[fluka-discuss]: RE: Secondaries from low energy neutron interactions

From: Stefan Roesler <Stefan.Roesler_at_cern.ch>
Date: Fri, 20 Oct 2017 15:09:57 +0000

Dear Guanying Zhu

Neutron interactions below 20MeV are based on a multigroup algorithm with uncorrolated production of secondaries, see for example
https://indico.cern.ch/event/604018/contributions/2435695/attachments/1395458/2242762/10_Low_Energy_Neutrons_2017.pdf

In a very few specific materials point-wise neutron scattering can be switched on but in case of 40Ar this is limited to physical gammas from n capture. Please see the manual entry for the LOW-NEUT card, in particular Notes 4 and 5

Cheers
Stefan


From: owner-fluka-discuss_at_mi.infn.it [mailto:owner-fluka-discuss_at_mi.infn.it] On Behalf Of Zhu, Guanying
Sent: 20 October 2017 04:29
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: Secondaries from low energy neutron interactions

Dear fluka users,

I’m simulating 10 MeV neutron interactions in liquid 40Ar. The goal is to count how many 40Ar(n, g)41Ar and how many 40Ar(n, n+g)40Ar.

I try to separate these two types of interactions by looking at the secondaries produced in each interaction. Below are two examples:
Example 1:
      mgdraw.f:
      IF (NCASE .EQ. 56 .AND. JTRACK .EQ. 8) THEN
   ETNEW = ETRACK-Am(JTRACK)
           do ip = 1, NP
              WRITE(82,600) NCASE, JTRACK, ETNEW,
     & ip, Kpart(ip), Tki(ip), NP,
     &
ICHTAR, IBTAR, ICRES, IBRES
           end do
      END IF
      Output:
        56 8 0.10000E-01 1 7 0.60471E-03 3 18 40 18 40
        56 8 0.10000E-01 2 7 0.29167E-02 3 18 40 18 40
        56 8 0.10000E-01 3 7 0.57545E-02 3 18 40 18 40
Example 2:
      mgdraw.f:
      IF (NCASE .EQ. 12060 .AND. JTRACK .EQ. 8) THEN
   ETNEW = ETRACK-Am(JTRACK)
           do ip = 1, NP
              WRITE(83,600) NCASE, JTRACK, ETNEW,
     & ip, Kpart(ip), Tki(ip), NP,
     &
ICHTAR, IBTAR, ICRES, IBRES
           end do
      END IF
      Output:
     12060 8 0.10000E-01 1 7 0.27595E-02 5 18 40 18 40
     12060 8 0.10000E-01 2 7 0.14334E-02 5 18 40 18 40
     12060 8 0.10000E-01 3 7 0.64536E-02 5 18 40 18 40
     12060 8 0.10000E-01 4 8 0.10126E-01 5 18 40 18 40
     12060 8 0.10000E-01 5 8 0.26580E-02 5 18 40 18 40

So the output shows two interactions: n + 40Ar -> 40Ar + gamma ; n + 40Ar -> 2n + 40Ar + gamma. However, they are not physical.

Does anyone know how to interpret the outputs shown here?




Thank you!
Guanying Zhu

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Received on Fri Oct 20 2017 - 18:41:24 CEST

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