From: Alberto Fasso' <fasso@SLAC.Stanford.EDU>
Date: Tue Apr 08 2008 - 20:35:23 CEST

I think that John's question was rather how to distinguish proton recoils
from other recoils when both are deposited as kerma (due to the high
transport threshold set by him, for whatever reason).
I am not sure, but I suggest that this could be done by looking at the=20
secondaries created with code 300 in USDRAW:
* Icode =3D 30x: call from Kasneu *
* 300: interaction secondaries *

Those secondaries are stored in COMMON GENSTK:

* /Genstk/ is the storage for secondaries created in hadronic *
* events *
* Np =3D total number of secondaries *
* Kpart (ip) =3D (Paprop) id of the ip_th secondary *
* Tki (ip) =3D laboratory kinetic energy of ip_th secondary (GeV)*

If an ENDRAW kerma deposition happens just after a proton has been
generated, I guess that that kerma corresponds to that proton (and it could
be compared to the proton energy (see Kpart above).


On Tue, 8 Apr 2008, Vasilis Vlachoudis wrote:

> Dear John,
> as it is written in the FLUKA manual, during low energy neutron transport
> only proton recoils are produced from H and N(n,p).
> "Generation of charged particles
> Recoil protons and protons from N(n,p) reaction are produced and
> transported explicitly, taking into account the detailed kinematics
> of elastic scattering, continuous energy loss with energy straggling,
> delta ray production, multiple and single scattering."
> all the rest you will see it as kerma deposition. Not very useful quantit=
> for you since it is the average kinetic energy release to matter per neut=
> group.
> Not in the next, but in a following FLUKA release dpa will be included as=
> generalized scoring particle. This will be a quantity of interest for you=
> since the recoil of Carbon at these energies thought non-ionizing energy =
> will produce defects in matter. And dpa is related with the energy of th=
> primary knock-on atom.
> Best Regards
> Vasilis
> John Clem wrote:
>> All,
>> We are in the process of studying energy deposition of ~2MeV neutrons in=
>> scintillator materials (as a ToF study). In our test case, we setup a=20
>> rectangular parallelepiped (RPP) 30X30X4cm filled with CH2 ~1g/cm^2 and =
>> 30x30 surface was illuminated with a perpendicular 2MeV Neutron pencil=
>> beam. Threshold for protons are set E>2MeV such that all recoils are=20
>> reported in ENDRAW as depositions, however I can not find an obviously w=
>> to seperate Proton recoils from Carbon in ENDRAW as JTRACK =3D 308 (low=
>> energy neutron kerma) is reported for both cases. An alternative of cour=
>> is the lower the proton threshold so it can be tracked in MGDRAW main,=
>> however this will increase the output size (excluding some level of=20
>> processing inside MGDRAW). Any suggestions ??
>> Thanks,
>> John
>> John Clem
>> Research Associate Professor
>> Bartol Research Institute
>> Department of Physics and Astronomy
>> University of Delaware
>> Newark, DE 19716 USA=3D20
>> 302-831-4354

Alberto Fass=F2
SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
Received on Tue Apr 8 21:31:43 2008

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