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SQL schema (data structure)

The data structure for the (n,n'γ) data [1] is described using two relational tables, nucleus and sample. The nucleus table contains the nuclear-structure type information related to the (n,n'γ) reaction product of the irradiated sample, whereas the sample table contains the meta data associated with the irradiated sample. The schema has the following format: 

	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 [keV] */
            d_energy_gamma FLOAT,     /* Uncertainty: Gamma-ray transition energy [keV] */
	    intensity_gamma FLOAT,    /* Gamma-ray transition intensity [RI] */
	    d_intensity_gamma FLOAT,  /* Uncertainty: Gamma-ray transition intensity [RI] */
	    transition_type CHAR(2),  /* Gamma flag: f (firm); d (doublet); t (tentative); c (calibration); m (multiply placed) */
	    residual CHAR(16),        /* Residual-nucleus reaction product; usually the (n,n') compound */
	    residual_type CHAR(2),    /* Residual-nucleus identification flag: f (firm); t (tentative) */
	    energy_ex FLOAT,          /* Excitation energy in compound nucleus [keV] */
	    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 [keV] */
	    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 */
	);

Notes:

  1. nucleus.intensity_gamma is 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.N information.
  2. sample.N is a normalization factor representing the intensity of the corresponding sample.e_gamma_norm transition relative to the 2+1 → 0+gs γ-ray transition in 56Fe; sample.N = 100 and sample.e_gamma_norm = 847 keV for 56Fe.
  3. nucleus.transition_type = 'c' and nucleus.transition_type = 'm' refer to calibration and multiply-placed γ rays, respectively, as explained in [1].
  4. Though less frequent, the nucleus.transition_type variable 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.
  5. nucleus.residual also includes radiative capture (n,γ) lines (identified as nucleus.residual = 'NG') as well as contaminant and background lines (identified by the corresponding nucleus). Earlier versions of the database previously defined the residual and residual_type member variables as compound and compound_type, respectively.
  6. nucleus.energy_ex is generally a float-type variable [keV] where its corresponding nucleus.ex_type flag is 'f' (firm) or 't' (tentative). However for unknown cases, i.e., nucleus.ex_type = 'u', then nucleus.energy_ex = '?'.

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