Speaker
Description
Noble gas detectors are a leading technology in low energy rare-event
search experiments. The dominant source of background in these experiments is induced by radioactive decays of radon (and its daughter nuclides), which emanates from detector materials and distributes in the detection volume.
Thorough material selection and surface cleaning are important
measures against radon emanation. They may be combined with continuous
active radon removal techniques (by adsorption or distillation) to
reach a background level of less than 1 µBq/kg as recently demonstrated
by the XENONnT experiment. But to meet the even more demanding purity
goals of next-generation experiments, novel radon mitigation
techniques are required to complement the existing ones.
We have explored the applicability of surface coatings as barriers
against radon emanation. The approach requires a diffusion-tight, thin
and mechanically stable coating layer, which itself does not contain
radon sources. In the talk I will discuss different coating methods
that have been studied and focus on recent results of the most
promising technique: Electro-deposition of thin copper films. Using a
custom-made stainless steel $^{222}$Rn source produced at the ISOLDE
facility at CERN, a $^{222}$Rn suppression of more than a factor 1000 has
been achieved. Possible applications and future challenges of this
technique will be discussed.
| Submitted on behalf of a Collaboration? | No |
|---|
