Muon Ionisation Cooling Experiment

μ子电离冷却实验（MICE）正试图证明电离冷却，即减少带电粒子束的发射度。发射度是光束在位置和动量相空间中所占的体积。在电离冷却期间，带电粒子束通过一系列吸收器和射频（RF）腔。吸收剂，如液氢或氢化锂，减少粒子的总动量，而射频腔沿着光束运动方向的轴重新加速粒子。这个过程补充了梁的纵向动量，但减少了横向动量。这样，光束的发射度就降低了。电离冷却背后的主要动机之一是未来中微子实验的可能性，以分析中微子振荡，中微子质量和质量层次，以及中微子是否是马约拉纳粒子。为中微子工厂的探测器创造足够强度的μ子束需要足够密度的μ子束。然而，介子束的寿命非常短（2.2秒）。介子束是由高度分散的介子束衰变产生的。介子束是高度分散的，因为它是由质子束轰击目标产生的。目前的约束技术无法在μ子的生命周期内产生足够密度的μ子光束；然而，电离冷却将允许这一点。MICE使用许多探测器来识别在实验中运动的粒子（介子，介子，电子），如飞行时间系统，切伦科夫计数器，克洛光和电子介子游侠。粒子识别系统的有效性将在本项目中进行研究。MICE还使用了两个螺线管光谱仪，每个都有五个闪烁的光纤站，其中包含粒子束并跟踪穿过它的粒子的运动。进行的各种实验的结果需要进行广泛的分析，以确定电离冷却的有效性和精确度。例如，由于磁体的光学像差（如球面、色差）而导致的发射度增长将在本项目中进行探索。

The Muon Ionisation Cooling Experiment (MICE) is trying to demonstrate ionisation cooling, that is a reduction in the emittance of a charged particle beam. The emittance is the volume occupied by a beam in position and momentum phase space. During ionisation cooling the charged particle beam is passed through a series of absorbers and radio-frequency (RF) cavities. The absorbers, such as liquid Hydrogen or Lithium Hydride, reduce the overall momentum of the particles, while the RF cavities reaccelerate the particles along the axis of the direction of motion of the beam. This process replenishes the longitudinal momentum of the beam but reduces the transverse momentum. Thus, the emittance of the beam has been reduced.One of the main motivations behind ionisation cooling is the possibility of future neutrino experiments to analyse neutrino oscillations, neutrino masses and the mass hierarchy and whether the neutrino is a Majorana particle.To create a muon beam of sufficient intensity for neutrino factory detectors requires a muon beam of sufficient density. However, the muon beam has an incredibly short lifetime (2.2s). The muon beam is created from the decay of a highly dispersed pion beam. The pion beam is highly dispersed as it has been created from the bombardment of a proton beam against a target. Current confinement techniques are not able to create muon beams of sufficient density within the lifetime of the muon; however, ionisation cooling would allow for this.MICE uses a number of detectors to identify the particles travelling in the experiment (pions, muons, electrons) such as Time-of-Flight systems, Cherenkov counters, Kloe Light and an electron Muon Ranger. The effectiveness of the Particle Identification system will be looked at in this project.MICE also uses two solenoidal spectrometers, each having five scintillating fibre stations which contain the particle beam and track the motion of the particles travelling through it. The results from the various experiments carried out need to be extensively analysed to determine the effectiveness of ionisation cooling and to what accuracy. For example, the emittancegrowth due to optical aberrations (e.g spherical, chromatic) in the magnets will be explored during this project.