RE: [fluka-discuss]: modelling scatter

From: Joachim Vollaire <joachim.vollaire_at_cern.ch>
Date: Tue, 17 Mar 2015 15:31:39 +0000

Dear Faith
Your input (in attachment) is crashing because neutron transport is activated in the PRECISION calculation and you are missing the neutron cross section for some material during the initialization phase.
The most straightforward is to run with EM-CASCA and use 1 keV for the transport threshold defined with the EMF-CUT card :
*
EMFCUT -1.0E-06 1.0E-06 0.0 3.0 _at_LASTMAT PROD-CUT
EMFCUT -1.0E-06 1.0E-06 0.0 1.0 _at_LASTREG
*
Hoping this help
Greetings
Joachim


From: owner-fluka-discuss_at_mi.infn.it [mailto:owner-fluka-discuss_at_mi.infn.it] On Behalf Of "Mikhail Polkovnikov <?????? ???????????>"
Sent: 15 March 2015 13:10
To: Faith Green; fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: modelling scatter

On 14.03.2015 17:10, f.h.green_at_surrey.ac.uk<mailto:f.h.green_at_surrey.ac.uk> wrote:

Hi Mikhail,



I tried that and it didn't seem to make any difference. Could you please confirm the exact settings on the EMFCUT card that I should enter just to check I applied it correctly?



Faith

________________________________
From: "Mikhail Polkovnikov <Михаил Полковников>" <pmk_at_ihep.ru><mailto:pmk_at_ihep.ru>
Sent: 12 March 2015 18:02
To: Green FH Miss (PG/R - Physics); fluka-discuss_at_fluka.org<mailto:fluka-discuss_at_fluka.org>
Subject: Re: [fluka-discuss]: modelling scatter

On 12.03.2015 14:15, f.h.green_at_surrey.ac.uk<mailto:f.h.green_at_surrey.ac.uk> wrote:

Hi all,



I am trying to model the scatter produced from a low energy photon beam (20 keV - 30 keV) interacting with a perspex block and being detected by a thin layer of CdTe as my detector.

A few questions I have are firstly I have chosen EM-CASCA but found I was getting very little scatter in my spectrum so tried PRECISION but I only got errors, is there a reason why PRECISION wouldn't work?

Secondly I played around with the EMFCUT and DELTARAY options but this had no effect. Does anyone have any suggestions as to why you think I am getting such a small amount of scatter on my spectrum?



Here are the beam characteristics I used:

  * 20keV photon beam
  * Momentum spread (Δp) = flat – 0GeV/c
  * Divergence type (Δφ) = Gauss – 100.00mrad
  * Beam shape (x-axis) = Gauss – FWHM 0.05cm
  * Beam shape (y-axis) = Gauss – FWHM 0.05cm

The initial beam position was at -10cm on the z axis and the number of start events was 1E7.



Thank you for any suggestions you may have



Faith


Hi,

It looks like some kind of a bug with low neutrons in DEFAULTS where LOW-NEUT is activated by default,

Try to use EM-CASCA and photon particle transport threshold in 1 keV (EMFCUT card).

Best regards,
Mikhail
Hi,

What do you mean by saying "it didn't seem to make any difference"?

I don't know your exact geometry, but he is my test with fluences on different angles after a small perspex target.
USRBDX card clearly shows a 20 keV peak and a spectrum of scattered photons even without any threshold manipulations.

Best regards,



__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info

Received on Tue Mar 17 2015 - 19:11:31 CET

This archive was generated by hypermail 2.3.0 : Tue Mar 17 2015 - 19:11:33 CET