Re: [fluka-discuss]: magnetic field in vacuum

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Fri, 14 Feb 2014 21:57:45 +0100

Dear Mina,

first of all we just saw with Brandon that, if you are fine with a
constant field, you do not need to write a magfld.f routine but it is
enough to define it in the MGNFIELD card. Then ASSIGNMAT is essential to
tell the code in which regions that field should be applied.

Furthermore and more important, you definitely do not want to ask the code
to go always through the magnetic tracking algorithm - by far more complex
than a straight step - despite the fact that no magnetic field is present
in your region, and to call the magfld.f routine at each substep to get
back a humiliating zero.

Ciao

Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854

On Fri, 14 Feb 2014, Mina Nozar wrote:

> Hello Francesco and everyone else.
>
> Just trying to understand the flow/logic of assigning magnetic fields in a
> region.
>
> Here is my understanding and a question where I lack understanding...
>
> 1) MGNFIELD card activates calling the subroutine MAGFLD defined in mgfld.f
> 2) In subroutine MAGFLD, one defines the intensity and direction of the
> magnetic field(s) and assigns it to a given region(s).
> 3) Set Field to Magfiled in the ASSINMAT card for the region(s) with magnetic
> field.
>
> What I don't understand is why do we need to turn on magnetic field in the
> ASSIGNMAT card? Is this not already set via MAGFLD?
>
> Best wishes,
> Mina
>
> On 14-02-14 01:57 AM, Francesco Cerutti wrote:
>>
>> Hallo,
>>
>> actually, in case of constant magnetic field in all magnetic regions, the
>> MGNFIELD card is enough (as stated in the manual). It will automatically
>> feed the default magfld routine (the one provided in usermvax, where in
>> fact the comment
>> * 2 Tesla uniform field along +z:
>> does not apply) and you do NOT need to link the latter into a customized
>> executable, unless you want to modify it, since it is already in the
>> standard FLUKA library and linked in the standard executable.
>>
>> Cheers
>>
>> Francesco
>>
>> **************************************************
>> Francesco Cerutti
>> CERN-EN/STI
>> CH-1211 Geneva 23
>> Switzerland
>> tel. ++41 22 7678962
>> fax ++41 22 7668854
>>
>> On Thu, 13 Feb 2014, Dr. Vittorio Boccone wrote:
>>
>> > No you should still include and link the default magfld routine which is
>> > configured for a uniform magnetic field, as explained in the lecture and
>> > the
>> > tutorial.
>> > Best
>> > V.
>> > Sent from my iPad
>> >
>> > On 13/feb/2014, at 22:42, "REDDELL, BRANDON D. (JSC-EV511)"
>> > <brandon.d.reddell_at_nasa.gov> wrote:
>> >
>> > Thanks Vittorio.
>> >
>> > So in my simple problem, I am not using the magfld.f routine,
>> > just only the MGNFIELD card. So, could you confirm if these
>> > cards should work:
>> >
>> > MGNFIELD 20.0 0.2 0.10 0.0
>> > 0.0 1.0
>> > STEPSIZE 0.5 0.0 VAC2 0.0
>> > 0.0 0.0
>> > EMF
>> > EMF-OFF
>> > .
>> > .
>> > .
>> > ASSIGNMA VACUUM VAC2 1.0
>> > (the 1 here is at WHAT(5)
>> >
>> > Thanks.
>> >
>> > Brandon
>> >
>> >
>> >
>> > ____________________________________________________________________________
>> >
>> > From: Vittorio Boccone [dr.vittorio.boccone_at_ieee.org]
>> > Sent: Thursday, February 13, 2014 2:47 PM
>> > To: REDDELL, BRANDON D. (JSC-EV511); fluka-discuss_at_fluka.org
>> > Subject: Re: [fluka-discuss]: magnetic field in vacuum
>> >
>> > Sure, check out the magnetic field exercise (solution) on the advanced
>> > course:
>> > http://www.fluka.org/fluka.php?id=course&sub=program&navig=2&which=triumf20
>> >
>> > 12
>> > Best
>> > V.
>> >
>> > On 2/13/2014 8:47 PM, REDDELL, BRANDON D. (JSC-EV511) wrote:
>> >
>> > FLUKA Users/Experts,
>> >
>> >
>> >
>> > Do the magnetic field settings in a region (using MGNFIELD
>> > card along with WHAT card 5 in ASSIGNMA Card) work if the
>> > region of the B field is a vacuum?
>> >
>> >
>> >
>> > Brandon
>> >
>> >
>> >
>> >
>
>
Received on Fri Feb 14 2014 - 23:02:37 CET

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