# The `Test_mask` Instrument

*McStas: Simple test instrument for mask functionality in Union framework.*

## Identification

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

## Description

```text
Masks allow restricing some geometry to the internal part of a mask
geometry. All Union geometry components can be used as masks.
```

## Input parameters

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

| Name | Unit | Description | Default |
|------|------|-------------|---------|

## Links

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

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