标题： WSRT观测对超高能中微子流的限制 显示英文标题

标题： Constraints on the flux of Ultra-High Energy neutrinos from WSRT observations

摘要： 超高能（UHE）中微子和宇宙射线在月球表面下引发粒子级联。 这些级联带有负电荷过剩，并在一种称为Askaryan效应的过程中辐射切伦科夫无线电发射。 使用地球上射电望远镜观测这些脉冲的最佳频率窗口约为150 MHz。 通过使用韦斯特博克综合射电望远镜阵列观测月球，我们能够对UHE中微子通量设定一个新的限制。 PuMa II后端用于在113到175 MHz之间的4个频带内以40 MHz的采样频率监测月球。 窄带射频干扰被数字滤除，并补偿了地球电离层的色散效应。 实现了一个触发系统来搜索短脉冲。 通过在原始数据中插入模拟脉冲，计算了各种强度脉冲的探测效率。 通过47.6小时的观测时间，我们能够对UHE中微子通量设定一个限制。 这个新的限制比现有限制低一个数量级。 在未来不久，数字射电阵列LOFAR将被用来达到更低的限制。 显示英文摘要

摘要： Ultra-high energy (UHE) neutrinos and cosmic rays initiate particle cascades underneath the Moon's surface. These cascades have a negative charge excess and radiate Cherenkov radio emission in a process known as the Askaryan effect. The optimal frequency window for observation of these pulses with radio telescopes on the Earth is around 150 MHz. By observing the Moon with the Westerbork Synthesis Radio Telescope array we are able to set a new limit on the UHE neutrino flux. The PuMa II backend is used to monitor the Moon in 4 frequency bands between 113 and 175 MHz with a sampling frequency of 40 MHz. The narrowband radio interference is digitally filtered out and the dispersive effect of the Earth's ionosphere is compensated for. A trigger system is implemented to search for short pulses. By inserting simulated pulses in the raw data, the detection efficiency for pulses of various strength is calculated. With 47.6 hours of observation time, we are able to set a limit on the UHE neutrino flux. This new limit is an order of magnitude lower than existing limits. In the near future, the digital radio array LOFAR will be used to achieve an even lower limit.