RE: RE: Please suggest

From: Markus Brugger <Markus.Brugger@cern.ch>
Date: Wed May 21 2008 - 14:12:23 CEST

Hi,

after some discussions we have the following comments and suggestions
for your problem:

- not knowing ALICE91 we assume that what you get is particle and energy
spectra originating from the actual alpha interaction
- from a technical point-of-view there is no problem in using this as a
source for a subsequent FLUKA calculations, however it's applicability
remains questionable due to the following points
  o if we understand your email correctly you would use the
pre-calculated neutron and photon spectra as a source impinging on the
Fe cylinder, thus you loose the transport part of the remaining (after
the interaction) thick Ta target
  o there might be a certain problem in the choice of the energy you use
as input for ALICE, i.e., as the target is thick interactions will not
only occur at the starting beam energy, but also further below
  o even if you consider the latter in terms of using different
energies, thus different production spectra, the problem remains where
to correctly start the 2nd FLUKA simulation (in the thick target)
- as accuracy is generally difficult to judge for both ALICE (we don't
know), as well as RQMD when lowering the production threshold (alphas at
50 MeV), we can only suggest to compare the following approaches
  + set the production threshold of RQMD down to 50 and do a
calculations -> this way you get the 'location' of the interactions
sampled correctly (at least down to 50MeV)
  + use the ALICE spectra as input to your calculations and start the
2nd (FLUKA) calculations=20
    o downstream of the Ta target
    o at the start of the Ta target
    o at a calculated average penetration depth

hope this helps you in some respect, cheers

Markus

> -----Original Message-----
> From: owner-fluka-discuss@mi.infn.it [mailto:owner-fluka-
> discuss@mi.infn.it] On Behalf Of rravi@veccal.ernet.in
> Sent: Sonntag, 18. Mai 2008 08:42
> To: Markus Brugger; fluka-discuss@fluka.org
> Subject: Re: RE: Please suggest
>=20
> Dear Mr. Markus Brugger, and Others of the Forum,
> Thanks for your detailed reply. My source itself is
> less than 100 MeV/n and as you say if the default RQMD is set to 100
> MeV/nucleon for Heavy Ions, there is no point in setting "TRANSPORT"
> less ( as initial INTERACTION itself can't be compromised). Hope BME
> model will be fully implemented in Future versions for public domain.
> In the mean time, I would like to request experts, if I use neutron
> Spectrum input in Fluka ( Spectrum generated from codes like ALICE91
> etc for 320 MeV Falling on Ta) to interact on Fe Cylinder ( as
> described in problem described earlier) and estimate the resultanting
> neutron and photon flux, will it be anywhere near approximation of the
> problem described earlier ?
> Kindly advise me.
>=20
>=20
> R. Ravi Shankar
> Scientific Officer,
> Health Physics Unit,
> VECC, 1/AF, Bidhan Nagar,
> Kolkata 700 064.
> India. Tel: +91 033 23371230-34 extn:3153
>=20
>=20
> ----- Original Message -----
> From: Markus Brugger <Markus.Brugger@cern.ch>
> Date: Friday, May 16, 2008 3:03 pm
> Subject: RE: Please suggest
>=20
> > Hi,
> >
> > there is another problem related to your question which was missed
> > yesterday. As your source particles are 320 MeV Alphas FLUKA
> > currently
> > performs the 'transport', however does not perform 'interactions'
> > (with
> > the default RQMD being set to 100MeV/nucleon). To a limited
> > extend, the
> > sampling of 'interactions' could be reached by lowering the
> > threshold of
> > the RQMD model (PHYSICS card) but again the !!! lowest !!!
> > possible
> > limit (for 'interactions') is 51MeV, thus only of limited use in
> > your
> > case. In addition, by lowering this limit, especially for alphas,
> > the
> > accuracy of the results remains questionable.=3D20
> >
> > Besides, and as a possible outlook for future FLUKA releases, a
> > new BME
> > model is currently under development however not yet available for
> > public use.
> >
> > Please find further information also in the following answer of
> > the
> > fluka-discuss list:
> >
> >
http://www.fluka.org/web_archive/earchive/new-fluka-discuss/0885.html
> >
> > cheers
> >
> > Markus
> >
> > >> > > -----Original Message-----
> > > > From: owner-fluka-discuss@mi.infn.it [owner-fluka-
> > > > discuss@mi.infn.it] On Behalf Of rravi@veccal.ernet.in
> > > > Sent: Dienstag, 13. Mai 2008 08:04
> > > > To: fluka-discuss@fluka.org
> > > > Subject: Please suggest
> > > >
> > > > Hi All,
> > > >
> > > > I am new to this forum and also a novice user of Fluka.
> > My =3D
> > best
> > > > regards to those great people who developed and made it
> available.
> > > > I have a problem. Can any body give me a suggestion ?
> > > >
> > > > I want to estimate the photon and neutron fluence emerging
> > out of
> > > the
> > > > system
> > > > The system is:
> > > > 320 MeV Alpha beam falling on thick target of Tantalum; the =3D
> > emerging
> > > > neutrons etc falling on Fe cyclinder.
> > > > *******
> > > >
> > > > Is it possible to do that with 320 MeV alpha in Fluka?
> > > >
> > > > With best regards to all of you,
> > > >
> > > > R. Ravi Shankar
> > > > Scientific Officer,
> > > > Health Physics Unit,
> > > > VECC, 1/AF, Bidhan Nagar,
> > > > Kolkata 700 064.
> > > > India. Tel: +91 033 23371230-34 extn:3153
>=20
> >
> >
Received on Wed May 21 18:00:24 2008

This archive was generated by hypermail 2.1.8 : Wed May 21 2008 - 18:00:27 CEST