Re: Question about energy deposition in the matter.

From: Alberto Fasso' <>
Date: Mon, 30 Jul 2012 22:56:22 +0200

A neutron doesn't deposit directly any dose, since it has no charge.
It can deposit dose via the secondary particles it produces in nuclear
collisions. The total energy deposited is not necessarily equal or
smaller than that of the primary neutron. It can be bigger if its
interaction, and/or that of many of its secondaries, is exoenergetic.
That depends of course on the materials where the interactions take place.
To extend the idea to the limit, think about a nuclear reactor, or even a
nuclear bomb: the energy released and deposited can be many orders of magnitude
larger than that of the neutron which has started the chain reaction.

Having said that, I would like to discourage you strongly from doing your own
energy deposition scoring using userdump. It is very easy for the average user
to make mistakes: please stick to the built-in FLUKA scoring commands, which
have been checked and optimized over many years.
I have recently noticed frequent attempts of users to do their own scoring
using userdump and the mgdraw routine: these facilities are available
for various purposes, but getting energy deposition is not one of them.


On Mon, 30 Jul 2012, Rogerio Burgugi wrote:

> Hello!
> Using Fluka I built a geometrical setup similar to the detector ZDC of Large
> Hadron Collider. Then I simulates one neutron of momentum 1 TeV/c
> impinging on this detector. The output file userdump (collision tape) produces
> data concerning continuous energy deposition and data concerning local (point)
> energy deposition. After the simulation=2C I built a program using ROOT to get
> the sum total of the variable RULL (amount of energy deposited) and the sum
> total of the variable DTRACK (energy deposition along the trajectory). Now,
> realizing the sum of these two quantities I get a value greater than 1 TeV.
> Where is the mistake? I was expecting a result less than 1 TeV.
> Could you explain the reason of this difference?
> Thank you in advance=2C
> Rogerio G. Burgugi
> Institute of Physics=2C University of Sao Paulo - Brazil
Received on Mon Jul 30 2012 - 23:27:19 CEST

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