[mcstas-users] Guide_gravity Problem
Lingnan Shen
ls8vm at virginia.edu
Wed Feb 13 02:57:37 CET 2019
Hi all,
I am interested in how many reflection happened with one
guide_gravity component. I am able to printf() the number of bounces (
*nbounces*) in the EXTEND section after the guide_gravity. But the
monitor_nD component is not giving any data. It outputs only zeros. And on
the "variables" line in the output file it shows "I I_err N"
* COMPONENT UserMonitor = Monitor_nD(*
* user1 = nbounces,*
* username1 = "Number of bounces",*
* options = "auto user1")*
* AT(......)*
How should I use the Monitor_nD component for displaying the number
of bounces in the guide?
Sincerely,
Lingnan Shen
On Sat, Feb 9, 2019 at 5:44 PM Markus Appel <masolomaster3000 at googlemail.com>
wrote:
> Hi,
> "it didn't work" is kind of a vague error to work with, but on first
> glance your problem might be that the nbounces variable is not reset in
> the TRACE section, it will just keep counting up through the simulation.
>
> Check again the example in the manual, there is an Arm component before
> the guide with an EXTEND that sets nbounces=0 for each iteration.
>
> Best,
> Markus
>
> On 09/02/2019 22:56, Lingnan Shen wrote:
> > Hi all,
> >
> > I now have my reflectivity file working and I'm trying to
> > understand how many reflections happened in the guide. I followed the
> > example in the component manual in the end of section 9.8.7. It didn't
> > work. I attached the .instr and .rfl file to this email.
> > Thanks for all the great help.
> >
> > Sincerely,
> > Lingnan Shen
> >
> > On Sat, Feb 9, 2019 at 2:42 AM Kim Lefmann <lefmann at nbi.ku.dk
> > <mailto:lefmann at nbi.ku.dk>> wrote:
> >
> > Hi Shen,
> >
> > It is also my understanding that the k value is the momentum
> transfer.
> >
> > Sorry, I do not have the time to look into you problem now.
> >
> > best, Kim
> >
> >
> > On 2/7/19 4:53 PM, ls8vm at virginia.edu <mailto:ls8vm at virginia.edu>
> wrote:
> >>
> >> Hi all,____
> >>
> >> __ __
> >>
> >> I checked the supermirror_m3.rfl file and it ranges
> >> from 0 to 0.09 [Angs-1] so I’m really confused with the k value in
> >> the first column of reflectivity file. I thought it represent the
> >> total momentum transferred. Can you explain more on “better the k
> >> values in the reflectivity file to be around e.g. 1.0 Angs-1.”
> >> Does the guide_gravity component have a different definition on
> >> reflectivity file? My actual source wavelength ranges from 0 to 10
> >> [Angs].____
> >>
> >> __ __
> >>
> >> And also for Peter, my actual problem is to optimize a polarizer
> >> which is built by stack of supermirror. I’m trying to find a way
> >> to get the most transmission through that setup. So I want to
> >> calculate the ratio neutron_out/neutron_in. Now it seems that I
> >> should just divide the intensity instead of event numbers?____
> >>
> >> __ __
> >>
> >> __ __
> >>
> >> Happy Lunar New Year,____
> >>
> >> Lingnan Shen____
> >>
> >> __ __
> >>
> >> *From: *Peter Kjær Willendrup <mailto:pkwi at fysik.dtu.dk>
> >> *Sent: *Tuesday, February 5, 2019 4:20 AM
> >> *To: *Lingnan Shen <mailto:ls8vm at virginia.edu>
> >> *Cc: *Emmanuel Farhi <mailto:farhi at ill.fr>
> >> *Subject: *Re: [mcstas-users] Guide_gravity Problem
> >>
> >> __ __
> >>
> >> Hello again, ____
> >>
> >> __ __
> >>
> >> __ __
> >>
> >> A better starting point for understanding Guide_gravity and
> >> reflectivity files may be the instrument file Test_Guides which is
> >> included with your McStas installation, in combination with one of
> >> the example reflectivity files from the data folder - e.g.
> >> supermirror_m3.rdl.____
> >>
> >> __ __
> >>
> >> Also, for a pencil beam with controllable divergence, an option is
> >> to use Source_div.____
> >>
> >> __ __
> >>
> >> Hope this helps - otherwise you are welcome to write again,
> >> preferably with a good description of what exact problem you are
> >> trying to solve. :-)____
> >>
> >> __ __
> >>
> >> Best,____
> >>
> >> __ __
> >>
> >> Peter____
> >>
> >>
> >>
> >> ____
> >>
> >> On 5 Feb 2019, at 10.12, Peter Kjær Willendrup
> >> <pkwi at fysik.dtu.dk <mailto:pkwi at fysik.dtu.dk>> wrote:____
> >>
> >> __ __
> >>
> >> Hello Lingnan, ____
> >>
> >> __ __
> >>
> >> __ __
> >>
> >> Agree with Emmanuel. ____
> >>
> >> __ __
> >>
> >> Further, the combination of a pencil-beam, i.e. almost
> >> non-divergent source and using 500 channels in a rotated
> >> Guide_gravity means that transport through the guide becomes
> >> close to impossible. ____
> >>
> >> __ __
> >>
> >> With regard to your second question you should always consider
> >> the transported intensity I. The event count is simply a
> >> measure of statistics (of "neutron rays", not “neutrons”).____
> >>
> >> __ __
> >>
> >> __ __
> >>
> >> Best,____
> >>
> >> __ __
> >>
> >> Peter Willendrup____
> >>
> >> __ __
> >>
> >> __ __
> >>
> >> On 5 Feb 2019, at 10.01, Emmanuel FARHI <farhi at ill.fr
> >> <mailto:farhi at ill.fr>> wrote:____
> >>
> >> __ __
> >>
> >> Hello Lingnan,
> >>
> >> Your reflectivity file is given for k=0 to 0.14 Angs-1.
