From: Stefan Roesler (sroesler@mail.cern.ch)
Date: Thu Jun 28 2007 - 22:15:54 CEST
Dear Dr Mausumi,
The "adopted cross section" is the inelastic scattering cross section as
requested with What(6) of the USRYIELD continuation card. As indicated in
the Manual this cross section, or better the normalization to such a cross
section, has no meaning in case of a thick target.
In addition, in your case I think the value of What(6) (=50) has no
meaning since ixm is either zero or the material index and ixa=1...6
WHAT(6) = ixa + 100 * ixm, where ixa indicates the kind of yield or
cross section desired and ixm the target material (if needed
in order to calculate a cross section, otherwise ixm = 0)
ixa = 1 : plain double-differential cross section
d2 sigma / d x1 d x2 where x1, x2 are the first
and second quantity
ixa = 2 : invariant cross section E d3 sigma / dp3
ixa = 3 : plain double differential yield
d2 N / d x1 d x2 where x1, x2 are the first
and second quantity
ixa = 4 : double differential yield
d2 (x2 N) / d x1 d x2 where x1, x2 are the
first and second quantity
ixa = 5 : double differential yield
d2 (x1 N) / d x1 d x2 where x1, x2 are the
first and second quantity
ixa = 6 : double differential fluence yield
1/cos(theta) d2 N / d x1 d x2 where x1, x2 are
the first and second quantity, and theta is
the angle between the particle and the normal
to the surface
ixm = : material number of the target
Default: 1.0 (plain double-differential cross section)
Note that calculating a cross section has little meaning
in case of a thick target.
In your case the code assumes hydrogen as a target and the cross section
seems to be the muon - hydrogen scattering cross section. In any case, all
numbers in the detector are multiplied with this value and are therefore
of the order of 10^-30.
Regarding NEW-DEFAUL, I suppose you have to assign a low-energy neutron
cross section data set to your material which is done with the LOW-MAT
card. Please see the manual, Chapter 10, for the identifieres required in
the What's of LOW-MAT.
Hope this helps,
Regards
Stefan
On Thu, 28 Jun 2007 mausumi@veccal.ernet.in wrote:
> Hi Sorry, I forgot to send attachment with the previous mail. Therefore
> I am sending the mail again. Very Sorry for this inconvenience. Please
> ignore the previous mail. I want to know the distribution of angular
> deviation of transmitted muon when a monoenergetic beam of muon of
> energy 3GeV passes through a slab of plutonium. Also I want to know the
> energy distribution of transmitted muon. The input file is attached
> herewith. The output of usryield is showing adopted cross section (if
> any) is ~1.0E-30 mb. The results of usryield are also of the order of
> ~1.0E-28 to 1E-33. What is adopted cross section? Is there any problem
> in the input file? I started with Default option Newdefa. But it was not
> running and in the output file it was writing that low energy neutron
> cross section was not found. Then I changed the Default as Em-cascade
> because I needed only transmitted muon. Thanks Mausumi
>
>
>
>
>
>
-- ___________________________________ Stefan Roesler CERN, SC/RP CH-1211 Geneva 23 Switzerland Phone: +41-22-7679891 Fax: +41-22-7669639 E-mail: Stefan.Roesler@cern.ch
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