| Message: Aluminum Stopping Power Validation | Not Logged In (login) |
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Hello,
I'm trying to verify GEANT4 v6.0 before using it on a more complex problem. In my GEANT setup, I'm firing electrons of various energies at a block of aluminum 100 m on a side. I use track length of each fired electron when it dissipates all its energy to calculate the electron stopping power of aluminum. And I've been comparing it to ESTAR data to validate(http://physics.nist.gov/cgi-bin/Star/e_table.pl) To calculate the stopping power from GEANT, I'm running 10,000 events, at each initial electron energy. I find the the maximum track length out of all 10,000 events at a particular initial energy and calculate stopping power using the following equation: Stopping_Power = Initial_Energy/(Maximum_Track_Length(cm)*Aluminum_Density) I've been getting good agreement until initial energies above 900 KeV. Then the results start to deviate significantly. I've also tried this calculation using the median track length for all events, and the result appears to match even more poorly.(Better at high energies worse at low) I've attached a plot with my results. I aggregate the track lengths using hits from a sensitive detector for the block of aluminum. I've attached the important parts of my code, I don't use any special cuts and it essentially uses the defaults from some of the examples. My suspicion is that I don't have some important process turned on. I found some plots from a talk by Maria Grazia Pia online, and it showed nearly perfect agreement between ESTAR and GEANT4 for aluminum. So there must be some way to make it work. I'm just not sure how.
Attachment:
http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/08/10/15.54-88375-GEANT4STP.png
http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/08/10/15.54-20127-physlistcode.txt
http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/08/10/15.54-45916-detectorconstruction.txt
http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/08/10/15.54-1766-primarygenerator.txt
http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2009/08/10/15.54-5723-main.txt
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