[neutron-mc] Other problems with Powder modules

[Chapon, LC (Laurent)]

Dear all, 

following last email, I think there are possibly two more problems in
the Powder modules in McStas : 

 

First in the definition of the coherent scattering cross section, the
expression: 

 

my_s_v2 = PI*PI*PI*pack*DW/(Vc*Vc*V2K*V2K)*(j_1*F2_1/q_1) is not quite
right. I think a factor 4 is missing, it should be 4PI^3. 

 

In the definition of the absorbing and incoherent, my_inc and my_a_v,
the multiplication by the packing fraction is missing. 

 

 80 my_a_v = sigma_a/Vc*2200;           /* Is not yet divided by v */

 81 my_inc = sigma_inc/Vc;

 

Best,

______________________________________

Dr Laurent Chapon

Instrument Scientist

ISIS department

Bldg R3

Rutherford Appleton Laboratory

Chilton, Didcot

OX11 0QX

UK

+44(0)1235-446090

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman2.mcstas.org/pipermail/mcstas-users/attachments/20050331/07e058f1/attachment.html>