Coordination Funds

协调基金

• 批准号: 272268388
• 负责人: Professor Dr. Christian Walter Dietrich Enss
• 金额: --
• 依托单位: Arbeitsgruppe Fundamentale Teilchen und Wechselwirkungen
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/272268388?language=en
• 关键词: Coordination; Funds

The determination of the absolute scale of the neutrino masses is one of the major challenges of today’s particle physics. Different approaches are fol-lowed to achieve a sensitivity on neutrino masses in the sub-eV range. Among them, experiments exploring the beta decay and electron capture processes of suitable nuclides can provide model-independent information on the electron (anti)- neutrino mass value purely using momentum and ener-gy conservation. The Electron Capture 163Ho experiment, ECHo, is aimed at investigating the electron neutrino mass in the sub-eV range by means of the analysis of the calorimetrically measured energy spectrum following the elec-tron capture process of 163Ho. In the ECHo experiment, arrays of low tem-per-ature metallic magnetic calorimeters with high energy resolution and fast response time, having the 163Ho source embedded in the absorber, will be used to calorimetrically measure the EC spectrum. Independent measure-ments of the decay energy (QEC-value), for which different experiments cur-rently provide values ranging from 2.3 to 2.8 keV, will be performed using Penning-trap mass spectrometry. For the QEC measurements as well as for the calorimetric measurement of the 163Ho spectrum, high purity 163Ho sources will be produced. Detailed studies of the background and of meth-ods for its reduction will be carried out to increase the sensitivity of the calo-rimetric measurement. Based on the preparatory work and the presently on-going R&D in the research groups of ECHo we propose to establish a DFG Re-search Unit with the goal to achieve the required experimental conditions and the knowledge to be able to investigate the electron neutrino mass in the sub-eV range and to foster the collaboration between the groups involved. Within the scope of this Research Unit, we propose to develop and construct a medium-size experiment featuring an activity of 1 kBq (ECHo-1k) with the aim of investigating the value of the electron neutrino mass in the range be-low 10 eV/c2 by means of a high-precision, high-statistics calorimetric measure-ment of the 163Ho EC spectrum. The expected result will improve the limit on the electron neutrino mass by more than one order of magnitude with respect to the presently most stringent limit of m(νe) < 225 eV/c2 (95% CL).

确定中微子质量的绝对尺度是当今粒子物理学面临的主要挑战之一。采用了不同的方法来实现对亚eV范围内中微子质量的灵敏度。其中，探索合适核素的β衰变和电子俘获过程的实验可以纯粹利用动量守恒和能量守恒来提供电子(反)中微子质量值的与模型无关的信息。电子俘获163Ho实验ECHO的目的是通过分析163Ho电子俘获过程后的量热测量能谱，研究亚eV范围内的电子中微子质量。在回波实验中，将使用能量分辨率高、响应时间快的低温金属磁力量热仪阵列，将~(163)Ho源嵌入吸收体中，对EC光谱进行量热测量。衰变能(QEC值)的独立测量将使用Penning-Trap质谱仪进行，不同的实验目前提供的值范围在2.3到2.8keV之间。对于QEC测量以及~(163)Ho谱的量热测量，将产生高纯度的~(163)Ho源。将对其背景和减少消耗臭氧层物质的方法进行详细研究，以提高量热测量的灵敏度。基于ECHO研究小组的准备工作和目前正在进行的研究，我们建议建立一个DFG研究组，目的是达到所需的实验条件和知识，以便能够研究亚EV范围内的电子中微子质量，并促进有关小组之间的合作。在这个研究单位的范围内，我们建议发展和建设一个活度为1kBq(ECHO-1K)的中型实验，目的是通过对~(163)Ho电子能谱的高精度、高统计量热测量来研究在10 eV/c2以下范围内的电子中微子质量的值。与目前最严格的m(νe)和lt；225 eV/c2(95%CL)相比，预期的结果将使电子中微子质量的限制提高一个数量级以上。