A Wideband Intelligent Trigger

观测极低能电子的能力对于日本神冈矿的超级神冈（SK）实验的物理范围至关重要。它影响了从太阳中微子到质子衰变到粒子识别的广泛物理主题的灵敏度。这项工作将为SK实验开发新的极低能量触发器的新软件和硬件。 2008年底，SK中的所有电子和数据采集组件都被更换，导致使用实时软件触发器的全新数据采集方法;然而，该系统的初始计算和存储能力仅允许类似于以前系统的能量阈值。宽带智能触发（WIT）系统将提供足够的连接、存储和CPU功率，以完全处理未触发的原始流中的数据，并以高效率提取电子，总能量低至3 MeV，它通过以大规模并行方式独立评估每个数据块并应用新的软件算法来运行最终会进行两阶段的顶点重建此过程将后台、处理时间和最终数据大小减少到可管理的水平。 新的低能量阈值将：（1）提高SK对由米赫耶夫-斯米尔诺夫-沃尔芬斯坦（MSW）效应引起的太阳中微子光谱畸变的灵敏度，从而对由大混合角MSW振荡引起的尚未观测到的太阳中微子光谱的上升带来新的灵敏度;（2）通过充当银河系超新星爆发触发器提供新的功能;（3）通过在水中加入钆，使SK能高效率地探测中子，大大降低了质子衰变和超新星遗迹中微子观测的大气中微子本底。该奖项所支持的研究是一个例子，说明了计算技术的进步如何扩展现有基础研究仪器的能力，有效地扩展了物理学的范围并利用了现有的投资。日本的神冈实验室有一个广泛的项目，让公众、本科生和K-12学生参与到物理研究的兴奋中。从事WIT研究的博士后和研究生将融入这些活动和讲座，这些活动和讲座涉及通过观察超级神冈中的低能事件而产生的物理学。 来自美国的本科生将在夏季与日本的这个小组合作一到两个月，帮助实施WIT并帮助分析第一批数据。 他们将与当地本科院校的教师保持合作关系。他们还将通过参加超级神冈合作会议、轮班实验和参与科学研究来参与这项工作。

The ability to observe very low-energy electrons is crucial for the physics reach of the Super-Kamiokande (SK) experiment at the Kamioka mine in Japan. It influences the sensitivity to a wide range of physics topics from solar neutrinos to proton decay to particle identification. This work will develop new software and hardware for a new very low-energy trigger for the SK experiment. In late 2008, all of the electronics and data acquisition components in SK were replaced, leading to an entirely new data-taking approach using real-time software triggers; however, the initial computing and storage capabilities of this system only allow an energy threshold similar to that of the previous system. The Wideband Intelligent Trigger (WIT) system will provide sufficient connectivity, storage, and CPU power to completely process the data in the un-triggered, raw stream and extract electrons with high efficiency down to a total energy of 3 MeV, which is the limit of stable and reliable event reconstruction at SK. It operates by evaluating each data block independently in a massively parallel fashion and applying new software algorithms that culminate in a two-stage vertex reconstruction. This procedure reduces the background, the processing time and the final data size to a manageable level. The new low energy threshold will: (1) improve SK's sensitivity to spectral distortions of solar neutrinos due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect, bringing new sensitivity to to the as-yet-unobserved upturn in the solar neutrino spectrum expected from large mixing angle MSW oscillations; (2) provide new functionality by acting as a galactic supernova burst trigger; and (3) by adding Gadolinium to the water, enable SK to detect neutrons with high efficiency, significantly reducing the atmospheric neutrino background to both the observation of proton decay and relic supernova neutrinos. The research supported by this award is an example of how advances in computing can extend the capabilities of existing instruments for basic research, effectively extending the physics reach and leveraging existing investments. The Kamioka Laboratory in Japan has an extensive program for involving the public, undergraduate students and K-12 students in the excitement of physics research. The postdoc and graduate student working on WIT will be integrated into these activities and lectures on the physics that comes from looking at low-energy events in Super-Kamiokande. Undergraduate students from the U.S. will work with this group in Japan during the summer for one to two months to help implement WIT and to help analyze the first data. They will maintain a collaborative relationship with faculty at a local undergraduate institution. They will also participate in the effort by attending Super-Kamiokande collaboration meetings, taking shifts at the experiment and participating in the scientific research.