vIOLETA

Neutrino Interaction Observation with a Low Energy Threshold Array

a Reactor Neutrino Experiment based on Skipper-CCD technology

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Physics Goals

CEvNS

Coherent Elastic Neutrino Nucleus Interaction (CEvNS) was observed for the first time in 2017 [arXiv:1708.01294]. The exposure time required for vIOLETA to observe the CEvNS at a 95 % of confidence level at Atucha II Power Plant will be just a couple of days.

Neutrino Magnetic Moment

Neutrino Magnetic Moment (NMM) is one of the key neutrino's property since it would allow to disentangled the still unknown Majorana or Dirac neutrino's nature. Besides, NMM strongly depends on the Beyond Standard Model (SM) scenario chosen.

Light Vector Mediators

Light Vector Mediator Models can be strongly constrained in a Short Baseline Neutrino Experiment using a Low Energy Threshold Array as the Skipper-CCD technology can offer, since their cross section increase as the inverse of the squared of the recoil energy.

Projected Sensitivities

CEvNS - The large number of opportunities to study non-standard neutrinos interaction in the low energy range –below the inverse beta decay process– along with the observation of the CEvNs interaction, have witnessed a growing interest during the last years. In this contest, we propose a short baseline reactor neutrino experiment to cover three orders of magnitude of unexplored energy range for neutrino interaction using 10 kg of Skipper-CCD detectors with an energy threshold of approximately 1 eV. We discuss constraints to the SM and also benchmark beyond SM. In particular, we claim that our prospective for the exposure time required for observing the CEvNs at a 90% of confidence level at one of the most powerful nuclear reactors available in Argentina is only 1.5 days
Measuring the weak mixing angle - We analyze in detail the physics potential of an experiment like the one recently proposed by the vIOLETA collaboration: a kilogram-scale Skipper CCD detector deployed 12 meters away from a commercial nuclear reactor core. This experiment would be able to detect coherent elastic neutrino nucleus scattering from reactor neutrinos, capitalizing on the exceptionally low ionization energy threshold of Skipper CCDs. To estimate the physics reach, we elect the measurement of the weak mixing angle as a case study. We choose a realistic benchmark experimental setup and perform variations on this benchmark to understand the role of quenching factor and its systematic uncertainties,background rate and spectral shape, total exposure, and reactor antineutrino flux uncertainty. We take full advantage of the reactor flux measurement of the Daya Bay collaboration to perform a data driven analysis which is, up to a certain extent, independent of the theoretical uncertainties on the reactor antineutrino flux. We show that, under reasonable assumptions, this experimental setup may provide a competitive measurement of the weak mixing angle at few MeV scale with neutrino-nucleus scattering.
Neutrino Magnetic Moment - This spectra present all the contributions where NMM is measured. At very low energy, the number of events expected by CEvNS are pretty similar to the one expected by background, it is around 1 kdru. Thus, this channel twice the competing signal events summing up electron and nucleus contributions. By contrast, weak interaction produced a negligible number of events at such low energies. As a result we get a Bayesian upper limit as good as 10^-11 Bohr magneton after running vIOLETA for 3 years.
Light Vector Mediator

CEvNS - The large number of opportunities to study non-standard neutrinos interaction in the low energy range –below the inverse beta decay process– along with the observation of the CEvNs interaction, have witnessed a growing interest during the last years. In this contest, we propose a short baseline reactor neutrino experiment to cover three orders of magnitude of unexplored energy range for neutrino interaction using 10 kg of Skipper-CCD detectors with an energy threshold of approximately 1 eV. We discuss constraints to the SM and also benchmark beyond SM. In particular, we claim that our prospective for the exposure time required for observing the CEvNs at a 90% of confidence level at one of the most powerful nuclear reactors available in Argentina is only 1.5 days

