MRI: Development of a Superconducting Magnet Coil and a 201 MHz RF Cavity for Testing Muon Ionization Cooling Techniques

这一建议是为了测试技术所需的仪器开发，以推进μ子电离冷却实验（MICE）。在粒子物理学领域，人们对使用粒子加速器来形成非常强烈的高能μ介子束越来越感兴趣。1937年发现的介子是一种亚原子粒子，比电子的质量更大，它与物质的相互作用简单而又容易理解，这使它成为一种有用的探针，用于一系列目的。然而，到目前为止，由于μ子的平均寿命很短，只有2.2微秒，所以不可能加速μ子。证明介子加速器可行性的关键步骤是介子电离冷却实验（MICE）。加速强μ子光束的主要障碍是，这种光束太大，无法放入同步加速器的典型真空室，而且μ子的寿命很短，几乎没有时间充分收缩和加速光束。电离冷却是一种快速收缩或冷却介子束的新技术。在这个过程中，一束μ子穿过选定的材料，通过电离附近的原子而失去能量。这些相互作用降低了介子速度的三个组成部分：水平、垂直和纵向。然后，μ子束被射频腔加速，只取代μ子的纵向速度分量。由于水平和垂直分量越来越少，同时保持纵向分量，μ子轨迹变得更接近平行，从而允许聚焦磁体大大减小光束的尺寸。这项提议的广泛影响包括密西西比大学的学生和当地的QuarkNet教师，他们将参与其中，并将使用声学传感器来定位和表征射频腔中的火花（电击穿）。μ子冷却的发展可能导致建立中微子工厂，并在轻子扇区发现CP违逆。轻子CP违逆很可能导致宇宙中的重子-反重子不对称。来自中微子工厂的中微子束可能会瞄准美国国家科学基金会深层地下科学与工程实验室（DUSEL）的探测器。这将给美国一个一流的物理项目来理解宇宙和培养学生。

This proposal is for instrumentation development needed to test techniques to advance the Muon Ionization Cooling Experiment (MICE). In the field of particle physics, there is increasing interest in using particle accelerators to form very intense beams of high-energy muons. Discovered in 1937, the muon, a more massive cousin of the electron, is a subatomic particle, whose simple and well-understood interactions with matter make it a useful probe for a range of purposes. Until now, however, due to its short average lifetime of 2.2 microseconds, it has not been possible to accelerate muons. The key step in demonstrating the feasibility of muon accelerators is the Muon Ionization Cooling Experiment (MICE). The main obstacle to accelerating an intense muon beam is that such beams are created too large to fit into the typical vacuum chamber of a synchrotron and the short muon lifetime leaves little time to adequately shrink and accelerate the beam. Ionization cooling is a new technique to shrink, or cool a muon beam quickly. In this process, a beam of muons passes through selected material in which it loses energy by ionizing nearby atoms. These interactions reduce all three components of a muons velocity: horizontal, vertical, and longitudinal. The muon beam is then accelerated by radio-frequency cavities, replacing only the longitudinal velocity component of the muons. As the horizontal and vertical components are increasingly reduced while the longitudinal component is maintained, the muons trajectories become more nearly parallel, allowing focusing magnets to substantially reduce the size of the beam.The broader impacts of this proposal includes University of Mississippi students and local QuarkNet teachers who will be involved and will use acoustic sensors to locate and characterize sparking (electrical breakdown) in the RF cavity. Development of muon cooling could lead to building a neutrino factory and discovering CP violation in the lepton sector. Lepton CP violation may quite possibly cause the baryon-antibaryon asymmetry in the universe. A neutrino beam from a Neutrino Factory might be aimed at a detector in the National Science Foundation Deep Underground Science and Engineering Laboratory (DUSEL). This would give the United States a first rate physics project for understanding the universe and for training students.