[ Identification | Description | Examples | Input parameters | Links ]

The Test_Mirror_conic Instrument

Compares the conic.h reflection routines with Mirror.comp

Identification

• Site: Tests_optics
• Author: Peter Willendrup
• Origin: DTU
• Date: October 2026

Description

A collimated, polychromatic beam hits a single flat mirror at grazing angle theta.
The mirror is either Mirror.comp or Mirror_conic.comp, which uses the reflection
routines from conic.h (as used by Conics_*, FlatEllipse_finite_mirror and NMO).
Reflected and transmitted beams are recorded separately as function of wavelength.
For a given theta, pairs of COMP settings should give identical results:

COMP=0: Mirror, transmit=1           (reference for COMP=1)
COMP=1: Mirror_conic, conic=0        (FlatSurf, reflectNeutronFlat)
COMP=2: Mirror, transmit=0           (reference for COMP=3)
COMP=3: Mirror_conic, conic=1        (ConicSurf, reflectNeutronConic)

COMP=0 and COMP=1 should agree exactly, and so should COMP=2 and COMP=3 when
no figure error is applied (sigma_m=sigma_s=0).
With sigma_m comparable to the grazing angle (e.g. theta=0.1 sigma_m=1.745e-3),
COMP=3 uses the waviness model of Hansen et al., arXiv:1612.03763 (see conic.h).

Examples

(Test cases in bold)

• Test: COMP=0 Detector: L_refl_I=8.98208e-07
• Test: COMP=1 Detector: L_refl_I=8.98208e-07
• Test: COMP=0 Detector: L_trans_I=7.01789e-07
• Test: COMP=1 Detector: L_trans_I=7.01789e-07
• Test: COMP=2 Detector: L_refl_I=8.9763e-07
• Test: COMP=3 Detector: L_refl_I=8.9763e-07
• Test: COMP=3 theta=0.1 sigma_m=1.745e-3 Detector: L_refl_I=1.35886e-06

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
COMP	1	Mirror implementation, see description	0
theta	deg	Grazing angle of the beam on the mirror	1
length	m	Mirror length	1
m	1	Mirror m-value	2
R0	1	Low-angle reflectivity	0.99
Qc	AA^-1	Critical scattering vector	0.0217
alpha	AA	Slope of reflectivity	6.07
W	AA^-1	Width of supermirror cut-off	0.003
Lmin	AA	Minimum source wavelength	1
Lmax	AA	Maximum source wavelength	11
sigma_m	rad	RMS meridional slope (figure) error, COMP=3 only	0
sigma_s	rad	RMS sagittal slope (figure) error, COMP=3 only	0

Links

• Source code for Test_Mirror_conic.instr.

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[ Identification | Description | Examples | Input parameters | Links ]

Generated for mcstas 3.10.0

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Last Modified: Friday, 23-Oct-2026 18:32:10 CEST