Studies of Al metabolism in animal by accelerator mass spectrometry

The correlation between Al metabolism and senile dementia in animal has been studied by AMS(accelerator mass spectrometry).Three groups of laboratory rats were fed with normal food.food with high Al content,and with enriched Ca and Mg together with high Al,respectively for six to eight months.Mapping test was made to recored th degree of wisdom degeneration.Half of the rats were sacrificed and Al contents in various organs were measured by atomic absorption spectroscopy.The rest were injected with ^26Al,killed after 5,10,15,25,and 35d and ^26Al contents measured by AMS.The distribution of Al as well as the correlation among the accumulation of ^26Al,and the existed Al content and dementia was studied.     

Al_2O_3样品制备技术及~(26)Al的AMS测量

报道了用于加速器质谱计2 6 Al分析的Al2 O3的制备流程及2 6 Al的测量过程。制备的空白样品2 6 Al/ 2 7Al比值 <10 - 13,显示出同量异位素2 6 Mg干扰小。制备流程是成功的。     

Simulation of experimental spectra for medium-heavy nuclides in accelerator mass spectrometry

Some interferences are often encountered in accelerator mass spectrometry （AMS） measurements, especially for medium-heavy nuclide measurement, It is difficult for online discrimination of the nuclide of interest from the interfering ones. In order to solve this problem, we developed a method to simulate the experimental spectra of medium-heavy nuclides in AMS measurements. The results obtained from this method are in good agreement with experimental values.     

加速器质谱法研究新的无铅汽油添加剂与生物大分子的作用

介绍了无铅汽油添加剂甲基叔丁基醚、甲基叔戊基醚及甲基环戊二烯三羰基锰的应用现状和毒理学研究进展,提出用加速器质谱法研究所新的汽油添加剂甲基叔戊基基因毒性的研究方向。     

U measurement with accelerator mass spectrometry at CIAE

²³⁶U is a long-lived radioactive isotope which is produced principally by thermal neutron capture on ²³⁵U. ²³⁶U may be potentially applied in geological research and nuclear safeguards. Accelerator mass spectrometry is presently the most sensitive technique for the measurement of ²³⁶U and a measurement method for long-lived heavy ion ²³⁶U has been developed. The set-up uses a dedicated injector and the newly proposed ²⁰⁸Pb¹⁶ molecular ions for the simulation of ²³⁶U ion transport. A sensitivity of lower than 10⁻¹⁰ has been achieved for the isotopic ratio ²³⁶U/²³⁸U in present work.     

Measurement of the natural ^36Cl and ^236U in uranium mineral with accelerator mass spectrometry

The concentration of the natural ultra-trace radionuclides CI and U in the uranium depended on the neutron flux.In this article,a method for measuring ³⁶C1 and ²³⁶U in the same uranium mineral with accelerator mass spectrometry was developed in China Institute of Atomic Energy,providing a protocol of the potential application of ²³⁶U in uranium mining,environmental,and geological research.The two samples were from Guangxi and Shanxi province,China,and their ratios ³⁶Cl/C1 and ²³⁶U/²³⁸U were measured.More experimental data conduced to understand the natural nuclides in the uranium mineral.We plan to conduct more efforts on the research.     

A primary study on biological behavior of aluminum using 26Al-AMS

Aluminum is concerned as a possible cause of many diseases.To investigate the long-term A1 biokinetics and bioavailability in various kinds of Al-contained medicine and food,an accelerator mass spectrometry(AMS)based on the HI-13 tandem has been established for biological analysis with ~(26)A1(T_(1/2) = 716,000 years) as the tracer.In this paper,the animal tracing,sample preparation procedure and ~(26)A1-AMS measurement are presented.The sample preparation procedure has been simplified.A high sensitivity of 5×10~(-15) for ~(26)A1/~(27)A1 has been achieved.Two phases were found before and after a break time(t_b)for the ~(26)A1 retained in blood and brain,with t_b≈8 and12 h after the ~(26)Al tracer injection,respectively.     

加速器质谱计在地球科学中的应用

本文介绍加速器质谱计用于测定天然物质中超微量同位素~(10)Be及其在地球科学中的应用。环绕样品~(10)Be的测定可用于研究大气和海洋中发生的各种传输作用过程;大陆沉积物~(10)Be分布及迁移直接与黄土(或土壤)的堆积和侵蚀有关。~(10)Be是一种反映各种地球化学作用过程的理想的示踪剂。     

北京HI—13串列加速器质谱计测定^36Cl的研究

描述了中国原子能科学研究院的基于ＨＩ－１３串列加速器建立的加速器质谱计装置和测定＾３６Ｃｌ的实验方法。利用这台加速器质谱计测定＾３６Ｃｌ／Ｃｌ同位素原子比值的灵敏度已好于３×１０×－１５，对地下水，盐湖和铀矿石样品中的＾３１Ｃｌ进行了测定，这些样品的＾３６Ｃｌ／Ｃｌ同位素比为１．２×１０×－１２－２．２×１０＾－１４。     

加速器质谱(AMS)测量中的粒子鉴别探测器

描述了中国原子能科学研究院AMS测量中使用的飞行时间探测器、多阳极电离室、Bragg探测器、入射离子X射线探测器以及充气飞行时间探测器。通过它们可以获得粒子的飞行时间、部分能量和总能量,从而达到粒子鉴别的目的。介绍了采用这些探测器在HI—13串列AMS系统上做的相关工作以及取得成果。     

Measurement of Sm with the HI-13 accelerator mass spectrometry system

¹⁵¹Sm is an interesting nuclide in many research fields. Measurement methods of the long-lived ¹⁵¹Sm with accelerator mass spectrometry have been developed at China Institute of Atomic Energy. The chemical form of samples was Sm₂O₃ and the extracted ion was SmO⁻. To date, the sensitivity, that is, the isotopic ratio, of ¹⁵¹Sm measured using accelerator mass spectrometry is about 10⁻⁸. This method was also used to measure the concentration of tracer ¹⁵¹Sm in biological samples for clarifying whether the rare earth elements can enter into the brain. It is not possible at present to determine whether the tracer has penetrated the blood-brain barrier into the brain.     

