# The `External_component` Instrument

*McStas: Union example: External_component*

## Identification

- **Site:** Union_demos
- **Author:** Mads Bertelsen
- **Origin:** University of Copenhagen
- **Date:** September 2015

## Description

```text
Example showing the use of the "number_of_activations" parameter to include
an external component into an ensamle of Union components

Example: stick_displacement=0 Detector: detector_I=189.144
```

## Input parameters

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

| Name | Unit | Description | Default |
|------|------|-------------|---------|
| stick_displacement | m | height displacement of sample stick | 0 |

## Links

- [Source code](External_component.instr) for `External_component.instr`.

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