In this work, carbon $^{14}$C and Tritium were considered as possible background source in the XENON1T experiment. The simulation results show that if $^{14}$C is located in dust particles with a characteristic size of tens of micrometers, then its beta spectrum is softened and can contribute to the low-background part of the spectrum (up to 20 keV) of the XENON1T experiment. In addition, it has been shown that the tritium spectrum is also significantly distorted due to the threshold effect and the form in which tritium is living in xenon. Comparison of the simulation results with experimental data allowed us to estimate the activity level of $^{14}$C at about 1500 decays / t / year, which gives the level of organic impurities containing $^{14}$C at the level of 2x10$^{-13}$ g/g. In the case of tritium background, spectrum distortions are already caused by nanoparticles. Wherein the shape of the spectrum from tritium sitting on the surface of the dust fits better into the experimental data than the spectrum from pure tritium. In addition, since the dust absorbs part of the decays, the total amount of tritium in xenon can be several times greater than assuming a background from pure tritium in xenon (the factor strongly depends on the size of the dust particles).
Stochastic Heating by ECR as a Novel Means of Background Reduction in the KATRIN Spectrometers
KATRIN实验的主要目标是探测绝对中微子质量标度，灵敏度为200 meV（90% C. L.）。通过精确的氚β衰变光谱学为了达到这个目的，在氚β衰变终点区域需要10 ^（-2）cps量级的低本底。用静电减速谱仪进行的测量表明，在谱仪的体积中由核衰变产生的电子被长时间储存，从而作为超过该极限的本底的主要来源。在本文中，我们提出了一种新的主动本底降低方法的基础上随机加热的存储电子的众所周知的过程中的电子回旋共振（ECR）。在KATRIN预光谱仪的测试测量中，ECR技术的原理证明是成功的，从而大大降低了背景速率。此外，我们已经进行了广泛的蒙特卡罗模拟，以揭示潜在的ECR技术，以消除所有被困的电子在主光谱仪的测量时间可以忽略不计的损失。这将使KATRIN实验充分发挥其物理潜力。
Monitoring the tagging efficiency of the Low-Energy Muon beamline through background analysis: Insights into the long-term performance of ultrathin carbon foils
PSI Center for Neutron and Muon Sciences CNM（瑞士保罗谢勒研究所中子与μ子科学中心）；Department of Physics, University of Basel（巴塞尔大学物理系）
