TRiP98 yield command
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Yield


yield | beamenergy / echannels(0)         write        debug
        projectile   braggpos()           export(gd)
        target       erelfwhm(0)          path()
                     outbins(8,8,16,16)   delete
                     braggeps(0.003)   
                     braggdiff(0.01)   
                     braggiter(5)   

Purpose

This is the beam model. Fragment spectral distributions (differential in charge and energy, but 1-dimensional in space) as well as derived depth dose distributions can be calculated and stored on file. To be functional, valid dE/dx as well as reaction cross section tables must be loaded. Note that from the 0509e release onwards external fragmentation cross sections have to be loaded as well.
The respective tables can be found in the DATA/DEDX, DATA/SIGTOT, and DATA/XS subdirectories of the installation directory.

Parameters

beamenergy
If specified, a new calculation is started with this energy (MeV/u).
projectile
Primary projectile to be calculated. At present C.
target()
Material. At present H2O.
echannels(echn)
Number of fragment energy bins. If <echn> <= 0 the number of bins and the binsize are chosen automatically so that the relative change of energy loss of the projectile is less than 2E-3 across a single bin.
If <echn> > 0 this number of equidistant bins is used. It should be large enough to allow for correct prediction of the depth dose maximum. Since this is determined by the primary particle, the number of energy bins for the primary is enlarged by a factor of 8. The maximum fragment energy (in MeV/u) is chosen 1.1 times larger than the original beam energy.
braggpos(bpos)
Estimated position of the depth dose maximum (aka "Bragg peak"), g/cm**2. This is very important because the internal depth spacing is chosen relative to <bpos>. Usually the calculations have to be iterated 2-3 times manually until a "stable" position is achieved. That is, the resulting approximate peak position should be used as a better estimate for the next iteration.
You may, however, choose bpos=0, in this case the iteration is performed automatically, with the following control parameters:
bragg(bdiff)
For bdiff>0 the iteration is aborted if the difference of subsequent positions is <bdiff.
bragg(beps)
For beps>0 the iteration is aborted if the relative change of subsequent positions is <beps. beps takes precedence over bdiff.
bragg(biter)
Maximum number of iterations to find appropriate Bragg peak position.
erelfwhm(erelf)
The original beam energy is assumed to have a spread of <erelf> percent FWHM.
write
Writes the calculated spectra and depth dose distributions. File naming conventions:
<path><proj><targ>.MeV<eeeee>.spc
<path><proj><targ>.MeV<eeeee>.ddd
where <eeeee> is the energy in MeV/u times 100.
(path)
export(fmt)
Exports the calculated distributions in some non-native format, at present only <fmt>="gd" is implemented to export for the gd plot program. File naming convention is:
<path><proj><targ>.MeV<eeeee>.um<dddddd>.spc.gd
<path><proj><targ>.MeV<eeeee>.ddd.gd
where <eeeee> is the energy in MeV/u times 100, where <dddddd> is the depth in micrometers.
(path)
path(path)
Output path for the calculated distributions. It is just a prefix put in front of the file naming convention. Might be a directory or just part of a file name.
delete
Releases memory occupied by dose profiles and spectra from previous calls of this command. Sometimes useful if large data sets are processed. Note that "old" data are not discarded until the allocation of new ones is successful, which may cause memory bottlenecks.
outbins(oblist)
Specifies a list of binsizes by which the output energy distributions are compressed in order to save space and time.
debug
Debug switch. Lots of output !

Remark

none

Examples

dedx "$TRIP98BEAM/DATA/DEDX/20070326.dedx" /read
sigtot "$TRIP98BEAM/DATA/SIGTOT/20070516.sigtot"  /read
xs '$TRIP98BEAM/DATA/XS/0705.1H.nf.xs,$TRIP98BEAM/DATA/XS/0705.16O.nf.xs' /read
yld 270 / braggpos(14.4) write path(/s/bio/kraemer/) outbins(8,16,32)
Compute the beam model for 270 MeV/u with an estimated peak position at 14.4 cm in water. The spectra and the depth dose tables should be written immediately after calculation into directory /s/bio/kraemer/. The fragment spectra are compressed by a factor of 8 in the first third of the energy range, by 16 in the second third and by 32 in the last third, respectively.
| GSI Biophysics | TRiP98 long write-up |
Last updated:
$Id: trip98cmdyld.html,v 1.10 2009/03/13 17:26:19 kraemer Exp $
M.Kraemer@gsi.de,