[neutron-mc] problem(?) with component monochromator_flat...
Ulrich C. Wildgruber MPI fuer Metallforschung Stuttgart
wildgrub at dxray.mpi-stuttgart.mpg.de
Tue Jun 1 10:02:41 CEST 2004
"Ulrich C. Wildgruber MPI fuer Metallforschung Stuttgart" wrote:
>
> Hi everybody!
>
> I'd like to draw your attention to an instrument file (attached) were
> we don't understand what happens for certain input parameter sets:
>
> parameter set 1: TTM = 80.0
> PHM = 40.0
> E = 4.131meV (4.45A)
> DWERT = 3.461(A)
>
> parameter set 2: TTM = 84.0
> PHM = 42.0
> E = 4.131meV
> DWERT = 3.325
>
> If I did Bragg's equation right we should see a reflection in both
> cases. However the intensity is 0 for parameter set "2".
> What are we doing wrong?
>
> Any advice is appreciated!
>
> Thanks
>
> Ulrich
>
> --
> Ulrich WILDGRUBER
> wildgrub at dxray.mpi-stuttgart.mpg.de
> wwwmf.mpi-stuttgart.mpg.de/abteilungen/dosch/dosch.html
> -----------------------------------------------------------------------------
> Max-Planck-Institut für Metallforschung | Technische Universität München
> Heisenbergstr. 3 | ZWE Neue Forschungs-Neutronenquelle
> | Instrumentierung
> D-70569 Stuttgart | D-85747 Garching/München
> Tel.: (+49)-711-689-1900 | Tel.: (+49)-89-289-14681
> Fax.: (+49)-711-689-1902 | Fax.: (+49)-89-289-14666
>
> --------------------------------------------------------------------------------
> DEFINE INSTRUMENT MCRY_test(TTM, PHM, E, DWERT)
>
> /* test version 05/2004 */
> /* */
>
> DECLARE
> %{
> double dist1 = 2.5;
> double dist2 = 2.5;
> double beam_width = 0.05;
> double beam_height = 0.05;
> double mos0 = 22.6;
> double ref0 = 0.7;
> %}
>
> INITIALIZE
> %{
> %}
>
> TRACE
>
> COMPONENT a1 = Arm()
> AT (0,0,0) ABSOLUTE
>
> /*
> COMPONENT source = Source_div_lambda(
> width = 0.062,
> height = 0.122,
> hdiv = 1.0,
> vdiv = 1.0,
> //lambda_0 = 2.0,
> lambda_0 = LAMBDA,
> d_lambda = 0.1)
> AT (0,0,0) RELATIVE a1 ROTATED (0,0,0) RELATIVE a1
> */
>
> COMPONENT source = Source_div(
> width = 0.062,
> height = 0.122,
> hdiv = 1.0,
> vdiv = 1.0,
> E0 = E,
> dE = 0.1)
> AT (0,0,0) RELATIVE a1 ROTATED (0,0,0) RELATIVE a1
>
> /* monitoring primary beam... */
> COMPONENT sum1 = Monitor(
> xmin = -0.1, xmax = 0.1,
> ymin = -0.1, ymax = 0.1)
> AT(0, 0, dist1+0.0171) RELATIVE a1 ROTATED (0,0,0) RELATIVE a1
>
> COMPONENT psd1 = PSD_monitor(
> xmin = -0.1, xmax = 0.1,
> ymin = -0.1, ymax = 0.1,
> nx = 41,
> ny = 41,
> filename = "NL1.psd")
> AT(0, 0, dist1+0.0172) RELATIVE a1 ROTATED (0,0,0) RELATIVE a1
>
> COMPONENT div1 = Divergence_monitor(
> xmin = -0.1, xmax = 0.1,
> ymin = -0.1, ymax = 0.1,
> nh = 41,
> nv = 41,
> h_maxdiv = 2.0,
> v_maxdiv = 2.0,
> filename = "NL1.div")
> AT(0, 0, dist1+0.0173) RELATIVE a1 ROTATED (0,0,0) RELATIVE a1
>
> /* end of monitoring primary beam... */
>
> /********************************************************/
> /* Monochromator */
> /********************************************************/
> /****************************************/
> /* center crystal package - position 0 */
