Muon Ionisation Cooling Experiment

Muon电离冷却实验(MICE)正试图证明电离冷却，即降低带电粒子束的发射度。发射度是光束在位置相空间和动量相空间中所占的体积。在电离冷却过程中，带电粒子束通过一系列的吸收体和射频(RF)腔。吸收体，如液氢或氢化锂，降低了粒子的总动量，而射频腔沿着光束运动方向的轴重新加速粒子。这一过程补充了光束的纵向动量，但降低了横向动量。因此，束的发射度降低了。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、中微子质量和质量等级，以及中微子是否为Majorana粒子。要为中微子工厂探测器创建足够强度的Muon束，需要有足够密度的Muon束。然而，µ子束的寿命短得令人难以置信(2.2秒)。介子束是由高度分散的介子束衰变而成的。介子束是高度分散的，因为它是由质子束对目标的轰击而产生的。目前的限制技术不能在Muon的寿命内产生足够密度的Muon束；然而，电离冷却可以做到这一点。MICE使用一些探测器来识别实验中传播的粒子(介子、Muon、电子)，如飞行时间系统、切伦科夫计数器、Kloe光和电子Muon Ranger。这个项目将考察粒子识别系统的有效性。MICE还使用了两个螺线管光谱仪，每个光谱仪有五个闪烁的光纤站，其中包含粒子束，并跟踪通过它的粒子的运动。需要对各种实验的结果进行广泛的分析，以确定电离冷却的有效性和精确度。例如，在这个项目中，将探索磁体中光学像差(例如球面、色差)导致的发射生长。

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.