> ## Documentation Index
> Fetch the complete documentation index at: https://docs.atomscale.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Physical Samples

> Representing growth runs and grouping related data

Physical samples group instrument and characterization data from the same run together for comparison and analysis. You can think of a physical sample as the central organizing unit for a single experiment or growth.

## Associations

Each physical sample can be linked to the following:

| Association       | Relationship  | Description                                                              |
| ----------------- | ------------- | ------------------------------------------------------------------------ |
| Growth Instrument | Optional, one | The synthesis instrument used for this growth (MBE, PVD, CVD, etc.).     |
| Target Material   | Optional, one | The material being grown, including substrate and layer definitions.     |
| Projects          | Many-to-many  | Physical samples can belong to multiple projects.                        |
| Data Items        | One-to-many   | Individual files (RHEED, XPS, SEM, etc.) linked to this physical sample. |
| Notes             | Optional, one | Free-form notes that auto-save as you edit.                              |

## Creating a Physical Sample

When creating a physical sample, you provide:

1. **Sample Name** (required): a descriptive name for the growth run
2. **Growth Instrument** (optional): select from instruments configured in Metadata
3. **Target Material** (optional): select from materials configured in Metadata
4. **Notes** (optional): goals, remarks, processing conditions, or other context

After creation, you can link data items to the physical sample from the Data page by setting the **Physical Sample** column on each data item.

## Detail Page

The physical sample detail page shows:

1. **Header**: editable name with a "Physical Sample" badge
2. **Metadata bar**: last modified date, growth instrument, target material, project assignment, and owner
3. **Notes**: auto-saving free-form text
4. **Data Items**: a list of all data items linked to this physical sample, with a count badge and a link to add more from the Data page
5. **Analysis Results**: a chart aggregating processed results across all linked data items
6. **Similarity**: explore how this physical sample's data compares to others in your organization

## Related

<CardGroup cols={2}>
  <Card title="Data Items" icon="file" href="/platform/reference/models/data-items">
    Individual files grouped under physical samples.
  </Card>

  <Card title="Projects" icon="folder" href="/platform/reference/models/projects">
    Group physical samples for cross-sample analysis.
  </Card>
</CardGroup>