Re: Understanding EMF-CUT and residual dose rate

From: Alberto Fasso' <fasso_at_SLAC.Stanford.EDU>
Date: Thu, 29 Mar 2012 08:50:34 -0700 (PDT)

Dear Mina,

you say:
> I am sorry but there is no where in the manual where I see a default
> transport/production energy cut-off of 333 keV for photons and 1 MeV for
> electrons.

Read Note 1 to EMFCUT:

"Default values are available for the electron and photon production thresholds
in electromagnetic interactions, but they are generated by a complex logic based
on possible other settings (transport cutoffs, delta-ray production thresholds,
DEFAULTS card, other defaults)".

A "complex logic" cannot be expressed in a simple way. To the user, it should
suffice to know that many different things contribute to generate those
defaults: "transport cutoffs, delta-ray production thresholds, DEFAULTS card,
other defaults". Especially because the user is strongly discouraged to
rely on those defaults: "It is not always guaranteed that the resulting values
be appropriate to the problem of interest. Therefore, in order to have good
control of the physics, the user is recommended to provide explicit threshold
values, or at least to check them on the main output".

I am sorry: it is true that in general defaults play a very important role
in FLUKA and the user can take advantage of them. This is an exception.
As far as I know, the only exception.

Received on Fri Mar 30 2012 - 13:40:45 CEST

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