Understanding the reults

From: Tomasz Cybulski <T.Cybulski_at_liv.ac.uk>
Date: Thu, 21 Jul 2011 13:57:59 +0100


      I did my simulations and I would like to ask few questions about
the interpretation of the results as I do not
fully understand what Fluka gives in return.

      Getting you back to the case of my set-up:

There is a proton beam impinging on the copper target as in the geometry
in input files. It is a 60MeV proton beam of annular shape with radius
of 1 cm. It hits the target and I want to score the proton fluence with
respect to angle and energy one way only - from Target to Vacuum 1. I
used USRBDX for that. The USRBDX's results are normalised to particles /
GeV / sr / cm2 per primary. As far as the tab.lis files are integrated
over solid angle the normalisation is in particles / GeV / cm2 per
primary. I understand that to get absolute value of Fluence I should
multiply the results by number of primaries, surface (100.531cm2 in this
case) and the energy bin width in GeV. When I do the multiplication I
get results like 0.5 proton. I do not really understand the result I get.

I did two runs:
1. 5e5 protons in 20 cycles
2. 1e6 protons in 10 cycles.

I was expecting that the number of primaries was too small for
statistics but Increasing the number of primaries did not change
anything. How should I understand that for 1e6 or 5.e5 protons I get 0.5
proton of certain energy (please, refer to the plots and data attached).

Thank you very much for your help in advance,

Tomasz Cybulski

Tomasz Cybulski
Marie Curie Fellow
The Cockcroft Institute
4 Keckwick Lane
Department of Physics
The University of Liverpool
L69 7ZE
United Kingdom
phone: +44 1925 864057
e-mail: t.cybulski_at_liv.ac.uk

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Received on Thu Jul 21 2011 - 21:32:52 CEST

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