WITec Alpha reader¶
Reads .txt exports from WITec Alpha Raman spectrometers, combined with a separately supplied ELN file for the instrument/sample/user metadata the raw export doesn't carry. See Learn > The WITec and ROD parsers for what the parser actually does with the data, and How-to > Adjust the config file for customizing the mapping.
Supported format¶
| Format | Extension | Parser | Source |
|---|---|---|---|
| WITec Alpha ASCII export | .txt |
WitecParser |
src/pynxtools_raman/parsers/witec.py |
The parser reads the [Data] section of the export (comma-separated wavelength/intensity pairs) into data/x_values and data/y_values, and the [Header] section into scalar metadata (XAxisUnit, DataUnit, PositionX/Y/Z, FileName, GraphName, SizeX/Y/Graph, ...). XAxisUnit and DataUnit are mapped directly onto the data axes' @units attributes (see Config file below); the rest currently has no NXraman home and lands in COLLECTION[unused_witec_keys], same treatment as unmapped ROD CIF keys get — not dropped, just not (yet) structured.
Example data¶
An example dataset ships with the repository under examples/witec/txt/: Si-wafer-Raman-Spectrum-1.txt (a silicon wafer measurement) and eln_data.yaml (its metadata).
pynx convert examples/witec/txt/eln_data.yaml examples/witec/txt/Si-wafer-Raman-Spectrum-1.txt src/pynxtools_raman/config/config_file_witec.json --reader raman --nxdl NXraman --output witec_example.nxs
See Tutorial > Convert your first Raman dataset for a walkthrough of this exact command.
Config file¶
config_file_witec.json maps most NXraman concepts to "@eln" — meaning the value comes directly from the ELN file you supply, at the path derived from the NeXus concept path itself (see Learn > Reader architecture). The exceptions: the spectrum data (data/x_values, data/x_values_raman, data/y_values) and the two axis @units (@attrs:XAxisUnit, @attrs:DataUnit) come from the parsed .txt file rather than the ELN, and the Raman shift axis is computed by the parser rather than read directly from either source (see Learn > The WITec and ROD parsers).
Known warnings¶
Converting the shipped example currently produces a few benign warnings — values that don't exactly match one of NXraman's open enumerations (the source type laser, for instance) and a missing unit-documentation note for beam_incident/wavelength. None of these stop the conversion; the values are still written correctly, with custom=True added automatically where an enum doesn't match exactly.