Barium Chemosensors with Dry-Phase Fluorescence for Neutrinoless Double Beta Decay

Thapa, Pawan; Arnquist, I. J.; Byrnes, N.; Denisenko, A. A.; Foss, Frank W.; Jones, B. J. P.; McDonald, A. D.; Nygren, D. R.; Woodruff, K.

doi:10.48550/arxiv.1904.05901

Cited by 4 publications

(8 citation statements)

References 53 publications

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“…KamLAND-Zen has also found a 7% dead-time from spallation products, the largest source being 137 Xe with (3.9 ± 2.0) × 10 −3 tonne −1 day −1 produced [19]. Finally, it is notable that 137 Xe activation provides a slow but non-zero source of non-double-betadecay related barium production through the chain 137 Xe→ 137 Cs→ 137 Ba, a potentially relevant consideration for barium tagging [20][21][22][23][24][25]. In the NEXT detectors these may be largely rejected by time-coincidence cuts with energy deposits of interest as the Q β for 137 Cs→ 137 Ba is lower than the Q ββ of interest.…”

Section: Cosmogenic Neutron Backgroundsmentioning

confidence: 96%

Mitigation of Backgrounds from Cosmogenic $^{137}$Xe in Xenon Gas Experiments using $^{3}$He Neutron Capture

Rogers,

Jones,

Laing

et al. 2020

Preprint

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136 Xe is used as the target medium for many experiments searching for 0νββ. Despite underground operation, cosmic muons that reach the laboratory can produce spallation neutrons causing activation of detector materials. A potential background that is difficult to veto using muon tagging comes in the form of 137 Xe created by the capture of neutrons on 136 Xe. This isotope decays via beta decay with a half-life of 3.8 minutes and a Q β of ∼4.16 MeV. This work proposes and explores the concept of adding a small percentage of 3 He to xenon as a means to capture thermal neutrons and reduce the number of activations in the detector volume. When using this technique we find the contamination from 137 Xe activation can be reduced to negligible levels in tonne and multi-tonne scale high pressure gas xenon neutrinoless double beta decay experiments running at any depth in an underground laboratory.

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Section: Cosmogenic Neutron Backgroundsmentioning

confidence: 96%

Mitigation of Backgrounds from Cosmogenic $^{137}$Xe in Xenon Gas Experiments using $^{3}$He Neutron Capture

Rogers,

Jones,

Laing

et al. 2020

Preprint

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“…As described in our previous works [14,16,17], our intention is to generate a self-assembled monolayer of barium responsive fluorescent molecules, rather than a set embedded in a thick matrix, as in recent studies. Adding surface-tethering groups for surface monolayer formation can interfere with fluorescence and binding, and thus for the single molecule studies described in the previous section we used molecules with fully formed tether groups attached to the receptor.…”

Section: Construction Of Self Assembled Monolayersmentioning

confidence: 99%

“…The limitations of the FLUO dyes for dry barium sensing include that the receptor uses carboylic acids that must deprotonate to accept dications, and that the fluor undergoes configurational changes between ground and excited states that are suppressed in dry conditions. In Ref [16], we proposed, synthesized and demonstrated custom-made crown-ether derivative fluorophores for dry barium ion sensing. The receptor group 18-crown-6 has shown high selectivity towards barium in the past and does not require deprotonation in order to bind, suggesting promise for dry function.…”

Section: Introductionmentioning

confidence: 99%

“…Our goals in continued chemosensor development beyond Ref [16] include moving from UV to visible excitation; continued improvement of the response difference between a barium sparse and barium enriched sample; re-introduction of photo-bleaching effects; and enhanced selectivity towards barium vs other ions. Specifically, any residual monocation sensitivity would be very problematic for implementation in a gaseous 0νββ experiment due to possible chelation, even at a sub-leading level, with Xe + .…”

Section: Introductionmentioning

confidence: 99%

“…Specifically, any residual monocation sensitivity would be very problematic for implementation in a gaseous 0νββ experiment due to possible chelation, even at a sub-leading level, with Xe + . To this end, we extended the 18c6 family of Ref [16] to include a new molecule, 18c6-nap, built according to the same principles but using naphthalimide as the fluorescent group. The structure of this molecule is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Barium Tagging with Selective, Dry-Functional, Single Molecule Sensitive On-Off Fluorophores for the NEXT Experiment

Byrnes¹,

Denisenko²,

Foss³

et al. 2019

Preprint

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In the search for neutrinoless double beta decay, understanding and reducing backgrounds is crucial for success. An advance that could drive backgrounds to negligible levels would be the ability to efficiently detect the barium daughter in 136 Xe to 136 Ba double beta decay, since no conventional radioactive process can produce barium ions or atoms in xenon at significant rates. In xenon gas, the barium daughter most likely survives as a dication. An approach under development by the NEXT collaboration involves transporting this ion from the active medium onto a coated transparent plane supporting a barium-sensitive fluorescent dye, monitored via fluorescence microscopy. Upon exposure to a barium dication, the dye will begin fluorescing, which, when correlated with the detection of a double electron signal at the anode, would confirm double beta decay. Our results have shown that a single barium ion can be resolved via Single Molecule Fluorescent Imaging (SMFI). The next challenge is a realization of this technique within in a large volume of xenon gas. Significant advances have recently been made: custom barium-tagging molecules that fluoresce strongly in the dry state when exposed to barium have been demonstrated, and devices constructed that can observe fluorescence via in-vacuum or in-gas Total Internal Reflection Fluorescence Microscopy. We present the status of this technique and the outlook for barium tagging with On-Off switchable fluorophores, including new results with a Ba 2+ -selective dye that functions under our desired conditions in the visible region and with single ion sensitivity.

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Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches

Adams¹,

Álvarez²,

Arazi³

et al. 2020

Preprint

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The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless double beta (0νββ) decay of 136 Xe using high-pressure xenon gas TPCs with electroluminescent amplification. A scaled-up version of this technology with ∼ 1 tonne of enriched xenon could reach, in a few years of operation, a sensitivity to the half-life of 0νββ decay better than 10 27 years, improving the current limits by at least one order of magnitude. This prediction is based on a well-understood background model dominated by radiogenic sources. The detector concept presented here represents a first step on a compelling path towards sensitivity to the parameter space defined by the inverted hierarchy, and beyond.

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Barium Chemosensors with Dry-Phase Fluorescence for Neutrinoless Double Beta Decay

Cited by 4 publications

References 53 publications

Mitigation of Backgrounds from Cosmogenic $^{137}$Xe in Xenon Gas Experiments using $^{3}$He Neutron Capture

Mitigation of Backgrounds from Cosmogenic $^{137}$Xe in Xenon Gas Experiments using $^{3}$He Neutron Capture

Barium Tagging with Selective, Dry-Functional, Single Molecule Sensitive On-Off Fluorophores for the NEXT Experiment

Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches

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