A promising approach to detect high-energy tau neutrinos is through the measurement of impulsive radio emission from horizontal air showers initiated in the Earth's atmosphere. Observations at frequencies between 30 and 80 MHz seem particularly promising -- if high-gain antennas focused at the horizon and blocking out as much as possible of the noisy sky are employed. Due to the large wavelengths, however, designing an antenna with the required properties is highly non-trivial at such low frequencies. In this article, we explore suitable antenna designs that provide the desired high gain, possess a smooth beam, are insensitive to ground conditions, are easily impedance-matched over the wide band, and are mechanically simple for deployment in large numbers in inaccessible terrain. In particular, we consider the "rhombus" antenna design for both horizontally and vertically polarized radiation a very attractive option for tau neutrino detection efforts in the atmosphere with the radio technique.
The detection of very-high-energy (VHE) neutrinos ($E_ν\gtrsim 10$ PeV) is a challenge that future generations of experiments are being designed and constructed to address. One promising method relies on using the Earth as a neutrino target for indirect detection of skimming tau neutrinos interacting within the Earth and producing tau leptons that are able to escape and decay in the atmosphere. The tau decay produces upward-moving Extensive Air Showers (EASs). A space-based or suborbital instrument observing the ground near the Earth limb can search for the beamed Cherenkov signal produced by …
Earth-skimming neutrinos are those which travel through the Earth's crust at a shallow angle. For Ultra-High-Energy (E > 1 PeV; UHE) earth-skimming tau neutrinos, there is a high-probability that the tau lepton created by a neutrino-Earth interaction will emerge from the ground before it decays. When this happens, the decaying tau particle initiates an air shower of relativistic sub-atomic particles which emit Cherenkov radiation. To observe this Cherenkov radiation, we propose the Trinity Observatory. Using a novel optical structure design, pointing at the horizon, Trinity will observe the Ch…
Neutrino Telescope Array Letter of Intent: A Large Array of High Resolution Imaging Atmospheric Cherenkov and Fluorescence Detectors for Survey of Air-showers from Cosmic Tau Neutrinos in the PeV-EeV Energy Range
本意向书（LoI）描述了中微子望远镜阵列（NTA）项目的大纲和计划。高能中微子为强子加速提供了独特而无可争辩的证据。最近，冰立方已经报道了超过预期的来自大气秒的天文中微子候选者，但受到水切伦科夫探测方法的限制。下一代高能中微子望远镜应该能够为宇宙高能中微子建立无可争辩的证据。它不仅应该有数量级的更大的灵敏度，而且还应该有足够的指向精度来探测已知或未知的天文物体，而不会受到大气层的影响。拟议的装置是一个大型阵列的成像大气切伦科夫和荧光探测器的复眼站，具有宽视场和精细的观测能力，从PeV-EeV能量范围的宇宙τ中微子的空气簇射。这套先进的光学复杂系统主要是在全天空巡天高分辨率空气簇射探测器（Ashra）的基础上发展起来的，并采用τ簇射掠地方法对PeV-EeV τ中微子进行巡天。在标准GRB中微子注量的条件下，它可以对PeV-EeV τ中微子进行宽（30 ° x 360 °）和深（~400 Mpc）的巡天观测，而且在基本无背景的条件下，它的指向精度优于0.2 °。通过在宽视场中对掠地τ阵雨进行先进成像，我们的目标是明确发现和识别天文τ中微子源，为天体物理强子模型提供不可逃避的证据，以加速和/或在精确确定的方向上传播极高能量的质子。
This paper investigates the potential to detect tau neutrinos in the energy range of 1-1000 PeV searching for very inclined showers with imaging Cherenkov telescopes. A neutrino induced tau lepton escaping from the Earth may decay and initiate an air shower which can be detected by a fluorescence or Cherenkov telescope. We present here a study of the detection potential of Earth-skimming neutrinos taking into account neutrino interactions in the Earth crust, local matter distributions at various detector sites, the development of tau-induced showers in air and the detection of Cherenkov photon…
