Michel Sorel
The NEXT experiment at the LSC
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a next
LSC
Laboratorio Subterráneo de Canfranc
Jornadas sobre los proyectos científicos del IFIC
January 2017
NEXT experiment
• What: search for the neutrinoless double beta decay (ββ0ν) of 136Xe
• Neutrino identity (Majorana vs Dirac), neutrino mass, lepton number violation
• How: time projection chamber filled with high-pressure (10-15 bar) xenon gas
• Where: Laboratorio Subterraneo de Canfranc
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a next
LSC
Laboratorio Subterráneo de Canfranc
Autónoma Madrid • Girona • IFIC Valencia • Politécnica Valencia • Santiago de Compostela ANL • FNAL • Iowa State • Ohio State • Texas Arlington • Texas A&M
Coimbra GIAN • Coimbra LIP • Aveiro JINR A. Nariño
Spokespersons: J.J. Gomez Cadenas (IFIC), D. Nygren (UTA)
• Who:
NEXT-IFIC
Group members
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SENIOR Juan Jose Gómez Cadenas Pau Novella
Michel Sorel
POSTDOCS
Paola Ferrario
Neus Lopez March Andrew Laing
Josh Renner
PhD STUDENTS
Jose Maria Benlloch Ryan Felkai
Javier Muñoz Miquel Nebot Brais Palmeiro Javier Perez Luis Serra Ander Simón
ENGINEERS &
TECHNICIANS
Vicente Álvarez Sara Cárcel
Jose Vicente Carrion Alberto Martínez
Jose Manuel Monserrate Mafalda Musti
Marc Querol Javier Rodríguez Jordi Torrent
ADMINISTRATIVE
ASSISTANT Jose Perez
OTHER IFIC SENIOR MEMBERS COLLABORATING WITH NEXT
Anselmo Cervera José Diaz
Carlos Peña Garay Nadia Yahlali
NEXT-IFIC
Current funding
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GRANT REF. PERIOD AMOUNT (MEUR) PIs
PROMETEO 2016/120 2016-2019 0.30 J.J. Gomez Cadenas
PLAN NACIONAL FIS2014-53371-C4-1-R 2015-2018 0.74 J.J. Gomez Cadenas M. Sorel
ERC-AdG 339787 2014-2019 2.79 J.J. Gomez Cadenas
SEVERO OCHOA SEV-2014-0398 2015-2019 J.J. Hernandez Rey
• NEXT project started in 2008 thanks to CONSOLIDER grant. Ended in 2015
• Currently, grants from Generalitat Valenciana, MINECO and particularly EU
• Personnel, equipment, travel
• Important personnel support from IFIC’s Severo Ochoa “umbrella” grant
Double beta decay
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•Rare (Z,A)→(Z+2,A) nuclear transition, with emission of two electrons
n1
n2
e-
e- ν̅
ν̅
Two neutrino mode
•Observed in several nuclei
•1019-1021 yr half-lives
•Standard Model allowed
n1
n2
e- e-
ν ν
Neutrinoless mode
•So far unobserved
•>1026 yr half-lives
•Would signal BSM physics
• ββ0ν would imply Majorana neutrinos and lepton number violation
• Under some assumptions, ββ0ν rate can also constrain neutrino mass:
1/T
1/20ν= G
0ν⋅ ⎜ M
0ν⎜
2⋅ m
ββ2 Majorana ν mass:mββ ≡ ⎜∑i mi Uei2⎜ State with e mass mi
μ τ
|Uei|2
Observables for ββ0ν discovery
Rare process to be isolated in radio-pure detector underground
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2.Topology of decay electrons (AN ADDITIONAL HANDLE):
•
Two electrons from common vertex3.Daughter ion tagging (A “DREAM”):
•
Observe ion produced in the decay 1.Calorimetry (A MUST):•
2ν mode: continuous spectrum for sum electron kinetic energy T1+T2•
0ν mode: mono-energetic line at Qββ for T1+T2 spectrumCurrent status of ββ0ν searches
(eV) 7 lightest
m
−4
10 10−3 10−2 10−1
3
10−
−2
10
1
10−
1
IH
NH
136Xe) KamLAND-Zen (
A
50 100 150
Ca
Ge Se Zr
Mo CdTe
Te
Xe Nd
(eV)m
Experiment Isotope Exposure
(kg⋅yr)
T1/20ν Sensitivity (1025 yr)
T1/20ν Limit (1025 yr)
mββ Limit (meV)
GERDA 76Ge 27.9 4.0 5.2 160 - 260
CUORE 130Te 29.6 0.4 0.4 260 - 630
EXO-200 136Xe 100.0 1.9 1.1 190 - 450
KamLAND-Zen 136Xe 504 5.6 9.2 60-160
NEXT innovative detection concept
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Idea #2:
Use electroluminescence (EL) as nearly noiseless amplification for ionisation
Idea #3:
EL light used for separated energy and tracking measurements
Idea #4:
Energy sensors detect also primary scintillation for t0 determination
170 ➞430 nm light with TPB waveshifter Idea #5:
Use a xenon gas TPC Idea #1:
ENERGY PLANE (PMTs) TRACKING PLANE (SiPMs)
CATHODE ANODE
scintillation (S1)
e-
e- e- e- e-
e-
electroluminescence (S2)
xenon gas
TPB coated surfaces
ionization
NEXT detector strengths
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Cost and Scalability
(Least Expensive ßß Isotope) (Source = detector)
Energy Resolution
Topological Signature
| m | 2 < K
✏
r E · B M t
Sensitivity to 0vßß
NEXT phases
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Prototypes (~1 kg) [2009 - 2014]
NEXT-NEW (~10 kg) [2015 - 2018]
NEXT-100 (~100 kg) [2018 - 2020’s]
NEXT-tonne (~1000 kg) [future generation]
