SENSEI: Direct-Detection Constraints on Sub-GeV Dark Matter from a Shallow Underground Run Using a Prototype Skipper-CCD

Orr Abramoff, Liron Barak, Itay M. Bloch, Luke Chaplinsky, Michael Crisler, Dawa, Alex Drlica-Wagner, Rouven Essig, Juan Estrada, Erez Etzion, Guillermo Fernandez, Daniel Gift, Joseph Taenzer, Javier Tiffenberg, Miguel Sofo Haro, Tomer Volansky, Tien-Tien Yu

We present new direct-detection constraints on eV-to-GeV dark matter interacting with electrons using a prototype detector of the Sub-Electron-Noise Skipper-CCD Experimental Instrument. The results are based on data taken in the MINOS cavern at the Fermi National Accelerator Laboratory. We focus on data obtained with two distinct readout strategies. For the first strategy, we read out the Skipper-CCD continuously, accumulating an exposure of 0.177 gram-days. While we observe no events containing three or more electrons, we find a large one- and two-electron background event rate, which we attribute to spurious events induced by the amplifier in the Skipper-CCD readout stage. For the second strategy, we take five sets of data in which we switch off all amplifiers while exposing the Skipper-CCD for 120k seconds, and then read out the data through the best prototype amplifier. We find a one-electron event rate of (3.51 +- 0.10) x 10^(-3) events/pixel/day, which is almost two orders of magnitude lower than the one-electron event rate observed in the continuous-readout data, and a two-electron event rate of (3.18 +0.86 -0.55) x 10^(-5) events/pixel/day. We again observe no events containing three or more electrons, for an exposure of 0.069 gram-days. We use these data to derive world-leading constraints on dark matter-electron scattering for masses between 500 keV to 5 MeV, and on dark-photon dark matter being absorbed by electrons for a range of masses below 12.4 eV.

Dual-sided Charge-Coupled Devices

Javier Tiffenberg, Daniel Egaña-Ugrinovic, Miguel Sofo Haro, Peizhi Du, Rouven Essig, Guillermo Fernandez-Moroni, Sho Uemura

Existing Charge-Coupled Devices (CCDs) operate by detecting either the electrons or holes created in an ionization event. We propose a new type of imager, the Dual-Sided CCD, which collects and measures both charge carriers on opposite sides of the device via a novel dual-buried channel architecture. We show that this dual detection strategy provides exceptional dark-count rejection and enhanced timing capabilities. These advancements have wide-ranging implications for dark-matter searches, near-IR/optical spectroscopy, and time-domain X-ray astrophysics.

Single-electron and single-photon sensitivity with a silicon Skipper CCD

Javier Tiffenberg, Miguel Sofo-Haro, Alex Drlica-Wagner, Rouven Essig, Yann Guardincerri, Steve Holland, Tomer Volansky, Tien-Tien Yu

We have developed a non-destructive readout system that uses a floating-gate amplifier on a thick, fully depleted charge coupled device (CCD) to achieve ultra-low readout noise of 0.068 e- rms/pix. This is the first time that discrete sub-electron readout noise has been achieved reproducibly over millions of pixels on a stable, large-area detector. This allows the precise counting of the number of electrons in each pixel, ranging from pixels with 0 electrons to more than 1500 electrons. The resulting CCD detector is thus an ultra-sensitive calorimeter. It is also capable of counting single photons in the optical and near-infrared regime. Implementing this innovative non-destructive readout system has a negligible impact on CCD design and fabrication, and there are nearly immediate scientific applications. As a particle detector, this CCD will have unprecedented sensitivity to low-mass dark matter particles and coherent neutrino-nucleus scattering, while astronomical applications include future direct imaging and spectroscopy of exoplanets.

Charge collection efficiency in back-illuminated Charge-Coupled Devices

Guillermo Fernandez-Moroni, Kevin Andersson, Ana Botti, Juan Estrada, Dario Rodrigues, Javier Tiffenberg

Low noise CCDs fully-depleted up to 675 micrometers have been identified as a unique tool for Dark Matter searches and low energy neutrino physics. The charge collection efficiency (CCE) for these detectors is a critical parameter for the performance of future experiments. We present here a new technique to characterize CCE in back-illuminated CCDs based on soft X-rays. This technique is used to characterize two different detector designs. The results demonstrate the importance of the backside processing for detection near threshold, showing that a recombination layer of a few microns significantly distorts the low energy spectrum. The studies demonstrate that the region of partial charge collection can be reduced to less than 1 micrometer thickness with adequate backside processing.

