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

# The `Guide_honeycomb` Component

Neutron guide with gravity and honeycomb geometry. Can be channeled and focusing.

## Identification

- Author: G. Venturi
- Origin: ILL (France).
- Date: Aug 03 2001
- Version: 1.6
- Modification history:
  - E. Farhi, from Honeycomb_guide by K. Lefmann (buggy).
  - E. Farhi, focusing channels are now ok (Sept 4th, 2001).
  - E. Farhi, 2D channel array. Correct focus bug (Dec 14th 2002)
  - G. Venturi, Made Honeycomb from Guide_gravity (Apr 2003)
  - E. Farhi, corrected gravitation bug (Feb 2005)

## Description

    Models a honeycomb guide tube centered on the Z axis. The entrance lies
    in the X-Y plane. Gravitation applies also when reaching the guide input
    window. The guide can be channeled (hexagonal channel section; k,d parameters).
    The guide coating specifications may be entered via different ways (global,
    or for each wall m-value).
    For details on the geometry calculation see the description in the McStas
    reference manual.

    Example: Guide_honeycomb(w1=0.1, w2=0.1, l=12,
              R0=0.99, Qc=0.0219, alpha=6.07, m=1.0, W=0.003, k=1, d=0.0005)

    Example values: m=4 Qc=0.02 W=1/300 alpha=6.49 R0=1

WARNING: This is a contributed Component.

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default
--- | --- | --- | ---
w1 | m | Width at the guide entry |
w2 | m | Width at the guide exit |
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. | 1.0
W | AA-1 | Width of supermirror cut-off | 0.003
k | k-1 vertical dividing walls | [1] Number of horizontal channels in the guide (>= 1) [1] | 1
d | m | Thicxkness of subdividing walls [0] | 0.0005
mleftup | 1 | m-value of material for leftup. oblique mirror | -1
mrightup | 1 | m-value of material for rightdown. oblique mirror | -1
mleftdown | 1 | m-value of material for rightdown. oblique mirror | -1
mrightdown | 1 | m-value of material for leftup. oblique mirror | -1
mleft | 1 | m-value of material for left. vertical mirror | -1
mright | 1 | m-value of material for right. vertical mirror | -1
G | m/s2 | Gravitation norm. 0 value disables G effects. | 0

## Output parameters

Name | Unit | Description | Default
--- | --- | --- | ---
GVars | - | .N_reflection: (1) Array of the cumulated Number of reflections N_reflection[0] total nb of reflections N_reflection[1,2,3,4.5.6] reflections N_reflection[7] total nb neutrons exiting guide N_reflection[8] total nb neutrons entering guide |

## Links

- Source code for `Guide_honeycomb.comp`.

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