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

# The `Sapphire_Filter` Component

Sapphire filter at 300K

## Identification

- Author: Jonas Okkels Birk (based upon Filter_Graphite by Thomas C Hansen (2000))
- Origin: PSI
- Date: 6 December 2006
- Version: 1.1.1.1

## Description

    This sapphire filter, defined by two identical rectangular opening apertures,
    is based upon an absorption function

    absorp=exp(L*A+C*(exp(-(B/L^2+D/L^4))))

    decribed by Freund (1983) Nucl. Instrum. Methods, A278, 379-401.

    Default values are for Sapphire at 300K as found by measurement (Mildner &
    Lamaze (1998) J. Appl. Cryst. 31,835-840

    The transmission in sapphire only depends slightly on temperature.
    The above formula has only been verified at wavelenths between 0.5 and 14 AA (0.4 meV 0.3
    eV).

    A filter of this type is used in the Eiger beamline at PSI to cut of high energy neutrons.

WARNING: This is a contributed Component.

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default
--- | --- | --- | ---
xmin | m | Lower x bound (-0.16) |
xmax | m | Upper x bound ( 0.16) |
ymin | m | Lower y bound (- 0.16) |
ymax | m | Upper y bound ( 0.16) |
len | m | Thickness of filter ( 0.10) |
A | m^-1 AA^-1 | Material constant | 0.8116
B | AA^2 | Material constant | 0.1618
C | m^-1 | Material constant | 21.24
D | AA^4 | Material constant | 0.1291

## Links

- Source code for `Sapphire_Filter.comp`.

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