# The `Test_shells` Instrument

*McXtrace: Single shell model of a true Wolter Type I optic*

## Identification

- **Site:** AstroX_ESA
- **Author:** Erik B Knudsen <erkn@fysik.dtu.dk> & Desiree D. M. Ferreira <desiree@space.dtu.dk> (email)
- **Origin:** DTU Physics/DTU Space
- **Date:** 12/12/2016

## Description

```text
Single shell example telescope using a combinatiopn of parabolic/hyperbolic shell
optical plates covering the full circle. Reflectivity is 1 for all energies.

Example: Test_shells.instr shell_type=1
```

## Input parameters

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

| Name | Unit | Description | Default |
|------|------|-------------|---------|
| FL | m | The focal length of the optical system | 12 |
| plate_zdepth | m | Plate length. | 0.5 |
| channel_yheight | m | Channel height. | 1e-2 |
| radiusin | m | Radius at the entry to the primary (parabolic) shell. | 0.535532 |
| radiusout | m | Radius at the optics centre and at the exit of the secondary (hyperbolic) shell. | 0.533113 |
| shell_type | 1 | Shell type 0=parabolic; 1=hyperbolic; 2=conical | 1 |

## Links

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

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