The Sub-Library of Giant Dipole Resonance Parameters for γ-Ray (CENPL-GDP-1)

The data file and management-retrieval code system of the giant dipole resonance parameter sub-library (CENPL-GDR) are described. Because there are no giant dipole resonance parameters obtained from the experimental data for many nuclei, a treatment method in the management-retrieval code system was presented. Some problem on the giant dipole parameters are discussed in the report.     

The Sub-Library of Nuclear Level Density —The Data File of Nuclear Level Density Parameters (CENPL.LDP)

One of the basic statistical properties of the excited nuclear levels is the nuclear level density, which are a crucial ingredient in the nuclear reaction models and neutron transport calculations. For example, the level densities are needed in the calculations of the widths, cross sections, spectra etc. for various reaction channels, and the requirements of their accuracy and reliability are ever higher     

The Management-Retrieval Code of Nuclear Level Density Sub-Library (CENPL-NLD)

The management-retrieval code of the Nuclear Level Density (NLD) is presented. It contains two retrieval ways: single nucleus (SN) and neutron reaction (NR). The latter contains four kinds of retrieval types. This code not only can retrieve level density parameter and the data related to the level density, but also can calculate the relevant data by using different level density parameters and do comparison of the calculated results with related data in order to help user to select level density parameters.     

The extraction and smoothing algorithms for γ-ray spectrum of a CdZnTe detector system

The extraction algorithms for pulse amplitude and smoothing of energy spectrum have a great influence on energy spectrum of γ-rays during the digital detection and analysis procedure. For a CdZnTe digital γ detector system, different extraction algorithms for pulse amplitude and smoothing of energy spectrum are discussed in this paper. The results show that extraction of pulse amplitude using the first-order derivative method and smoothing of energy spectrum using the wavelet transformation method may obtain energy spectrum with good performance.     

Use of TlBr crystals for x- and γ-ray detectors

The development and investigations of uncooled semiconductor x- and γ-ray detectors based on thallium bromide crystals grown by the Bridgman–Stockbarger method are reported. The procedure for preparing Me–TlBr–Me (Me = Au, In) detector structures is described, and the current–voltage characteristics are investigated. The counting and spectrometric characteristics of the detectors fabricated have been measured. The best energy resolution was 0.54, 1.3, 1.41, 2.1, and 7.1 keV at energy 5.8 (⁵⁵Fe), 22.1 (¹⁰⁹Cd), 59.6 (²⁴¹Am), 122 (⁵⁷Co), and 662 keV (¹³⁷Cs), respectively. Translated from Atomnaya énergiya,Vol. 106, No. 4, pp. 214–217, April, 2009.     

The Sub-Library of Atomic Masses and Characteristic Constants of Nuclear Ground States (CENPL-MCC2) (Ⅳ)

The MCC 2 (the Second Version) is an updated edition of the sub-library of atomic masses and characteristic constants of nuclear ground states(MCC) of the Chinese Evaluated Nuclear Parameter Library (CENPL). It contains data files: "MCC2-1.DAT" and "MCC2-2.DAT".     

Design of Graphite-wall Ionization Chamber as Air-kerma Standard for γ-ray

<正>The graphite-wall ionization chamber which is based on Bragg-Gary cavity theory is used as air-kerma primary standard for ~(137)Cs and ~(60)Coγ-ray reference radiation.     

The effects of Co γ-ray on poly(ethylene-co-vinyl acetate)/carbon black composites

Cables used in a nuclear power plant are irradiation suppressing ones. Until now, researches on the irradiation suppressing cables have mainly been focused on insulation materials. Therefore, in this paper, the non-isothermal crystallization behaviors and degradation characteristics of ethylene vinyl acetate-carbon black (EVA-CB), used as a shielding material, were investigated by means of the Differential scanning calorimetry (DSC) and chemiluminescence analyzer (CL). The specimens were cooled after removing thermal history at 150 °C for 5 min by changing the cooling rates to 5, 7.5, 10, 15 and 20 °C/min with DSC. In addition, after maintaining a thermal equilibrium at each temperature of 25, 50, 75, 100, 125, 150 and 175 °C, their thermoluminescence was measured for 20 min with CL equipment. The ⁶⁰Co γ-ray was used for irradiation. T_c, T₀, T_∞ and t_1/2 in the DSC experiments are found to decrease gradually as radiation dose increases. Secondly, with the CL experiment, the 0.1, 0.25 and 0.5 MGy EVA-CB composites were found to show a much smaller thermoluminescence than the intact EVA-CB composites, while the 0.75 and 1 MGy EVA-CB composites were found to show a much higher thermoluminescence than ones.     

Fine Structure of Giant Resonance in the 28Si(γ, abs) Reaction

The photo-absorption cross section for ²⁸Si has been measured in the energy range 17.5–21.5 MeV, using a high- resolution high-energy photon spectrometer and laser Compton photons. Four intermediate structure peaks in the giant dipole resonance of ²⁸Si have been resolved into about thirty fine-structure peaks. The comparison of the observed structure with those in (γ, p ₀) and (γ, n ₀) reactions shows that the energies of the fine structure peaks in (γ, abs) reaction have a correlation with those in both of the (γ, p ₀) and (γ, n ₀) reactions.     

