Problem 1146 - G4TripathiLightCrossSection parameters
Summary: G4TripathiLightCrossSection parameters
Status: RESOLVED WONTFIX
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/cross_sections (show other problems)
Version: 9.3
Hardware: All All
: P5 trivial
Assignee: dennis.herbert.wright
URL:
Depends on:
Blocks:
 
Reported: 2010-09-22 20:38 CEST by tkoi
Modified: 2011-12-22 00:24 CET (History)
0 users

See Also:

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this problem.
Description tkoi 2010-09-22 20:38:20 CEST 
Hi

246 // R_c is also highly dependent upon the A and Z of the projectile and
247 // target.
248 //
249   G4double R_c = 1.0;
250   if (AP==1 && ZP==1)
251   {
252     if      (AT==2 && ZT==1) R_c = 13.5;
253     else if (AT==3 && ZT==2) R_c = 21.0;
254     else if (AT==4 && ZT==2) R_c = 27.0;
255     else if (ZT==3)          R_c = 2.2;
256   }
257   else if (AT==1 && ZT==1)
258   {
259     if      (AP==2 && ZP==1) R_c = 13.5;
260     else if (AP==3 && ZP==2) R_c = 21.0;
261     else if (AP==4 && ZP==2) R_c = 27.0;
262     else if (ZP==3)          R_c = 2.2;
263   }
264   else if (AP==2 && ZP==1)
265   {
266     if       (AT==2 && ZT==1) R_c = 13.5;
267     else if (AT==4 && ZT==2)  R_c = 13.5;
268     else if (AT==12 && ZT==6) R_c = 6.0;
269   }
270   else if (AT==2 && ZT==1)
271   {
272     if       (AP==2 && ZP==1) R_c = 13.5;
273     else if (AP==4 && ZP==2)  R_c = 13.5;
274     else if (AP==12 && ZP==6) R_c = 6.0;
275   }
276   else if ((AP==4 && ZP==2 && (ZT==73 || ZT==79)) ||
277            (AT==4 && ZT==2 && (ZP==73 || ZP==79))) R_c = 0.6;

The value of "R_c" is given discretely without any inter(extra)polation.
Other parameters in the class are also implemented like this.
I believe some kind of interpolation is required.

Tatsumi
Comment 1 dennis.herbert.wright 2011-12-22 00:24:02 CET 
The values of R_c seem to change a lot from nucleus to nucleus which leads me to believe that they result from fits to data.   It would be difficult to find an interpolation function and maybe unjustified without either more data or theoretical input.   Without specific information from the cross section code author, I would prefer not to change this.