... obviously in my previous message the title for the CERN Yellow Report
should have been "Energy loss of muons in the energy range 1-10000 GeV"
(GeV not eV....) sorry.
+----------------------------------------------------------------------+
| Alfredo Ferrari || Tel.: +41.22.76.76119 |
| CERN-EN/STI || Fax.: +41.22.76.69474 |
| 1211 Geneva 23 || e-mail: Alfredo.Ferrari_at_cern.ch |
| Switzerland || |
+----------------------------------------------------------------------+
On Mon, 24 Sep 2018, Maarten Van Dijk wrote:
> Dear Luigi,
> Thank you for your answer; I have taken some time to think about it, and it
> makes sense. I do have some (small) remaining followup questions.
>
> The thing that was confusing me, mostly, is that the particle setting in
> motion the USDRAW entry is itself also tagged with that ICODE, meaning that
> the muon which is interacting is labelled with ICODE 104: it has just kicked
> off the production of an e+/e- pair.
>
> The missing entry you pointed out in my table was not logged on purpose; I
> limited the ICODEs for which I dump information (since there is always a lot
> happening, and processing the files is difficult). This has since been
> fixed.
>
> There are a few implications; the main one being that I was confused about
> the meaning of USDRAW. It does not give the creation process for a particle,
> it merely tags the LAST interaction in which it was last involved.
>
> My remaining question is this - it has been my impression that the process
> for pair creation would be the muon giving off a gamma, and this gamma
> turning into an e+/e- pair. Am I correct in deriving from the above that
> FLUKA directly produces the pair (which is then, most likely, lost because
> of the energy limit) from the muon?
>
> Thanks in advance for your help,
>
> Kind regards,
>
> Maarten
>
>
> ____________________________________________________________________________
> From: Luigi Salvatore Esposito
> Sent: 16 September 2018 22:54
> To: Maarten Van Dijk
> Cc: Fluka Discuss
> Subject: Re: [fluka-discuss]: USDRAW logging - meaning of ICODE?
>
> Dear Maarten,
> USDRAW is called with the ICODE = 104 after the direct production of a pair
> e+/e- in a Coulomb field by any heavy charged particle at high energy.
>
> The ISPUSR / SPAUSR are at user’s disposal. They are not internally
> manipulated by FLUKA.
>
> It’s difficult to comment more on your table without your input and user
> routines.
> However, in your table the ICODE = 103 (delta ray production) does not
> appear in the column “creation”, but only in the column “parent creation”.
> As consequence, there is a jump in the momentum and in the z-position. I’m
> wondering if this could suggest a problem in your logging procedure…
>
> Best, luigi
>
>
> On 13 Sep 2018, at 10:47, Maarten Van Dijk
> <maarten.van.dijk_at_cern.ch> wrote:
>
> Dear Fluka discuss, Fluka experts,
>
> I have been trying to track the production of high energy muons
> through a 250m long beamline section; and want to ask about the ICODE
> variable as given by the USDRAW entry of the mgdraw.f user routine.
>
> I have set up logging for the parents of muons by dumping information
> (under certain conditions) in the USDRAW routine. By means of the
> stupre.f and stuprf.f user routines, after writing the information at
> a given USDRAW event I then propagate it as parent information for the
> next generation of particles. The beamline I have constructed contains
> several magnets and other material regions.
>
> In the yoke of the magnets, where a return field is present, the muons
> lose energy (as expected). What is unexpected however, is that this is
> logged under ICODE 104 (pair production, as indicated
> byhttp://www.fluka.org/fluka.php?id=man_onl&sub=99 ). I should add
> that I have limited the transport energy of particles at 1 GeV (1
> GeV/c) because I am mainly interested in the higher energy part.
