Abstract
The nature of the neutrino is one of the major open questions in experimental nuclear and particle physics. The most sensitive known method to establish the Majorana nature of the neutrino is detection of the ultra-rare process of neutrinoless double beta decay. However, identification of one or a handful of decay events within a large mass of candidate isotope, without obfuscation by backgrounds is a formidable experimental challenge. One hypothetical method for achieving ultra- low-background neutrinoless double beta decay sensitivity is the detection of single 136Ba ions produced in the decay of 136Xe (“barium tagging”). To implement such a method, a single-ion-sensitive barium detector must be developed and demonstrated in bulk liquid or dry gaseous xenon. This paper reports on the development of two families of dry-phase barium chemosensor molecules for use in high pressure xenon gas detectors, synthesized specifically for this purpose. One particularly promising candidate, an anthracene substituted aza-18-crown-6 ether, is shown to respond in the dry phase with almost no intrinsic background from the unchelated state, and to be amenable to barium sensing through fluorescence microscopy. This interdisciplinary advance, paired with earlier work demonstrating sensitivity to single barium ions in solution, opens a new path toward single ion detection in high pressure xenon gas.
Highlights
The search for neutrinoless double beta decay (0νββ) is a major focal point of experimental nuclear physics worldwide
We demonstrated that commercially available calcium chemosensors FLUO-3 and FLUO-4 are sensitive probes for Ba2+, making them potentially promising barium tagging agents[29]
This paper presents the first family of molecules designed for this purpose, experimentally investigating aza-crown ether binding site of various sizes bound through the crown-ether amine to a methyl www.nature.com/scientificreports aromatic fluorophore, creating a benzylic nitrogren “switch” to regulate rigid aromatic fluorophores, pyrene and anthracene
Summary
The search for neutrinoless double beta decay (0νββ) is a major focal point of experimental nuclear physics worldwide. Well-motivated theoretical models involving light neutrino exchange predict that 0νββ could be observed with any lifetime beyond this limit[8,9,10], given present knowledge of neutrino masses and mixing angles Observing such a rare process above experimental background from sources such as detector material gamma rays[11], dissolved radioisotopes[12,13], neutron captures[14], and others is a formidable experimental challenge, requiring deep underground detectors, exquisite radio-purity[15,16,17], and extremely selective signal identification and background rejection methods. As recognized 17 years ago[22], in experiments using the isotope 136Xe, efficient and selective detection of the daughter nucleus 136Ba2+, accompanied by electron energy measurements of precision better than ∼2% FWHM to reject the two- neutrino double beta decay background, could provide an effectively background free approach to search for 0νββ. No sensor capable of direct deployment within the working medium of a running detector has been produced
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
