In order to understand the detailed influence from the collimator system to the main index of the Residual Stress Nertron Diffractometer(RSND) such as the flux at sample position,and the resolution of the spectrometer,the MCStas simulation software is used to build the proper Model of the Collimator system to complete the calculation and simulation.During the simulation,the authors setup the divergence and length of each collimator to check if it had big effect to the whole system.Based on the simulation,the authors obtained an optimized result;When theα_1 =α_2= 30′,the horizontal flux at the sample position can be 2.3×10~6 n·cm~(-2)·s~(-1),the vertical flux can be 3.5×10~6 n·cm~(-2)·s~(-1), and when theα_1=α_2= 10′the best resolution of the spectrometer can be 0.2°. This is a valuable result for the RSND.
Pinhole imaging of the neutron production in laser-driven inertial confinement fusion experiments can provide important information about performances of various capsules designs. In order to get good results in experiments, it is needed to judge the performance of various pinhole designs qualitatively or quantitatively before experiment. Calculation of imaging can be simply separated into pinhole imaging and image spectral analysis. In this paper, pinhole imaging is discussed, codes for neutron pinhole imaging and image showing is programed. The codes can be used to provide theoretical foundation for pinhole designing, either to provide simulating data for image analysing.
In this article a program of Quasi-monochromatic X-ray 2-dimension imaging is proposed through incorporation of a nanosecond framing camera and a soft X-ray energy separation device using grazing incidence mirror and filter. A conceptional 2-D imaging system with limited spectral resolution is constructed and can be applied to detect X-ray emission by Z-pinch implosion plasmas at two independent energy ranges.Thus the evolution of plasma materials with different temperatures can be studied with this technology.The desired photon energy range can be chosen from 200 eV to 1 560 eV through altering the couples of filters and mirrors.
The research on novel radioiodopharmaceutical which treat tumor efficiently is meaningful,moreover,this result just base on the synthesis of the prodrug of radiopharmaceutical.About 85%of malignacy express positive for telomerase. It aims to search for a kind of new compound,which can restrain telomerase and therapy tumor.In this work,a novel prodrug of radioiodopharmaceutical (C_6H_4IPOClNH(CH_2)_6NH-Leu-Gly-Boc) had been designed and synthesized. Some important inter-mediates also had been synthesized.The compound had been analysed using E.S.,~1HNMR(D_2O,200 MHz) and ESI-MS.The results indicated that the synthesis was successful.C_6H_4IPOC1NH(CH_2)_6NH-Leu -Gly-Boc was synthesised from liquid phase instead of trational state phase, which would reduce the cost and improve the maneuverability.
Based on the inverse square dependence of neutron signal amplitude on the distance between neutron detector and neutron source,a new method is suggested for radiation scattering background deduction in sensitivity calibration experiment for current-mode neutron detectors.Using this method,the traditional collimators and shielding materials are not necessary anymore.As the scattering background typically does not vary with the distance in the same way as the signal,a series of current can be measured at different positions and then analyses can be conducted,which give not only the sensitivity of the detector, but also background distributions at various positions.
A new numerical method based on calculating spatial distribution of transmitted neutron intensity is studied for the design of neutron pin-hole relaying system,and WINPSF code is then developed for calculating image quality, point spread function,as well as neutron flux distribution at the image plane.It indicates that the results given by WINPSF agree well with those given by MCNP5,and WINPSF can give results in better statistical quality in shorter computer time than MCNP5.
A mathematical model describing the complex fluid-dynamics of a bubble extractor from liquid LiPb loop for ITER is presented.A parametric analysis of the extraction efficiency of a bubble column as a function of the process parameters is carried out and the design of a bubble extractor system is proposed.On this base,a mathematical model is built by taking into consideration the kinetics of deuterium desorption from liquid LiPb alloy.The calculation data of deuterium release-behavior from liquid LiPb under different operating conditions of temperature and deuterium partial pressures and helium gas flow-rates in the liquid LiPb alloy are obtained.These results have shown that the overall release process is governed by the diffusion of deuterium atoms in the LiPb and by the heterogeneous reaction at the gas-eutectic interface of the deuterium atoms recombination under the probable working temperature range.
In order to measure the nuclide abundance ratio of uranium in environmental water,the method of717 anion exchanging resinis discussed.The distraction circuit is determined by 717 anion exchange leaching curve,recovery ratio of anion exchaging,recovery ratio of former disposal and recovery ratio of electrodeposit.The circuit has good result in distracting and enriching uranium by using717 anion exchanging resin,the resolution of uranium in the a spectrum is perfect.The activities and the nuclide abundance ratios of ~(238)U, ~(235) U,~(234)U in the different reach of some location of INPC have been gained.
Monochromator is one of the most important parts of neutron Triple-Axis Spectrometer(TAS),and its performance has an effect on data detecting and analyzing.We have investigated some monochromator parameters of neutron TAS in China,ILL and LLB.Because there is different location and focus on wavelength in experiment,appropriate neutron source and location limit should be taken into account in the design of monochromator.According to the basic principle of the focusing monochromator,investigation and analysis of typical monochromator in the world,including size,crystal,research capability,we can offer references on the type and parameters for the construction of tripleaxis spectrometer monochromator.
