Re: Energy deposited greater that incident energy for neutron?

From: Alberto Fasso' <>
Date: Thu, 27 Oct 2011 16:59:12 +0200


in a 27 m3 scintillator you get a lot of thermal neutrons.
A thermal neutron of energy 1.e-2 eV is easily captured by 10B in Boron,
emitting an alpha particle, a 7Li nucleus and a gamma ray: the total energy of
the reaction is 2.8 MeV.
There is nothing wrong in the fact that E_deposited > E_initial: it will
happen every time you have an exoenergetic reaction.

By the way, that reaction in 10B is the base of BNCT (Boron Neutron Capture
Therapy), where you use the large local energy deposition to destroy a tumor.


On Wed, 26 Oct 2011, denis wrote:

> Dear Fluka experts,
> Summing up all energy deposited by a incident neutron of 600 MeV inside a
> cube of 3*3*3 m made of pure
> Plastic Scintillator (BC408) , i get counts in the final E_deposit/E_initial
> spectrum greater than 1. .
> I would like to understand how can it be that FLUKA gives in some cases
> E_deposited > E_initial (neutron).
> Could this be linked to wrong Energy threshold defintion for secondary
> particles,
> wrong physic model ( i used CALORIMETRY and DELTARAYS card ). I have seen
> many reports using FLUKA showing
> the same problem with incident neutron particle. It seems to be a known
> problem but i can not figure out why ?
> I will be very thankful for any explanation here.
> Best regards,
> Denis Bertini
Received on Fri Oct 28 2011 - 11:15:57 CEST

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