Activities and Cooperations

In 1987 and 1988,CNDC involved many activities.Mainly they are: ·1988.4.8～15,“Nuclear Data Measurement and Evaluation Symposium”,Sichuan University.Exchanged the progress in nuclear data measurements andreviewed some of evaluation data.Also introduced the international developmentand arranged the future work.     

Investigation of the mouse cerebellum using STIM and μ-PIXE spectrometric and FTIR spectroscopic mapping and imaging

The cerebral biochemistry associated with the development of many neurological diseases remains poorly understood. In particular, incomplete understanding of the mechanisms through which vascular inflammation manifests in tissue damage and altered brain function is a significant hindrance to the development of improved patient therapies. To this extent, a combination of spectrometric/spectroscopic mapping/imaging methods with an inherent ability to provide a wealth of biochemical and physical information have been investigated to understand further the pathogenesis of brain disease.In this study, proton-induced X-ray emission (PIXE) mapping was combined with scanning transmission ion microscopy (STIM) mapping and Fourier-transform infrared (FTIR) imaging of the same tissue sample to study directly the composition of the murine (mouse) cerebellum. The combination of the elemental, density and molecular information provided by these techniques enabled differentiation between four specific tissue types within the murine cerebellum (grey matter, white matter, molecular layer and micro blood vessels). The results presented are complementary, multi-technique measurements of the same tissue sample. They show elemental, density and molecular differences among the different tissue types.     

The structure and thermal expansion of δ- and η-plutonium

Based on the increase in the covalent component of a bond with reduction in temperature in crystalline modifications of uranium, neptunium and plutonium, a new idea is put forward for the structure of - and -plutonium. The crystalline structure of these modifications is considered as the result of a comparatively small deviation from the ideal face-centered lattice under the action of four covalent bonds. This idea makes it possible to explain a number of anomalous properties of - and -plutonium, in particular the negative values of the volume coefficient of thermal expansion and the high values of the atomic volume.     

Design and performance of a high-speed and low-noise preamplifier for SiPM

Considering the R&D for upgrading the K⁰_L and μ detectors in the Belle II experiment using a scintillator and silicon photomultiplier(SiPM), we designed a compact high-speed and low-noise preamplifier. The preamplifier demonstrated a good gain stability, bandwidth of 426 MHz, baseline noise level of σ ≈ 0.6 mV, dynamic range of up to 170 mV of the input signal amplitude, good time resolution of 20 ps, and it can be comprehensively applied to SiPMs. Adopting pole-zero-ca...     

Sonluminescence and cold fusion

A theory of sonoluminescence(SL) proposed asserts bubbles collapse in a pancake shape almost isothermally at constant volume.SL induced hot fusion at -10^7℃is most likely impossible.By the proposed theory,the bubbles are treated as miniature IRasers with the dimension between pancake faces equal to the half wavelength of the standing wave in resonance with the IRaser cavity dimensions.Before collapse,the IRasers are filled with 5-10eV of IR radiation from the Plank energy in the ambient surroundings.During collapse,the IUR radiation is trapped within the IRaser by the high IR reflectivity of the bubble wall water molecules.As the IRaser cavity dimension dercreases,the cavity resonant frequency increases.The bubble wall molecules undergo a continuous population inversion by always being pumped to higher energy states that favor stimulated emission instead of absorption.IRaser resonant intensification produces 5-10MeV,i.e.,-10^6UV photons with 5-10eV.On average,SL induced cold fuison does not occur although a few X-ray photons are produced.If the IR thermal energy before collapse is enhanced to a total energy of 10keV.say by exciting the vibration modes of the water molecules at 2.73um with a HF laser,collapse produces an average X-ray energy of about 10keV.unlike hot fusion ,Sl induced cold fusion is not impossible.     

Formation and decay of neutron—deficient nuclei Po and Pb

ＦｏｒｍａｔｉｏｎａｎｄｄｅｃａｙｏｆｎｅｕｔｒｏｎｄｅｆｉｃｉｅｎｔｎｕｃｌｅｉＰｏａｎｄＰｂＣｈｅｎＸｕｅＳｈｉ１，２，ＡｈｍａｄＩ３，ＡｎｄｒｅｙｅｖＡＮ４，ＢａｔｃｈｅｌｄｅｒＪＣ７，ＢｉｊｎｅｎｓＮ４，ＢｉｎｇｈａｍＣＲ２，５，Ｂｌｕｍ...     

Sonoluminescence and cold fusion

Ｓｏｎｏｌｕｍｉｎｅｓｃｅｎｃｅａｎｄｃｏｌｄｆｕｓｉｏｎ￥ＴＶＰｒｅｖｅｎｓｌｉｋ（２ＥＧｒｅｅｎｅｒｙＣｏｕｒｔ，ＤｉｓｃｏｖｅｒｙＢａｙ，ＨｏｎｇＫｏｎｇ）Ａｂｓｔｒａｃｔ：Ａｔｈｅｏｒｙｏｆｓｏｎｏｌｕｍｉｎｅｓｃｅｎｃｅ（ＳＬ）ｐｒｏｐｏｓ...     

