Re: source, damage

Dear Mojdeh,

for the time being you need to write a source routine where you
insert a call:
       CALL SFLOOD ( XXX, YYY, ZZZ, UXXX, VYYY, WZZZ )
this will return a random position XXX, YYY, ZZZ on the surface of
a sphere of unit radius centered at 0,0,0, and a random direction vector UXXX,
VYYY, WZZZ such that a uniform and isotropic fluence will be created at all
points inside the sphere. If the sphere you want is not centred in 0,0,0, and
if it has a radius RRR, you need to add the shift and scale the position:
       XXX = XSHIFT + XXX * RRR
       YYY = YSHIFT + YYY * RRR
       ZZZ = ZSHIFT + ZZZ * RRR
In the next FLUKA release, all this will not be necessary, since there will
be a SDUM option in command BEAMPOS to obtain the same result without writing
any user routine.

The generalized particle SI1MEVNE (Silicon 1 MeV Neutron Equivalent Fluence)
is the fluence of 1 MeV neutrons producing the same damage in a silicon
detector as induced by an arbitrary particle fluence with a given energy
distribution. It is a quantity often used to quantify radiation damage in
silicon due to NIEL (Non Ionizing Energy Losses). If you do a Google
search "1 MeV Neutron Equivalent" you will find more than 17000 results.
See for instance
http://wwwhep.physik.uni-freiburg.de/graduiertenkolleg/talks/GK_2008-10-15_1.pdf
SI1MEVNE (generalized particle 236) is essentially a weighted fluence, and
therefore can be scored by all FLUKA fluence-scoring commands (USRBIN,
USRTRACK, USRBDX, etc.)

For DPA, you need to wait for the next FLUKA release (very soon, I hope). It
cannot be scored with the present version.

Alberto

On Thu, 1 Apr 2010, mojdeh najm wrote:

> Dear Fluka Eperts
> I want to calculate of cosmic radiation damage on semiconductor devices in
> space weather. I have to introduce a simple silicium cube that is
> submerged(flood) in a source which is a sphere so covers target from all of
> sides as isotopic with different rays. I want to use source subroutine with
> a energy spectrum, but i don't know how can i introduce beampos and this
> type of source as mentioned above?. i heard before about "sflood subroutine"
> but i dont know how can i use it or achieve to its routine.
> second question is about usage of SI1MEVNE for calculating of damage And
> third how can i introduce and calculate DPA?
> please guide me with complete expalin.
> Thank you so much.
> Best regards
> Mojdeh Anjom
Received on Mon Apr 05 2010 - 22:02:26 CEST