Re: tunnel geometry

From: Santana, Mario <msantana_at_slac.stanford.edu>
Date: Wed, 30 Jan 2013 09:25:08 -0800

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For your problem you should also consider that if the tunnel walls are not =
going to be blackhole, then particles can be reflected back into the tunnel=
  air and each time this happens FLUKA will need to check to which of the ~6=
0 contiguous regions the particles fly back to. This will slightly delay th=
e tracking. In such cases it is advisable to subdivide the outer volume (e.=
g. four or eight sectors) so that the number of neighboring regions to a gi=
ven point is not so high.


On Jan 30, 2013, at 4:43 AM, Maruyama, Takashi wrote:

> Thank you, Mario. I have not used parenthesis for region defs and I will =
study.
> Takashi
>=20
> ________________________________________
> From: Santana, Mario
> Sent: Tuesday, January 29, 2013 10:14 AM
> To: Maruyama, Takashi; fluka-discuss
> Subject: Re: tunnel geometry
>=20
> Hi Takashi,
>=20
> A 20-line long region definition is actually not that bad. Depending on t=
he purpose of your simulation you may want to make the outside a blackhole,=
  but even then you will need to define the region(s) where blackhole materi=
al is to be applied.
>=20
> In your case the geometry definition of the tunnel surroundings could be =
more easily implemented by using parenthesis (section 8.6 or the FLUKA manu=
al). Then you may want to activate the parenthesis optimization in WHAT(5) =
of the GEOBEGIN card.
>=20
> Mario
>=20
> On Jan 25, 2013, at 9:22 AM, Maruyama, Takashi wrote:
>=20
>> I am setting up a tunnel geometry shown with a thick black curve in the =
attached figure. The tunnel is represented by ~60 segments of linear sectio=
ns (all PLA and RCC). My question is how I can define the region outside th=
e tunnel. I see two ways of doing this.
>>=20
>> 1) define ~60 segments of inside two PLA and outside RCC. The region def=
inition gets very long, probably ~20 lines long. It looks ugly, but it shou=
ld work.
>>=20
>> 2) make the outside tunnel a black hole. When a particle comes out of th=
e tunnel, kill it so that no transport is necessary in this region. Is it p=
ossible to set up an one-way street without defining this region?
>>=20
>> Takashi Maruyama
>> SLAC
>> <Tunnel.pdf>
Received on Wed Jan 30 2013 - 22:29:44 CET