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&CELL: FIELD-MAP: FILES: format


PARAMETER-EXTRACTOR-2D

Specifies that the field map has been generated by the Ansoft program called "Maxwell 2D Parameter Extractor". The format of these files is identified automatically, and the format doesn't have to be specified therefore.

To generate your field maps with Maxwell Parameter Extractor 2D, you may wish to follow this recipe:

  1. Go through the various steps until "Solve Parameters", taking care (before drawing anything) to adjust in "Draw Cross Section" the "Model Drawing Size" such that it fits exactly the area of your detector - do not leave any empty space around it. Then enter "View Fields" from where you perform the following steps:
  2. Click on "calc", select "plane", if the upper area is not empty then click on "clear". Do also a "smooth" and a "push" to ensure the mesh is the same for all maps. Then click on "voltage" and do an ASCII "write" to a file ("write" is in the second set of commands to which you access via "next", to get back to the first set click on "prev"). Maxwell appends the string ".arg" to the file name you enter. This creates a map of the potential.
  3. Repeat step 2 with "E_vector" instead of "voltage", choose a file name different from the one used in step 2. This creates a file that contains both Ex and Ey.
  4. Depending on the Solver that you use:
  5. If you do not wish to compute signals, you are ready at this point. Otherwise, go back to the "Parameter Extractor" main menu, click on "Setup Boundaries/Sources", and select "Define", confirm that you wish to "Modify" and then adjust the voltages of all electrodes such that the electrode that you wish to read out is at 1 V and all other electrodes at 0 V. Then "Exit", confirming that you wish to save the modifications.
  6. Go to the "Setup Solution Parameters" in the Parameter Extractor, click on "Capacitance", select "Current" as Starting Mesh, suppress "Adaptive Analysis". This ensures that the field is calculated on the same mesh as the field calculated in point 1.
  7. Write out the electric field as described in step 2, choosing a file name different from the names chosen in steps 2, 3 and 4. This generates the weighting field. Repeat from step 5, if you intend to read out more than one electrode.

These steps should lead to a set files with names that end on .arg and that are located in the es.pjt subdirectory of your project.

Be sure to create the E, V, epsilon/sigma and weighting field maps with identical meshes and the E, V and epsilon/sigma maps with identical boundary conditions.

The names of these 4 files should be placed after the FILES keyword of the FIELD-MAP command, the name of the weighting field maps should be preceded by the keyword "WEIGHTING-FIELD" to distinguish it from the regular electric field map. The order is not important. There is no need to specify that the files come from Maxwell Parameter Extractor 2D.

Maxwell documentation at CERN can be found in http://wwwinfo.cern.ch/ce/ae/Maxwell/documentation.html

(Instructions from Pawel Majewski)


FIELD-SIMULATOR-2D

Specifies that the field map has been generated by the Ansoft program called "Maxwell 2D Field Simulator". The format of these files is identified automatically, and the format doesn't have to be specified therefore.

To generate your field maps with Maxwell 2D Field Simulator, you may wish to follow this recipe:

  1. Go through the various steps until "Solve". Then enter "Post Process" for the "nominal problem", from where you perform the following steps:
  2. Click on "calc", select "Plane", if the upper area is not empty then click on "clear". Then click on "voltage" and do an ASCII "write" to a file ("write" is in the second set of commands to which you access via "next", to get back to the first set click on "prev"). Choose a file name like "V", Maxwell appends the string ".arg" to the file name you enter. This creates a map of the potential.
  3. Repeat step 2 with "E_Vector" instead of "voltage", choose a file name different from the one used in step 2. This creates a file that contains both Ex and Ey.
  4. If you wish Garfield to know about the materials present in the chamber, then either:
  5. If you do not wish to perform signal calculations, you're ready at this point. Otherwise go back to the "2D Field Simulator" main menu, enter "Setup Boundaries/Sources", confirm that you wish to "Modify" and then adjust the voltages of all electrodes such that the electrode that you wish to read out is at 1 V and all other electrodes at 0 V. Then "Exit", confirming that you wish to save the modifications.
  6. Go to the "Setup Solution" in the main menu, select "Options", select "Current" as Starting Mesh, suppress "Adaptive Analysis" and click "OK". Next go to "Solve" in the main menu and select "Nominal Problem". These steps compute the weighting field on the same mesh as the field calculated in point 1.
  7. Write out the electric field as described in step 2, choosing a file name different from the names chosen in steps 2, 3 and 4. This generates the weighting field map. Repeat from step 5 if you intend to read more than one electrode.

These steps should lead to a set of files with names that end on .arg and that are located in your project directory.

Be sure to create the E, V, epsilon/sigma and weighting field maps with identical meshes and the E, V and epsilon/sigma maps with identical boundary conditions.

The names of these 4 files should be placed after the FILES keyword of the FIELD-MAP command, the name of the weighting field maps should be preceded by the keyword "WEIGHTING-FIELD" to distinguish it from the regular electric field map. The order is not important. There is no need to specify that the files come from Maxwell 2D Field Simulator.

Information about using Maxwell at CERN can be found in http://wwwinfo.cern.ch/ce/ae/Maxwell/Maxwell.html


PARAMETER-EXTRACTOR-3D

Specifies that the field map has been generated by the Ansoft program called "Maxwell 3D Parameter Extractor", version 1.1 (Feb 1993). The format of these files is identified automatically, and the format doesn't have to be specified therefore.

