From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>

Date: Fri, 16 Apr 2010 14:52:17 +0200

Date: Fri, 16 Apr 2010 14:52:17 +0200

Dear Hantao,

you did not get any interaction simply because you injected your 1 eV

neutrons downstream of your tungsten target, so they travel for 20m in

vacuum before reaching the blackhole. Note that over this distance the

neutron decay probability is of the order of 1e-6, so you can observe a

few beta- decay events, releasing an energy six orders of magnitude

higher than the initial one and therefore dramatically impacting the final

energy balance.

If you correct the BEAMPOS settings and move upstream to < -50cm the

longitudinal starting position of the beam, you will find a good amount of

low energy neutron interactions

Have a nice weekend

Francesco

**************************************************

Francesco Cerutti

CERN-EN/STI

CH-1211 Geneva 23

Switzerland

tel. ++41 22 7678962

fax ++41 22 7668854

On Fri, 16 Apr 2010, Hantao Jing wrote:

*> Dear fluka experts,
*

*> I want know about total number of interactions between particles. But
*

*> I find the output data always are zero
*

*> in xxx.out file. e.g.
*

*> * ==========================================================================
*

*> *
*

*> * ====== Summary of FLUKA-2008 run (Copyright 1989-2009 INFN & CERN) ======
*

*> *
*

*> * ====== Authors: A.Fasso` (SLAC), A.Ferrari (CERN & INFN), ======
*

*> *
*

*> * ====== J.Ranft (Siegen), P.R.Sala (INFN) ======
*

*> *
*

*> * ==========================================================================
*

*> *
*

*>
*

*>
*

*>
*

*> Total number of primaries run: 10000000 for a weight of: 1.000000E+07
*

*> !!! Please remember that all results are normalized per unit weight !!!
*

*> The main stack maximum occupancy was 2 out of 40000 available
*

*>
*

*>
*

*> Total number of inelastic interactions (stars): 0
*

*> Total weight of the inelastic interactions (stars): 0.000000E+00
*

*>
*

*>
*

*> Total number of elastic interactions: 0
*

*> Total weight of the elastic interactions: 0.000000E+00
*

*>
*

*>
*

*> Total number of low energy neutron interactions: 0
*

*> Total weight of the low energy neutron interactions: 0.000000E+00
*

*>
*

*> How to setup fluka and let it show these interaction data. Please tell me. My
*

*> input file and .out file in attachments.
*

*> Thank you very much.
*

*>
*

*> Hantao
*

*> Jing
*

*> 2010-4-16
*

*>
*

Received on Fri Apr 16 2010 - 16:34:28 CEST

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