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Notes:
Additional information on:
There are 3 ways to select the drift medium:
Beware: DRIFT-MEDIUM 3 is not the same as DRIFT-MEDIUM 3.0 ! In the first case, the medium with the 3rd dielectric constant or the 3rd conductivity will be selected. In the second case, the medium with the dielectric constant or the conductivity closest to 3 will be taken.
When using the DC conduction mode, it may be more natural to use the keywords SMALLEST-SIGMA, SECOND-SMALLEST-SIGMA, SECOND-LARGEST-SIGMA and LARGEST-SIGMA which are treated as synonyms of the keywords listed in the command description.
[By default, the medium with the lowest dielectric constant or the lowest conductivity is assumed to be the drift medium.]
[This is the default.]
The length of one period is taken to be the maximum extent in x of the field map.
A cell can not be both X-PERIODIC and X-MIRROR-PERIODIC, but can be X-AXIALLY-PERIODIC in addition to being translation periodic in the x-direction.
[By default, a field map is not assumed to be periodic.]
A cell can not be both X-PERIODIC and X-MIRROR-PERIODIC, but can be X-AXIALLY-PERIODIC in addition to being translation periodic in the x-direction.
[By default, a field map is not assumed to be periodic.]
The length of one period is deduced from the field map, and is therefore not specified on the FIELD-MAP statement.
The symmetry axis must pass through y=z=0.
A cell can not be both X-PERIODIC and X-MIRROR-PERIODIC, but can be X-AXIALLY-PERIODIC in addition to being translation periodic in the x-direction.
[By default, a field map is not assumed to be periodic.]
[This is the default.]
The length of one period is taken to be the maximum extent in y of the field map.
A cell can not be both Y-PERIODIC and Y-MIRROR-PERIODIC, but can be Y-AXIALLY-PERIODIC in addition to being translation periodic in the y-direction.
[By default, a field map is not assumed to be periodic.]
A cell can not be both Y-PERIODIC and Y-MIRROR-PERIODIC, but can be Y-AXIALLY-PERIODIC in addition to being translation periodic in the y-direction.
[By default, a field map is not assumed to be periodic.]
The length of one period is deduced from the field map, and is therefore not specified on the FIELD-MAP statement.
The symmetry axis must pass through x=z=0.
A cell can not be both Y-PERIODIC and Y-MIRROR-PERIODIC, but can be Y-AXIALLY-PERIODIC in addition to being translation periodic in the y-direction.
[By default, a field map is not assumed to be periodic.]
[This is the default.]
The length of one period is taken to be the maximum extent in z of the field map.
A cell can not be both Z-PERIODIC and Z-MIRROR-PERIODIC, but can be Z-AXIALLY-PERIODIC in addition to being translation periodic in the z-direction.
[By default, a field map is not assumed to be periodic.]
A cell can not be both Z-PERIODIC and Z-MIRROR-PERIODIC, but can be Z-AXIALLY-PERIODIC in addition to being translation periodic in the z-direction.
[By default, a field map is not assumed to be periodic.]
The length of one period is deduced from the field map, and is therefore not specified on the FIELD-MAP statement.
The symmetry axis must pass through x=y=0.
A cell can not be both Z-PERIODIC and Z-MIRROR-PERIODIC, but can be Z-AXIALLY-PERIODIC in addition to being translation periodic in the z-direction.
[By default, a field map is not assumed to be periodic.]
This method can be applied to all field maps.
[By default, the highest order method permitted by the field map will be used.]
This method can only be applied to field maps with additional nodes halfway the vertices. This information is present in for instance all Maxwell field maps.
[By default, the highest order method permitted by the field map will be used.]
This method can only be applied to field maps with additional nodes at 1 third and at 2 thirds between the vertices. There are currently no field map formats with which this interpolation order can be used.
[By default, the highest order method permitted by the field map will be used.]
Requests the calculation of the electric field by interpolating in the electric field tables as provided by the finite element program.
This interpolation is reliable only on interfaces between materials with different epsilons if the finite element program writes fields for each element, not only for each node.
[This option is default.]
Requests the calculation of the electric field using the potentials at the nodes. This technique works by taking the derivatives of the shape functions to the natural coordinates, multiplied by the Jacobian of the transformation of the natural coordinates to user coordinates. For hexahedral coordinates, this calculation is relatively cheap since the Jacobian is reused from the calculation of the natural coordinates.
These derivatives are reliable also in case the nodes happen to lie on an interface between materials of different epsilons.
[This option is not default.]
Removes the excluded parts of the background from the field map.
This option uses the projects .shd file, which must therefore be present in the same directory as the mesh files.
[This option is on by default.]
A triangle or a tetrahedron is eliminated whenever one of its vertices is located outside the window.
This argument is ignored if the field map is 3-dimensional.
[By default, the cell is assumed to go from -50 cm to +50 cm in the z-direction.]
By default, Garfield uses the coordinate system from the finite element program. As a rule, this doesn't lead to limitations.
However, in case overlays an analytic field with a finite element field, it may happen that the fields need to be aligned. Such an alignment can be obtained with the OFFSET option.
If you specify an offset of (xoff,yoff,zoff), then Garfield will interpolate the field map at (x-xoff,y-yoff,z-zoff) when it needs a field at (x,y,z).
All 3 coordinates should be specified, even if the field map is 2-dimensional.
[By default, the 3 offsets are set to 0. The offsets are saved with the binary field maps.]
Materials are distinguished by their dielectric constant or their conductivity. A map of either of these must therefore be available for this option to have effect. Maps of the dielectric constant an the conductivity can be supplied as such. A map of the dielectric constant will automatically be computed also if maps of both E and B are present.
The material with the smallest dielectric constant is shown with representation MATERIAL-1. The medium with the next highest dielectric constant with MATERIAL-2 etc. The drift medium is never shown.
Elements of a 2D field map are only shown in X-Y views and in CUT views at a constant z. The cross sections of the viewing plane with the elements of a 3D field map are shown in X-Y, X-Z, Y-Z and CUT views, but not in 3D views.
Field maps do not usually cover areas filled with conducting material since there is no field inside. To visualise these, one has to enter them manually with the SOLIDS command. SOLIDS doesn't interfere with PLOT-MAP.
This option can also be switched on and off with the PLOT-MAP option of the AREA command.
[By default, the map is shown.]
Tetrahedrons and triangles with large aspect ratios can be a sign that the mesh is of poor quality. When using Maxwell, one should consider adding virtual volumes which constrain the mesh elements (contact CERN Maxwell support or Ansoft for further information).
Tetrahedrons with a very large volume and triangles with a very large surface are likely to cause problems while drifting particles since the finite element method only guarantees continuity of the potential, not of the electric field. With large elements, the discontinuity across element boundaries is likely to be large.
[These histograms are not made by default.]
Formatted on 0105-10-15 at 17:17.