> >> This is very small and covers neutrons around lambda=60
> >> Angs, which are not even created by your source. Change
> >> either the lambda setting at the source, or better the k
> >> values in the reflectivity file to be around e.g. 1.0
> Angs-1.
> >>
> >> Cheers, Emmanuel.
> >>
> >> __ __
> >>
> >> On 2/5/19 7:17 AM, Lingnan Shen wrote:____
> >>
> >> Hi all, ____
> >>
> >> __ __
> >>
> >> I was trying to learn how to use the
> >> guide_gravity component. I tried to define the
> >> reflectivity curve but I get zero neutrons at the
> >> wavelength monitor in the end of guide. I have
> >> attached my .instr and .rfl file. I also found that
> >> even if the neutron beam just go through the guide.
> >> The detector at the end still see nothing.____
> >>
> >> Also another question about transmission of
> >> certain setup. To calculate the ratio of neutron_in /
> >> neutron_out. I want to know how much neutron remained
> >> after passing through that setup. Should I use the
> >> flux or the events count?____
> >>
> >> __ __
> >>
> >> Sincerely,____
> >>
> >> Lingnan Shen____
> >>
> >>
> >>
> >> ____
> >>
> >> _______________________________________________
> >>
> >> mcstas-users mailing list
> >>
> >> mcstas-users at mcstas.org <mailto:mcstas-users at mcstas.org
> >
> >>
> >>
> https://mailman2.mcstas.org/mailman/listinfo/mcstas-users
> >>
> >> --
> >>
> >> Emmanuel FARHI,
> \|/ ____ \|/
> >>
> >> Spectroscopy Group Institut Laue-Langevin (ILL) Grenoble
> ~@-/ oO \-@~
> >>
> >> 71 av des Martyrs,CS 20156,38042 Grenoble Cedex 9,France
> /_( \__/ )_\
> >>
> >> Work :Tel (33/0) 4 76 20 71 35. Fax (33/0) 4 76 48 39
> 06 \__U_/
> >>
> >> _______________________________________________
> >> mcstas-users mailing list
> >> mcstas-users at mcstas.org <mailto:mcstas-users at mcstas.org>
> >>
> https://mailman2.mcstas.org/mailman/listinfo/mcstas-users____
> >>
> >> __ __
> >>
> >>
> >> Peter Kjær Willendrup
> >> Forskningsingeniør, Specialkonsulent
> >> Næstformand for DTU Fysik LSU
> >>
> >> DTU Physics____
> >>
> >>
> >> <image001.gif>
> >>
> >>
> >> Technical University of Denmark
> >>
> >>
> >> <image002.gif>
> >>
> >>
> >>
> >> Department of Physics
> >> Fysikvej
> >> Building 307
> >> DK-2800 Kongens Lyngby
> >> Direct +45 2125 4612
> >> Mobil +45 2125 4612
> >> Fax +45 4593 2399
> >> pkwi at fysik.dtu.dk <mailto:pkwi at fysik.dtu.dk> ____
> >>
> >> __ __
> >>
> >> __ __
> >>
> >>
> >> Peter Kjær Willendrup
> >> Forskningsingeniør, Specialkonsulent
> >> Næstformand for DTU Fysik LSU
> >>
> >> DTU Physics____
> >>
> >>
> >> cid:b6339554-7f28-441d-9f31-5944f811397c at win.dtu.dk
> >>
> >>
> >> Technical University of Denmark
> >>
> >>
> >> cid:e108e480-fcab-46e2-9531-b38165079572 at win.dtu.dk
> >>
> >>
> >>
> >> Department of Physics
> >> Fysikvej
> >> Building 307
> >> DK-2800 Kongens Lyngby
> >> Direct +45 2125 4612
> >> Mobil +45 2125 4612
> >> Fax +45 4593 2399
> >> pkwi at fysik.dtu.dk <mailto:pkwi at fysik.dtu.dk> ____
> >>
> >> __ __
> >>
> >> __ __
> >>
> >>
> >> _______________________________________________
> >> mcstas-users mailing list
> >> mcstas-users at mcstas.org <mailto:mcstas-users at mcstas.org>
> >> https://mailman2.mcstas.org/mailman/listinfo/mcstas-users
> > _______________________________________________
> > mcstas-users mailing list
> > mcstas-users at mcstas.org <mailto:mcstas-users at mcstas.org>
> > https://mailman2.mcstas.org/mailman/listinfo/mcstas-users
> >
> >
> > _______________________________________________
> > mcstas-users mailing list
> > mcstas-users at mcstas.org
> > https://mailman2.mcstas.org/mailman/listinfo/mcstas-users
> >
>
>
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