DAMIC at SNOLAB

Alvaro Chavarria, Javier Tiffenberg, Alexis Aguilar-Arevalo, Dan Amidei, Xavier Bertou, Gustavo Cancelo, Juan Carlos D'Olivo, Juan Estrada, Guillermo Fernandez Moroni, Federico Izraelevitch, Ben Kilminster, Yashmanth Langisetty, Junhui Liao, Jorge Molina, Paolo Privitera, Carolina Salazar, Youssef Sarkis, Vic Scarpine, Tom Schwarz, Miguel Sofo Haro, Frederic Trillaud, Jing Zhou

We introduce the fully-depleted charge-coupled device (CCD) as a particle detector. We demonstrate its low energy threshold operation, capable of detecting ionizing energy depositions in a single pixel down to 50 eVee. We present results of energy calibrations from 0.3 keVee to 60 keVee, showing that the CCD is a fully active detector with uniform energy response throughout the silicon target, good resolution (Fano ~0.16), and remarkable linear response to electron energy depositions. We show the capability of the CCD to localize the depth of particle interactions within the silicon target. We discuss the mode of operation and unique imaging capabilities of the CCD, and how they may be exploited to characterize and suppress backgrounds. We present the first results from the deployment of 250 um thick CCDs in SNOLAB, a prototype for the upcoming DAMIC100. DAMIC100 will have a target mass of 0.1 kg and should be able to directly test the CDMS-Si signal within a year of operation.

SENSEI: First Direct-Detection Results on sub-GeV Dark Matter from SENSEI at SNOLAB

SENSEI Collaboration, Prakruth Adari, Itay M. Bloch, Ana M. Botti, Mariano Cababie, Gustavo Cancelo, Brenda A. Cervantes-Vergara, Michael Crisler, Miguel Daal, Ansh Desai, Alex Drlica-Wagner, Rouven Essig, Juan Estrada, Erez Etzion, Guillermo Fernandez Moroni, Stephen E. Holland, Jonathan Kehat, Yaron Korn, Ian Lawson, Steffon Luoma, Aviv Orly, Santiago E. Perez, Dario Rodrigues, Nathan A. Saffold, Silvia Scorza, Aman Singal, Miguel Sofo-Haro, Leandro Stefanazzi, Kelly Stifter, Javier Tiffenberg, Sho Uemura, Edgar Marrufo Villalpando, Tomer Volansky, Yikai Wu, Tien-Tien Yu, Timon Emken, Hailin Xu

We present the first results from a dark matter search using six Skipper-CCDs in the SENSEI detector operating at SNOLAB. We employ a bias-mitigation technique of hiding approximately 46% of our total data and aggressively mask images to remove backgrounds. Given a total exposure after masking of 100.72 gram-days from well-performing sensors, we observe 55 two-electron events, 4 three-electron events, and no events containing 4 to 10 electrons. The two-electron events are consistent with pileup from one-electron events. Among the 4 three-electron events, 2 appear in pixels that are likely impacted by detector defects, although not strongly enough to trigger our "hot-pixel" mask. We use these data to set world-leading constraints on sub-GeV dark matter interacting with electrons and nuclei.

Search for reactor-produced millicharged particles with Skipper-CCDs at the CONNIE and Atucha-II experiments

Alexis A. Aguilar-Arevalo, Nicolas Avalos, Pablo Bellino, Xavier Bertou, Carla Bonifazi, Ana Botti, Mariano Cababié, Gustavo Cancelo, Brenda A. Cervantes-Vergara, Claudio Chavez, Fernando Chierchie, David Delgado, Eliana Depaoli, Juan Carlos D'Olivo, João dos Anjos, Juan Estrada, Guillermo Fernandez Moroni, Aldo R. Fernandes Neto, Richard Ford, Ben Kilminster, Kevin Kuk, Andrew Lathrop, Patrick Lemos, Herman P. Lima, Martin Makler, Agustina Magnoni, Katherine Maslova, Franciole Marinho, Jorge Molina, Irina Nasteva, Ana Carolina Oliveira, Santiago Perez, Laura Paulucci, Dario Rodrigues, Youssef Sarkis, Ivan Sidelnik, Miguel Sofo Haro, Diego Stalder, Javier Tiffenberg, Pedro Ventura

Millicharged particles, proposed by various extensions of the standard model, can be created in pairs by high-energy photons within nuclear reactors and can interact electromagnetically with electrons in matter. Recently, the existence of a plasmon peak in the interaction cross-section with silicon in the eV range was highlighted as a promising approach to enhance low-energy sensitivities. The CONNIE and Atucha-II reactor neutrino experiments utilize Skipper-CCD sensors, which enable the detection of interactions in the eV range. We present world-leading limits on the charge of millicharged particles within a mass range spanning six orders of magnitude, derived through a comprehensive analysis and the combination of data from both experiments.

