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Installing MAGBOLTZ
The MAGBOLTZ program is currently installed in ~gmd/garfield
To install MAGBOLTZ first download the FORTRAN file from here and
compile in a directory of your choice.
g77 -o magboltz.run magboltz.f -L/local/cern/pro/lib -lpacklib -lmathlib -lkernlib
MAGBOLTZ Results
To view some results for various gas mixtures from Magboltz click here.
To view calculations of drift distances for ArCO2 90/10 and 80/20 click here or to download/view the data file -->
(OpenOffice - Excel)
Input Cards
The parameters are set in an input file (for example:
magboltz.input) and read in by the program. Each line
of this file is an input card.
Formatting refers to the amount of space reserved for each variable in that line,
for example if the format is 2I10 and the values you want to enter are "2" and "10",
then you would need to write 2 followed by nine spaces, then 10 followed by eight
spaces. You do not need to include spaces at the end of a line.
Note: the format syntax is the same at that of FORTRAN, in this case 2I10 means
two integers with ten place holders each.
First Card
Format: 2I10,F10.5, variables: NGAS,NMAX,EFINAL
| NGAS |
number of gases in mixture |
| NNMAX |
number of real collisions (multiple of 10**7),
use a value between 2 and 5 for inelastic gas to
obtain 1 % accuracy, use a value above 10 for better
than 0.5 % accuracy and a value of at least 10 for
pure elastic gases like Argon |
| NEFINAL |
upper limit of the electron energy in electron
Volts, if EFINAL = 0.0, program automatically calculates
upper integration energy limit |
Second Card
Format: 6I5, variables: NGAS1,NGAS2,NGAS3,NGAS4,NGAS5,NGAS6
For exmple if only two gases are used slots 3-6 should
be 77.
| NGAS1 etc. |
gas number identifiers (between 1 and
80) see gas list below for identifying numbers. Use
77 for any unused slots |
Third Card
Format: 8F10.4, variables: FRAC1,FRAC2,FRAC3,FRAC4,FRAC5,FRAC6,TEMP,TORR
| FRAC1 etc. |
percentage fraction of gas1 etc. |
| TEMP |
temperature of gas in centigrade |
| TORR |
pressure of gas in Torr |
Fourth Card
Format: 6F10.3, variables: EFIELD,BMAG,BTHETA
| EFIELD |
electric field in Volt/cm |
| BMAG |
magnitude of the magnetic field in kilogauss; |
| BTHETA |
angle between the electric and magnetic fields
in degrees |
Fifth Card
Use NGAS=0 to terminate correctly.
Example of an input file:
2 5 0.0
2 8 77 77 77 77
90.0 10.0 0.0 0.0 0.0 0.0 20.0 760.0
3300.0 0.0 0.0
0
Running Simulation
This program is used to determine the diffusion parameters in gas samples.
Currently the files used are in ~gmd/magboltz6/. In this folder are several
example .output files, using ArCO2 90-10 and 80-20 gas at different E-field
strengths. The input files are described above. Currently mag.input is used.
The meaning of the numbers in the file are described above, be careful to leave
decimal points if there already is one, and to keep the field widths for each
number the same. (ie. if the old number was 45.2 and the new number 50, type
in 50. or 50.0, and that the numbers all still line up). The only numbers that
need usually be changed are the gas percentages, or the EField, the rest can
remain the same (unless the gas type is changed).
The output files are labelled nicely. After running magboltz, these .output files
are created. From the transverse and longitudinal diffusion, and the drift velocities,
a drift distance vs. diffusion table can be created. An example of one is linked
to above (under Magboltz results).
After saving the input file (eg. magboltz.input) the simulator is run from the
~gmd/garfield/ directory, or wherever you can find magboltz.run (or magboltz7.run):
magboltz.run < inputfilename.input >
outputfilename.output - A path can be used in the filenames if your input
and output files are not in the same directory as the program
This will save the output to the .output file which can be viewed at any time.
*NEW
You can use a script to run multiple simulations over a range of electric field
values.
Currently found in ~gmd/garfield/, you can use either magrun.script for version
5.1 or magrun7.script for version 7.1
Form: magrun.script input maxval minval interval
< input >
is an input file created as described above. The last three fields describe the
desired maximum and minimum electric fields, with < interval > specifying
the interval between each run (ie 50 would indicate going from max to min changing
50 V/cm each time).
Gas Codes
Argon = 2
Methane = 8
CO2 = 12
Click here for full listing
of gases and the full page containing the above information
.
Last updated October 3, 2004 - Dan Burke
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