Demonstration of detector concept
Underground and radio-pure operations, background, ββ2ν
Neutrinoless double beta decay search
Recent achievements
Energy resolution with 1 kg prototypes
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• 1.1% FWHM resolution for 662 keV electrons
• 1.6% FWHM resolution for 511 keV electrons
Calibrated S2 Charge (keV) 600 610 620 630 640 650 660 670 680 690 700
Counts per keV
0 20 40 60 80 100
120 NIM A708 (2013) 101 1.1% FWHM
Data
Photoelectric
X-ray escape
NEXT-DBDM
NEXT measurements extrapolate to 0.5-0.7% FWHM energy resolution at Qββ
Na22
Entries 341932 Mean 304.2 RMS 181.8
Energy (keV)
0 100 200 300 400 500 600
Entries/bin
0 500 1000 1500 2000 2500 3000 3500
4000 Na22
Entries 341932 Mean 304.2 RMS 181.8
X-ray escape Compton
X-ray
Photoelectric JINST 9 (2014) P10007
NEXT-DEMO Data
Recent achievements
Tracking capabilities with 1 kg prototypes
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• Require identification of two Bragg peaks for ββ candidate events
• Validated with calibration data
Background rejection
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Signal efficiency
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Data MC
JHEP 8 1601 (2016) 104
Data
Energy in blob 1 (keV)
0 200 400 600 800 1000 1200 1400
Energy in blob 2 (keV)
0 200 400 600 800 1000 1200 1400
0 10 20 30 40 50 60 70
Blob energies
X (mm)
-60 -40 -20 0 20 40 60
Y (mm)
-60 -40 -20 0 20 40 60
X (mm)
40 60 80 100 120 140 160
Y (mm)
-100 -80 -60 -40 -20 0 20
✔
✔ ✔
✘
SIGNALSIGNAL BACKGROUND
Energy in blob 1 (keV)
0 200 400 600 800 1000 1200 1400
Energy in blob 2 (keV)
0 200 400 600 800 1000 1200 1400
0 5 10 15 20 25 30
Blob energies
X (mm)
-60 -40 -20 0 20 40 60
Y (mm)
-60 -40 -20 0 20 40 60
X (mm)
40 60 80 100 120 140 160
Y (mm)
-100 -80 -60 -40 -20 0 20
✔
✔ ✔
✘
SIGNAL BACKGROUNDBACKGROUND
MC
NEW detector overview
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Mother can:
12 cm copper plate that separates pressure from vacuum and adds shielding.
Pressure vessel:
316-Ti steel, 30 bar max pressure
Inner shield:
copper, 6 cm thick Time Projection Chamber:
5 kg active region(@15bar), 50 cm drift length
Energy plane:
12 PMTs,
operating at vacuum.
30% coverage Tracking plane:
1,800 SiPMs, 1 cm pitch
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Recent achievements
NEW construction
Recent achievements
NEW installation at the LSC
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Recent achievements
NEW commissioning and first results
• After much work, NEW is up and running (Xe-136 depleted) Xenon since Oct 2016
• Current focus: detector calibration and performance with radioactive sources, upgrades to improve operational stability and radiopurity
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Map of Kr-83 events (42 keV) Single electron from Na-22 (511 keV)
NEXT in 2017-2018
NEW program
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Run period Configuration Goals
2016-2017 Depleted Xe Calibration, energy resolution, topological rejection 2017 Depleted Xe Background rate and energy spectrum
2018 Enriched Xe ββ2ν rate
Energy (MeV)
0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8
Events / 20 keV
1 10 102
103
Exp. 1.88 yr, Events 29896.8
60Co
40K
214Bi
208Tl
136Xe
ββ event selection
MC NEW
Qββ
ββ2ν signal
Energy (MeV)
0 0.5 1 1.5 2 2.5 3
FWHM Energy Resolution (%)
0 0.1 0.2
0.3 0.4 0.5 0.6 0.7 0.8
MC NEW
Na-22 (1.28 MeV)
Tl-208 (1.59 MeV)
Tl-208 (2.61 MeV)
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Pressure vessel:
stainless steel,15 bar max pressure
Inner shield:
copper, 12 cm thick Time Projection Chamber:
100 kg active region, 130 cm drift length
Outer shield:
lead, 20 cm thick Energy plane:
60 PMTs, 30% coverage
Tracking plane:
7,000 SiPMs, 1 cm pitch
NEXT in 2019–2022
NEXT-100 installation and operations
NEXT-100 physics reach versus state-of-the-art
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Experiment Exposure (kg⋅yr) Background events in ROI ROI width (keV)
EXO 100 31.1 (measured) 150 (±2σ)
KamLAND-Zen 504 32.1 (measured) 400
NEXT 300 2.2 (expected) 19 (FWHM)
• NEXT: lower exposure, but lower background than KamLAND-Zen (energy, tracking)
• Comparable sensitivities with different approaches → mutually indispensable searches
Equivalent exposures:
• 300 kg⋅yr (NEXT) 650 kg⋅yr (K-Zen)
• 600 kg⋅yr (NEXT) 1600 kg⋅yr (K-Zen)
year) Exposure (kg ⋅
0 500 1000 1500 2000
years)26 (10 1/2T
0 0.5 1 1.5
Ba + 2 e-
→ 136 136Xe
KamLAND-Zen 2016 Limit KamLAND-Zen 2013 Limit EXO-200 2014 Limit
NEXT-100 Sensitivity KamLAND-Zen Sensitivity