Studies on small charge packet transport in high-resistivity fully-depleted CCDs

Miguel Sofo Haro, Guillermo Fernandez Moroni, Javier Tiffenberg

In this work, we will present a physical model and measurements of the transport of small charge packets in the bulk of thick high resistivity CCD before being collected by the pixel potential wells. A new technique to measure the lateral spread of the charge as a function of the ionization depth in the bulk is presented. Results from measurements on CCD currently in use for several scientific instruments are shown and validated with a new mathematical algorithm to extend the current modeling based only on the diffusion of the charge in silicon.

DAMIC: a novel dark matter experiment

The DAMIC Collaboration, Alexis A. Aguilar-Arevalo, Xavier Bertou, Melissa J. Butner, Gustavo Cancelo, Alvaro Chavarria, Juan Carlos D'Olivo, Juan Cruz Estrada Vigil, Guillermo Fernandez Moroni, Federico Izraelevitch, Ben Kilminster, Ian T. Lawson, Fernando Marsal, Jorge Molina, Paolo Privitera, Tom Schwarz, Miguel Sofo Haro, Javier Tiffenberg, Frederic Trillaud, Jing Zhou

DAMIC (Dark Matter in CCDs) is a novel dark matter experiment that has unique sensitivity to dark matter particles with masses below 10 GeV. Due to its low electronic readout noise (R.M.S. ~3 e-) this instrument is able to reach a detection threshold below 0.5 keV nuclear recoil energy, making the search for dark matter particles with low masses possible. We report on early results and experience gained from a detector that has been running at SNOLAB from Dec 2012. We also discuss the measured and expected backgrounds and present the plan for future detectors to be installed in 2014.

SENSEI: Direct-Detection Results on sub-GeV Dark Matter from a New Skipper-CCD

Liron Barak, Itay M. Bloch, Mariano Cababie, Gustavo Cancelo, Luke Chaplinsky, Fernando Chierchie, Michael Crisler, Alex Drlica-Wagner, Rouven Essig, Juan Estrada, Erez Etzion, Guillermo Fernandez Moroni, Daniel Gift, Sravan Munagavalasa, Aviv Orly, Dario Rodrigues, Aman Singal, Miguel Sofo Haro, Leandro Stefanazzi, Javier Tiffenberg, Sho Uemura, Tomer Volansky, Tien-Tien Yu

We present the first direct-detection search for eV-to-GeV dark matter using a new ~2-gram high-resistivity Skipper-CCD from a dedicated fabrication batch that was optimized for dark-matter searches. Using 24 days of data acquired in the MINOS cavern at the Fermi National Accelerator Laboratory, we measure the lowest rates in silicon detectors of events containing one, two, three, or four electrons, and achieve world-leading sensitivity for a large range of sub-GeV dark matter masses. Data taken with different thicknesses of the detector shield suggest a correlation between the rate of high-energy tracks and the rate of single-electron events previously classified as "dark current." We detail key characteristics of the new Skipper-CCDs, which augur well for the planned construction of the ~100-gram SENSEI experiment at SNOLAB.

Low Threshold Acquisition controller for Skipper CCDs

Gustavo Cancelo, Claudio Chavez, Fernando Chierchie, Juan Estrada, Guillermo Fernandez Moroni, Eduardo Emilio Paolini, Miguel Sofo Haro, Angel Soto, Leandro Stefanazzi, Javier Tiffenberg, Ken Treptow, Neal Wilcer, Ted Zmuda

The development of the Skipper Charge Coupled Devices (Skipper-CCDs) has been a major technological breakthrough for sensing very weak ionizing particles. The sensor allows to reach the ultimate sensitivity of silicon material as a charge signal sensor by unambiguous determination of the charge signal collected by each cell or pixel, even for single electron-hole pair ionization. Extensive use of the technology was limited by the lack of specific equipment to operate the sensor at the ultimate performance. In this work a simple, single-board Skipper-CCD controller is presented, aimed for the operation of the detector in high sensitivity scientific applications. The article describes the main components and functionality of the Low Threshold Acquisition (LTA) together with experimental results when connected to a Skipper-CCD sensor. Measurements show unprecedented deep sub-electron noise of 0.039 e$^-_{rms}$/pix for 5000 pixel measurements.

