SQL schema (data structure)
The data structure for the (n,n'γ) data  is described using two relational tables,
CREATE TABLE nucleus( id INTEGER PRIMARY KEY, nuc_symb CHAR(5), /* Chemical symbol (with mass number for enriched isotopes) of the irradiated sample */nuc_Z INTEGER, /* Atomic number of irradiated sample */energy_gamma FLOAT, /* Gamma-ray transition energy */d_energy_gamma FLOAT, /* Uncertainty: Gamma-ray transition energy */intensity_gamma FLOAT, /* Gamma-ray transition intensity */d_intensity_gamma FLOAT, /* Uncertainty: Gamma-ray transition intensity */transition_type CHAR(2), /* Gamma flag: f (firm); d (doublet); t (tentative); c (calibration); m (multiply placed) */compound CHAR(16), /* Activated compound nucleus; usually the (n,n') product */compound_type CHAR(2), /* Compound-identification flag: f (firm); t (tentative) */energy_ex FLOAT, /* Excitation energy in compound nucleus */ex_type CHAR(2), /* Excitation-energy flag: f (firm); t (tentative); u (unknown) */sample CHAR(1) /* Sample flag: E (isotopically enriched); N (natural elemental abundance) */); CREATE TABLE sample( id INTEGER PRIMARY KEY, flag CHAR(1), /* Meta-data identification flag: X */element TEXT, /* Name of element/enriched isotope */Z INTEGER, /* Atomic number of element/enriched isotope */symbol TEXT, /* Chemical symbol for element/enriched isotope */N FLOAT, /* Normalization factor for determination of absolute partial gamma-ray cross sections */dN FLOAT, /* Uncertainty: Cross-section normalization factor */e_gamma_norm FLOAT, /* Gamma-ray transition energy used for normalization */A INTEGER, /* Atomic mass of enriched isotope (A=0 for natural elemental samples) */mass FLOAT, /* Mass [g] of irradiated sample */exposure_time FLOAT, /* Measurement period [h] of irradiated sample */enrichment FLOAT, /* Enrichment factor [%] of principal isotope in sample (0 for natural elemental samples) */sample_composition TEXT, /* Chemical composition of irradiated sample */isotope_norm TEXT /* Isotope used for gamma-ray intensity normalization */);
nucleus.intensity_gammais the relative γ-ray intensity measured at θ=90° to the neutron beam. In each data set, one of the γ-ray lines is assumed to be 100%. These relative intensities may be converted to absolute partial γ-ray production cross sections (σγ) using the corresponding sample.Ninformation.
sample.Nis a normalization factor representing the intensity of the corresponding sample.e_gamma_normtransition relative to the 2+1 → 0+gs γ-ray transition in 56Fe; sample.N = 100and sample.e_gamma_norm = 847keV for 56Fe.
nucleus.compoundalso includes radiative capture (n,γ) lines (identified as nucleus.compound = ‘NG’) as well as contaminant and background lines (identified by the corresponding nucleus).
nucleus.transition_type = ‘c’and nucleus.transition_type = ‘m’refer to calibration and multiply-placed γ rays, respectively, as explained in .
Though less frequent, the
nucleus.transition_typevariable may hold more than one flag, e.g., nucleus.transition_type = ‘mt’indicates a multiply-placed γ-ray transition that is also a tentative assignment.