Dear experts,
I need to get total number of neutrons from the body (lead)
to compare FLUKA results with those published in articles.
For this I use 2 cards : USRBDX and USRYIELD
I observed that output of N total is very different
and depends on the size of taget !
I have got the following results for the "small" geometry:
Tuto-lead-3.5.inp
Lead, R= 5 cm, L = 9 cm, beam - P , E= 3.5 GeV
-----------------------------------------------
*) USRBDX: N Fl from Pb into Air : Area: 1 cmq,
Tot. resp. (Part/cmq/pr) 27.26922 +/- 0.5661705 %
( --> (Part/pr) 27.26922 +/- 0.5661705 % )
*) USRYIELD: Fl from Pb into Air : linOmega LogE (0-5)
Tot. response (integrated over x1) 3.654836 +/- 0.7171366 %
( --> Tot. response without normaliz. 3.654836 +/-
0.7171366 % )
Ntot= 3.654836 * 5 = 18.27418
*) USRYIELD: Fl from Pb into Air : LogE LinOmega (0-4pi)
Tot. response (integrated over x1) 1.819517 +/- 0.7171366 %
( --> Tot. response without normaliz. 1.819517 +/- 0.7171366 % )
Ntot= 1.819517 *4*3.14156 = 22.864487
------------------------------------------------------
Then I use bigger volume :
accoring to the article: N.SOBOLEVSKY :
"Monte Carlo Calculation of Neutron Yield from Extended
Iron and Lead Targets Irradiated by 1 and 3.65 GeV/u Ion Beams"
where for Ep = 3.5 GeV Ntotal = 65 - 77 neutrons
----------------
So, I use :
Lead, R= 10 cm, L = 60 cm, beam - P , E= 3.5 GeV --
Tuto-lead-3.5-Big.inp
-----------------------------------------------
Results:
*) USRBDX: N Fl from Pb into Air : area = 1
Tot. resp. (Part/cmq/pr) 125.0001 +/- 0.2880751 %
( --> (Part/pr) 125.0001 +/- 0.2880751 % )
*) USRYIELD: N Fl from Pb into Air : linOmega LogE (0-5)
------------------
Tot. response (integrated over x1) 16.10910 +/-
0.2112415 %
( --> Tot. response without normaliz. 16.10910 +/- 0.2112415
Ntot = 16.10910 * 5 = 80.545
*) USRYIELD: N Fl from Pb into Air : LogE LinOmega (0-4pi)
Tot. response (integrated over x1) 8.019730 +/-
0.2112417 %
( --> Tot. response without normaliz. 8.019730 +/- 0.2112417
Ntot = 8.019730 *4*3.14156 = 100.777
---------------------------------------
Questions:
- are there large leakage from "small" target even for this
small energy ?
- the presented results are very different from the published ones.
How to get "right" number of the output neutrons from a body
with FLUKA ?
Summary: measured N : 70 +- 7
simulated : a) 125
b) 80
c) 100
thank you
Vladimir
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Received on Tue Jan 15 2019 - 19:17:52 CET