RE: definition of liquid hydrogen?

Date: Fri, 11 May 2012 11:10:52 -0500

Thank you for the help with the H2 definition in FLUKA. The problem I am still having is that it is well known that liquid hydrogen shielding drastically lowers dose. In the case that I am running, I am only seeing an ~18% reduction from what aluminum shielding provides. I've attached the two cases. Both cases have approximately the same shielding mass (~55 g/cm2). Whether I run a spectrum of protons (like the GCR protons) or mono-energetic beam of around 1 GeV, I get similar results. Other data shows that the reduction should be ~90% or so. Is there something wrong with either my input file or the definition of the material still? If, these input files are correct, then the secondary particles that FLUKA generates contribute 4-5x more than the beam particles (at this shielding thickness)..which suggests the effectiveness of the liquid hydrogen shielding isn't as great as thought to be.

From: [] On Behalf Of Alberto Fasso' []
Sent: Thursday, May 10, 2012 1:43 PM
Subject: RE: definition of liquid hydrogen?


the COMPOUND command is used to define compounds (or mixtures or alloys) of two
or more different elements. The H2 molecule is not a compound: it is made of two
atoms of the same element. You need only a normal MATERIAL card to define it.


On Thu, 3 May 2012, REDDELL, BRANDON D. (JSC-EV511) wrote:

> Apparently my last email got messed up. Here it is again for clarity:
> I am having trouble defining liquid hydrogen. Below is the email exchange from when this
> question was brought here before. I tried to create the Material/Compound cards for the
> latest version of FLUKA , such as:
> *Liquid H2
> MATERIAL 1.0 1.00794 0.0000837 3.0 0.0 0.0 HYDROGEN
> LOW-MAT HYDROGEN 1. -2. 87. 0.0 0. HYDROGEN
> MATERIAL 0.0 0.0 0.07 26.0 0.0 0.0 LH2
> COMPOUND 2.0 3.0 0.0 0.0 0.0 0.0 LH2
> I am not quite getting the results I thought I would (using PRECISIOn defaults)
> and suspect that this is not being defined correctly. Can someone tell me what I am doing wrong?
> Thanks.

Received on Sat May 12 2012 - 17:57:57 CEST

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