Component Manual for the Neutron Ray-Tracing Package McStas, version 3.10.0

14.24  The Mirror_conic McStas Component

Single flat mirror plate using the conic.h reflection routines (test component)

Identification

Description

Test component for the reflection routines in conic.h (ConicTracer), which are used by e.g. Conics_*, FlatEllipse_finite_mirror and NMO. It models a single flat mirror so that the results can be compared directly with Mirror.comp.

The mirror lies in the local y-z plane at x=0, extending from z=0 to z=length and from y=-yheight/2 to y=yheight/2. Only neutrons arriving from the x<0 side (vx>0) interact; everything else passes unaffected. Each neutron interacts at most once.

conic=0: the mirror is a conic.h FlatSurf and is handled by reflectNeutronFlat(), which reflects with probability R and otherwise transmits the neutron unaffected. Compare with Mirror(transmit=1). conic=1: the mirror is a conic.h ConicSurf cylinder of (very large) radius 1 km, handled by reflectNeutronConic(), which always reflects and weights by R. Compare with Mirror(transmit=0). A Gaussian figure (slope) error can be applied via sigma_m and sigma_s; the default is 0 here, whereas the Conics_* components default to the conic.h values of 1 and 250 urad.

Example: Mirror_conic(length=1, yheight=0.1, m=2)

Input parameters

Parameters in boldface are required; the others are optional.

Name

Unit

Description

Default

length

m

Length of the mirror along z

1

yheight

m

Height of the mirror along y

0.1

R0

1

Low-angle reflectivity

0.99

Qc

Å\(^{-1}\)

Critical scattering vector

0.021

alpha

Å

Slope of reflectivity

6.07

m

1

m-value of material

2

W

Å\(^{-1}\)

Width of supermirror cut-off

0.003

conic

1

0: use FlatSurf/reflectNeutronFlat(), 1: use ConicSurf/reflectNeutronConic()

0

sigma_m

rad

RMS meridional slope (figure) error, conic=1 only; for grazing angles below 10*sigma_m the waviness model of Hansen et al., arXiv:1612.03763 is used

0

sigma_s

rad

RMS sagittal slope (figure) error, conic=1 only

0

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