Double Beta Decay Experiments With Loaded Liquid Scintillator

Shimizu, I.; Chen, Mark

doi:10.3389/fphy.2019.00033

Cited by 20 publications

(31 citation statements)

References 66 publications

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“…The search for neutrinoless double beta (0νββ) decay is the most promising experimental path to determine whether the neutrino is a Majorana fermion, with far-reaching implications in particle physics and cosmology [1][2][3][4][5]. Presently, several collaborations pursue different technologies for detecting 0νββ decay with the leading experiments focusing on 76 Ge [6][7][8], 136 Xe [9][10][11][12][13][14][15], 130 Te [10,16,17], and 100 Mo [18][19][20]. The long half-life of 0νββ decay (above 1.8 × 10 26 yr in 76 Ge [6] and 1.07 × 10 26 yr in 136 Xe [9]) makes its detection extremely difficult, with only a few candidate 0νββ events expected throughout the running life of an experiment, calling for outstanding background suppression capabilities.…”

Section: Introductionmentioning

confidence: 99%

Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Simón¹,

Ifergan²,

Redwine³

et al. 2021

J. High Energ. Phys.

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Next-generation neutrinoless double beta decay experiments aim for half-life sensitivities of ∼ 1027 yr, requiring suppressing backgrounds to < 1 count/tonne/yr. For this, any extra background rejection handle, beyond excellent energy resolution and the use of extremely radiopure materials, is of utmost importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of NEXT. Previous studies demonstrated a topological background rejection factor of ∼ 5 when reconstructing electron-positron pairs in the 208Tl 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterráneo de Canfranc, with 72% signal efficiency. This was recently improved through the use of a deep convolutional neural network to yield a background rejection factor of ∼ 10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT TPC. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV e−e+ pairs, it leads to a background rejection factor of 27 at 57% signal efficiency.

show abstract

Section: Introductionmentioning

confidence: 99%

Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Simón¹,

Ifergan²,

Redwine³

et al. 2021

J. High Energ. Phys.

View full text Add to dashboard Cite

show abstract

“…The search for neutrinoless double beta (0νββ) decay is the most promising experimental path to determine whether the neutrino is a Majorana fermion, with far-reaching implications in particle physics and cosmology [1][2][3][4][5]. Presently, several collaborations pursue different technologies for detecting 0νββ decay with the leading experiments focusing on 76 Ge [6][7][8], 136 Xe [9][10][11][12][13][14][15], 130 Te [10,16,17], and 100 Mo [18,19]. The long half-life of 0νββ decay (above 1.8 × 10 26 yr in 76 Ge [6] and 1.07 × 10 26 yr in 136 Xe [9]) makes its detection extremely difficult, with only a few candidate 0νββ events expected throughout the running life of an experiment, calling for outstanding background suppression capabilities.…”

mentioning

confidence: 99%

Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Simón,

Ifergan,

Redwine

et al. 2021

Preprint

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Next-generation neutrinoless double beta decay experiments aim for halflife sensitivities of ∼ 10 27 years, requiring suppressing backgrounds to a level of < 1 count/tonne/year. To reach those levels any extra background rejection handle, in addition to excellent energy resolution and the use of extremely radiopure materials, is of utter importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of the NEXT experiment. Previous studies demonstrated a topological background rejection factor of ∼ 5 when reconstructing electron-positron pairs in the 208 Tl 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterráneo de Canfranc, while retaining ∼ 72% of the signal. These results were recently improved through the use of a deep convolutional neural network to yield a background rejection factor of ∼ 10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT time projection chamber. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV electron-positron pairs (at this stage without using deep neural networks), it leads to a background rejection factor of 27 at 57% signal efficiency.C Examples of successful RL-based classification vs. failure of the classical analysis 31

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“…Large neutrino detectors used for oscillation studies based liquid scintillators can also be considered to investigate DBD thanks to the techniques developed for loading nuclei into the liquid scintillator. These types of detectors have poor energy resolution (increasing the leakage of the two-neutrino DBD signal into the neutrinoless peak), but event reconstruction is possible and fiducial volumes can be defined to reduce background [131].…”

Section: Tellurium Dbd Experimentsmentioning

confidence: 99%

Cosmogenic Activation in Double Beta Decay Experiments

Cebrián

2020

Universe

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Double beta decay is a very rare nuclear process and, therefore, experiments intended to detect it must be operated deep underground and in ultra-low background conditions. Long-lived radioisotopes produced by the previous exposure of materials to cosmic rays on the Earth’s surface or even underground can become problematic for the required sensitivity. Here, the studies developed to quantify and reduce the activation yields in detectors and materials used in the set-up of these experiments will be reviewed, considering target materials like germanium, tellurium and xenon together with other ones commonly used like copper, lead, stainless steel or argon. Calculations following very different approaches and measurements from irradiation experiments using beams or directly cosmic rays will be considered for relevant radioisotopes. The effect of cosmogenic activation in present and future double beta decay projects based on different types of detectors will be analyzed too.

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Double Beta Decay Experiments With Loaded Liquid Scintillator

Cited by 20 publications

References 66 publications

Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Cosmogenic Activation in Double Beta Decay Experiments

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