# The `Test_StatisticalChopper` Instrument

*McStas: An example using a statistical/correlation chopper and its de-correlation monitor*

## Identification

- **Site:** Tests_optics
- **Author:** <a href="mailto:farhi@ill.fr">Emmanuel Farhi</a>
- **Origin:** <a href="http://www.ill.fr">ILL (France)</a>
- **Date:** 1st Dec 2009.

## Description

```text
This instrument is a simple model of a kind of TOF instrument, with powder sample
and statistical chopper. The de-correlation is also performed in a dedicated monitor.
```

## Input parameters

Parameters in **boldface** are required; the others are optional.

| Name | Unit | Description | Default |
|------|------|-------------|---------|
| lambda | Angs | source wavelength | 1 |

## Links

- [Source code](Test_StatisticalChopper.instr) for `Test_StatisticalChopper.instr`.
- R. Von Jan and R. Scherm. The statistical chopper for neutron time-of-flight spectroscopy. Nuclear Instruments and Methods, 80 (1970) 69-76.

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