Difference between revisions of "Magnetic Field Map"

Revision as of 19:44, 8 February 2011

Refer to the design of Solid_Magnet

create field map for GEMC from possion output

located at Solid website http://hallaweb.jlab.org/12GeV/SoLID/download/

• BaBar map
• CDF map
• ZEUS map

convert SF7 to GEMC map

For solenoid type of magnet, assume azimuthal symmetry.

SF7 map format produced by Possion program SF7.exe contain text lines for explanation, map range and grid size, map values (R, Z, Br, Bz, B, A, dBz/dr, dBr/dz, field index).

GEMC map format requires R, Z, Br, Bz

Additional difference is SF7 map values are in order of R increasing first when Z is fixed, while GEMC map values are in order of Z increasing first when R is fixed.

Thus we need the conversion script SF7toGEMCmap.C at svn "database_io/halla12/solid/field/"

for example:
in terminal, run "root", 
then load the function ".L SF7toGEMCmap.C", 
covert SF7 map file CDFv2.sf7, run "SF7toGEMCmap("CDFv2.sf7");
the output should be like:
  open SF7 file CDFv2.sf7 ok
  (Rmin,Zmin) = (0.0,-300)
  (Rmax,Zmax) = (300,475)
  R and Z increments:     300     775
  put these info into database
  covert to GEMC map file CDFv2.sf7.GEMCmap ok

field map file info in database

To make GEMC aware the field map file name, grid, position etc, we need to put those in database table "magnetic_fields"

The scripts are at svn "database_io/halla12/solid/field/"

edit the file "magnetic_fields.txt" with grid info from output of "SF7toGEMCmap.C"

no need to change "magf_table_commands"

just run "go_table_magf"