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This modernized and graphic version of a charged particle beam transport code consists mainly of the old
CERN/SLAC/FERMILAB version of Transport coded in portable FORTRAN-77 [1] and C for the
OS-dependant system calls. Some enhancements have been added [2], mainly the possibility
to compute space charge effects
[3,3a,3b], an alternative stochastic fit algorithm [4],
which allows doing envelope fits
with second order or space charge using stochastic fitting. To vary parameters by imposing
constraints (fitting to desired values) is the most powerful option in Transport.
This improved version of Transport has been embedded in a new graphic shell written in C++
(see Fig.1, 69 kB)
(or Tcl/Tk + csh for x86-Linux and Mac OS X - X11
[see Fig.2, 53 kB]) and is providing some
pretty and handy GUI type tools (much more
elaborated under Windows than under x86-Linux), which makes it a lot easier and swifter
to either design new beam lines or debug and investigate existing ones online. A
screen shot of a modern GUI Transport Input Editor for Windows is shown in
Fig.3 (44 kB). This fruitful
and valuable symbiosis of legacy and modern coding shows that you don't
have to break with tradition in order to stay up-to-date. The computational part of
this version of Transport contains plenty of new and old - but still needed -
features and has been well tested over the last 30 years by many expert physicists
from PSI and elsewhere around the world. In order to get a list of the currently available
most important features of the Graphic Transport Framework (in comparison with the
Graphic Turtle Framework), please click here.
Because of the rapid development in computer technology and the preservation of code-efficiency
for this framework, the turnaround time (run Beam Transport->
plot results) has improved by 4 orders of magnitude over the last 27 years. A short résumé
about the usefulness of Transport (together with Turtle and MENT) has been published in the
PSI Scientific and Technical Report 2000 Volume VI (Large Research Facilities) on
pages 24 & 25. A whole collection of
Transport input files
from different users is available for inspection and/or downloading.
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To keep the graphic transport framework in good shape some modifications and bug fixes are sometimes necessary. So -
from time to time - watch out for modifications and new
features.
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Once a beam line has been designed in first or even in second order it is recommended
to switch to the Graphic Turtle Framework in order to look at properties like
particle losses, phase space and momentum acceptances or beam profiles. Only a few
lines of the Transport input file have to be modified for being used by Turtle.
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If you prefer to run the Windows versions of Graphic Transport and Turtle Frameworks under x86-Linux, then
you may do this today by installing the
VMware for some x86-Linux Systems. After configuration and licensing of VMware and the
installation of one of the 32-bit Windows operating systems inside this virtual machine for
x86-Linux, you may then download and install the Windows versions of Graphic Transport and/or Graphic Turtle and
run these programs under Windows while x86-Linux is up.
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If you prefer to run the Windows versions of Transport and Turtle on an Apple Computer, then you may
do this today by installing the
Virtual PC 6.1 for Mac OS X. After installation and licensing of Virtual PC and the
installation of one of the 32-bit Windows operating systems inside this virtual machine for
the Mac, you may then download and install the Windows versions of Graphic Transport and/or Graphic Turtle and
run these programs under Windows while Mac OS X is up.
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The usefulness of Graphic Transport for even large acceptance secondary beam lines was demonstrated for the case of
the new µE4 muon beam line at PSI.
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A bootable live CD (see screen shot of the booted system)
has been created which contains among many other preinstalled programs
'Transport for Windows' and 'Transport for Cygwin'. (Cygwin is a UNIX/Linux-like OS
running on top of Windows.) It may be downloaded as iso-file (
U_R_live_CD.iso, 655 MB,
instructions at
1-readme.txt). With low-speed internet connections you may download the
split images.
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This version of Beam Transport maintained by Urs Rohrer is freely available and distributable with one restriction:
If you use it for some work whose results are made public in a report or a journal publication,
then in a gentlemen's agreement you have to reference it properly like: PSI Graphic Transport Framework by U. Rohrer
based on a CERN-SLAC-FERMILAB version by K.L. Brown et al. A reference like: Beam Transport by
K.L. Brown et al. is considered as inappropriate, because more than half of this framework's
code has not been produced by K.L. Brown et al. (See: Compendium of Transport Enhancements
and Modifications and new features.) Nevertheless, I appreciate very much the excellent
work done by K.L. Brown et al. and all the others, who have contributed to the content of the
present version. (See also the references at the end of the Compendium.)
Notice:
PSI and the author of this program do not
guarantee the accuracy and/or usefulness
of the results achieved with this program.
The output of it is strongly dependent on
the given input and therefore the confirmation
of the correctness of all the results is the
responsibility of the user.
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Limitations of the beam TRANSPORT code:
For TRANSPORT the equation of motion is solved by applying a Taylor series up
to second (or third) order and using the matrix formalism to compute the propagation
of the beam through a beam line.
Therefore TRANSPORT calculations are usually describing a beam accurate enough
in the paraxial approximation {sines and tangents of the angles can be replaced with
the angles (valid up to about 100 mr or 5 degrees)}.
As long as the 5 first order sine- and cosine-functions (cx, sx, dx, cy and sy) and
their derivatives are small as feasible through the used magnetic or electrostatic
elements, then aberrations (2nd and higher order terms) remain reasonable small.
If above conditions are not fulfilled, then a ray-tracing program, which solves
the equation of motion through 4th order Runge-Kutta integration should be used
for checking the validity of the results computed with the beam TRANSPORT code.
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References:
[1] K.L. Brown, D.C. Carey, Ch. Iselin and F. Rothacker: Transport,
a Computer Program for Designing Charged Particle Beam Transport
Systems. See yellow reports CERN 73-16 (1973) &
CERN 80-04 (1980).
[2] Urs Rohrer: Compendium of Transport Enhancements,
Show text (66 kB)
[3] F. Sacherer and T.R. Sherwood, Space-Charge Modifications
for Transport. MPS-SI/Note - LIN/71-7 (1971).
[3a]
Frank J. Sacherer, RMS Envelope Equations with Space Charge,
IEEE Transactions of Nuclear Science, NS-18, (1971), p.1105-1107.
[3b]
F.J. Sacherer and T.R. Sherwood, The Effect of Space Charge in Beam
Transport Lines, IEEE Transactions of Nuclear Science, NS-18, (1971),
p.1066-1067.
[4] Udo Witzke, c't Computer Journal (in German), July 1991, p. 182-187.
Last updated by
Urs Rohrer on 20-April-2007
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