Charge Trap Analysis in a SENSEI Skipper-CCD: Understanding Low-Energy Backgrounds in Rare-Event Searches

Agustin Brusco, Bruno Sivilotti, Ana M. Botti, Brenda Cervantes, Ansh Desai, Rouven Essig, Juan Estrada, Erez Etzion, Guillermo Fernandez Moroni, Stephen E. Holland, Ian Lawson, Steffon Luoma, Santiago E. Perez, Dario Rodrigues, Javier Tiffenberg, Sho Uemura, Yikai Wu

Skipper Charge-Coupled Devices (Skipper-CCDs) are ultra-low-threshold detectors capable of detecting energy deposits in silicon at the eV scale. Increasingly used in rare-event searches, one of the major challenges in these experiments is mitigating low-energy backgrounds. In this work, we present results on trap characterization in a silicon Skipper-CCD produced in the same fabrication run as the SENSEI experiment at SNOLAB. Lattice defects contribute to backgrounds in rare-event searches through single-electron charge trapping. To investigate this, we employ the charge-pumping technique at different temperatures to identify dipoles produced by traps in the CCD channel. We fully characterize a fraction of these traps and use this information to extrapolate their contribution to the single-electron background in SENSEI. We find that this subpopulation of traps does not contribute significantly but more work is needed to assess the impact of the traps that can not be characterized.

Fast Single-Quantum Measurement with a Multi-Amplifier Sensing Charge-Coupled Device

Ana M. Botti, Brenda A. Cervantes-Vergara, Claudio R. Chavez, Fernando Chierchie, Alex Drlica-Wagner, Juan Estrada, Guillermo Fernandez Moroni, Stephen E. Holland, Blas J. Irigoyen Gimenez, Agustin J. Lapi, Edgar Marrufo Villalpando, Miguel Sofo Haro, Javier Tiffenberg, Sho Uemura

A novel readout architecture that uses multiple non-destructive floating-gate amplifiers to achieve sub-electron readout noise in a thick, fully-depleted silicon detector is presented. This Multi-Amplifier Sensing Charge-Coupled Device (MAS-CCD) can perform multiple independent charge measurements with each amplifier; measurements with multiple amplifiers can then be combined to further reduce the readout noise. The readout speed of this detector scales roughly linearly with the number of amplifiers without requiring segmentation of the active area. The performance of this detector is demonstrated, emphasizing the ability to resolve individual quanta and the ability to combine measurements across amplifiers to reduce readout noise. The unprecedented low noise and fast readout of the MAS-CCD make it a unique technology for astronomical observations, quantum imaging, and low-energy interacting particles.

The Oscura Experiment

Alexis Aguilar-Arevalo, Fabricio Alcalde Bessia, Nicolas Avalos, Daniel Baxter, Xavier Bertou, Carla Bonifazi, Ana Botti, Mariano Cababie, Gustavo Cancelo, Brenda Aurea Cervantes-Vergara, Nuria Castello-Mor, Alvaro Chavarria, Claudio R. Chavez, Fernando Chierchie, Juan Manuel De Egea, Juan Carlos D`Olivo, Cyrus E. Dreyer, Alex Drlica-Wagner, Rouven Essig, Juan Estrada, Ezequiel Estrada, Erez Etzion, Guillermo Fernandez-Moroni, Marivi Fernandez-Serra, Steve Holland, Agustin Lantero Barreda, Andrew Lathrop, Jose Lipovetzky, Ben Loer, Edgar Marrufo Villalpando, Jorge Molina, Santiago Perez, Paolo Privitera, Dario Rodrigues, Richard Saldanha, Diego Santa Cruz, Aman Singal, Nathan Saffold, Leandro Stefanazzi, Miguel Sofo-Haro, Javier Tiffenberg, Christian Torres, Sho Uemura, Rocio Vilar

The Oscura experiment will lead the search for low-mass dark matter particles using a very large array of novel silicon Charge Coupled Devices (CCDs) with a threshold of two electrons and with a total exposure of 30 kg-yr. The R&D effort, which began in FY20, is currently entering the design phase with the goal of being ready to start construction in late 2024. Oscura will have unprecedented sensitivity to sub-GeV dark matter particles that interact with electrons, probing dark matter-electron scattering for masses down to 500 keV and dark matter being absorbed by electrons for masses down to 1 eV. The Oscura R&D effort has made some significant progress on the main technical challenges of the experiment, of which the most significant are engaging new foundries for the fabrication of the CCD sensors, developing a cold readout solution, and understanding the experimental backgrounds.

