> ## 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.

# Data Items

> Individual instrument and characterization files

Data items are individual files uploaded to Atomscale. Each data item represents a single measurement or recording from an instrument: a RHEED video, an XPS spectrum, an SEM micrograph, a tool state log, and so on.

## Data Types

Every data item is classified by its data type. The platform supports these types, grouped by category:

### RHEED

| Data Type         | Description                                           |
| ----------------- | ----------------------------------------------------- |
| RHEED Rotating    | RHEED pattern captured during substrate rotation.     |
| RHEED Stationary  | RHEED pattern captured with the substrate held still. |
| RHEED Image       | A single RHEED pattern image.                         |
| RHEED Radial Scan | A radial scan sequence for lattice-spacing analysis.  |

### Spectroscopy

| Data Type         | Description                                     |
| ----------------- | ----------------------------------------------- |
| XPS               | X-ray photoelectron spectroscopy spectrum.      |
| Raman             | Raman spectroscopy data.                        |
| Photoluminescence | Photoluminescence emission spectrum.            |
| OES               | Optical emission spectroscopy data.             |
| ARPES             | Angle-resolved photoemission spectroscopy data. |

### Imaging

| Data Type     | Description                         |
| ------------- | ----------------------------------- |
| SEM           | Scanning electron microscopy image. |
| Optical Image | Optical microscopy or camera image. |

### Other

| Data Type    | Description                                                              |
| ------------ | ------------------------------------------------------------------------ |
| Tool State   | Metrology and instrument log data (temperatures, pressures, flow rates). |
| Ellipsometry | Ellipsometry measurement data.                                           |
| SIMS         | Secondary ion mass spectrometry data.                                    |
| Recipe       | Growth recipe file.                                                      |
| Other        | Any file type not covered above.                                         |

## Pipeline Status

After upload, each data item moves through a processing pipeline. The status reflects where it is in that process:

| Status                                                                       | Description                                      |
| ---------------------------------------------------------------------------- | ------------------------------------------------ |
| <Badge color="gray" icon="clock">Pending</Badge>                             | Queued for processing.                           |
| <Badge color="blue" icon="spinner">Running</Badge>                           | Analysis workflow is actively processing.        |
| <Badge color="green" icon="circle-check">Success</Badge>                     | Processing completed successfully.               |
| <Badge color="red" icon="circle-xmark">Error</Badge>                         | Processing failed.                               |
| <Badge color="gray" icon="box-archive">Stored</Badge>                        | File stored but not processed (quarantined).     |
| <Badge color="blue" icon="circle-play">Stream Active</Badge>                 | Live stream is currently recording.              |
| <Badge color="yellow" icon="circle-pause">Stream Paused</Badge>              | Live stream is paused.                           |
| <Badge color="orange" icon="triangle-exclamation">Stream Interrupted</Badge> | Live stream was unexpectedly interrupted.        |
| <Badge color="blue" icon="arrows-spin">Stream Finalizing</Badge>             | Live stream is being finalized into a data item. |
| <Badge color="red" icon="circle-xmark">Stream Error</Badge>                  | An error occurred during streaming.              |

## Associations

Each data item can be linked to:

| Association       | Relationship  | Description                                 |
| ----------------- | ------------- | ------------------------------------------- |
| Physical Sample   | Optional, one | The growth run this data came from.         |
| Growth Instrument | Optional, one | The instrument that produced this data.     |
| Target Material   | Optional, one | The material being measured.                |
| Tags              | Many-to-many  | Flexible labels for filtering and grouping. |
| Notes             | Optional, one | Free-form notes attached to this data item. |

You can set these associations from the Data catalog table or from a data item's detail page.

## Adding Data

The **Add Data** dialog provides four methods for getting data into the platform:

1. **Upload**: manually select files from your computer. Uploaded files can trigger [automations](/platform/reference/workflows) if configured.
2. **Stream**: record your screen to stream RHEED data directly into the platform. Only RHEED data is currently supported for streaming.
3. **File Watcher**: install a Windows application that watches a local directory for new files and uploads them automatically. Requires an API key from your user settings.
4. **API Integration**: use your API key to programmatically upload data. See the [API reference](/api-reference/upload/get-upload-urls) for details.

## Related

<CardGroup cols={2}>
  <Card title="Physical Samples" icon="vial" href="/platform/reference/models/samples">
    Group data items by growth run.
  </Card>

  <Card title="Workflows" icon="diagram-project" href="/platform/reference/workflows">
    Process data items to extract analysis results.
  </Card>
</CardGroup>