Re: Is it possible to discard beam particles past a certain region?

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Wed, 24 Aug 2011 16:57:38 +0200

Dear Mina,

> My question is: is it possible to discard (stop) the primary beam particles
> (electrons) past the converter, in order to speed up the processing?

yes, you can implement a very thin fake region filled with low
density gas downstream the converter and set there a high electron
transport threshold via EMFCUT (you need the gas since particles cannot
stop in vacuum). [This is a trick already discussed by Alberto, though I
cannot find now the proper link].

As an alternative (needed for other particles to which EMFCUT do not
apply), you can selectively kill particles at a boundary by zeroing their
weight WEE inside the usrmed routine, to be activated in connection
with the downstream region material via MAT-PROP (SDUM=USERDIRE, see the
manual as well as the thread
http://www.fluka.org/web_archive/earchive/new-fluka-discuss/3152.html).

I have then to warn you about the fact that the calculated photofission
yields are affected by the issue mentioned in the release notes,
responsible for significant underestimation especially at low
photon energies

Best regards

Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854

On Tue, 23 Aug 2011, Mina Nozar wrote:

> Hi everyone,
>
> I am working on a setup, producing RIB out of photo-fissions in a Uranium
> Carbide.
>
> primary beam: electrons
> converter: to produce photons
> target: depleted Uranium Carbide
>
> In order to optimize the length of the converter, I look at number of
> fissions in the target as a function of the converter thickness (several runs
> with different converter thickness).
>
> My question is: is it possible to discard (stop) the primary beam particles
> (electrons) past the converter, in order to speed up the processing? I
> looked at the DISCARD card but this card doesn't allow for setting transport
> thresholds in a given regions or a set of regions.
>
> Thank you,
> Mina
>
>
>
>
Received on Wed Aug 24 2011 - 17:48:39 CEST

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