SQL schema (data structure)
The data structure for the (n,n'γ) data [1] is described using two relational tables,
CREATE TABLE nucleus (id INTEGER PRIMARY KEY , nuc_symbCHAR(5) ,/* Chemical symbol (with mass number for enriched isotopes) of the irradiated sample */ nuc_ZINTEGER ,/* Atomic number of irradiated sample */ energy_gammaFLOAT ,/* Gamma-ray transition energy */ d_energy_gammaFLOAT ,/* Uncertainty: Gamma-ray transition energy */ intensity_gammaFLOAT ,/* Gamma-ray transition intensity */ d_intensity_gammaFLOAT ,/* Uncertainty: Gamma-ray transition intensity */ transition_typeCHAR(2) ,/* Gamma flag: f (firm); d (doublet); t (tentative); c (calibration); m (multiply placed) */ compoundCHAR(16) ,/* Activated compound nucleus; usually the (n,n') product */ compound_typeCHAR(2) ,/* Compound-identification flag: f (firm); t (tentative) */ energy_exFLOAT ,/* Excitation energy in compound nucleus */ ex_typeCHAR(2) ,/* Excitation-energy flag: f (firm); t (tentative); u (unknown) */ sampleCHAR(1) /* Sample flag: E (isotopically enriched); N (natural elemental abundance) */ );CREATE TABLE sample (id INTEGER PRIMARY KEY , flagCHAR(1) ,/* Meta-data identification flag: X */ elementTEXT ,/* Name of element/enriched isotope */ ZINTEGER ,/* Atomic number of element/enriched isotope */ symbolTEXT ,/* Chemical symbol for element/enriched isotope */ NFLOAT ,/* Normalization factor for determination of absolute partial gamma-ray cross sections */ dNFLOAT ,/* Uncertainty: Cross-section normalization factor */ e_gamma_normFLOAT ,/* Gamma-ray transition energy used for normalization */ AINTEGER ,/* Atomic mass of enriched isotope (A=0 for natural elemental samples) */ massFLOAT ,/* Mass [g] of irradiated sample */ exposure_timeFLOAT ,/* Measurement period [h] of irradiated sample */ enrichmentFLOAT ,/* Enrichment factor [%] of principal isotope in sample (0 for natural elemental samples) */ sample_compositionTEXT ,/* Chemical composition of irradiated sample */ isotope_normTEXT /* Isotope used for gamma-ray intensity normalization */ );
Notes:
-
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 correspondingsample.N information. -
sample.N is a normalization factor representing the intensity of the correspondingsample.e_gamma_norm transition relative to the 2+1 → 0+gs γ-ray transition in 56Fe;sample.N = 100 andsample.e_gamma_norm = 847 keV for 56Fe. -
nucleus.compound also includes radiative capture (n,γ) lines (identified asnucleus.compound = ‘NG’ ) as well as contaminant and background lines (identified by the corresponding nucleus). -
nucleus.transition_type = ‘c’ andnucleus.transition_type = ‘m’ refer to calibration and multiply-placed γ rays, respectively, as explained in [1]. -
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.