The Stopping Power Conundrum
It is well known that the stopping powers in RUMP are not very good
for high Z projectiles. Why do I let this problem persist?
The issues are not all that complex and basically come down to three issues:
The second of these issues is minor and I would be more than happy to implement
a much more comprehensive algorithm for stopping powers. The third,
though, is much more difficult to work around. Even if I write the
code and attempt to place it in the public domain, there remains a very
strong conflict of interest since I also sell RUMP. I do not doubt
that the copyright lawyers would have no difficulty charging a violation,
and I do not have the will or resources to challenge such a lawsuit.
For the majority of users, ion beam analysis is done using alpha particle
scattering and the existing stopping power calculations are pretty good.
There are now modifications to improve on the He stopping power in Si and
My own work has only involved He and H backscattering to date and I haven't
had to personally worry about the problems with high Z projectiles
I've been informed that I cannot include more recent stopping power calculation
algorithms in a commercial (for fee) package. The copyright issues
are unclear ...
The best that I believe I can do legally is to provide an internal mechanism
for loading alternate stopping power calculation routines. Users
can write (or download from others) a DLL which provides more accurate
stopping power information. The NT version presently has this
DLL load mechanism built in. UNIX does not support DLL's but I'd
be happy to help users modify the code if an appropriate public domain
algorithm were available.
What is needed?
A commerical, shareware, or public domain implementation of a DLL
module providing dE/dx in units of ev/10^15 atoms as a function of the
incident particle Z and mass, and the target element Z.
What I can (and will) do:
IF you can show that the code has all appropriate licenses and copyright
permissions, I would like to negotiate an agreement to include the code
in the default RUMP distribution (with appropriate royalties).
Provide programming information and support to make the module compatible
with the calling mechanism in RUMP.
Provide a working code example of the current stopping power algorithm
as a template for your work.
Donate my time to improve the algorithms, debug, and test the code.
Copyright for any and all code will remain with you independent of my effort.
Provide space on this WEB page for users to download the DLL (if you request).
Responsibility for any commercial or shareware charges will remain with
you, though I will attempt to help in any reasonable way.
Contact Mike Thompson if
you want to discuss these issues further.