燃料循环后段临界安全技术前期研究

考虑由于燃料的燃耗而带来的反应性降低的做法即为燃耗信任制技术,这种在核临界安全分析时采用燃料中实际成分的做法使得贮存、运输和后处理的能力大大提高,经济效益非常显著。燃料循环后段临界安全技术涉及燃耗计算技术研究、核临界安全计算技术研究、燃耗测量技术研究、临界实验装置设计技术研究、热室解剖和封装技术研究、化学分析测试技术研究和关键核素核数据处理技术研究。为了应用燃耗信任制技术,必须准确知道乏燃料的各种成分。利用SCALE、CASMO等程序进行计算,得出乏燃料的成分范围。为了实验验证乏燃料成分计算的准确性,初步…     

核脉冲计数测量的虚拟实验仪

研究了应用虚拟仪器技术实现核脉冲计数功能的方案,利用NI公司的USB-6009-DAQ板卡设计核脉冲计数测量的软硬件系统;开发了核领域常用核子仪器计数器,扩大虚拟仪器技术的应用领域;实验验证了测量系统具有较好的计数测量功能.     

核辐射实验室环境辐射评估及其核信息共享平台构建

利用辐射仪测量实验室的辐射剂量率,得出核辐射测量实验室环境辐射场分布规律及核信息共享平台的构建。实验采用单一变量原则,利用不同屏蔽材料对不同放射源进行屏蔽。结果表明:核辐射测量实验室辐射场呈现辐射状分布,辐射剂量与距离,屏蔽材料的性质以及辐射时间有关,并提出了核辐射测量实验的优化方案:即将核辐射信号共享,将放射源、高压电源、闪烁探测器、前置放大器作为共享仪器,通过核信息共享器将核信息输送到各个实验台,然后对核信息进行测量、分析。     

中子测量技术在核保障中的应用

中子测量技术是核保障领域非破坏性分析技术中重要方法之一.利用该技术结合同位素组成信息可以对铀、钚材料进行定量测量.本文简述了该技术测量原理、测量分析方法以及一些常见用于核保障中的测量设备.     

弱束缚核系统17F＋13C光学势

光学势是核核碰撞研究中重要的基本输入量。随着放射性束流的发展，探索弱束缚核和晕核系统的光学势已经成为了一热点问题。抽取光学势最直接的方法是利用弹性散射角分布，但目前放射性束流的品质限制了实验的测量精度。事实上，因为缺少弹性散射的实验数据，在弱束缚核和紧束缚核之间的光学势区别并不是很明确。鉴于以上情况，利用稳定的弹靶组合间接地测量稳定核的光学势。     

CEFR全量程周期保护功能的优化研究

为解决中国实验快堆（CEFR）核测量系统调试过程中出现的短周期误报警问题,本文结合CEFR核测量系统设计的特点,通过系统分析及理论计算,对CEFR核测量系统全量程周期保护功能进行了优化研究。同时,利用Matlab/Simulink仿真软件对系统进行仿真,仿真结果表明优化方案是准确可行的。     

成分对双能γ射线穿透法测灰的影响

成分的影响是核分析的主要问题。理论计算和分析表明,由Fe_2O_3含量变化所产生的误差,是双能γ射线穿透法测量煤炭灰分的主要误差。根据误差随成分及灰分变化的规律,可进行补偿,以修正Fe_2O_3和H_2O的变化对测量的影响。     

反应堆堆外核测量系统的实时仿真

堆外核测量系统实时仿真是核电厂全范围培训模拟器的重要组成部分。本文给出一种基于测量原理的功能仿真处理方法,利用堆芯物理仿真计算出堆芯中子通量密度．建立了堆外核测量值与反应堆内三维中子通量密度分布之间的拟合公式．根据反应堆物理计算或功率刻度实验确定拟合系数．可以实时准确仿真堆外核测量系统,满足核电厂全范围培训模拟器的要求．     

中国原子能科学研究院的PX-AMS系统及其应用(英文)

