Status and prospects of the NEXT experiment J.J. Gómez Cadenas on behalf of the NEXT collaboration Donostia International Physics Center (DIPC) J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 1 / 40
Table of Contents Desperately seeking Majorana 1 Neutrino Experiment with a Xenon TPC (NEXT) 2 NEXT White (NEW) 3 Background measurement in NEXT-White 4 NEXT-100 5 NEXT-2.0 6 Summary and outlook 7 J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 2 / 40
Table of Contents Desperately seeking Majorana 1 Neutrino Experiment with a Xenon TPC (NEXT) 2 NEXT White (NEW) 3 Background measurement in NEXT-White 4 NEXT-100 5 NEXT-2.0 6 Summary and outlook 7 J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 3 / 40
Majorana’s challenge Today: T 0 ν 1 / 2 ∼ 10 26 yr . “Good luck case”: if T 0 ν 1 / 2 ∼ 10 27 yr , observe 3 signal events (per ton and year) for m ββ ∼ 15 meV . “Tough luck case”: if T 0 ν 1 / 2 ∼ 10 28 yr , observe 0.5 signal events (per ton and year) for m ββ ∼ 15 meV . Bottom line: To explore IO exposures in the range of ton (tens of ton) year needed and virtually background free detectors . A. Giuliani, Neutrino 2018 J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 4 / 40
Table of Contents Desperately seeking Majorana 1 Neutrino Experiment with a Xenon TPC (NEXT) 2 NEXT White (NEW) 3 Background measurement in NEXT-White 4 NEXT-100 5 NEXT-2.0 6 Summary and outlook 7 J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 5 / 40
What is NEXT? A HPXe: High pressure gas chamber (10-20 bar) with EL amplification of the signal. Uses xenon, a noble gas (source = detector) with relatively high Q ββ and no long-lived radioactive isotopes. An optical TPC: all signals are light. Primary scintillation (S1) gives t 0 (needed to fiducialize the event and to correct for finite electron lifetime), EL amplification gives S2, which is used to measure energy and to reconstruct the electron trajectory. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 6 / 40
NEXT assets Topological signal , capable to separate signal “double electrons”, from backgrounds “single electrons”. Excellent energy resolution , 20 keV at Q ββ . Possibility to identify Ba ++ produced in 136 Xe → Ba ++ + 2e (+ 2 ν ) , through SMFI. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 7 / 40
The NEXT program J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 8 / 40
Table of Contents Desperately seeking Majorana 1 Neutrino Experiment with a Xenon TPC (NEXT) 2 NEXT White (NEW) 3 Background measurement in NEXT-White 4 NEXT-100 5 NEXT-2.0 6 Summary and outlook 7 J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 9 / 40
NEXT White (NEW) J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 10 / 40
J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 11 / 40
J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 12 / 40
Goals of NEW Demonstrate technology is robust. Demonstrate energy resolution and topological signature. Measure backgrounds to establish a reliable background model (and to improve it as needed). J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 13 / 40
Operation of NEW Taking data since 2016. Very stable operation since 2017. Less than 1 gram of gas lost per year. Very high lifetime, measured on a daily basis with Krypton calibrations. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 14 / 40
NEW energy resolution J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 15 / 40
NEW topological signature J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 16 / 40
Blob analysis , in 208 Tl double escape peak shows good agreement data/MC. DNN analysis , optimizes separation signal/background. Shown MC prediction: 90 % signal efficiency 10% background contamination. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 17 / 40
Table of Contents Desperately seeking Majorana 1 Neutrino Experiment with a Xenon TPC (NEXT) 2 NEXT White (NEW) 3 Background measurement in NEXT-White 4 NEXT-100 5 NEXT-2.0 6 Summary and outlook 7 J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 18 / 40
Background measurements (Run IV, 2018) Figure: Fiducial background rate for Run IV (2018) as a function of data taking calendar day. Vertical dashed lines mark the times where Run-IVa, Run-IVb and Run-IVc started. Run IVa . No radon free air, no inner shielding. Run IVb . Radon free air. Run IVc . Radon free air and inner shielding J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 19 / 40
Background composition Figure: Contribution of the dominant background isotopes to NEXT-White radioactive budget. Notice, only 214 Bi and 208 Tl relevant for ββ 0 ν searches. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 20 / 40
Run V (enriched xenon) Figure: We really have enriched xenon... J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 21 / 40
Measurement of ββ 2 ν mode (Run V) Figure: Energy spectra, Run V. Notice, Run V just started (15 days taking data with enriched xenon). Will run until the end of the year to provide a measurement of ββ 2 ν lifetime. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 22 / 40
High energy spectrum with topological cuts Figure: Energy spectra with topological cuts data and MC. Topological cut cleans high energy region where signal is expected (notice the hole). One candidate event found in the data by basic topological analysis (visual inspection shows badly reconstructed single electron event). J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 23 / 40
Table of Contents Desperately seeking Majorana 1 Neutrino Experiment with a Xenon TPC (NEXT) 2 NEXT White (NEW) 3 Background measurement in NEXT-White 4 NEXT-100 5 NEXT-2.0 6 Summary and outlook 7 J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 24 / 40
NEXT-100 Scales up NEXT-White by roughly 2:1 in dimensions. Currently in construction. Commissioning in 2020. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 25 / 40
Next-100 radioactive budget Expected background rate , 4 × 10 − 4 counts / ( keV · kg · y ) . Expected background , 1 event per year in ROI. Dominant source PMTs. J.J. Gómez Cadenas on behalf of the NEXT collaboration (Donostia International Physics Center (DIPC)) Status and prospects of the NEXT experiment March, 19, 2019 26 / 40
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