01 mm
       total=               3.8856614E-01 mm
Angle=                      3.1415927E+00 rad
Angle=                      1.8000000E+02 deg
Slope x'=                   3.8856614E-03
      y'=                   0.0000000E+00 mm

Main deflection aberration coefficients
Aberration coefficient                                   | Error in micrometers
 coma length:             5.0000E-01,  0.0000E+00        |   1.8750E-02,  6.2500E-03 um
 field curvature:         1.6476E-02              1/mm   |   1.6476E-01              um
 astigmatism:            -1.5796E-02,  0.0000E+00 1/mm   |   0.0000E+00, -1.5796E-01 um
 distortion:              3.9075E-05,  0.0000E+00 1/mm^2 |   7.8149E-02,  7.8149E-02 um
 chromatic:              -5.0000E-01,  0.0000E+00        |  -5.0000E-02, -5.0000E-02 um
 landing error:          -1.0000E-02,  0.0000E+00 rad/mm |  -5.7296E-01, -5.7296E-01 deg
 ----- Total aberration (geom. and. chrom)                   2.6401E-01 um

Mixed aberration coefficients for finite object
 kappa   F=   0.0000E+00,  0.0000E+00   A=  -5.0000E-03,  0.0000E+00 1/mm
 dist.   D1=  0.0000E+00,  0.0000E+00   D2=  0.0000E+00,  0.0000E+00 1/mm^2
         D3=  2.4022E-04,  0.0000E+00   D4= -1.0761E-04,  0.0000E+00 1/mm^2