Calorimetric low temperature detectors for low-energetic heavy ions and their application in accelerator mass spectrometry.
Calorimetric low temperature detectors for low-energetic heavy ions and their application in accelerator mass spectrometry.
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低能重离子量热低温探测器及其在加速器质谱中的应用。
DOI：
10.1063/1.3213622
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
C. Vockenhuber
中科院分区：
文献类型：
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作者：
S. Kraft;V. Andrianov;A. Bleile;A. Echler;P. Egelhof;A. Kiseleva;O. Kiselev;H. Meier;J. Meier;A. Shrivastava;M. Weber;R. Golser;W. Kutschera;A. Priller;P. Steier;C. Vockenhuber
在加速器质谱（AMS）常用的能量范围E=0.1- 1mev /amu内，研究了量热低温探测器对重离子的能量敏感探测。所使用的探测器由蓝宝石吸收器和超导铝过渡边缘温度计组成，工作温度约为1.5 K。它们被奥地利维也纳VERA串联加速器提供的各种离子束（13C, 197Au, 238U）照射。得到的相对能量分辨率为DeltaE/E=(5-9) × 10(-3)，即使对于最重的离子如238U也是如此。此外，没有观察到脉冲高度缺陷的证据。这种性能首次允许在AMS实验中应用量热低温检测器。目的是精确测定几种天然铀样品中236U/238U的同位素比率，236U被认为是中子通量的敏感监测器。用量热检测器取代VERA的传统检测系统，大大减少了邻近同位素的背景，提高了检测效率。由于获得了很高的灵敏度，可以得到236U/238U=6.1 × 10（-12）的值，这是当时测量到的最小的236U/238U比值。此外，我们还帮助建立了改进的236U/238U材料标准，可作为未来AMS测量的参考。
The energy-sensitive detection of heavy ions with calorimetric low temperature detectors was investigated in the energy range of E=0.1-1 MeV/amu, commonly used for accelerator mass spectrometry (AMS). The detectors used consist of sapphire absorbers and superconducting aluminum transition edge thermometers operated at T approximately 1.5 K. They were irradiated with various ion beams (13C, 197Au, 238U) provided by the VERA tandem accelerator in Vienna, Austria. The relative energy resolution obtained was DeltaE/E=(5-9) x 10(-3), even for the heaviest ions such as 238U. In addition, no evidence for a pulse height defect was observed. This performance allowed for the first time to apply a calorimetric low temperature detector in an AMS experiment. The aim was to precisely determine the isotope ratio of 236U/238U for several samples of natural uranium, 236U being known as a sensitive monitor for neutron fluxes. Replacing a conventionally used detection system at VERA by the calorimetric detector enabled to substantially reduce background from neighboring isotopes and to increase the detection efficiency. Due to the high sensitivity achieved, a value of 236U/238U=6.1 x 10(-12) could be obtained, representing the smallest 236U/238U ratio measured at the time. In addition, we contributed to establishing an improved material standard of 236U/238U, which can be used as a reference for future AMS measurements.