Dong Kejun

AMS Measurement of 53 Mn at CIAE

The long-lived isotope 53Mn cosmogenically produced in situ is a very useful indicator for geochronological dating. A new 53Mn accelerator-mass-spectrometry (AMS) measurement method is developed based on the HI-13 Tandem Accelerator and ΔE-Q3D detection system at China Institute of Atomic Energy. The performance of 53Cr isobar separation and suppression is tested by a series of 53Mn standards and commercial MnO samples. The results show that the ΔE-Q3D detection system brought about an overall suppression factor of more than 107 for the interfering isobar 53Cr.

Methodological Study on AMS Measurement of U Isotope Ratios in Nanogram U Samples

The determination of uranium isotopic composition in trace samples is important in different fields. A new measurement method that uses an accelerator mass spectrometry (AMS) technique has been developed for the analysis of uranium isotopic ratios in ultra-trace uranium samples at the China Institute of Atomic Energy. As a result, about 5-nanogram level uranium samples analyzed with AMS is achieved.

Methodological Study on Change in Half Life of 210Po Embedded in a Metallic Medium at Ultra-Low Temperature

It has been claimed that the half-life of radioactive nuclides embedded in metals may be significantly affected by the screening of quasi-free electrons provided by the metals, especially at the cryogenic temperature. We determine the α-decay half-life values of 210Po in high purity metallic bismuth at 4.2 K and 293 K. The results show that the α-decay half-life of 210Po at T = 4.2 K is about (24 ± 8)% shorter than that at room temperature.

Progress in AMS Measurement of 182Hf at CIAE

Accelerator mass spectrometry (AMS) is one of the most promising methods to detect minute amounts of 182Hf. However, the sensitivity of 5 × 10−11 for 182Hf/180 Hf obtained previously by the AMS method at China Institute of Atomic Energy (CIAE) cannot meet the requirement of some applications. We present some new improvements of measurement method for AMS measurement of 182Hf at the CIAE HI-13 tandem accelerator system. As a result, a sensitivity of 1.0 × 10−11 for 182Hf/180 Hf is achieved.

Application of41Ca Tracer and Its AMS Measurement in CIAE

The man-made calcium isotope 41Ca is an ideal tracer for the study of calcium metabolism. We represent the first application of accelerator mass spectrometry (AMS) measurement of 41Ca tracer in China. The technique is being applied to the research field of cell messenger at the China Institute of Atomic Energy (CIAE). The sample preparation methods and the AMS measurements are discussed and some interesting results are presented.

Improvement on AMS Measurement of 236U at CIAE

In order to improve the detection efficiency and sensitivity for 236U measurement at China Institute of Atomic Energy (CIAE) accelerator mass spectrometry (AMS) system to meet the requirement of some applications, we present some new improvements of the measurement method for AMS measurement of 236U at CIAE AMS. The main features of the method include: (i) measurement optimization; (ii) improvement of the TOF time resolution ~500ps. Based on these improvements, the sensitivity is ~10−11 for 236U/238U in the present work, higher than before (236U/238U~5 × 10−10).

用于加速器质谱测量的 151 Sm实验室参考标准的研制

介绍了用于HI-13串列加速器质谱（Accelerator Mass Spectra, AMS）测量的 151 Sm实验室参考标准的研制。 151 Sm是长寿命放射性核素，自然界不存在。通过富集稳定同位素 150 Sm（n, γ）反应合成 151 Sm，并以热电离同位素质谱仪（Thermal Ionization Mass Spectrometry, TIMS）测得样品中同位素比 151 Sm/ 150 Sm为3.75×10 -3 ，相对不确定度为0.06%。然后加入稳定的同位素 154 Sm稀释，制得 151 Sm/ 154 Sm比值分别为（9.25±0.08）×10 -7 、（8.87±0.08）×10 -8 、（8.08±0.08）×10 -9 的系列参考标准。

Developing AMS measurement of59Ni at CIAE

Accelerator mass spectrometry (AMS) measurement of

AMS Measurement of 36Cl with a Q3D Magnetic Spectrometer at CIAE

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Molecular Dynamics Simulation of Microstructure Transitions in a Large-Scale Liquid Metal Al System During Rapid Cooling Processes

Ni has been established at CIAE with the HI-13 tandem accelerator and the recently developed