Re: Problem with deuton converter

From: Feracci Vincent (
Date: Wed May 16 2007 - 16:42:20 CEST

  • Next message: Sebastien WURTH: "Re: Problem with deuton converter"

    Dear Sebastien and Stefan,

    First thank you very much for answering my previous mail, however there
    are a still a few things which still seem a bit obscure to me: are there
    pertinent models for nuclear interaction below 100 MeV/nucleon available
    somewhere for FLUKA (i.e which would properly deal with the interaction
    of 40 MeV deutons with carbon for example) and if there are not, how did
    you Sebastien manage to have coherent results in your Fluka Spiral2
    I have run my simulation without DPMJET nor PHYSICS: IONSPLIT and no
    nuclear interaction is taken into account.
    Thank you in advance and regards,

    Vincent Feracci
    Intern at the GANIL on SPIRAL2 project

    Stefan Roesler wrote:

    >Dear Vincent,
    >In addition to what Sebastien wrote (i.e., there is no model for nuclear
    >interactions below 100MeV/nucleon in the distributed version) you are
    >PHYSICS 1.0 0.001 IONSPLIT
    >which splits the deutron into its nucleons before being transported. This
    >way you always get at minimum one neutron, which is unphysical in this
    >-----Original Message-----
    >From: on behalf of Sebastien WURTH
    >Sent: Tue 5/15/2007 5:28 PM
    >To: Feracci Vincent
    >Subject: Re: Problem with deuton converter
    >Hello Vincent,
    >Your beam energy is too low to get interactions through DPMJET (it is
    >transparent here). I did a SPIRAL2 simulation with FLUKA, and although
    >it wasn't the purpose of my study, I scored neutron fluence in the
    >converter (a cylinder of 7.7 cm radius and 1 cm thick) : 2.17e+14
    >n/cm²/s (with usrtrack then) and coming out from converter (usrbdx over
    >4 pi) : 1.17e+14 n/cm²/s. My beam was not cylindrical but rectangular
    >3cm*3cm, 40 MeV, 5 mA (ie 3.125e+16 d/s).
    >I found that is was not so far of the given values for 2.83 and 4 cm
    >beam diameters respectively 1.1e+14 and 7e+13 n/cm²/s.
    >I read that the neutron yield should be ~2.5% per deuteron over 4pi.
    >Feracci Vincent a écrit :
    >>Hello Fluka users,
    >>I am simulating the bombardment of a cylindric graphite converter (8
    >>cm diameter, 1 cm thick) by a 40 MeV deuton beam (gaussian spatial
    >>repartition) in order to produce neutrons. However in my simulation I
    >>measure a convertion factor which is close to 1 ( 1 deuton creates 1.1
    >>neutron) while it should be, according to other simulations and
    >>experiments about 0.01. In order to take into account deuton
    >>interaction, I used the following parameters:
    >>EVENTYPE 2.0
    >>DPMJET (i have linked the DPMJET library)
    >>PHYSICS 1.0
    >>PHYSICS 3.0
    >>PHYSICS 1.0 0.001
    >>LOW-NEUT 72.0 22.0 0.0196 1.0
    >>I used Usrtrack and Usrbdx to measure fluence inside the converter and
    >>at given angles of the incident deuton beam. I run my calculations on
    >>FLAIR V0.4 and simulated with 20.000.000 primaries separated in 50 runs.
    >>I am unsure of the physics models I have used but I can't manage to
    >>understand what is wrong with my simulation. I have attached my input
    >>file to this mail. Is it a problem of energy threshold for the deutons
    >>who by consequence all split to give neutrons?
    >>Thanks in advance,
    >>Vincent Feracci
    >>Intern at the GANIL on SPIRAL2 project

  • Next message: Sebastien WURTH: "Re: Problem with deuton converter"

    This archive was generated by hypermail 2.1.6 : Wed May 16 2007 - 17:00:54 CEST