加速器质谱(AMS)中的入射离子X射线方法是为解决AMS测量中重核同量异位素而发展的一种方法(PX AMS),在中国原子能科学研究院建立了PX AMS方法之后,利用这套系统开展了79Se,75Se,64Cu等核素的PX AMS方法测量,基于此技术实现了79Se,75Se半衰期的测量和64Cu放射性核束强度及库仑激发截面的测量。     

固体核径迹参数的测量

研究了利用图象分析进行固体核径迹参数的测量方法。简要介绍了图像分析系统硬件设备,较详细地描述了径迹参数测量的方法,同时对测量结果进行了统计分析。     

Isobar separation at very low energy for AMS

The separation of atomic and molecular isobars, prior to injection into a tandem accelerator for Accelerator Mass Spectrometry (AMS), is discussed. To accomplish this separation, the anions from a standard sputter ion source are retarded to eV energy. The advantages of using very low energy (eV) for this purpose are twofold. The ionic reactions in gases can be isobar specific and the multiple scattering of the eV ions, unlike that at higher energy, can be controlled in linear radio-frequency multipoles. An example of current interest to AMS practice, the suppression of the S⁻ isobar ions from negative ion sources generating mainly Cl⁻ ions, will be described. It will be argued that this is a universal method for isobar separation prior to AMS, which is applicable to atomic anions and cations as well as their molecular counterparts. This procedure should be applicable to the AMS analysis of most rare radioactive species, as atomic or molecular ions, starting with either anions or cations, with appropriate charge changing. In some cases the ions may be analysable without AMS.     

Selective isobar suppression for accelerator mass spectrometry and radioactive ion-beam science

A new method of selective isobar suppression by photodetachment in a radio-frequency quadrupole ion cooler is being developed at HRIBF with a twofold purpose: (1) increasing the AMS sensitivity for certain isotopes of interest and (2) purifying radioactive ion beams for nuclear science. The potential of suppressing the ³⁶S contaminants in a ³⁶Cl beam using this method has been explored with stable S^? and Cl^? ions and a Nd:YLF laser. In the study, the laser beam was directed along the experiment’s beam line and through a RF quadrupole ion cooler. Negative ³²S and ³⁵Cl ions produced by a Cs sputter ion source were focused into the ion cooler where they were slowed by collisions with He buffer gas; this increased the interaction time between the negative-ion beam and the laser beam. As a result, suppression of S^? by a factor of 3000 was obtained with about 2.5 W average laser power in the cooler while no reduction in Cl^? current was observed.     

First results from the nuclear astrophysics AMS program at the NSL using the MANTIS system in gas-filled mode

The Magnet for Astrophysical Nucleosynthesis studies Through Isobar Separation (MANTIS) system is the new Accelerator Mass Spectrometry (AMS) set-up created during recent upgrades of the Browne-Buechner spectrograph at the University of Notre Dame. Commissioning measurements performed on the separation of ⁵⁸Fe-⁵⁸Ni isobars at 114 MeV out of the FN tandem accelerator have shown clear separation, opening the door for a number of future measurements in nuclear astrophysics. The separation of mass-58 isobars has made this system the first in the world to utilise a Browne-Buechner spectrograph in gas-filled mode for AMS measurements with a special focus on nuclear astrophysics.     

Isobaric identification techniques of AMS at CIAE

Some long-lived nuclides, such as ³⁶Cl, ⁴¹Ca, ⁵³Mn, ⁷⁹Se, etc., are very interested in life science, environment science, geo- and cosmo-sciences, nuclear wastes management, and other fields. Taking the advantages in high sensitivity and the strong ability to reduce the interferences from molecular ions and isobars, AMS has been one of the most promising methods for the measurement of these nuclides. However, the sensitivity of AMS is often unsatisfactory due to the interferences of stable isobars especially for medium and heavy radioisotopes. Gas-filled time of flight (GF-TOF), Gas-filled Magnet with a time of flight (GFM-TOF), Bragg Curve detector and energy loss (ΔE) combined with a Q3D magnetic spectrometer (ΔE-Q3D) are among the techniques used or being developed in AMS lab of China Institute of Atomic Energy, in an attempt to further reduce the interferences from isobars. These techniques will be tested in our AMS measurement of ⁵³Mn, ⁷⁹Se, ⁹³Zr, ⁹⁹Tc, etc., for identifying isobaric interferences.     

