RE: [fluka-discuss]: USRYIELD two-way vs. one-way

From: REDDELL, BRANDON D. (JSC-EV511) <"REDDELL,>
Date: Mon, 10 Mar 2014 05:12:48 +0000

My expectation was that switching the upstream and downsteam assignments will give forward or backward USRYIELD distributions. I have a simple slab, a proton beam normally incident and I am looking at the differential flux of neutrons crossing the surface. I have the following USRYIELD CARDS for the forward flux of neutrons and the backward flux of neutrons between two adjacent bodies. The two files are exactly the same? I haven’t seen this before in previous versions of FLUKA, so I am wondering if I am doing something wrong. My source is a beam of protons normally incident on a slab surface. I must be overlooking something very simple here?

RPP BLKH -500000.0 500000.0 -500000.0 500000.0 -500000.0 100.0000.0
RPP SPCE -50000.0 50000.0 -50000.0 50000.0 -50000.0 50.000.0
RPP TARG -5000.0 500.0 -5000.0 5000.0 0.0 14.9
XYP P1 12.967766
XYP P2 14.820304
  END
BLKH 5 +BLKH -SPCE
SPCE 5 +SPCE -TARG
BOD1 5 +TARG +P1
BOD2 5 +TARG +P2 -P1
BOD3 5 +TARG -P2
  END
GEOEND
*
ASSIGNMA BLCKHOLE BLKH
ASSIGNMA VACUUM SPCE
ASSIGNMA ALUMINUM BOD1
ASSIGNMA ALUMINUM BOD2
ASSIGNMA ALUMINUM BOD3
* Forward
USRYIELD 2174 NEUTRON -50.0 BOD1 BOD2 1.0Nu35
USRYIELD 2.5 1.0D-5 50.0 0.5 -0.5 1006&
* Backward
USRYIELD 2174 NEUTRON -60.0 BOD2 BOD1 1.0Nu35
USRYIELD 2.5 1.0D-5 50.0 0.5 -0.5 1006&
*
From: me_at_marychin.org [mailto:me_at_marychin.org]
Sent: Sunday, March 09, 2014 8:46 PM
To: fluka-discuss_at_fluka.org; REDDELL, BRANDON D. (JSC-EV511)
Subject: Re: [fluka-discuss]: USRYIELD two-way vs. one-way

Hi Brandon,
Swapping the upstream and downstream regions generally would not produce the same results. Is there any corresponding symmetry of some sort in your set up?
Cheers,
mary
On 08 March 2014 at 05:35 "REDDELL, BRANDON D. (JSC-EV511)" <brandon.d.reddell_at_nasa.gov<mailto:brandon.d.reddell_at_nasa.gov>> wrote:
Hello,

I recently performed a simulation and used the USRYIELD card to get the double differential spectrum crossing a boundary defined by reg1 and reg2. I swapped the upstream and downstream assignments in WHAT(4) and WHAT(5) expecting different results to get both forward and backward estimates. I got the same results in both cases. Can someone tell me if this is the expected result? In the past, I was under the impression that it would give me forward or backward double differential scoring and not just the total.

I am aware that I can use USRBDX to do this same problem.

Thanks,

Brandon


Received on Mon Mar 10 2014 - 07:11:54 CET