在ILL用STEREO探测器寻找无菌中微子

Improved Sterile Neutrino Constraints from the STEREO Experiment with 179 Days of Reactor-On Data

The STEREO experiment is a very short baseline reactor antineutrino experiment. It is designed to test the hypothesis of light sterile neutrinos being the cause of a deficit of the observed antineutrino interaction rate at short baselines with respect to the predicted rate, known as the reactor antineutrino anomaly. The STEREO experiment measures the antineutrino energy spectrum in six identical detector cells covering baselines between 9 and 11 m from the compact core of the ILL research reactor. In this article, results from 179 days of reactor turned on and 235 days of reactor turned off ar…

用于STEREO实验的触发和读出电子学

Trigger and readout electronics for the STEREO experiment

STEREO实验将通过测量反中微子能谱作为与源ILL核反应堆距离的函数来寻找无菌中微子。一个专用的电子系统，托管在一个单一的microTCA板条箱，是专为这个实验。它在两个阶段中执行触发，具有各种可选条件，通过UDP/IPBUS处理和读出68个光电倍增管信号，以250 MSPS连续数字化。此外，对于检测器性能监测，电子设备允许通过与数据采集同步地驱动LED来进行在线校准。本文介绍了电子的要求，架构和实现的性能。

STEREO实验的结果（119天反应器开启数据）

Results from the STEREO Experiment with 119 days of Reactor-on Data

在过去的几十年里，围绕实验或商业反应堆堆芯的短基线中微子振荡研究揭示了两个异常现象。第一个与绝对通量相关，第二个与光谱形状相关。第一个异常，称为反应堆反中微子异常（RAA），可以通过引入一个新的反中微子振荡来解释。自2016年底以来，\stereo探测器一直在法国格勒诺布尔劳厄-朗之万研究所堆芯10米处采集数据。其目标体积沿中微子传播轴的分离允许在多个基线处测量中微子光谱，提供了短基线振荡的清晰测试。在这篇文章中，一个特别的重点放在数据分析和中微子提取使用的脉冲形状歧视观察。然后报告反应器开启119天和反应器关闭210天的结果。由此产生的抗中微子率为（365.7~ $\pm$ ~3.2）\anue /天。对无菌中微子的新振荡的检验与无振荡假设是一致的，在99 C. L.

立体反应堆中微子实验用液体闪烁体的制备和性能

Production and Properties of the Liquid Scintillators used in the Stereo Reactor Neutrino Experiment

利用有机液体闪烁体中的反β衰变信号测量了立体反应堆实验（ILL Grenoble）中的电子反中微子谱。立体探测器的六个靶室填充有约1800升的Gd装载的液体闪烁体，其针对实验的要求进行了优化。这些靶细胞被包含没有Gd负载的液体闪烁体的类似细胞包围。本文介绍了这类制冷剂的发展和特点。特别地，讨论了有机液体的透明度、光产生和脉冲形状辨别能力。

利用反应堆中微子搜寻惰性中微子的RENE实验

RENE experiment for the sterile neutrino search using reactor neutrinos

本文介绍RENE反应堆中微子实验的探测器设计、模拟研究与物理目标，旨在精细探究RAA预言、现有实验尚未排除的惰性中微子振荡参数区间。

STEREO实验

The STEREO Experiment

STEREO实验是一个非常短基线的反应堆反中微子实验，旨在测试轻无菌中微子的假设，作为观测到的中微子相互作用速率相对于预测速率的不足的解释，称为反应堆反中微子异常。探测器中心距离法国格勒诺布尔劳厄朗之万研究所研究核反应堆的紧凑、高$^{235}$铀富集堆芯10米。本文介绍了STEREO现场，探测器组件和相关的屏蔽设计，以抑制外部来源的背景，其特点是现场。它报告了在探测器响应和能量重建方面的性能。

The analysis of the results of the Neutrino-4 experiment on search for sterile neutrino and comparison with results of other experiments

We present new results of measurements of reactor antineutrino flux and spectrum dependence on the distance in the range 6-12 meters from the center of the reactor core at SM-3 reactor (Dimitrovgrad, Russia). Additional measurements were carried out and set of data to perform statistical analysis was almost doubled since the previous report. Using all collected data we performed the model independent analysis on the oscillation parameters $Δm^2_{14}$ and $\sin^2(2θ_{14})$. The method of coherent summation of results of measurements allows us to directly observe the effect of oscillations. We o…

First antineutrino energy spectrum from $^{235}$U fissions with the STEREO detector at ILL

This article reports the measurement of the $^{235}$U-induced antineutrino spectrum shape by the STEREO experiment. 43'000 antineutrinos have been detected at about 10 m from the highly enriched core of the ILL reactor during 118 full days equivalent at nominal power. The measured inverse beta decay spectrum is unfolded to provide a pure $^{235}$U spectrum in antineutrino energy. A careful study of the unfolding procedure, including a cross-validation by an independent framework, has shown that no major biases are introduced by the method. A significant local distortion is found with respect t…