[ Identification | Description | Input parameters | Links ]

# The `Guide_simple` Component

Neutron guide.

## Identification

- Site:
- Author: Kristian Nielsen
- Origin: Risoe
- Date: September 2 1998

## Description

    Models a rectangular guide tube centered on the Z axis. The entrance lies
    in the X-Y plane.
    For details on the geometry calculation see the description in the McStas
    reference manual.
    The reflectivity profile may either use an analytical mode (see Component
    Manual) or a 2-columns reflectivity free text file with format
    [q(Angs-1) R(0-1)].

    Example: Guide(w1=0.1, h1=0.1, w2=0.1, h2=0.1, l=2.0, R0=0.99, Qc=0.021, alpha=6.07, m=2, W=0.003

    %VALIDATION
    May 2005: extensive internal test, no bugs found
    Validated by: K. Lieutenant

    %BUGS
    This component does not work with gravitation on. Use component Guide_gravity then.

## 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 |  |
w2 | m | Width at the guide exit | 0 |
h2 | m | Height at the guide exit | 0 |
l | m | length of guide |  |
R0 | 1 | Low-angle reflectivity | 0.99 |
Qc | AA-1 | Critical scattering vector | 0.0219 |
alpha | AA | Slope of reflectivity | 6.07 |
m | 1 | m-value of material. Zero means completely absorbing. glass/SiO2 Si Ni Ni58 supermirror Be Diamond m= 0.65 0.47 1 1.18 2-6 1.01 1.12 | 2 |
W | AA-1 | Width of supermirror cut-off | 0.003 |

AT ( | , | , |  | ) RELATIVE |  |
ROTATED ( | , | , |  | ) RELATIVE |

## Links

- Source code for `Guide_simple.comp`.

[ Identification | Description | Input parameters | Links ]