> /****************************************/
>
> COMPONENT mono0 = Arm()
> AT (0, 0, dist1+0.167+0) RELATIVE a1 ROTATED (0, PHM, 0) RELATIVE a1
>
> COMPONENT m0 = Monochromator_flat(
> zmin = -0.011, zmax = +0.011,
> ymin = -0.003, ymax = +0.003,
> mosaich = mos0,
> mosaicv = mos0,
> r0 = ref0,
> DM = DWERT)
> AT (0, 0, 0) RELATIVE mono0 ROTATED (0, 0, 0) RELATIVE mono0
>
> /* monitoring transmitted beam... */
> COMPONENT psd2 = PSD_monitor(
> xmin = -beam_width, xmax = beam_width,
> ymin = -beam_height, ymax = beam_height,
> nx = 41,
> ny = 41,
> filename = "MatDet2.psd")
> AT(0, 0, dist1+.501) RELATIVE a1 ROTATED (0,0,0) RELATIVE a1
>
> COMPONENT sum2 = Monitor(
> xmin = -beam_width, xmax = beam_width,
> ymin = -beam_height, ymax = beam_height)
> AT(0, 0, dist1+0.502) RELATIVE a1 ROTATED (0,0,0) RELATIVE a1
> /* end of monitoring transmitted beam... */
>
> /* Bragg reflected beam along a2 */
> COMPONENT a2 = Arm()
> AT (0, 0, 0) RELATIVE mono0 ROTATED (0, TTM, 0) RELATIVE a1
>
> /* monitoring Brag reflected beam... */
> COMPONENT psd3 = PSD_monitor(
> xmin = -beam_width, xmax = beam_width,
> ymin = -beam_height, ymax = beam_height,
> nx = 41,
> ny = 41,
> filename = "MatDet3.psd")
> AT(0, 0, dist2+0.001) RELATIVE a2 ROTATED (0,0,0) RELATIVE a2
>
> COMPONENT sum3 = Monitor(
> xmin = -beam_width, xmax = beam_width,
> ymin = -beam_height, ymax = beam_height)
> AT(0, 0, dist2+0.002) RELATIVE a2 ROTATED (0,0,0) RELATIVE a2
>
> COMPONENT div3 = Divergence_monitor(
> xmin = -beam_width, xmax = beam_width,
> ymin = -beam_height, ymax = beam_height,
> nh = 41,
> nv = 41,
> h_maxdiv = 2.0,
> v_maxdiv = 2.0,
> filename = "MatDet3.div")
> AT(0, 0, dist2+0.004) RELATIVE a2 ROTATED (0,0,0) RELATIVE a2
> /* end of monitoring Bragg reflected beam... */
>
> END
>
> --------------------------------------------------------------------------------
> _______________________________________________
> neutron-mc mailing list
> neutron-mc at risoe.dk
> http://neutron.risoe.dk/mailman/listinfo/neutron-mc
Hi again!
Sorry for bothering everybody with my little problem on Friday.
I was not aware of the fact that my components 'psd2' and 'sum2'
which were supposed to monitor the beam transmitted through the
monochromator caused the strange behaviour.
Do I need to learn how to use 'groups' to avoid this effect?
Thanks for reading my mail and for suggestions...
I am assuming there is no simple fix to teach
McStas to respond in a more 'natural' way...
Thanks!
Uli
--
Ulrich WILDGRUBER
wildgrub at dxray.mpi-stuttgart.mpg.de
wwwmf.mpi-stuttgart.mpg.de/abteilungen/dosch/dosch.html
-----------------------------------------------------------------------------
Max-Planck-Institut für Metallforschung | Technische Universität München
Heisenbergstr. 3 | ZWE Neue Forschungs-Neutronenquelle
| Instrumentierung
D-70569 Stuttgart | D-85747 Garching/München
Tel.: (+49)-711-689-1900 | Tel.: (+49)-89-289-14681
Fax.: (+49)-711-689-1902 | Fax.: (+49)-89-289-14666
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