[ Identification | Description | Input parameters | Links ]

# The `Transmission_V_polarisator` Component

Transmission V-polarisator including absorption by Fe in the supermirror. Experimentally benchmarked.

## Identification

- Site:
- Author: Andreas Ostermann (additions from Michael Schneider, SNAG)
- Origin: TUM
- Date: 2024

## Description

    Transmission V-polarisator including absorption by Fe in the supermirror.

    Example: Transmission_V_polarisator(w1=0.050, h1=0.050,
    w2=0.050, h2=0.050, l=2.700,
    waferD=0.0003, FeD=2.16e-06,
    Si_i=0.2, Si_a=0.215,
    R0=0.99, Qc=0.02174, alpha=4.25, W=0.001,
    mleft=1.2, mright=1.2, mtop=1.2, mbottom=1.2,
    reflectUP="measured_up_q.dat",reflectDW="measured_dw_q.dat")

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default |
reflectUP | str | Reflectivity profile of the FeSi-wafer for spin-up neutrons; columns [q,R] | 0 |
reflectDW | str | Reflectivity profile of the FeSi-wafer for spin-down neutrons; columns [q,R] | 0 |
w1 | m | Width at the polarizer entry |  |
h1 | m | Height at the polarizer entry |  |
w2 | m | Width at the polarizer exit |  |
h2 | m | Height at the polarizer exit |  |
l | m | length of polarizer |  |
waferD | m | Thickness of Si wafer |  |
Si_i | barns | Scattering cross section per atom (barns) |  |
Si_a | barns | Absorption cross section per atom (barns) at 2200m/s |  |
FeD | m | Thickness of Fe in supermirror, Ti is neglected |  |
R0 | 1 | Low-angle reflectivity of the outer guide | 0.99 |
Qc | AA-1 | Critical scattering vector of the outer guide | 0.02174 |
alpha | AA | Slope of reflectivity of the outer guide | 4.25 |
W | AA-1 | Width of supermirror cut-off of the outer guide | 0.001 |
mleft | 1 | m-value of material for left. vert. mirror of the outer guide | -1 |
mright | 1 | m-value of material for right. vert. mirror of the outer guide | -1 |
mtop | 1 | m-value of material for top. horz. mirror of the outer guide | -1 |
mbottom | 1 | m-value of material for bottom. horz. mirror of the outer guide | -1 |

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

## Links

- Source code for `Transmission_V_polarisator.comp`.
- P. Böni, W. Münzer and A. Ostermann: Physica B: Condensed Matter Volume 404, Issue 17, 1 September 2009, Pages 2620-2623

[ Identification | Description | Input parameters | Links ]