SENSEI: Characterization of Single-Electron Events Using a Skipper-CCD

Liron Barak, Itay M. Bloch, Ana Botti, Mariano Cababie, Gustavo Cancelo, Luke Chaplinsky, Fernando Chierchie, Michael Crisler, Alex Drlica-Wagner, Rouven Essig, Juan Estrada, Erez Etzion, Guillermo Fernandez Moroni, Daniel Gift, Stephen E. Holland, Sravan Munagavalasa, Aviv Orly, Dario Rodrigues, Aman Singal, Miguel Sofo Haro, Leandro Stefanazzi, Javier Tiffenberg, Sho Uemura, Tomer Volansky, Tien-Tien Yu

We use a science-grade Skipper Charge Coupled Device (Skipper-CCD) operating in a low-radiation background environment to develop a semi-empirical model that characterizes the origin of single-electron events in CCDs. We identify, separate, and quantify three independent contributions to the single-electron events, which were previously bundled together and classified as "dark counts": dark current, amplifier light, and spurious charge. We measure a dark current, which depends on exposure, of (5.89+-0.77)x10^-4 e-/pix/day, and an unprecedentedly low spurious charge contribution of (1.52+-0.07)x10^-4 e-/pix, which is exposure-independent. In addition, we provide a technique to study events produced by light emitted from the amplifier, which allows the detector's operation to be optimized to minimize this effect to a level below the dark-current contribution. Our accurate characterization of the single-electron events allows one to greatly extend the sensitivity of experiments searching for dark matter or coherent neutrino scattering. Moreover, an accurate understanding of the origin of single-electron events is critical to further progress in ongoing R&D efforts of Skipper and conventional CCDs.

Absolute measurement of the Fano factor using a Skipper-CCD

Dario Rodrigues, Kevin Andersson, Mariano Cababie, Andre Donadon, Ana Botti, Gustavo Cancelo, Juan Estrada, Guillermo Fernandez-Moroni, Ricardo Piegaia, Matias Senger, Miguel Sofo Haro, Leandro Stefanazzi, Javier Tiffenberg, Sho Uemura

Skipper-CCD can achieve deep sub-electron readout noise making possible the absolute determination of the exact number of ionized electrons in a large range, from 0 to above 1900 electrons. In this work we present a novel technique that exploits this unique capability to allow self-calibration and the ultimate determination of silicon properties. We performed an absolute measurement of the variance and the mean number of the charge distribution produced by $^{55}$Fe X-rays, getting a Fano factor absolute measurement in Si at 123K and 5.9 keV. A value of 0.119 $\pm$ 0.002 was found and the electron-hole pair creation energy was determined to be (3.749 $\pm$ 0.001) eV. This technology opens the opportunity for direct measurements of the Fano factor at low energies.

SENSEI: First Direct-Detection Constraints on sub-GeV Dark Matter from a Surface Run

The SENSEI Collaboration, Michael Crisler, Rouven Essig, Juan Estrada, Guillermo Fernandez, Javier Tiffenberg, Miguel Sofo Haro, Tomer Volansky, Tien-Tien Yu

The Sub-Electron-Noise Skipper CCD Experimental Instrument (SENSEI) uses the recently developed Skipper-CCD technology to search for electron recoils from the interaction of sub-GeV dark matter particles with electrons in silicon. We report first results from a prototype SENSEI detector, which collected 0.019 gram-days of commissioning data above ground at Fermi National Accelerator Laboratory. These commissioning data are sufficient to set new direct-detection constraints for dark matter particles with masses between ~500 keV and 4 MeV. Moreover, since these data were taken on the surface, they disfavor previously allowed strongly interacting dark matter particles with masses between ~500 keV and a few hundred MeV. We discuss the implications of these data for several dark matter candidates, including one model proposed to explain the anomalously large 21-cm signal observed by the EDGES Collaboration. SENSEI is the first experiment dedicated to the search for electron recoils from dark matter, and these results demonstrate the power of the Skipper-CCD technology for dark matter searches.