Erosion and Modifications of Tungsten-Coated Carbon and Copper Under High Heat Flux

Tungsten-coated carbon and copper was prepared by vacuum plasma spraying (VPS) and inert gas plasma spraying (IPS), respectively. W/CFC (Tungsten/Carbon Fiber-Enhanced material) coating has a diffusion barrier that consists of W and Re multi-layers pre-deposited by physical vapor deposition on carbon fiber-enhanced materials, while W/Cu coating has a graded transition interface. Different grain growth processes of tungsten coatings under stable and transient heat loads were observed, their experimental results indicated that the recrystallizing temperature of VPS-W coating was about 1400℃ and a recrystallized columnar layer of about 30μm thickness was formed by cyclic heat loads of 4 ms pulse duration. Erosion and modifications of W/CFC and W/Cu coatings under high heat load, such as microstructure changes of interface,surface plastic deformations and cracks, were investigated, and the erosion mechanism (erosion products) of these two kinds of tungsten coatings under high heat flux was also studied.     

Nitrogen utilization and transformation in red soil fertilized with urea and ryegrass

The influence of fertilization with urea and ryegrass on nitrogen utilization and transformation in red soil has been studied by using ^15N tracer method.When urea and ryegrass were applied alone or in combination,the percentage of N uptaken by ryegrass from labelled urea was 3 and 1.7 times that from labelled ryegrass for the application rate of 200mgN.kg^-1 and 100mgN.kg^-1,respectively;combining application of ryegrass and ureareduced uptake of urea N and increased uptake of ryegrass N by ryegrass plant,but the percentage of N residued in soil increased for urea and decreased for ryegrass.when urea and ryegrass were applied alone,the percentage of N residued in soil from labelled ryegrass was more than 69% while that from labelled urea was less than 25%,and much more ryegrass N was incorporated into humus than urea N.     

Design and Manufacture of Large Grained UO2 Pellets and Test Assembly

This paper introduces design and manufacture of fuel assembly for UO2 pellets irradiation program. The advanced UO2 pellet is large grained and is sintered with addictives of Al2O3/SiO2/Cr2O3. It will decrease the release rate of fission gas, reduce the PCI and inner pressure of the fuel rods, in result it will increase discharge bumup and extend loading period of fuel rod. The performance of large grain pellet must be proved through in-pile test.     

Design and Manufacture of Large Grained UO_2 Pellets and Test Assembly

This paper introduces design and manufacture of fuel assembly for UO2 pellets irradiation program. The advanced UO2 pellet is large grained and is sintered with addictives of Al2O3/SiO2/Cr2O3. It will decrease the release rate of fission gas, reduce the PCI and inner pressure of the fuel rods, in result it will     

Zonal Flows and Geodesic Acoustic Mode Oscillations in Tokamaks and Helical Systems

This paper reviews the theoretical foundations of zonal flow, putting emphasis on the linear response function of plasma to the external flow drive. An extension of the theory is made in order to apply it to helical systems and to study the properties of the zonal flow in the low frequency range. Further refinement of the theory is made incorporating the orbital effects of particles more precisely, and the role of neoclassical polarization current is identified.     

Comparison and physical interpretation of MCNP and TART neutron and γ Monte Carlo shielding calculations for a heavy-ion ICF system

Inertial confinement fusion (ICF) aims to induce implosions of D–T pellets to obtain a extremely dense and hot plasma with lasers or heavy-ion beams. For heavy-ion fusion (HIF), recent research has focused on “liquid-protected” designs that allow highly compact target chambers. In the design of a reactor such as HYLIFE-II [Fus. Techol. 25 (1984); HYLIFE-II Progress Report, UCID-21816, 4.82-100], the liquid used is a molten salt made of F¹⁰, Li⁶, Li⁷, Be⁹ (called flibe). Flibe allows the final-focus magnets to be closer to the target, which helps to reduce the focus spot size and in turn the size of the driver, with a large reduction of the cost of HIF electricity. Consequently the superconducting coils of the magnets closer to the D–T neutron source will potentially suffer higher damage though they can stand only a certain amount of energy deposited before quenching. This work has been primarily focusing on verifying that total energy deposited by fusion neutrons and induced γ rays remain under such limit values and the final purpose is the optimization of the shielding of the magnetic lens system from the points of view of the geometrical configuration and of the physical nature of the materials adopted.The system is analyzed in terms of six geometrical models going from simplified up to much more realistic representations of a system of 192 beam lines, each focused by six magnets. A 3-D transport calculation of the radiation penetrating through ducts, that takes into account the complexity of the system, requires Monte Carlo methods. The technical nature of the design problem and the methodology followed were presented in a previous paper [Nucl. Instr. and Meth. A 464 (2001) 410] by summarizing briefly the results for the deposited energy distribution on the six focal magnets of a beam line. Now a comparison of the performances of the two codes TART98 [TART98: A Coupled Neutron-Photon 3-D Combinational Geometry Monte Carlo Transport Code, Lawrence Livermore National Laboratory, UCRL-ID-126455, Rev. 1, November, 1997] and MCNP4B [MCNP – A General Monte Carlo N-Particle Transport Code, Version 4B, La-12625-m, March 1997, Los Alamos National Laboratory] for two different configurations of the system is discussed, separating the n and γ contributions, in the light of the physical interpretation of the results in terms of first flight and of scattered neutron fluxes, of primary γ and of secondary γ generated by inelastically scattered or radiatively captured neutrons. The final conclusions indicate some guidelines and suggest possible improvements for the future neutronic shielding design for a HIF facility.