xrs-analysis

A script for extracting x-ray spectra from XRS data.

To use it, drop your HDF5 file into the data/ subdirectory and call

python analyze_xrs.py {FILENAME} {MINIMUM_ENERGY} {MAXIMUM_ENERGY} {BLAST_SHIELD_THICKNESS} [--filter_material={MATERIAL}] [--filter_thickness={THICKNESS}] [--detector_type={DETECTOR}] [--{ELEMENT}...]

The arguments are as follows:

1. {FILENAME} is a substring of the filename (such as the shot number). The script will search data/ and analyze the first HDF5 filename it finds containing {FILENAME}. Alternatively, you can specify a full filepath, in which case you don’t have to put your scan files in data/. If you have multiple files to analyze, you can do multiple {FILENAME}s separated by commas.
2. {MINIMUM_ENERGY} is the lower bound of the energy range specified in the SRF, give in eV.
3. {MAXIMUM_ENERGY} is the upper bound of the energy range specified in the SRF, given in eV.
4. {BLASH_SHIELD_THICKNESS} is the thickness of the berylium blast shield given in thousandths of an inch.
5. --filter_material lets you specify the material of any additional filtering.
6. --filter_thickness lets you specify the thickness of any additional filtering in thousandths of an inch.
7. --detector_type lets you specify the type of detector used. Right now, only "BAS-MS", "BAS-SR", and "BAS-TR" are supported. If no detector type is given, it defaults to "BAS-MS".
8. For the purpose of aligning the spectrum, you may finally supply any number of atomic symbols as flags. These elements’ emission lines will appear on the screen where you adjust the spectral axis. Supported elements include Ne, Al, Si, Ar, Kr, Zr, and Xe. For example, if you intend to align your spectrum to K-alpha emission from silicon and argon, you should add --Si --Ar.

For example, a typical call might look something like

python analyze_xrs.py s104782,s104783 1809.0 3531.3 4 --Si --Ar

The script will automatically rectify the image if it’s rotated and subtract out any background. You will be prompted to identify the bounds of the data in space and energy. Don’t worry about being precise with those, tho, as it will adjust the bounds itself later.

The most important part is the afformentioned alignment to elemental emission lines. Skipping this and trusting XRS to view the energy range you asked for will typically produce an error of about 100–200 eV,¹ which may be acceptable depending on your use-case. The final spectrum will be saved as a plot and a HDF5 file next to the scan file.

There’s a simple script you can run after that to infer electron temperature by fitting an exponential Bremsstrahlung to the spectrum.

python infer_temperature.py {FILENAME}

The {FILENAME} here is the same as it was before, but make sure you point to the analyzed HDF5 file if you’re specifying the entire filename.

¹Personal communication from Dan Barnak.