NEXT-100 sensitivity may exceed expectations:
• Lower radioactivity than assumed
• Improved reconstruction
Ton-scale detector and need for R&D
NEXT-100 and beyond
years)
⋅ Exposure (ton
10-1 1 10
(meV) ββm
10 102
Inverted ordering,
mlight∼0
10 bgr counts/(ton
⋅yr)
1
0.1 bgr fr
ee NEXT-100
Goal:
15 meV
• Strong support worldwide to build 2-3 tonne-scale experiments
• Tonne-scale detector necessary but not sufficient requirement to reach 15 meV
• NEXT: need 1-2 orders of magnitude background reduction wrt NEXT-100
• R&D on active background reduction techniques
• Low-diffusion gas mixtures
• Barium tagging via Single Molecule Fluorescence Imaging
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Summary
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Dec. 23, 2016
Dr. Aldo Ianni
Director, Laboratorio Subterráneo de Canfranc Paseo de los Ayerbe S/N
22880 Canfranc Estacion Huesca, Spain Dear Dr. Ianni,
In this letter, I want to express my strong support for the NEXT experiment.
As is well known, physics of massive neutrinos is related to the physics of “beyond the Standard Model” of particle physics. In particular, in my opinion, neutrino-less double beta decay is the most important phenomenon to be discovered in the near future.
Neutrino-less double beta decays are expected to occur if neutrinos are Majorana particles, namely if neutrinos and anti-neutrinos are the same particles. The discovery of neutrino-less double beta decays is really the key to understand the smallness of the neutrino masses, and therefore the key to understand the “beyond the Standard Model”
physics. Furthermore, we expect that we might be able to understand the big mystery of the Universe, namely we may understand why the present Universe is dominated by matter.
The NEXT experiment is aiming to search for neutrino-less double beta decay using 136Xe.
NEXT is a unique experiment that can measure the tracks of beta particles. In addition, NEXT has a very good energy resolution. These features are very important for the measurement of neutrino-less double beta decays. NEXT is already demonstrated its high performance with the prototype detector. Therefore, I believe that it is time to move on to the planed experiment with a much larger detector with much more 136Xe. I very strongly support realizing the planed NEXT experiment.
Best regards,
Takaaki Kajita
Director, Institute for Cosmic Ray Research, The University of Tokyo
NEXT addresses key open questions in particle physics, has a large discovery potential, and is a rare opportunity for Spanish science
a next
LSC
Laboratorio Subterráneo de Canfranc
Backup slides
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NEXT-IFIC outreach activities
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• Students: regular school visits to NEXT laboratory at IFIC
• Local community: contributions to the yearly Open Day of the Parc Cientific
• Media: regular contributions to Jot Down Cultural Magazine and others
Actividades para estudiantes
Visitas guiadas al IFIC
868 visitantes de 40 centros (+40% sobre 2015)
Visitas especiales de Grados de la UV, Universidad Europea de Valencia (IFIMED), Grupo La
Esperanza, VLC Campus, Instituto #1517
Charlas en IES
Más de 30 charlas
15 miembros del IFIC involucrados
Más de 1500 estudiantes
CUP CONSOLIDER grant
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• CUP: Canfranc Underground Physics
• CUP (5 MEUR), plus LSC support, allowed us to start the NEXT project in 2008
• We have recently received the CUP final evaluation report:
LSC Scientific Committee
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“The committee congratulates with the NEXT collaboration as it was capable of respecting the schedule presented in the last meeting about the commissioning of the NEW detector. All the components of the set-up are in place. The NEXT team has been operating the detector with Xe gas at 7 bars for about two months, presenting very preliminary but encouraging data on energy resolution and tracking. In particular, X-ray data and krypton calibration already show that the target energy resolution (1% FWHM) in the region of interest can be reached. The collaboration showed also a first reconstructed electron track from a Na-22 source.”
• The LSC Scientific Committee has been essential to advise NEXT through the many technological and scientific challenges
• Outcome of NEXT reviews by this committee has generally been very positive
• Extracted from the last LSC Scientific Committee Meeting Report (Dec 2016):