The method of Al activation relative measurement of cross section has been studied.The cross sections of ~(27)Al(n,α)~(24 )Na have been measured in 13.4 MeV to 14.7 MeV.The PD-300 accelerator offered D-T neutron source.The distance from sample to Tritium target is 20 cm.It spent 5 h to radiate sample with neutron.The intensity of neutron source is monitored by theα-particles from the T(d,n) ~4He reaction.The induced neutron energy is determined using ratio of Nb(n,2n) and Zr(n,2n) cross section.The activated gamma ray is measured using GEM60P HPGe detector.The results of ~(27)Al(n,a)~(24)Na cross sections are compared with the nuclear data standard,and the deviation is less than 1%.It showed that the method of Al activation relative measurement of cross section is credible.
Peptide nucleic acid(PNA),which is one kind of antisense nucleic acid compounds and an oligonucleotide analogue that binds strongly to DNA and RNA in a sequence specific manner,has its unique advantages in the field of molecular diagnostics and treatment of diseases.Now,people gradually attach more importance to PNA.To optimize the application of PNA in genetic research and therapy,a great number of backbone modifications on the newly-type structures of PNA were synthesized to improve its physicochemical properties, such as hybridization speciality,solubility in biofluid,or cell permeability. The modified PNA labeled with radionuclides,which can obtain the aim at specific target and minimal non-target trauma,has important role in research and application of tumorous genitherapy.Here a review on the basic synthesis idea and several primary synthetic methods of PNA analogs was given,and also correlative studies and expectation on the compounds belonging to PNA series labeled with radionuclides were included.
Two-dimension aluminum assembly was established.Their diameters are all 30 cm.The thicknesses are 5 cm,10 cm,15 cm,20 cm and 25 cm,respectively. The energy spectra of penetrative neutron for D -T source were measured for five different thickness assemblies,as well as the neutron energy spectrum of the source.The uncollided neutron and the penetration ratio were obtained. The experiment shows that the penetration radio slowly changed to the uncollided neutron.The factors of experimental measurement influenced were analyzed.The disagreement between the uncollided neutron and the penetration ratio came from the small angle scatter neutron.
This article starts with the measurement of radon and its progeny, introduces some methods and techniques of radon measurement,and analyses the principle and detecting process of solid state nuclear track detector (SSNTD).The authors designed a electrostatic collection SSNTD,and carried out some experiments.Detecting time which is about 3 months by using SSNTD can be effectively shortened in less than a week by using the new method. The method has a high sensitivity and accuracy which can provide exact radon concentration in a short time and the designed apparatus has a practical application significance.
Small angle neutron scattering belongs to coherent elastic scattering,and for more accurate,it should called aslow q scattering.Because there are some inhomogeneous structure in which size is bigger than the distance of two atoms in the sample,so there is difference of neutron scattering length.After the scattering, the magnitude of scattering vector is not change but the direction of it will change.The experimental method of small angle neutron scattering has been introduced in this paper.The basic theories and several approximations has been sumed up and the preparation of experiment and the measurements have been described in detail.Meanwhile,the data treatment ways and the error estimation of result of data treatment also have been given briefly.
In this work,the development of production of long-lived isomer ~(178m2)Hf has been presented and the characteristics of relevant pathways have also been addressed.Considering the design parameters and operational status of reactors and accelerators,the possible approachs for ~(178m2)Hf isomer production has been put forword in research programe.Through calculating the basic parameters of prodution of ~(178m2)Hf isomer from two kinds of nuclear reactions ~(176)Yb(α,2n) and ~(179)Hf(n,2n),and camparing the advantages and disadvantages of these two production methods,an approriate scheme of producing 10~(13 178m2)Hf nuclei has been designed.
X-ray or neutron diffraction experiment can provide microstructural information of crystalline materials.At the moment without the model of microstructure, Warren-Averbach analysis is regarded as an important tool.For this purpose,a program of Warren-Averbach analysis has been developed.The program has nearly all basic functions,it can be conveniently used through a graphic user interface as well.In the end,the efficiency of the program is illustrated by an example of ceria.
By measuring the number ofγphotons produced by the annihilation of theβ~+ particles of ~(13)N's decay product in the sample air,the nuclide density of ~(13)N can be obtained,comparing with its density in the reactor coolant,we can get the leakage information of the reactor vessel and control rod driving system.the article describes the cause of improvement in monitoring for leakage of reactor vessel and control rod driving system of Qinshan Second Nuclear Power Plant (PWR reactor),also the determination of monitoring method and system configuration,as well as the main technical index and function.Furthermore, the main parts and its function of the monitor are introduced.After operation for more than four years,it is proved that both the stability and MTBF index of the monitor meet the design,even more,thanks to the improvement of the algorithm,the Compton Effect caused by other nuclide became neglectable,the MDA of the monitor was lowered also.
The structures and main components of neutron diffraction stress analyses spectrometer,SALSA,as well as functions and parameters of each components are presented.The technical characteristic and structure parameters of SALSA are described.Based on these aspects,the choice of gauge volume,method of positioning sample,determination of diffraction plane and measurement of zero stress d_0 are discussed.Combined with the practical experiments,the basic experimental measurement and the related settings are introduced,including the adjustments of components,pattern scattering,data recording and checking etc.The above can be an instruction for stress analyses experiments by neutron diffraction and neutron stress spectrometer construction.
The thesis introduces the basic theory of Small-Angle neutron scattering, enumerates several approximate law.It simply describes the components of Small-Angle neutron spectrometer(SANS) and the parameters of SANS of Budapest Neutron Center(BNC) in Hungary.During the period of studying at Budapest Neutron Center in Hungary,the experiments of wavelength calibration was carried out with SIBE and the SANS experiments of sample Micelles. The experiments are briefly introduced.Pxy program is used to fit these datum, and the results of wavelength and sizes of sample Micelles are presented.
