# Debug scripts

Throwaway diagnostics for investigating beamline problems. **Not** part of the plugin:
nothing here is imported by `csaxs_bec`, and none of it needs BEC or a venv beyond the
libraries each script names.

Kept on the `debug/scan-artefacts` branch rather than `main` so that a half-finished
diagnostic never reaches a production checkout. Promote anything that turns out to be
generally useful; delete the rest once the question it answered is settled.

## scan_artefact_check.py

Desk check for the July 2026 commissioning scan artefacts reported by Andreas Apseros
and Kazu Hirosawa. Read-only — opens BEC master files and writes nothing.

```sh
python3 scan_artefact_check.py --root /sls/x12sa/data/p23080/raw/data \
        --scan 473 --scan 450 --scan 411 --scan 254
```

Answers two questions without beam:

- **end-of-line intensity** — is the last point of every line systematically weaker, and
  is the *first* point affected too (which would mean a different mechanism)?
- **dropped line motion** — did the fast axis actually travel on every line? A line whose
  span collapsed is motion that did not happen while the scan still reported success.

Include a known-clean scan (254) so a null result distinguishes "this scan was fine" from
"the analysis is wrong".

Run `--list` first if anything looks off; it dumps the file structure.

> The motion check reads the fast-axis *readback*. If that axis is an open-loop stepper
> with no encoder, the readback is the commanded position and lost steps are invisible:
> a collapsed span still proves failure, but a healthy span proves nothing.