An improved limit to the diffuse flux of ultra-high energy neutrinos from the Pierre Auger Observatory

The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu, Marco Aglietta, Eun-Joo Ahn, Imen Al Samarai, Ivone Albuquerque, Ingomar Allekotte, Patrick Allison, Alejandro Almela, Jesus Alvarez Castillo, Jaime Alvarez-Muñiz, Rafael Alves Batista, Michelangelo Ambrosio, Amin Aminaei, Luis Anchordoqui, Sofia Andringa, Carla Aramo, Victor Manuel Aranda, Fernando Arqueros, Nicusor Arsene, Hernán Gonzalo Asorey, Pedro Assis, Julien Aublin, Maximo Ave, Michel Avenier, Gualberto Avila, Nafiun Awal, Alina Mihaela Badescu, Kerri B Barber, Julia Bäuml, Colin Baus, Jim Beatty, Karl Heinz Becker, Jose A Bellido, Corinne Berat, Mario Edoardo Bertaina, Xavier Bertou, Peter Biermann, Pierre Billoir, Simon G Blaess, Alberto Blanco, Miguel Blanco, Carla Bleve, Hans Blümer, Martina Boháčová, Denise Boncioli, Carla Bonifazi, Nataliia Borodai, Jeffrey Brack, Iliana Brancus, Ariel Bridgeman, Pedro Brogueira, William C Brown, Peter Buchholz, Antonio Bueno, Stijn Buitink, Mario Buscemi, Karen S Caballero-Mora, Barbara Caccianiga, Lorenzo Caccianiga, Marina Candusso, Laurentiu Caramete, Rossella Caruso, Antonella Castellina, Gabriella Cataldi, Lorenzo Cazon, Rosanna Cester, Alan G Chavez, Andrea Chiavassa, Jose Augusto Chinellato, Jiri Chudoba, Marco Cilmo, Roger W Clay, Giuseppe Cocciolo, Roberta Colalillo, Alan Coleman, Laura Collica, Maria Rita Coluccia, Ruben Conceição, Fernando Contreras, Mathew J Cooper, Alain Cordier, Stephane Coutu, Corbin Covault, James Cronin, Richard Dallier, Bruno Daniel, Sergio Dasso, Kai Daumiller, Bruce R Dawson, Rogerio M de Almeida, Sijbrand J de Jong, Giuseppe De Mauro, Joao de Mello Neto, Ivan De Mitri, Jaime de Oliveira, Vitor de Souza, Luis del Peral, Olivier Deligny, Hans Dembinski, Niraj Dhital, Claudio Di Giulio, Armando Di Matteo, Johana Chirinos Diaz, Mary Lucia Díaz Castro, Francisco Diogo, Carola Dobrigkeit, Wendy Docters, Juan Carlos D'Olivo, Alexei Dorofeev, Qader Dorosti Hasankiadeh, Maria Teresa Dova, Jan Ebr, Ralph Engel, Martin Erdmann, Mona Erfani, Carlos O Escobar, Joao Espadanal, Alberto Etchegoyen, Heino Falcke, Ke Fang, Glennys Farrar, Anderson Fauth, Norberto Fazzini, Andrew P Ferguson, Mateus Fernandes, Brian Fick, Juan Manuel Figueira, Alberto Filevich, Andrej Filipčič, Brendan Fox, Octavian Fratu, Martín Miguel Freire, Benjamin Fuchs, Toshihiro Fujii, Beatriz García, Diego Garcia-Pinto, Florian Gate, Hartmut Gemmeke, Alexandru Gherghel-Lascu, Piera Luisa Ghia, Ugo Giaccari, Marco Giammarchi, Maria Giller, Dariusz Głas, Christian Glaser, Henry Glass, Geraldina Golup, Mariano Gómez Berisso, Primo F Gómez Vitale, Nicolás González, Ben Gookin, Jacob Gordon, Alessio Gorgi, Peter Gorham, Philippe Gouffon, Nathan Griffith, Aurelio Grillo, Trent D Grubb, Yann Guardincerri, Fausto Guarino, Germano Guedes, Matías Rolf Hampel, Patricia Hansen, Diego Harari, Thomas A Harrison, Sebastian Hartmann, John Harton, Andreas Haungs, Thomas Hebbeker, Dieter Heck, Philipp Heimann, Alexander E Herve, Gary C Hill, Carlos Hojvat, Nicholas Hollon, Ewa Holt, Piotr Homola, Jörg Hörandel, Pavel Horvath, Miroslav Hrabovský, Daniel Huber, Tim Huege, Antonio Insolia, Paula Gina Isar, Ingolf Jandt, Stefan Jansen, Cecilia Jarne, Jeffrey A Johnsen, Mariela Josebachuili, Alex Kääpä, Olga Kambeitz, Karl Heinz Kampert, Peter Kasper, Igor Katkov, Balazs Kégl, Bianca Keilhauer, Azadeh Keivani, Ernesto Kemp, Roger Kieckhafer, Hans Klages, Matthias Kleifges, Jonny Kleinfeller, Raphael Krause, Nicole Krohm, Oliver Krömer, Daniel Kuempel, Norbert Kunka, Danielle LaHurd, Luca Latronico, Robert Lauer, Markus Lauscher, Pascal Lautridou, Sandra Le Coz, Didier Lebrun, Paul Lebrun, Marcelo Augusto Leigui de Oliveira, Antoine Letessier-Selvon, Isabelle Lhenry-Yvon, Katrin Link, Luis Lopes, Rebeca López, Aida López Casado, Karim Louedec, Lu Lu, Agustin Lucero, Max Malacari, Simone Maldera, Manuela Mallamaci, Jennifer