Re: FHEAVY common

Dear Vassili,

(FHEAVY) is intended to store fission/fragmentation products when they are
generated in an inelastic interaction. So, if inspected right after
such an interaction (as in USDRAW), of course NPHEAV easily exceeds 1: in
case of a (heavy nucleus) fission the fragments are two, whereas for a
(light nucleus) fragmentation they can be even more.

Now your question points at the JTRACK<-6 transport, being JTRACK<-6 the
above fragments during the ranging out process through ionization and
possibly delta ray emission (and no further interactions).
The answer is that, when you intercept them, you have to calculate their
energy/momentum from ETRACK in (TRACKR) and AMNHEA(-JTRACK) in (FHEAVY)
(with JTRACK from (TRACKR)).

AMNHEA is the nuclear mass of the fully stripped ion as transported in
FLUKA (then of course Z_eff is taken into account for ionization
purposes!). AMHEAV differs by the mass of the ICHEAV(-JTRACK) electrons
and their binding energy, and is not relevant here.

Ciao

Francesco

From: Vassili Maroussov <Vassili.Maroussov_at_cern.ch>
Date: Fri, 30 Apr 2010 15:52:20 +0200

Dear FLUKA experts,

as it was mentioned in several previous posts, in a case if JTRACK<-6
(TRACKR common at MGDRAW call) the information about the particle must
be obtained from FHEAVY common with kp=-JTRACK. In the documentation I
haven't found much details and got several questions.

- In my simulations I have never seen in NPHEAV>1 (number of
secondaries); should I always expect NPHEAV=1 in the current FLUKA
version?

- When JTRACK<-6, PTRACK<0 in TRACKR common. Should I take PHEAVY(1) as
the momentum? Or I must NOT rely on the assumption that NPHEAV=1 and to
calculate the momentum from ETRACK of TRACKR and the mass?

- If I have to calculate the momentum, mass I have to use, amheav(kp)
("atomic") or amnhea(kp) ("nuclear")? This terms are often mixed up in
literature... As I can see, amheav(kp)>amnhea(kp) and the difference is
~1.5-2.5MeV (binding energy?). So, amnhea(kp) must be used?

Regards,

Vassili

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854
Received on Tue May 11 2010 - 10:01:03 CEST