Re: Strange secondary particle ID

I have encountered a similar issue when looking at BXDRAW output with heavy
ion beams. However, I have seen -601207 and -601208, not -601200. My guess
is -601200 is a C-12 ion. If you look at source.f there is a segment of
code that assigns the particle ID based on the Z and A from user input

* | Heavy ion:
       ELSE IF ( IJBEAM .EQ. -2 ) THEN
          IJHION = IPROZ * 1000 + IPROA
          IJHION = IJHION * 100 + KXHEAV
          IONID = IJHION
          CALL DCDION ( IONID )
          CALL SETION ( IONID )
          ILOFLK (NPFLKA) = IJHION

where IPROZ and IPROA are the Z and A of the ion, respectively.

The negative sign, I think, indicates that the C-12 ion was produced in
evaporation. See footnote 1 of Table 5.1 in the manual.

That said, I would like to pose three further questions to the discussion
list:

1) What is the meaning of KXHEAV (the last two digits of a heavy ion
particle ID? It is set to PARAMETER ( KXHEAV = 30 ) in (FHEAVY). I suspect
that it is placeholder in the last two digits of the particle ID number
that identifies a particle as a heavy ion. Is the fact that particle ID 30
is labeled "Reserved" in Table 5.1 in the manual related to this discussion?

2) What differences are there, if any, between -601207, -601208, and 601230
for transport purposes? Is the difference simply the source of ion? It
seems that the negative and "07" in -601207 and the negative and "08" in
-601208 identify these two particles as either fission fragments or
fragments from Fermi break-up (footnote 1, Table 5.1).

3) Finally, and related to the previous question, what is the proper
procedure for implementing a two-step problem where particles such as
-601207 and -601208 are produced in the first part? I would like to use the
output from BXDRAW as the input for a second simulation. Do I keep the
-601207 and -601208 particle ID numbers? Or, is there any advantage in
changing the particle ID number to 601230 with a bit of code along the
lines of

IF((ID .EQ. -601207) .OR. (ID .EQ. -601208)) THEN
      ID = 601230
END IF

placed in the source subroutine for the second part? This question is not
limited in scope to these specific ions. Carbon is used simply as an
example.

Thanks in advance,
Jeremy Northum

On Wed, Oct 10, 2012 at 5:26 PM, Joseph Comfort <Joseph.Comfort_at_asu.edu>wrote:

> I am looking at some details from the USDRAW routine. An event starts
> with K0L --> pi- e+ nu. Then the pi- has an elastic interaction (icode
> = 100) and produces 2 particles (np = 2): a pi- and a -601200.
>
> Later in the chain, a neutron is produced. The neutron has an elastic
> interaction (icode=100) and produces 2 particles: a neutron and a -601200.
>
> What is a -601200? What is the meaning of an 'elastic interaction' in
> which 2 particles are produced? I also have interactions with icode=100
> and 2 secondaries that are 'normal' (e.g., n --> n + photon).
> How am I to understand the behavior?
>
> Thank you.
>
> Joe Comfort
>
>
>
Received on Mon Oct 15 2012 - 19:11:03 CEST