From: Alberto Fasso' (fasso@SLAC.Stanford.EDU)
Date: Wed Oct 29 2003 - 19:22:15 CET
Hi John,
if there is no transport at all in vacuum, you can just replace it by
any dummy material you wish, and do the reflection at the surface
boundary air-dummy_material.
It sounds funny, but you can use even lead for this purpose.
But maybe you could find less shocking to define a thin layer of
air with a different material name.
Alberto
On Wed, 29 Oct 2003, John Clem wrote:
>
> Hi Alberto,
>
> Thanks... Yes, I'm very familiar with USRMED from past work. I didn't
> realize it could be used in that way. One particular problem I'm
> interested in requires a 180 reflection at an air-vacuum boundary i.e.
> track departing an air region into a vacuum region is reflected back
> into the air region. In this case, it's not clear if the rotation
> occurs in air or the vacuum.
>
> John
>
>
>
> On Wed, 29 Oct 2003, Alberto Fasso' wrote:
>
> > I am not sure about MGDRAW, but I think it could be dangerous.
> > The proper way to modify the directional cosines of a particle
> > is by means of another user routine, USRMED (see details in
> > Chap. 19 of the Manual). It is activated by option MAT-PROP with
> > SDUM = USERDIRE. It can be used, for instance, to
> > implement some sort of albedo reflection at the surface of
> > a given medium. However, it cannot be used in vacuum.
> >
> > Sorry if this does not answer your question directly.
> >
> > Alberto
> >
> > On Fri, 24 Oct 2003, John Clem wrote:
> >
> > > Does anyone know the answer to this ?? Obviously, this can be tested, but
> > > there may be some subtle effects.
> > >
> > > Thanks,
> > > John
> > >
> > > ----- Original Message -----
> > > From: John Clem
> > > To: Alfredo.Ferrari@cern.ch
> > > Sent: Thursday, October 23, 2003 9:06 AM
> > > Subject: fluka
> > >
> > >
> > >
> > > Alfredo,
> > >
> > > Can the directional cosines of a particle trajectory be modified in MGDRAW ??
> > >
> > > Thanks,
> > > John
> > >
> > >
> > > >>
> > > >>John Clem
> > > >>Senior Scientist
> > > >>217 Sharp Lab
> > > >>Bartol Research Institute
> > > >>University of Delaware
> > > >>Newark, DE 19716 USA
> > > >>Tel 302-831-4354
> > > >>Fax 302-831-1843
> > > >>clem@bartol.udel.edu
> > > >>
> > >
> >
> > --
> > Alberto Fassò
> > SLAC-RP, P.O. Box 4349, MS 48, Stanford CA 94309
> > Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
> > fasso@slac.stanford.edu
> >
>
>
-- Alberto Fassò SLAC-RP, P.O. Box 4349, MS 48, Stanford CA 94309 Phone: (1 650) 926 4762 Fax: (1 650) 926 3569 fasso@slac.stanford.edu
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