Simple Radiograph (Format Specification)¶
Legend
Bolded datasets / attributes are required to meet the format spec. Italicized are optional.
HDF5 Datasets¶
| Name | Description | Array Shape | Units |
|---|---|---|---|
| image | Radiograph image | M x N | pixel counts |
| X | X position of pixel centers (radiograph coordinate system1) | M x N | meters |
| Y | Y position of pixel centers (radiograph coordinate system1) | M x N | meters |
| T | Change-of-basis matrix (a.k.a. transition matrix) to move from x, y, z radiograph coordinate system1 to x', y', z' global coordinate system of the target chamber. [x' y' z'] = T [x y z]. | 3 x 3 |
HDF5 Attributes¶
| Name | Description | Example | Units |
|---|---|---|---|
| object_type | Specification of the HDF5 object type | "radiograph" (always this value) | |
| radiograph_type | Specification of the radiograph sub-type | "simple" (always this value) | |
| pradformat_version | HDF5 pradformat file format version followed (see above for current version) | "0.1.0" | |
| scale_factor | Multiplier to convert pixel counts into particle counts | 1 | particles / pixel count |
| pixel_width | Physical pixel width / bin width, for the first image axis | 2.50E-05 | meters |
| pixel_width_ax2 | Physical pixel width / bin width, for the second image axis (not needed if using square pixels) | 2.50E-05 | meters |
| source_object_dist | Approximate distance from the particle source to the object plane (the E & M structures). Used to estimate image magnification. | 0.11 | meters |
| object_image_dist | Approximate distance from the object plane (the E & M structures) to the image plane (the radiograph). Used to estimate image magnification. | 1.43 | meters |
| source_radius | Approximate characteristic radius of the particle source (set as zero for a point source). Helpful in estimating image resolution. | 5.0e-5 | meters |
| spec_name | Shortname for the particle species2 | "p+" | |
| spec_mass | Particle mass | 1.67E-27 | kilograms |
| spec_charge | Particle charge | 1.60E-19 | Coulombs |
| spec_energy | Particle energy | 1.47E+07 | eV |
| label | Short, identifying label for this file (with no spaces or crazy characters). This can be stamped onto plots, etc. | "Feb21_shot3_14MeV" | |
| description | Longer description of this file. This can be read by people trying to figure out where this file came from. | "CR39 radiograph from shot 3 on the February 2021 NIF DISC run. Based on the CR39 scan from MIT named 20210231_scan_MIT.csv. Rotated and cropped, ready to feed into inversion algorithms." | |
| experiment_date | Date of the experiment (or synthetic particle tracing), in the format "YYYY-MM-DD". | "2021-02-29" | |
| file_date | Date this file was created, in the format "YYYY-MM-DD" | "2021-04-06" | |
| raw_data_filename | Filename of the raw data file (e.g. CSV from MIT) from which this derivative file was created, if applicable. | "20210231_scan_MIT.csv" |
Footnotes¶
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The convention of this format is that the image lies in the z=0 plane of the radiograph coordinate system, and that the z-axis will point towards the particle source. The image may be stored already cropped and rotated by any angle within the x-y radiograph coordinate system, which is why X and Y are specified as arrays rather than vectors. ↩↩↩
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For best compatibility, consider using the PlasmaPy particle symbol conventions. For example, protons can be specified as just “p+”, and electrons by "e-". Any arbitrary isotope of Hydrogen can be specified “ H-I q+” where I is the mass number and q is the charge. ↩