MEASUREMENT DATA FILES
-----------------------

This directory contains processed measurement data from Rutherford Backscattering Spectrometry (RBS) experiments conducted at CNA (Centro Nacional de Aceleradores).

RBS is a non-destructive analytical technique used to characterize the composition and thickness of materials. In RBS, a high-energy ion beam (typically He or H ions) is directed at the sample. The ions scatter elastically off the atomic nuclei, and the energy of the backscattered particles is measured. The energy spectrum provides information about the mass and depth distribution of elements in the sample.
https://en.wikipedia.org/wiki/Rutherford_backscattering_spectrometry

RBS is especially useful for quantifying heavy elements in light matrices and for depth profiling.

Each measurement file is provided in `.txt` format encoded in ASCII and structured in two columns:

- **Column 1**: Energy channel number (discrete bin index corresponding to energy intervals).
- **Column 2**: Number of events (counts) detected in that energy channel.

Each row represents one energy bin and its corresponding count.

NOTE: Raw binary data may be stored separately in proprietary formats and is not included in this export.


METADATA JSON FILES
--------------------

Each `.txt` measurement file is accompanied by a `.json` metadata file that describes the experimental configuration and conditions under which the data was acquired.

We recommend using a code editor to open and browse the metadata JSON files.

3. Variables list:

Unless otherwise specified, the units of numerical fields are defined in separate fields with the same name followed by `_units`.

Variable name: `name`  
    Description: Name or label of the measurement.  
    Units: Text

Variable name: `proposal`  
    Description: Identifier code of the proposal linked to the measurement.  
    Units: Text

Variable name: `beam_isotope`  
    Description: Incident beam particle. Structured object including name, symbol, mass number, and atomic number.  
    Units: Object

Variable name: `beam_charge_state`  
    Description: Charge state of the ion beam.  
    Units: Integer

Variable name: `beam_energy`  
    Description: Energy of the incident beam.  
    Units: Specified in `beam_energy_units`

Variable name: `sample_ID`  
    Description: Identifier for the sample being irradiated.  
    Units: Text

Variable name: `detector`  
    Description: Description of the detector used, including name, type, radiation type, and configuration file path.  
    Units: Object

Variable name: `injection_energy`  
    Description: Energy of the beam at injection point.  
    Units: Specified in `injection_energy_units`

Variable name: `terminal_voltage`  
    Description: Terminal voltage of the accelerator.  
    Units: Specified in `terminal_voltage_units`

Variable name: `magnetic_field`  
    Description: Value of magnetic field applied in the system.  
    Units: Specified in `magnetic_field_units`

Variable name: `beam_current`  
    Description: Measured beam current.  
    Units: Specified in `beam_current_units`

Variable name: `beam_shape`  
    Description: Geometrical shape of the beam.  
    Units: Text (e.g., circular, rectangular)

Variable name: `beam_shape_diameter`  
    Description: Diameter of the beam spot.  
    Units: Specified in `beam_shape_diameter_units`

Variable name: `beam_shape_width`, `beam_shape_height`  
    Description: Width and height of the rectangular beam spot.  
    Units: Specified in `beam_shape_width_units` and `beam_shape_height_units`

Variable name: `incident_angle`, `exit_angle`, `scattering_angle`  
    Description: Geometry of the interaction between beam, sample, and detector.  
    Units: Specified in their respective `_units` fields

Variable name: `is_filter_present`  
    Description: Whether a filter was placed in the path.  
    Units: Boolean (true/false)

Variable name: `filter_material`, `filter_thickness`  
    Description: Material and thickness of the filter if present.  
    Units: Material: Text; Thickness in `filter_thickness_units`

Variable name: `sample_detector_distance`  
    Description: Distance from sample to detector.  
    Units: Specified in `sample_detector_distance_units`

Variable name: `detector_BIAS_voltage`  
    Description: Bias voltage applied to the detector.  
    Units: Specified in `detector_BIAS_voltage_units`

Variable name: `shaping_time`, `peaking_time`  
    Description: Electronic shaping and peaking time constants.  
    Units: Specified in their respective `_units`

Variable name: `amplifier_coarse_gain`, `amplifier_fine_gain`  
    Description: Gain settings of the preamplifier.  
    Units: Unitless

Variable name: `adc_gain`, `adc_range`  
    Description: ADC gain and bit-depth/range used for digital conversion.  
    Units: Gain in unitless, range typically in number of channels

Variable name: `accumulated_charge`  
    Description: Total charge collected on the sample during measurement.  
    Units: Specified in `accumulated_charge_units`

Variable name: `detector_inverse_current`  
    Description: Leakage or inverse current in the detector.  
    Units: Specified in `detector_inverse_current_units`

Variable name: `file_type`  
    Description: Internal label for the file group.  
    Units: Text

Variable name: `notes`  
    Description: Any free-text notes associated with the measurement.  
    Units: Text


ADDITIONAL FILES
----------------

In this directory, you will also find (if applicable) a subdirectory named "config_files/".

This folder contains the detector configuration files referenced in the metadata fields "energy_detector" and "TOF_detector" under the "config_file" key.

Each file provides technical specifications and calibration details relevant to the corresponding detector. These documents are essential for understanding the experimental setup and may be required for reanalysis or data comparison.