Measuring the weak mixing angle - We analyze in detail the physics potential of an experiment like the one recently proposed by the vIOLETA collaboration: a kilogram-scale Skipper CCD detector deployed 12 meters away from a commercial nuclear reactor core. This experiment would be able to detect coherent elastic neutrino nucleus scattering from reactor neutrinos, capitalizing on the exceptionally low ionization energy threshold of Skipper CCDs. To estimate the physics reach, we elect the measurement of the weak mixing angle as a case study. We choose a realistic benchmark experimental setup and perform variations on this benchmark to understand the role of quenching factor and its systematic uncertainties,background rate and spectral shape, total exposure, and reactor antineutrino flux uncertainty. We take full advantage of the reactor flux measurement of the Daya Bay collaboration to perform a data driven analysis which is, up to a certain extent, independent of the theoretical uncertainties on the reactor antineutrino flux. We show that, under reasonable assumptions, this experimental setup may provide a competitive measurement of the weak mixing angle at few MeV scale with neutrino-nucleus scattering.

Neutrino Magnetic Moment - This spectra present all the contributions where NMM is measured. At very low energy, the number of events expected by CEvNS are pretty similar to the one expected by background, it is around 1 kdru. Thus, this channel twice the competing signal events summing up electron and nucleus contributions. By contrast, weak interaction produced a negligible number of events at such low energies. As a result we get a Bayesian upper limit as good as 10^-11 Bohr magneton after running vIOLETA for 3 years.

Light Vector Mediator

Skipper-CCD

Technical description

Technical description

Skipper-CCDs are able to achieve an readout noise as low as fraction of electrons. These detectors are developed by the MicroSystem Labs of Lawrence Berkeley National Laboratory and operated at Fermilab. They open an unique opportunity to detect neutrino interactions, that transfer a very small quantity of energy to the Skipper-CCD silicon. A part of the transferred energy is converted in a very small amount of electron-holes pairs that can be easily counted with a Skipper-CCD.

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Performance

Performance

Measured readout noise as a function of the number of non-destructive readout samples per pixel for the Skipper CCD. Black points show the standard deviation of the empty pixels distribution as a function of the number of averaged samples. The red line is the theoretical expectation assuming independent, uncorrelated samples. The number of readout samples can be dynamically con figured.

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Reading

Reading

Here you can find an animation describing how a Skipper-CCD reads the charge in each pixel. In the last step, when the charge is placed at the sense nose (SN), it can be measured repeatedly in a non-destructive way

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Low Threshold Acquisition

Low Threshold Acquisition

Extensive use of the Skipper technology was limited by the lack of specific equipment intrinsically designed to operate the sensor at the ultimate performance. The Low Threshold Acquisition controller, so called LTA, was developed by research groups in the USA and Argentina to tackle this problem. Those groups are now part of vIOLETA collaboration.

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About vIOLETA

vIOLETA is a future experiment that will measure reactor antineutrinos and their physical properties through two channels: neutrino-electronic interaction and Elastic Coherent Neutrino Nucleus interaction. This experiment will use the new Skipper-CCD technology that achieves sub-electronic readout noise and a detection threshold in the eV range. Two positions were identified to place vIOLETA within the Atucha II Nuclear Power Plant in Argentina, 8 and 12 meters away from the center of the reactor core.
About vIOLETA image

