Project details
- Symmetrical unipotential lens with very thin electrodes
- Accuracy of the computation is demonstrated with field maximum for different number of fine mesh points between the symmetry plane and the electrode
- Optical properties are computed and the results are saved also as CSV files of Excel
Field accuracy
To test the accuracy, the lens data were recalculated with denser meshes, which expand with factor 1.025
Focusing lens
Finally, there is an example of focusing, which shows output focus procedure. Electron with energy 1 eV is focused from z=-5 mm to 60 mm. Also aberrations are computed.
Trace file: C:\EOD\Examples\elens\1shot.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
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Fields used for tracing
Fields:
1 .\dem2-dense.EODinp
Electrostatic - field
Field is symmetrical
Interpolation Cubic spline
Field zmin (original) -60.000000000 mm
Field zmax (original) 60.0000000000 mm
Field magnitude 1.00000000000
Field z shift 0.00000000000 mm
Field rotation 0.00000000000 deg
# of points 284
Field maximum 0.03668 V/mm
Maximum z [mm] 7.06250
Field width [mm] 11.94513
2 .\dem2-dense.EODinp
Electrostatic - field
Field is symmetrical
Interpolation Cubic spline
Field zmin (original) -60.000000000 mm
Field zmax (original) 60.0000000000 mm
Field magnitude 1.00000000000
Field z shift 0.00000000000 mm
Field rotation 0.00000000000 deg
# of points 284
Field maximum 0.03668 V/mm
Maximum z [mm] 7.06250
Field width [mm] 11.94513
----------------------------------------------------
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Focus for: zobj= -5.0000 to zimg= 60.0000 mm
Searching for focus ...
Field magnitude search in interval -1.0000E+00, -5.0000E-01
Magnit. = -9.000000E-01, zimg = -7.091314E+02 mm, image # 0
Magnit. = -9.500000E-01, zimg = 3.101982E+01 mm, image # 1
Magnit. = -9.250000E-01, zimg = 7.630854E+01 mm, image # 1
Magnit. = -9.375000E-01, zimg = 4.566401E+01 mm, image # 1
Magnit. = -9.273290E-01, zimg = 6.826634E+01 mm, image # 1
Magnit. = -9.300710E-01, zimg = 6.053949E+01 mm, image # 1
Magnit. = -9.302891E-01, zimg = 5.999019E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000000E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000000E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000001E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000001E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000001E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000000E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000000E+01 mm, image # 1
Magnit. = -9.302851E-01, zimg = 6.000000E+01 mm, image # 1
Focus found for field magnitude -9.30285131E-01
Computation with asymptotic object
V* = 1.00000000E+00 V
U = 1.00000000E+00 eV
image # = 1 (asymptotic)
z object = -5.0000000 mm
z image = 60.0000 mm
rotation = 0.0000000 rad
0.0000000 deg
dir. magnif. = -6.216739
ang. magnif. = -0.1608560
V* object = 1.00000000E+00 V
V* image = 1.00000000E+00 V
1-M*Ma*sqrt(p(zi)/p(zo)) = -5.29420952E-12
fproj = 9.0820777 mm
zproj = 3.5390932 mm
Aberration coefficients related to object
axial spherical aber.: 9.0529E+01 mm
iso,aniso coma length: 8.9721E+00, 0.0000E+00
field curvature: 1.1784E+00 1/mm
iso,aniso astigmatism: 2.5496E-01, 0.0000E+00 1/mm
iso,aniso distortion: 4.6112E-02, 0.0000E+00 1/mm^2
axial chromatic: 1.2484E+02 mm
iso,aniso chromatic: 6.6222E+00, 0.0000E+00
Aberration coefficients for aperture
Aperture position at z= 0.0000000E+00 mm
|ra| = 1.1462E+01, |rb| = 1.0872E+00
axial spherical aber.: 9.0529E+01 mm
iso,aniso coma length: -8.2012E+00, 0.0000E+00
field curvature: 1.1053E+00 1/mm
iso,aniso astigmatism: 2.1840E-01, 0.0000E+00 1/mm
iso,aniso distortion: -1.4315E-02, 0.0000E+00 1/mm^2
axial chromatic: 1.2484E+02 mm
iso,aniso chromatic: -5.2188E+00, 0.0000E+00
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Examples 