When generating your field maps with this program, you may wish to follow this recipe:

  1. Go through the various steps until "Solve Parameters", taking care (before drawing anything) to adjust in "Draw Cross Section" the "Model Drawing Size" such that it fits exactly the area of your detector - do not leave any empty space around it. Then enter "View Fields" from where you perform the following steps:
  2. Click on "calc", select "space", if the upper area is not empty then click on "clear". Click on "phi", do a "push" to ensure the mesh is the same for all maps and then "smooth" the potential map. Do an ASCII "write" to a file. Maxwell appends the string ".arg" to the file name you enter, it is therefore sufficient to enter for instance just "V". This creates a map of the potential.
  3. Repeat step 2. for "E_vector" and "D_vector", without doing a "push", and writing to files with different names. Creating the D field map is optional.
  4. You may also wish to create weighting field maps as described for Maxwell Parameter Extractor 2D.

This procedure should create maps of the electrostatic potential, the E field, the D field and perhaps of a weighting field. The dielectric constants are computed by comparing E and D. These files will be located in the efs3d.pjt subdirectory of your project.

Be sure to create the E, V, D and weighting field maps with identical meshes and the E, V and D maps with identical boundary conditions.

Information about using Maxwell at CERN can be found in http://wwwinfo.cern.ch/ce/ae/Maxwell/Maxwell.html


FIELD-SIMULATOR-3D

Specifies that the field map has been generated by the Ansoft program called "Maxwell 3D Field Simulator", version 4.0. The format of these files is identified automatically, and the format doesn't have to be specified therefore.

When you use this program to create your field maps, you have to provide the following to Garfield:

  1. The mesh: The mesh is contained in a .hyd and a .pnt file stored in the project directory (and not in an "efs3d.pjt" subdirectory of the project directory). When requesting the DELETE-BACKGROUND option, the projects .shd file is needed in addition. The files have names like "fileset2", "fileset1", "current", "efs3d", "previous" and "initial".

  2. The field maps of V, D and E written out in .reg format. With Maxwell 3D Field Simulator, there is no need to smooth the field maps, as opposed to Maxwell 3D Parameter Extractor.

    The field maps can be created as follows: After having gone through the various steps, in the "Post Process" menu, select "Nominal Problem". From the "Data" menu, select "Calculator". In the "Input" column select the "Qty" menu where you pick "phi". In the "Output" column select "Write ..." and write out the field to a file called, for instance, "V.reg". Repeat the same steps replacing "phi" by "E" and "D".

  3. Optionally, you may also provide weighting fields. Weighting fields are electric fields that are obtained by setting the potential of all conductors to 0 V except the read-out conductor which is set to 1 V.

Be sure to create the E, V, D and weighting field maps with identical meshes and the E, V and D maps with identical boundary conditions.

Information about using Maxwell at CERN can be found in http://wwwinfo.cern.ch/ce/ae/Maxwell/Maxwell.html


TOSCA

To generate your field maps with Tosca on a Unix system, you have to:
  1. use OPERA version 7.0.

  2. Generate the geometrical mesh with the 3d Opera preprocessor.

  3. Click on "MESH" and then choose the "quadrilaters" option.

  4. Click again on "MESH" and choose the "Volume mesh ... Mesh *" option.

  5. Click on "FILE" and choose the "write node table" option in order to create the "username.table" file that contains the mesh node coordinates.

  6. Generate, clicking again on "FILE", the usual username.OP3 file ready to be analysed by TOSCA.

  7. Run the Fortran program "util" with the command: $VFDIR/opera/3d/util > "username1.table" and, after pushing the "return" buttom, typing "username.op3" on the keyboard and pushing "return" again. The file "username1.table" includes now a table that describes each element of the mesh, specifying the nodes that make it up.

  8. Run TOSCA.

  9. Run the 3d Opera postprocessor. Load the TOSCA result. Click on "FIELDS" and choose the "table of field points" sub-menu. In this sub-menu:
    1. Select "input from file" and give "username.table" (see item 6 above) as input.
    2. Choose an "username2.table" as output according to your taste
    3. Click on "output components options" and define:
      • Component 1 = X
      • Component 2 = Y
      • Component 3 = Z
      • Component 4 = Ex
      • Component 5 = Ey
      • Component 6 = Ez
      • Component 7 = Dx
      • Component 8 = Dy
      • Component 9 = Dz
      • Component 10 = V
    4. Click the "process table" option that will describe, for each mesh node, the value of the electric field and potential.

The files "username1.table" and "username2.table" (see item 6 and 10 above) are now ready for Garfield.

A Garfield input file that uses "username.table" and "username1.table" can be found in http://consult.cern.ch/writeup/garfield/examples/tosca/example

A single Tosca generated map can contain various kinds of data, such as the potential, the electric field and the D field. Since the file contains a description of the data, the contents field should only make clear that the file is not a mesh file. One can therefore set the contents field on the FIELD-MAP command to be any of the contained items.

(Recipe from Guido Maria Urciuoli, INFN Gruppo Collegata Sanitá, Viale Regina Elena 299, 00161 Roma, Italia.)


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Formatted on 0100-09-02 at 06:56.