Rn removal system for Xe-based detectors using resonant ionization

氡是低能实验中的主要背景源之一。因此，在未来针对暗物质和无中微子双β衰变的大规模氙气探测器中抑制氡事件是至关重要的。虽然利用蒸馏从氙气中去除Ar和氪是很好的方法，但由于所有材料都不断地释放出氡，所以这项技术不能使用。我们提出了一种利用共振增强多光子电离过程去除氙气的新方法。可调谐激光通过共振单光子或多光子吸收将氡原子提升到电子激发态，然后通过引入另一个光子使这些激发的氡原子电离。用这种方法可以选择性地电离氡杂质并在外加电场的作用下除去。在这项研究中，我们成功地论证了这一原则。

Radon is one of the major background sources in low energy experiments. Accordingly it is essential to suppress radon events in future large-scale xenon detectors aiming for dark matter and neutrino-less double beta decay. Although the removal of argon and krypton from xenon is well established using distillation, because radon is continuously emanated from all the materials, the technique cannnot be used. We propose a new radon removal method for xenon using a resonance-enhanced multiphoton ionization process. A tunable laser is used to promote radon atoms to an electronically excited state via resonant single- or multiple-photon absorption and these excited radon atoms are then ionized by the introduction of another photon. With this method radon impurities can be selectively ionized and removed with an applied electric field. In this study, we have successfully demonstrated this principle.