Characterization of the 163Ho Electron Capture Spectrum: A Step Towards the Electron Neutrino Mass Determination
Characterization of the 163Ho Electron Capture Spectrum: A Step Towards the Electron Neutrino Mass Determination
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DOI：
10.1103/physrevlett.119.122501
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发表时间：
2017-09-19
影响因子：
8.6
通讯作者：
Johnston, K.
中科院分区：
文献类型：
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作者：
Ranitzsch, P. C. -O.;Hassel, C.;Johnston, K.
在许多方面，同位素 Ho-163 是进行实验以研究电子中微子质量值的最佳候选者。它经历了 Dy-163 的电子捕获过程，可用于衰变的能量 Q(EC) 约为 2.8 keV。根据目前的了解，这是此类转变的最低 QEC 值。在这里，我们讨论新获得的 Ho-163 光谱，该光谱由低温金属磁量热仪拍摄，Ho-163 植入吸收器中，并以反重合模式操作以减少背景。首次通过量热测量观察到从 Ho-163 的 5s 壳层（OI 线）捕获电子后 Dy-163 子原子的原子去激发。峰值能量确定为48 eV。此外，通过分析光谱中的谱线强度，可以精确确定衰变可用的能量 Q(EC) = (2.858 +/- 0.010(stat)+/- 0.05(syst))keV。该值与通过潘宁阱质谱法获得的Ho-163和Dy-163之间的质量差的测量结果非常吻合，证明了量热技术的可靠性。
The isotope Ho-163 is in many ways the best candidate to perform experiments to investigate the value of the electron neutrino mass. It undergoes an electron capture process to Dy-163 with an energy available to the decay, Q(EC), of about 2.8 keV. According to the present knowledge, this is the lowest QEC value for such transitions. Here we discuss a newly obtained spectrum of Ho-163, taken by cryogenic metallic magnetic calorimeters with Ho-163 implanted in the absorbers and operated in anticoincident mode for background reduction. For the first time, the atomic deexcitation of the Dy-163 daughter atom following the capture of electrons from the 5s shell in Ho-163, the OI line, was observed with a calorimetric measurement. The peak energy is determined to be 48 eV. In addition, a precise determination of the energy available for the decay Q(EC) = (2.858 +/- 0.010(stat)+/- 0.05(syst))keV was obtained by analyzing the intensities of the lines in the spectrum. This value is in good agreement with the measurement of the mass difference between Ho-163 and Dy-163 obtained by Penning-trap mass spectrometry, demonstrating the reliability of the calorimetric technique.