Component Manual for the Neutron Ray-Tracing Package McStas, version 3.8.6

14.12  The Guide_curved McStas Component

Non-focusing curved neutron guide.

Identification

Description

Models a rectangular curved guide tube with entrance centered on the Z axis. The entrance lies in the X-Y plane. Draws a true depiction of the guide, and trajectories. Guide is not focusing.

Example: Guide_curved(w1=0.1, h1=0.1, l=2.0, R0=0.99, Qc=0.021,
alpha=6.07, m=2, W=0.003, curvature=2700)

%BUGS This component does not work with gravitation on. Use component Guide_gravity then. Systematic error on transmitted flux is found to be about 10%.

Input parameters

Parameters in boldface are required; the others are optional.

Name

Unit

Description

Default

w1

m

Width at the guide entry

h1

m

Height at the guide entry

l

m

length of guide

R0

1

Low-angle reflectivity

0.995

Qc

Å\(^{-1}\)

Critical scattering vector

0.0218

alpha

Å

Slope of reflectivity

4.38

m

1

m-value of material. Zero means completely absorbing.

2

W

Å\(^{-1}\)

Width of supermirror cut-off

0.003

curvature

m

Radius of curvature of the guide

2700

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