---
license: mit
tags:
  - electron-microscopy
  - 4D-STEM
  - materials-science
  - quantem
pretty_name: quantem-data
---

# quantem-data

Reference electron-microscopy datasets (gold 4D-STEM and HAADF) for browsing
and learning with [quantem.widget](https://github.com/bobleesj/quantem.widget).
This repo just hosts the data — all instructions live in one place:

**How to download and use this data:** follow the
[Download data tutorial](https://bobleesj.github.io/quantem.widget/tutorials/download_data.html)
in the quantem.widget docs. One call per dataset:

```python
from quantem.widget import Show4DSTEM
from quantem.widget.datasets import show4dstem_gold

Show4DSTEM(show4dstem_gold())
```

Layout — two trees:

- **`widget-tutorials/<widget>/<dataset>/<size>/`** — baseline tutorial
  bundles for the core widgets (`show1d/`, `show4dstem/`, `showfolder/`;
  data shared by Show2D and Show3D lives under `shared/`). These back the
  one-call loaders in `quantem.widget.datasets` and the Colab workshops.
  Baseline tutorials only — real work uses your own data.
- **`4dstem/`, `haadf/`** — full-size originals (Arina h5, Velox EMD) for
  power users.

Every NumPy bundle ships a `meta.json` (shape, dtype, sampling, units,
optics) next to `data.npy`.

Workshop notebooks (Google Colab, no local install):
[Show4DSTEM demo](https://colab.research.google.com/gist/bobleesj/54864ce5b2a6f0a4fd5ae1e5d5719b45/show4dstem_colab.ipynb)
·
[Workshop v1](https://colab.research.google.com/gist/bobleesj/a05a90185c6cddbb331342cae6d7e9c1/berk_workshop_v1.ipynb)

## Acquisition parameters

The 20260423 drift session's optics are **confirmed via the session's own
HAADF EMD** (`AccelerationVoltage`, `BeamConvergence`, `CameraLength`).
4D-STEM `scan_sampling` is an **operator pattern from a sibling SSB session**
— the drift acquisition itself was never per-file calibrated.

| dataset | voltage | probe | CL | scan | scan sampling | det pitch | mag |
|---|---|---|---|---|---|---|---|
| `haadf/gold_haadf_npy` | 300 kV ✓ | 30 mrad ✓ | 91 mm ✓ | 4096² image | 0.0186 nm/px | n/a | FOV 76.2 nm |
| `4dstem/gold_512_npy_bin8` | 300 kV ✓ | 30 mrad ✓ | 91 mm ✓ | 512² | 0.5 Å (op) | 3.68 mrad/px | unknown |
| `4dstem/gold_512_npy_bin4` | 300 kV ✓ | 30 mrad ✓ | 91 mm ✓ | 512² | 0.5 Å (op) | 1.84 mrad/px | unknown |
| `4dstem/gold_512` | 300 kV ✓ | 30 mrad ✓ | 91 mm ✓ | 512² | 0.5 Å (op) | 0.46 mrad/px | unknown |
| `4dstem/gold_30mrad1.3mx04`…`09` | 300 kV | 30 mrad | 91 mm | smaller | (session yaml) | 0.46 mrad/px | 1.3 Mx |
| `haadf/gold_haadf.emd` | 300 kV ✓ | 30 mrad ✓ | 91 mm ✓ | 4096² image | 0.0186 nm/px | n/a | FOV 76.2 nm |

✓ = confirmed via EMD/yaml. `(op)` = operator pattern, not file-certified.

## License

MIT — free to use for anything. Citing
[quantem.widget](https://github.com/bobleesj/quantem.widget) in publications
is appreciated.