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

# The `PSI_DMC` Instrument

## Identification

- Site: PSI
- Author: Peter Willendrup (Risoe), Uwe Filges (PSI), Lukas Keller (PSI)
- Origin:PSI
- Date: May 7th, 2008
- Version: 1.4

## Description

    McStas model of the DMC powder diffractometer at PSI, CH.

    Please note that this instrumentfile does not include the radial collimator of DMC.
    To generate the full 800-bin angle coverage at DMC, you should combine two simulations
    using this instrumentfile, with SHIFT=0 and 0.1. This will displace the detector by half
    a bin-width, which is a standard procedure at the DMC diffractometer

    Example:
    mcrun PSI_DMC.instr lambda=2.5666 FileName="Na2Ca3Al2F14.laz" -n1e8

## Input parameters

Parameters in boldface are required; the others are optional.

Name | Unit | Description | Default
--- | --- | --- | ---
lambda | AA | Choice of wavelength, affects both monochromator and source component | 2.5666
R | 1 | Reflectivity of non-curved guides | 0.87
R_curve | 1 | Reflectivity of curved guides | 0.87
FileName | str | Choice of reflection list filename, e.g. from McStas data dir | "Na2Ca3Al2F14.laz"
D_PHI | deg | Focusing 'd_phi' for PowderN, see mcdoc page | 6
SHIFT | deg | Rotation of detector, set to 0.1 to displace by half a bin | 0
PACK | 1 | Powder packing factor | 0.7
Dw | 1 | Powder Debye-Waller factor | 0.8
BARNS | 1 | Flag to define if powder reflection file |F2| is in Barns or fm | 1

## Links

- Source code for `PSI_DMC.instr`.
- The PSI Monte-Carlo website.
- P Willendrup, U Filges, L Keller, E Farhi, K Lefmann: Validation of a realistic powder sample using data from DMC at PSI, ICNS 2005 (Physica B, 386, (2006), 1032.)

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