Generalization ability of a CNN γ-ray localization model for radiation imaging

In γ-ray imaging,localization of the γ-ray interaction in the scintillator is critical.Convolutional neural network(CNN)techniques are highly promising for improving γ-ray localization.Our study evaluated the generalization capabilities of a CNN localization model with respect to the γ-ray energy and thickness of the crystal.The model maintained a high posi-tional linearity(PL)and spatial resolution for ray energies between 59 and 1460 keV.The PL at the incident surface of the detector was 0.99,and the resolution of the central incident point source ranged between 0.52 and 1.19 mm.In modified uniform redundant array(MURA)imaging systems using a thick crystal,the CNN γ-ray localization model significantly improved the useful field-of-view(UFOV)from 60.32 to 93.44％compared to the classical centroid localization methods.Additionally,the signal-to-noise ratio of the reconstructed images increased from 0.95 to 5.63.     

Data File of Optical Model Parameter Sub-Library (CENPL-OMP)

The optical model is the most fundamental and important one in nuclear physics, and the optical model parameters(OMP) play a very crucial role in the nuclear model calculations of nuclear data and many theoretical analyses. The OMP table compiled by Percy in 1976 is significant and useful. It is very necessary and valuable to set up a new OMP data file, in which the OMP sets should be collected and compiled in a suitable format.     

Development of a γ-ray Measurement System of Radioactive Wastes

According to the criteria of radioactive wastes, intermediate and low-level radioactive solid waste produced in nuclear fuel recycle must be characterized for near surface disposed. For this purpose, a special y-ray measuring system used for classifying low or medium-density drummed radioactive wastes was developed. The system consists of three sets of high purity germanium detectors with multi-channel analyzers. When the system works, waste drums rotate on axial and divided into three segments on radial.     

Measurements of Thermal Neutron Cross Section and Resonance Integral for 237Np(n, γ)238Np Reaction

Making use of a standard neutron spectrum field with a pure Maxwellian distribution, the thermal neutron cross section for the ²³⁷Np(n, γ)²³⁸Np reaction was measured at a neutron energy of 0.0253 eV by the activation method. The result is 158±3 b, which is obtained relative to the reference value of 98.65±0.09 b for the ¹⁹⁷Au(n, γ)¹⁹⁸Au reaction. Although the data in JENDL-3 is larger by about 15% than the present value, the recently revised data in JENDL-3.2 is close to the present. The ENDF/B-V, ENDF/B-VI, JEF-2 and Mughabghab's data are also larger by 7–15%. Old measurements are larger by 7–18% than the present data.

The resonance integral for the ²³⁷Np(n, γ)²³⁸Np reaction was also measured relative to the reference value of 1,550±28 b for the ¹⁹⁷Au(n, γ)¹⁹⁸Au reaction with a 1/E standard neutron spectrum field. By defining the Cd cut-off energy as 0.5 eV for the ²³⁷Np(n, γ)²³⁸Np reaction, the present resonance integral is 652 ± 24 b, which is in good agreement with the JENDL-3, -3.2, ENDF/B-V, -VI, JEF-2 and Mughabghab's data. However, most of the old experimental data are, in general, larger by 24–38% than the present measurement.     

Proposal for selective isotope transmutation of long-lived fission products using quasi-monochromatic γ-ray beams

We have proposed a new selective isotope transmutation method using photonuclear reactions with quasi-monochromatic γ-ray beams. This method is based on the fact that the particle threshold of a long-lived fission product (LLFP) such as ⁹³Zr, ¹⁰⁷Pd, or ⁷⁹Se is lower than those of stable isotopes of the same chemical element. Therefore, this method has the excellent advantage that LLFPs cannot, in principle, be produced newly even if the target materials include stable isotopes in addition to LLFPs. Furthermore, this method is effective for ¹²⁶Sn, ^{135, 137}Cs, ⁹⁰Sr, and ³H. The nuclear data involved and suitable γ-ray sources are discussed. Laser Compton scattering γ-ray sources and neutron capture γ-rays in nuclear reactors are candidates for this method.     

Properties of radicals created by γ-ray irradiation of silk fabrics

The properties of radicals from γ-ray irradiated silk fabrics were studied by electron spin resonance method (ESR). The ESR spectra of silk fabrics irradiated in N2 showed a doublet at room temperature. The doublet became a singlet at g=2.0057 after placing the sample in air for 24 hours. This can be explained by formation of peroxide radicals. The radical concentration of the irradiated silk fabric and the decay rate of radicals are significantly affected by irradiation conditions, which include the absorbed dose, atmosphere, and water content of the silk fabric samples. However, no dose rate effect on the radical concentration was observed. The results are of help in our practice of property modification of silk products by radiation graft copolymerization.     

The Sub-library of Atomic Mass and Characteristic Constants of Nuclear Ground State (CENPL-MCC 1.1) (Ⅲ)

The sub-library MCC 1.1 of atomic mass and characteristic constants of nuclear ground state (MCC, Version 1.1), which is a sub-library of the Chinese Evaluated Nuclear Parameter Library (CENPL), is an updated edition of MCC-1. The mass excess, atomic mass and total binding energy have been updated in the data file.