A sensitive method for Sr-90 analysis by accelerator mass spectrometry

ABSTRACT

Strontium-90 is one of the most important fission products due to the potential health risks of its uptake and retention in the human body. Conventional analysis techniques involve β counting, which requires ingrowth of ⁹⁰Y over a period of two weeks. Accelerator mass spectrometry (AMS) has the potential to shorten the analysis time while offering a lower limit of detection than β counting. Here, Sr in samples was recovered as SrF₂ to provide sufficient negative ions in the caesium-sputtering ion source. In the sample preparation step, 95–98% of Sr was recovered and 99–100% of Zr removed by ion-exchange separation. Sr recovery was ~30% in the precipitation process, and this can be improved. A maximum 500 nA beam current of SrF₃ ^– ions was obtained from SrF₂ samples mixed with PbF₂. A five-anode gas ionization detector was used to avoid isobaric interference from ⁹⁰Zr. The ⁹⁰Sr/Sr atomic ratio background of ~6 × 10^–13 (~3 mBq ⁹⁰Sr) was comparable with that achieved at other AMS facilities. Good linearity in ⁹⁰Sr/Sr atomic ratios was obtained from 1.75 × 10^–10 to 3.38 × 10^–9. Suitable techniques for sample preparation and measurement were thus achieved for ⁹⁰Sr analysis by AMS.     

Design and reality: Continuous-flow accelerator mass spectrometry (CFAMS)

In 2007 we published [1] the design of a novel accelerator mass spectrometry (AMS) system capable of analyzing gaseous samples injected continuously into a microwave plasma gas ion source. Obvious advantages of such a system are drastically reduced processing times and avoidance of potentially contaminating chemical preparation steps. Another paper in these proceedings will present the progress with the development of the microwave gas ion source that has since been built and tested at the National Ocean Sciences AMS Facility in Woods Hole [2]. In this paper we will review the original design and present updates, reflecting our recent encouraging experience with the system. A simple summary: large acceptance ion beam optics design is beneficial to accelerator mass spectrometry in general, but essential to AMS with plasma gas ion sources.     

回旋加速器质谱技术中氚和氦—3粒子的探测和鉴别

在利用回旋加速器质谱技术进行氚断代的测量中,工作气体是电解水样品时收集到的含氚氢气,并混入少许一定量的空气。空气中的微量~3He和样品中的~3H同时加速并被用作参考标准以监督加速器的束流变化。描述了利用金硅面垒探测器望远镜和铝吸收箔的组合来探测和鉴别~3H和~3He的实验方法和结果。     

超灵敏小型回旋加速器质谱计分析多种放射性核素的可行性

理论分析和实验结果表明，超灵敏小型回旋加速器质谱计分析的放射性核素主要有＾１４Ｃ、＾３Ｈ、＾２６Ａｌ＾４０Ｋ、＾４４Ｔｉ等。在采取一定的技术措施后，可以分析的放射笥核素还可更多。     

利用静电加速器质谱技术测定氚

本工作描述基于2.5MV静电加速器建立的加速器质谱计的基本原理、实验装置以及重水样品中氚浓度(T/D)的测定。为了比较,还用放射性法进行了测量。实验结果表明,基于一台能量约1—2MeV加速器测定氚的灵敏度已达到10~(-14),而潜在灵敏度还可能高2—3个量级。本文还讨论了这种技术的前景和问题。     

Accelerator mass spectrometry of U at low energies

The performance of the compact ETH-TANDY system for accelerator mass spectrometry measurements of ²³⁶U is presented. Despite the low ion energies of around 1.2 MeV we can demonstrate a background level that is comparable to larger facilities. The careful ion-optical design of the high-energy spectrometer leads to a high suppression of neighboring isotopes sufficient to measure samples with isotopic ratios of ²³⁶U/²³⁸U > 10^-11 the ion chamber only, as demonstrated by systematic investigations with different slit settings and time-of-flight measurements. Additionally, a high overall efficiency is achieved due to a high transmission through the accelerator.     

痕量锂同位素的热表面电离质谱高精度测量

建立了痕量锂同位素的高精度热电离质谱测量技术。通过双带测量、加入磷酸发射剂及采用预烧处理方法等途径,抑制了分馏效应,提高了痕量锂质谱分析的精度。采用浓缩锂同位素标准样品考察了测量效果,对于100ng锂样品,测量相对标准偏差好于0.086%;对于10ng锂样品,相对标准偏差好于0.90%。     

Development of a sequential data correction method for isotope ratio analysis by resonance ionization mass spectrometry

A sequential data correction method using several experimental parameters of pulsed resonance ionization mass spectrometry was developed to reduce mass discrimination effects for isotope ratio analysis as well as fluctuations in the ion count rate. This correction method was applied to isotope ratio determination of stable titanium isotopes using a two-step, single color ionization scheme. A significant improvement of the precision of the measured isotopic ratio of stable titanium isotopes was demonstrated after correction with a parameter set consisting of laser power, atmospheric pressure, and laser frequency.     

热电离质谱测定第四纪地质年龄

介绍用ＭＡＴ－２６２质谱仪对国内石笋标样（ＧＢＷ０４４１２），（ＧＢＷ０４４１３）和国际珊瑚标样（ＲＫＭ－４）进行的测试，取得了与标准一至的结果。