Search for tau neutrinos at PeV energies and beyond with the MAGIC telescopes
MAGIC望远镜位于Roque de los Muchachos天文台（2200 a.s.l.）。在加那利群岛的拉帕尔马，放置在山顶上，从那里在天顶大约5度和方位角80度的可见度窗口在周围海洋的方向上打开。这允许搜索的签名引起的粒子阵雨地球掠过宇宙τ中微子在PeV到EeV的能量范围内产生的海洋。我们研究了MAGIC对这类事件的响应，采用蒙特卡罗模拟的上行τ中微子簇射。对簇射图像的分析表明，τ中微子引起的空气簇射可以与来自相似方向的强子背景区分开来。我们已经计算了点源的接受和预期的事件率，为样本的一般中微子通量的光强子相互作用在活动星系核。如果MAGIC将AUGER观测时间专用于类似的数量，则对向海洋采集的约30小时数据的分析导致了在Pierre Auger天文台的下行点源分析水平上的τ中微子的点源灵敏度。
Tau neutrinos are expected to comprise roughly one third of both the astrophysical and cosmogenic neutrino flux, but currently the flavor ratio is poorly constrained and the expected flux at energies above $10^{17}$ eV is low. We present a detector concept aimed at measuring the diffuse flux of tau neutrinos in this energy range via a high-elevation mountaintop detector using the radio technique. The detector searches for radio signals from upgoing air showers generated by Earth-skimming tau neutrinos. Signals from several antennas in a compact array are coherently summed at the trigger level,…
We discuss the acceptance and sensitivity of a small air-shower imaging system to detect earth-skimming ultrahigh-energy tau neutrinos. The instrument we study is located on top of a mountain and has an azimuthal field of view of $360^\circ$. We find that the acceptance and sensitivity of such a system is close to maximal if it is located about 2 km above ground, has a vertical field of view of $5^\circ$, allows the reconstruction of an at least $0.3^\circ$ long air-shower image, and features an effective light-collection area of $10$ m$^2$ in any direction. After three years of operation, an …
The detection of astrophysical neutrinos by IceCube and the potential to constrain source models of ultra-high energy cosmic rays provide the motivation to develop instruments for the observation of neutrinos above $10^7$ GeV. Among the different techniques to detect ultra-high energy neutrinos is the Earth-skimming technique. It makes use of the fact that the tau produced in a tau neutrino interaction inside the Earth can emerge from the ground and initiate an upward-going particle shower in the atmosphere. The particle shower and thus the neutrino can be reconstructed by measuring the Cheren…
We present the status of the development of a Cherenkov telescope to be flown on a long-duration balloon flight, the Extreme Universe Space Observatory Super Pressure Balloon 2 (EUSO-SPB2). EUSO-SPB2 is an approved NASA balloon mission that is planned to fly in 2023 and is a precursor of the Probe of Extreme Multi-Messenger Astrophysics (POEMMA), a candidate for an Astrophysics probe-class mission. The purpose of the Cherenkov telescope on-board EUSOSPB2 is to classify known and unknown sources of backgrounds for future space-based neutrino detectors. Furthermore, we will use the Earth-skimmin…
