Trapped electron for neutrino mass measurement.

这项提议的重点是开发Geonium芯片中的俘获电子，作为基础物理应用中的微波辐射超灵敏探测器。具体地说，在该项目的两年时间里，我们的主要目标是为未来计划中的中微子绝对质量标度m_beta的测量提供一个基本的实验证明概念，该概念是从氚的β衰变的Kurie谱的能量终点E_0=18.6keV开始的。目前正在进行的KArslruhe氚中微子实验(Katrin)最近报告了m_β和lt的上界；1.1 eV/c^2，其目标是最终精度为0.2 eV/c^2。中微子味道振荡和宇宙学观测分别将m_beta&gt；50 mev/c^2或m_beta&gt；9 mev/c^2设定为中微子质量等级的“倒置”或“正常”排序的最终界限。这两个值定义了测量中微子质量所需的精度。这两个都超出了卡特林的能力范围。为了改进后者，人们提出了一种新的回旋共振发射光谱(CRES)技术来测量mβ。CRES允许检测(和计数)从放射源(如氚)发射的贝塔粒子，并测量它们的动能。总部设在美国的Project-8合作项目通过检测单个贝塔粒子(从气态克里普顿衰变)发射的微波辐射并测量其动能，实验证明了CRES的基本原理。通过这种方法，Project-8的目标是在未来的中微子质量测量中达到40 meV/c^2的精度。同时，在2021年初，由伦敦大学学院(UCL)领导的量子中微子质量测量(QTNM)联盟已经成立。QTNM正在开发CRES演示装置(CRESDA)，最初使用的是氢源。最终目标是在氚设施中测量m_beta(最终在国际合作中)，可能是在库勒姆聚变能源中心。虽然CRES的基本工作原理已经得到测试，但在测量β粒子动能时达到的分辨率达到15 eV/c^2。这大约比“保证”测量m_beta所需的灵敏度低三个数量级。这一提议旨在提供一种微波量子传感器，即陷阱电子，即使在最具挑战性的“正常”有序情况下，也能够使用CRES技术测量m_β。在该项目的两年时间内，我们的目标是用我们的Geonium微波传感器展示5 mev/c^2或更高的能量分辨率。这些实验将在苏塞克斯利用现有的Geonium芯片设施进行。我们与QTNM财团的合作将为Geonium传感器测量mβ的适宜性提供外部评估。它还将允许规划其最终随后并入未来准备好氚的CRES设施。

This proposal is focused on developing a trapped electron in the geonium chip as an ultra-sensitive detector of microwave radiation for fundamental physics applications. Specifically, in the two years duration of the project, our main goal is to provide a basic experimental proof-of concept of the capacity of our trapped electron (or 'geonium atom') for the planned future measurement of the neutrino's absolute mass scale, m_beta, from the energy endpoint E_0 = 18.6 keV of the Kurie spectrum of the beta-decay of tritium.The currently ongoing KArslruhe TRItium Neutrino experiment (KATRIN) has recently reported an upper bound of m_beta<1.1 eV/c^2, and it aims at a final accuracy of 0.2 eV/c^2. Neutrino flavour oscillations together with cosmology observations set the ultimate boundary to m_beta>50 meV/c^2, or m_beta>9 meV/c^2 in the case of "inverted" or "normal" ordering of the neutrino mass hierarchy, respectively. These two values define the required accuracy for measuring the neutrino mass. Both are beyond the reach of KATRIN. In order to improve the latter, the novel Cyclotron Resonance Emission Spectroscopy (CRES) technique has been proposed for measuring m_beta. CRES allows for detecting (and counting) beta particles emitted from a radioactive source, such as tritium, and for measuring their kinetic energy. The US-based Project-8 collaboration has demonstrated experimentally the basic principle of CRES, by detecting the microwave radiation emitted by one single beta particle (decayed from gaseous Kripton) and measuring its kinetic energy. With this method, Project-8 aims at a future accuracy in the neutrino mass measurement of 40 meV/c^2. Meanwhile, in early 2021, the Quantum Technologies for Neutrino Mass Measurement (QTNM) consortium, lead by University College London (UCL), has been launched. QTNM is developing a CRES demonstrator apparatus (CRESDA), initially operated with a deuterium source. The ultimate goal is to measure m_beta (eventually within an international collaboration) in a tritium facility, possibly at Culham Centre for Fusion Energy.While the basic working principle of CRES has been tested, the resolution achieved in the measurement of the kinetic energy of the beta particles amounts to 15 eV/c^2. This is around three orders of magnitude below the required sensitivity for a "guaranteed" measurement of m_beta. This proposal aims at delivering a microwave quantum sensor, the trapped electron, capable of measuring m_beta with the CRES technique, even in the most challenging scenario of "normal" ordering. Within the two years duration of the project we aim at demonstrating an energy resolution of 5 meV/c^2 or better with our geonium microwave sensor. The experiments will be performed at Sussex with an existing geonium chip facility. Our cooperation with the QTNM consortium will provide an external assessment of the suitability of the geonium sensor for measuring m_beta. It will also allow for planning its eventual subsequent integration into the future tritium-ready CRES facility.