| 1 | ======================================================================== |
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| 2 | |
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| 3 | cosmicray_charging advanced example |
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| 4 | |
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| 5 | Henrique Araujo & Peter Wass |
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| 6 | Imperial College London |
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| 7 | |
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| 8 | April 2004 |
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| 9 | |
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| 10 | ======================================================================== |
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| 11 | |
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| 12 | This Geant4 example was derived from an application aimed at |
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| 13 | simulating the electrostatic charging of isolated test masses in the |
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| 14 | LISA mission by galactic cosmic ray protons and helium nuclei. This |
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| 15 | work was supported by the European Space Agency through the SEPTIMESS |
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| 16 | project under Contract No. 16339/02/NL/FM. |
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| 17 | |
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| 18 | LISA, the Laser Interferometer Space Antenna for the detection of |
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| 19 | gravitational waves, is a joint ESA/NASA mission composed of three |
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| 20 | identical spacecraft orbiting the Sun in a triangular formation, each |
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| 21 | containing two cubic test masses in pure geodesic (drag free) motion. |
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| 22 | The interferometric measurements between different spacecraft |
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| 23 | are affected by the accrual of charge in the test masses caused by the |
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| 24 | interaction of energetic cosmic rays. |
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| 25 | |
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| 26 | With this example we intend to demonstrate an application of Geant4 to |
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| 27 | space environment simulations, using an extensive set of physics |
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| 28 | models spanning from TeV energies down to a few hundred eV. This code |
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| 29 | retains most (but not all) of the complex spacecraft and sensor |
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| 30 | geometry implemented for the original purpose. In particular, some |
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| 31 | complex elements of the inertial sensor surrounding the test masses |
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| 32 | have not been included. Differential energy spectra for protons, He-4 |
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| 33 | and He-3 nuclei at solar minimum conditions are the only input macros |
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| 34 | provided. The remaining application classes have been kept unchanged. |
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| 35 | |
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| 36 | A Software Users' Manual suitable for Geant4 users of all levels is |
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| 37 | distributed with this application (/docs). The technical description |
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| 38 | of the original software package, including further software |
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| 39 | documentation, physics analysis and a similar effort for the precursor |
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| 40 | ESA mission LISA Pathfinder are available from the SEPTIMESS project |
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| 41 | website at http://reat.space.qinetiq.com/septimess/ or from |
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| 42 | http://astro.ic.ac.uk/~haraujo/SEPTIMESS/ . |
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| 43 | |
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| 44 | Any queries regarding this example or the original work can be |
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| 45 | directed to h.araujo@imperial.ac.uk. |
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