>
> After some post processing of the userdump information, I extract (for
> one event, there are many more) the following chain of information:
>
> mu- found in shashlik
> fluka file, event: 1005 628896
> particle history:
> track ID, (pa track ID), PID, (pa PID), creation, (pa creation),
> momentum, (pa momentum), z_pos, (pa zpos):
> 8 (1) PION- (PROTON ) 102
> (101) 181.345 (399.985)
> 145.342 (-15.26)
> 14 (8) MUON- (PION- )
> 104 (102) 169.634 (181.345)
> 565.079 (145.342)
> 14 (14) MUON- (MUON- )
> 104 (104) 168.221 (169.634)
> 650.757 (565.079)
> 14 (14) MUON- (MUON- )
> 104 (104) 167.316 (168.221)
> 668.168 (650.757)
> 14 (14) MUON- (MUON- )
> 104 (104) 166.076 (167.316)
> 746.069 (668.168)
> 14 (14) MUON- (MUON- )
> 104 (104) 163.459 (166.076)
> 839.058 (746.069)
> 14 (14) MUON- (MUON- )
> 104 (104) 162.431 (163.459)
> 937.07 (839.058)
> 14 (14) MUON- (MUON- )
> 104 (103) 157.557 (162.214)
> 975.983 (941.479)
> 14 (14) MUON- (MUON- )
> 104 (104) 157.531 (157.557)
> 977.15 (975.983)
> 14 (14) MUON- (MUON- )
> 104 (104) 156.499 (157.531)
> 1042.26 (977.15)
> 14 (14) MUON- (MUON- )
> 104 (104) 156.05 (156.499)
> 1069.45 (1042.26)
> 14 (14) MUON- (MUON- )
> 104 (104) 155.343 (156.05)
> 1106.1 (1069.45)
> 14 (14) MUON- (MUON- )
> 104 (104) 151.37 (155.343)
> 1246.31 (1106.1)
> 14 (14) MUON- (MUON- )
> 104 (104) 149.78 (151.37)
> 4203.01 (1246.31)
> 14 (14) MUON- (MUON- )
> 104 (104) 149.258 (149.78)
> 4241.91 (4203.01)
> 14 (14) MUON- (MUON- )
> 104 (104) 148.529 (149.258)
> 4296.8 (4241.91)
> 14 (14) MUON- (MUON- )
> 104 (104) 147.935 (148.529)
> 4325 (4296.8)
> 14 (14) MUON- (MUON- )
> 104 (103) 144.4 (146.379)
> 4460.79 (4403.42)
> 14 (14) MUON- (MUON- )
> 104 (104) 143.978 (144.4)
> 4492.37 (4460.79)
> 14 (14) MUON- (MUON- )
> 104 (104) 140.951 (143.978)
> 8195.04 (4492.37)
> 14 (14) MUON- (MUON- )
> 104 (104) 140.14 (140.951)
> 8250.41 (8195.04)
> 14 (14) MUON- (MUON- )
> 104 (104) 139.653 (140.14)
> 8260.5 (8250.41)
> 14 (14) MUON- (MUON- )
> 104 (104) 135.677 (139.653)
> 8500.22 (8260.5)
> 14 (14) MUON- (MUON- )
> 104 (104) 134.944 (135.677)
> 8549.98 (8500.22)
> State when crossing detector volume:
> 14 (14) MUON- (MUON- )
> 19 (104) 133.189 (134.944)
> 11920 (8549.98)
> Reached end of particle history loop
>
> The final iteration is when it crosses into the detector volume and is
> logged by BXDRAW with icode 19. As you can see, the particle was
> generated in by a primary (400 GeV/c) proton, which generated a pi-,
> which then produced the muon that was followed.
>
> The magnetic regions are from z=184.8 to 544.8 , z=916.6 to 1276.6,
> z=4139.4 to 4499.4, z=8156.5 to 8356.5 and z=8429.5-8629.5 and are
> implemented by means of a custom magfld.f routine.
>
> What is the meaning of the ICODE = 104 for these muons?
>
> Are the ISPUSR / SPAUSR variables (and their related variables in
> stupre.f and stuprf.f) also modified internally in FLUKA outside of
> the stupre.f and stuprf.f user routines – this question observed by
> the ISPUSR variable seemingly changing to 103 (eighth line along the
> history)?
>
> I understand this is a highly complicated question, especially since
> it relates to the simultaneous use of five user routines. If the
> problem is not clear like this, or requires further demonstration; I
> can produce a self-contained (relatively) simple example of the
> behaviour described here.
>
> Thank you in advance for your advice and help, it is much appreciated.
>
> Kind regards,
>
> Maarten van Dijk
>
>
>
>
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Received on Mon Sep 24 2018 - 20:08:55 CEST