Magnetic deflectors
Article Index
Magnetic deflectors
Project details
Axial field function
The equipotentials of scalar and reduced potential
Aberrations
All Pages

# Project detail

• Three types of deflectors are shown that can be defined in EOD
• 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).

## The equipotentials of scalar and reduced potential

• Scalar magnetic potential
• Reduced magnetic potential

## Aberrations

The dipole field of saddle coil is used to calculate aberrations

### 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
Fields:
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 obj. height=      1.0000000E-03 mm
Deflection X=               1.0000000E+00 mm
Y=               1.0000000E+00 mm

Image position zi=         -1.0000000E+02 mm

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=                      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
```