Efforts to detect ultrahigh energy neutrinos are driven by several objectives: What is the origin of astrophysical neutrinos detected with IceCube? What are the sources of ultrahigh energy cosmic rays? Do the ANITA detected events point to new physics? Shedding light on these questions requires instruments that can detect neutrinos above $10^7$ GeV with sufficient sensitivity - a daunting task. While most ultrahigh energy neutrino experiments are based on the detection of a radio signature from shower particles following a neutrino interaction, we believe that the detection of Cherenkov and fl…
Artificial Neural Network as a FPGA Trigger for a Detection of Very Inclined Air Showers
中微子可以在大气层（向下的ν）或地壳（掠过地球的ν）中相互作用，产生可以用地面探测器阵列观察到的空气簇射。皮埃尔·俄歇天文台的地面探测器阵列可以探测到这些类型的级联。中微子事件的显著特征是在靠近地面的地方产生了非常倾斜的簇射（即，在穿过大量大气之后）。到目前为止，皮埃尔俄歇天文台没有发现任何中微子事件的候选者。中微子可能产生的事件发生率非常低，这对探测技术来说是一个重大挑战，需要复杂的算法和高分辨率的硬件。我们提出了一个触发器的基础上，在一个大型的FPGA实现的流水线人工神经网络（ANN），学习后，可以识别出对应于特殊类型的事件的痕迹。在MATLAB平台上开发的人工神经网络算法的结构已被实现到最大的Cyclone V E FPGA的快速逻辑中，该FPGA用于Auger-Beyond-2015工作的前端板原型。测试了几种算法，然而，Levenberg-Marquardt算法似乎是最有效的。该网络被教导：a）识别“旧”簇射（基于真实的非常倾斜的俄歇簇射（正标记）和特别是由超过阈值的时间触发的真实的标准簇射（负标记）进行学习，b）识别“新”簇射（基于模拟的“新”事件（正标记）和作为负参考的标准俄歇事件）。一个三层的神经网络被教导的真正非常倾斜的俄歇阵雨显示出良好的效率在模式识别的16点的轨迹与“老”阵雨的轮廓特征。
Neutrinos of astrophysical origin could be detected through the electromagnetic radiation of the particle showers induced in the atmosphere by their interaction in the Earth. This applies in particular for tau neutrinos of energies $E>10^{16}$eV following Earth-skimming trajectories. The $\sim1^{\circ}$ beaming of the radio emission in the forward direction however implies that the radio signal will likely fly above a detector deployed over a flat site and would therefore not be detected. We study here how a non-flat detector topography can improve the detection probability of these neutrino-i…
Sensitivity of BEACON to Ultra-High Energy Diffuse and Transient Neutrinos
Pennsylvania State University（宾夕法尼亚州立大学）；University of Warsaw（华沙大学）；University of Chicago（芝加哥大学）；The Ohio State University（俄亥俄州立大学）；Radboud University Nijmegen（奈梅亨拉德堡德大学）；NIKHEF（荷兰国家核与亚原子物理研究所）；University of Kansas（堪萨斯大学）；California Institute for Technology（加州理工学院）
Development of a radio-detection method array for the observation of ultra-high energy neutrino induced showers
最近由CODALEMA合作的无线电探测技术的UHE宇宙线的特性的能力的演示，要求使用这种强大的方法来观察UHE中微子。为此，目前正在对现有的21厘米阵列（中国）进行调整。在一个非常低的电磁噪声水平，10160对数周期50-200兆赫天线坐落在两个高的山谷，周围的山脉。这种布局导致中微子与沿着两个4-6公里基线方向的低入射轨道相互作用的有效岩石厚度为30-60公里。我们将首次进行现场射电测量，证明这种环境对于观测源自10^17-20 eV τ中微子相互作用的τ的电磁衰变信号具有特别有利的条件。
The four persistent radio sources in the northern sky with the highest flux density at metre wavelengths are Cassiopeia A, Cygnus A, Taurus A, and Virgo A; collectively they are called the A-team. Their flux densities at ultra-low frequencies (<100 MHz) can reach several thousands of janskys, and they often contaminate observations of the low-frequency sky by interfering with image processing. Furthermore, these sources are foreground objects for all-sky observations hampering the study of faint signals, such as the cosmological 21 cm line from the epoch of reionisation. We aim to produce robu…
用于中微子探测的巨型射电阵列（GRAND）是一个计划中的约20万个射电天线阵列，部署在约20万平方公里的山区。它的主要目的是通过观测由地球表面下宇宙中微子相互作用产生的taus大气衰变引起的大范围空气簇射来探测高能中微子。GRAND的目标是在3.10 $^{16}$ eV以上达到5.10 $^{11}$ E $^{-2}$ GeV $^{-1}$ cm $^{-2}$ s $^{-1}$ sr $^{-1}$的中微子灵敏度。这确保了在最悲观的源模型中检测到宇宙成因中微子，并且对于标准模型，预计每年约有50个事件。该仪器还将检测UHECR和可能的FRB。在这里，我们展示了我们的初步设计应该如何使我们达到我们的灵敏度目标，并讨论了要采取的步骤，以实现GRAND。