Maller, Dusan Mandat, Paul Mantsch, Analisa Mariazzi, Vincent Marin, Ioana Mariş, Giovanni Marsella, Daniele Martello, Lilian Martin, Humberto Martinez, Oscar Martínez Bravo, Diane Martraire, Jimmy Masías Meza, Hermann-Josef Mathes, Sebastian Mathys, James Matthews, John Matthews, Giorgio Matthiae, Detlef Maurel, Daniela Maurizio, Eric Mayotte, Peter Mazur, Carlos Medina, Gustavo Medina-Tanco, Rebecca Meissner, Victor Mello, Diego Melo, Alexander Menshikov, Stefano Messina, Rishi Meyhandan, Maria Isabel Micheletti, Lukas Middendorf, Ignacio A Minaya, Lino Miramonti, Bogdan Mitrica, Laura Molina-Bueno, Silvia Mollerach, François Montanet, Carlo Morello, Miguel Mostafá, Celio A Moura, Marcio Aparecido Muller, Gero Müller, Sarah Müller, Roberto Mussa, Gianni Navarra, Jose Luis Navarro, Sergio Navas, Petr Necesal, Lukas Nellen, Anna Nelles, Jens Neuser, Phong H Nguyen, Mihai Niculescu-Oglinzanu, Marcus Niechciol, Lukas Niemietz, Tim Niggemann, Dave Nitz, Dalibor Nosek, Vladimir Novotny, Lyberis Nožka, Livingstone Ochilo, Foteini Oikonomou, Angela Olinto, Noelia Pacheco, Daniel Pakk Selmi-Dei, Miroslav Palatka, Juan Pallotta, Philipp Papenbreer, Gonzalo Parente, Alejandra Parra, Thomas Paul, Miroslav Pech, Jan Pękala, Rodrigo Pelayo, Iuri Pepe, Lorenzo Perrone, Emily Petermann, Christine Peters, Sergio Petrera, Yevgeniy Petrov, Jamyang Phuntsok, Ricardo Piegaia, Tanguy Pierog, Pablo Pieroni, Mário Pimenta, Valerio Pirronello, Manuel Platino, Matthias Plum, Alessio Porcelli, Czeslaw Porowski, Raul Ribeiro Prado, Paolo Privitera, Michael Prouza, Victor Purrello, Eduardo J Quel, Sven Querchfeld, Sean Quinn, Julian Rautenberg, Olivier Ravel, Diego Ravignani, Benoît Revenu, Jan Ridky, Simone Riggi, Markus Risse, Pablo Ristori, Vincenzo Rizi, Washington Rodrigues de Carvalho, Gonzalo Rodriguez Fernandez, Jorge Rubén Rodriguez Rojo, Maria Dolores Rodríguez-Frías, Dmytro Rogozin, Jaime Rosado, Markus Roth, Esteban Roulet, Adrian Rovero, Steven J Saffi, Alexandra Saftoiu, Francesco Salamida, Humberto Salazar, Ahmed Saleh, Francisco Salesa Greus, Gaetano Salina, Federico Sánchez, Patricia Sanchez-Lucas, Edivaldo Moura Santos, Eva Santos, Fred Sarazin, Biswaijt Sarkar, Raul Sarmento, Ricardo Sato, Carlos Scarso, Markus Schauer, Viviana Scherini, Harald Schieler, Peter Schiffer, David Schmidt, Olaf Scholten, Harm Schoorlemmer, Petr Schovánek, Frank G Schröder, Alexander Schulz, Johannes Schulz, Johannes Schumacher, Sergio Sciutto, Alberto Segreto, Mariangela Settimo, Amir Shadkam, Ronald C Shellard, Iván Sidelnik, Guenter Sigl, Octavian Sima, Andrzej Śmiałkowski, Radomir Šmída, Gregory Snow, Paul Sommers, J Sorokin, Ruben Squartini, Yogendra N Srivastava, Denis Stanca, Samo Stanič, James Stapleton, Jaroslaw Stasielak, Maurice Stephan, Anne Stutz, Federico Suarez, Tiina Suomijärvi, A Daniel Supanitsky, Michael Sutherland, John Swain, Zbigniew Szadkowski, Oscar Alejandro Taborda, Alex Tapia, Andreas Tepe, Vanessa Menezes Theodoro, Javier Tiffenberg, Charles Timmermans, Carlos J Todero Peixoto, Gabriel Toma, Lenka Tomankova, Bernardo Tomé, Aurelio Tonachini, Guillermo Torralba Elipe, Diego Torres Machado, Petr Travnicek, Ralf Ulrich, Michael Unger, Martin Urban, Jose F Valdés Galicia, Ines Valiño, Laura Valore, Guus van Aar, Patrick van Bodegom, Ad M van den Berg, Sjoert van Velzen, Arjen van Vliet, Enrique Varela, Bernardo Vargas Cárdenas, Gary Varner, Rafael Vasquez, Jose R Vázquez, Ricardo Vázquez, Darko Veberič, Valerio Verzi, Jakub Vicha, Mariela Videla, Luis Villaseñor, Brian Vlcek, Serguei Vorobiov, Hernan Wahlberg, Oscar Wainberg, David Walz, Alan Watson, Marc Weber, Klaus Weidenhaupt, Andreas Weindl, Felix Werner, Allan Widom, Lawrence Wiencke, Henryk Wilczyński, Tobias Winchen, David Wittkowski, Brian Wundheiler, Sarka Wykes, Lili Yang, Tolga Yapici, Alexey Yushkov, Enrique Zas, Danilo Zavrtanik, Marko Zavrtanik, Arnulfo Zepeda, Yue Zhu, Benedikt Zimmermann, Michael Ziolkowski, Francesca Zuccarello