放射性核束的产生

为适应国际核物理学的发展，开展放射性核束物理这一世界前沿工作，对放射性核束的产生和加速方面的多项工作进行了研究。文章简要介绍相关的离子源和加速器工程技术问题。     

Determination of the detection limit of Ni at the Lund AMS facility by using characteristic projectile X-rays

Accelerator mass spectrometry (AMS) is an ultra-sensitive method for counting atoms, both radionuclides and stable nuclides. When using small tandem accelerators to measure heavy isotopes, interfering isobars are often troublesome. One way to reduce this interference is to combine AMS with the detection of characteristic X-rays of the projectile. After analysis in the AMS system it is possible to identify ions of different atomic number by their characteristic X-rays, by slowing down the ions in a suitable target. In this paper, the detection limit of ⁵⁹Ni at the Lund AMS facility is reported. A method for the chemical extraction of nickel from stainless steel, combined with a purification step to reduce the cobalt content in the sample by several orders of magnitude, is also described.     

基于加速器质谱测量的~(14)C呼气试验样品制备方法研究

采用加速器质谱法研究~(14)C呼气试验样品的制备方法。采用长寿命放射性核素~(14)C作为示踪核素,目前已广泛应用于生物代谢、疾病诊断和脏器功能评估。离子源引出的束流强度是衡量加速器质谱灵敏度的重要参数,为了获得较高的束流强度,本工作系统研究了~(14)C呼气试验样品的石墨法、碳酸盐法两种制备方法,拟建立~(14)C呼气试验样品制备流程,确定最高束流强度引出时的最优~(14)C呼气试验样品制备参数,为~(14)C呼气试验广泛应用提供实验基础。     

基于加速器质谱测量的~(41)Ca植物示踪样品制备方法研究

基于加速器质谱测量方法研究~(41)Ca植物示踪样品的制备。~(41)Ca是宇宙成因核素,半衰期较长,且对植物的代谢具有重要的作用。加速器质谱应用长寿命核素,检测方法具有灵敏度高、放射性剂量小、精度高、测量区间大、示踪周期长等优点。离子源引出束流是衡量加速器质谱灵敏度的重要参数,而较高束流强度的引出束流可以提高加速器质谱的灵敏度。为了获得较高的束流强度,本工作系统研究了~(41)Ca植物示踪样品的湿法、干法、以及湿法和干法相结合的二次氟化法,以建立~(41)Ca植物示踪样品制备流程,确定最高束流强度引出时的最优化~(41)Ca植物示踪样品制备参数,为~(41)Ca植物示踪样品广泛应用提供实验基础。     

An experimental apparatus proposed for efficient removal of isobaric contaminants in negative ion beams

Isobaric contaminants are often problematical in accelerated negative ion beams for research at certain radioactive ion beam (RIB) and accelerator mass spectrometry (AMS) facilities since their presence in low-intensity rare isotopic beams seriously compromise experimental results. This article describes a non-resonant, laser-based photo-detachment apparatus for use at these facilities, which, according to calculations efficiently removes isobaric contaminants from these beams. The advantage of the system for isobaric contaminant removal over other systems proposed to date lies in its ability to efficiently capture easily transportable energetic negative ion beams with low, intermediate or high energy spreads by a superconducting solenoid magnetic field. The ability to change the diameter of captured beams by adjusting the magnetic field strength permits optimum control of the radial overlap of the laser/negative ion beam profiles over an extended interaction region under high vacuum conditions without retarding optical affect, collision-cooling or capture losses.