Collaboration members

Aguilar Arévalo AlexisInstituto de Ciencias Nucleares of UNAM.Mexico
Arenillas Pablo Laboratorio de Metrología de Radioisótopos (CAC-CNEA)Argentina
Arnaldi Horacio Laboratorio Detección de Partículas y Radiación (CNEA/CONICET/UNCUYO)Argentina
Avalos Nicolas Laboratorio Detección de Partículas y Radiación (CNEA/CONICET/UNCUYO)Argentina
Ave Maximo Physics Institute of the São Paulo University (IFUSP)Brasil
Balpardo Christian Laboratorio de Metrología de Radioisótopos (CAC-CNEA)Argentina
Bellino Pablo Experimental Reactor Physics Division of the CNEA at Centro Atómico ConstituyentesArgentina
Bertou Xavier Laboratorio Detección de Partículas y Radiación (CNEA/CONICET/UNCUYO)Argentina
Bessia Fabricio Alcalde División Dispositivos y Sensores and the División Bajas TemperaturasArgentina
Blostein Jeronimo Neutron Physics Department of the Centro Atómico Bariloche (CAB), National Council of Science and Technology (CONICET), and Instituto Balseiro (UNCuyo)Argentina
Bonifazi Carla Physics Institute of the Federal University of Rio de Janeiro (IF-UFRJ),Brasil
Botti Ana Martina Physics Department of the Universidad de Buenos Aires (UBA) in ArgentinaArgentina
Cababie Mariano Physics Department of the Universidad de Buenos Aires (UBA) in ArgentinaArgentina
Cancelo Gustavo Fermi National Accelerator LaboratoryUSA
Cervantes Brenda Aurea Instituto de Ciencias Nucleares of UNAM.Mexico
Chavez Claudio Universidad Nacional del Sur (UNS)-CONICET,Argentina
Chierchie Fernando Universidad Nacional del SurArgentina
D'Olivo Juan Carlos Instituto de Ciencias Nucleares of UNAM.Mexico
Daneri Florencia Physics Department of the Universidad de Buenos Aires (UBA) in ArgentinaArgentina
Depaoli Eliana Laboratorio de Metrología de Radioisótopos (CAC-CNEA)Argentina
Derylo Greg Fermi National Accelerator LaboratoryUSA
Estrada Ezequiel Laboratorio Detección de Partículas y Radiación (CNEA/CONICET/UNCUYO)Argentina
Estrada Juan Fermi National Accelerator LaboratoryUSA
Fernandez Moroni Guillermo Fermi National Accelerator LaboratoryUSA
Gomez Berisso Mariano División Dispositivos y Sensores and the División Bajas TemperaturasArgentina
Izraelevitch Federico National University of San Martín (UNSAM) and the National Council of Technical and Scientific Research (CONICET) and CNEAArgentina
Kuk Kevin Fermi National Accelerator LaboratoryUSA
Lathrop AndrewFermi National Accelerator LaboratoryUSA
Lipovetzky José División Dispositivos y Sensores and the División Bajas TemperaturasArgentina
Lovino M.B. Laboratorio Detección de Partículas y Radiación (CNEA/CONICET/UNCUYO)Argentina
Machado Pedro Fermilab Theoretical Physics DepartmentUSA
Makler Martin National University of San Martín (UNSAM) and the National Council of Technical and Scientific Research (CONICET)Argentina
Martinez Gabino Lucio Jose Experimental Reactor Physics Division and to the Radioactive Waste Management National Program of the CNEA at Centro Atómico ConstituyentesArgentina
Martínez Mauricio Instituto de Ciencias Nucleares of UNAM.Mexico
Martinez-Soler Ivan J. Northwestern UniversityUSA
Molina Jorge Investigador, Facultad de Ingeniería – Universidad Nacional de AsunciónParaguay
Mota Philipe Physics Institute of the Federal University of Rio de Janeiro (IF-UFRJ),Brasil
Nasteva Irina Physics Institute of the Federal University of Rio de Janeiro (IF-UFRJ),Brasil
Paolini Eduardo (UNS) and Instituto de Investigaciones en Ingeniería Eléctrica “Alfredo Desages” (IIIE),Argentina
Perez Martin División Dispositivos y Sensores and the División Bajas TemperaturasArgentina
Perez-Gonzalez Yuber F. Northwestern UniversityUSA
Piegaia Ricardo National Council of Science and Technology (CONICET).Argentina
Rodrigues DarioPhysics Department of the Universidad de Buenos Aires (UBA) in Argentina, CNEA, CONICET.Argentina
Rosauro-Alcaraz Salvador Instituto de Física Teórica at the Universidad Autónoma de MadridEspaña
Sarkis Mobarak Youssef Instituto de Ciencias Nucleares of UNAM.Mexico
Sidelnik Ivan Neutron Physics Department of the Centro Atomico Bariloche (CAB) and the National Council of Science and Technology (CONICET)Argentina
Sofo Haro Miguel Laboratorio Detección de Partículas y Radiación (CNEA/CONICET/UNCUYO)Argentina
Stalder Diego Investigador, Facultad de Ingeniería – Universidad Nacional de AsunciónParaguay
Stefanazzi Leandro Fermi National Accelerator LaboratoryUSA
Tiffenberg Javier Fermi National Accelerator LaboratoryUSA

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