Charge Coupled Devices for detection of coherent neutrino-nucleus scattering

Guillermo Fernandez Moroni, Juan Estrada, Gustavo Cancelo, Eduardo Paolini, Javier Tiffenberg, Jorge Molina

This article details the potential for using Charge Coupled Devices (CCD) to detect low-energy neutrinos through their coherent scattering with nuclei. The detection of neutrinos through this standard model process has not been accessible because of the small energy deposited in such interactions with the detector nuclei. Typical particle detectors have thresholds of a few keV, and most of the energy deposition expected from coherent scattering is well below this level. The devices we discuss can be operated at a threshold of approximately 30 eV, making them ideal for observing this signal. For example, the number of coherent scattering events expected on a 52 gram CCD array located next to a power nuclear reactor is estimated as approximately 626 events/year. The results of our study show that detection at a confidence level of 99% can be reached within three months for this kind of detector array.

Exploring low-energy neutrino physics with the Coherent Neutrino Nucleus Interaction Experiment (CONNIE)

Alexis Aguilar-Arevalo, Xavier Bertou, Carla Bonifazi, Gustavo Cancelo, Alejandro Castañeda, Brenda Cervantes Vergara, Claudio Chavez, Juan C. D'Olivo, João C. dos Anjos, Juan Estrada, Aldo R. Fernandes Neto, Guillermo Fernandez Moroni, Ana Foguel, Richard Ford, Juan Gonzalez Cuevas, Pamela Hernández, Susana Hernandez, Federico Izraelevitch, Alexander R. Kavner, Ben Kilminster, Kevin Kuk, H. P. Lima, Martin Makler, Jorge Molina, Philipe Mota, Irina Nasteva, Eduardo E. Paolini, Carlos Romero, Y. Sarkis, Miguel Sofo Haro, Iruatã M. S. Souza, Javier Tiffenberg, Stefan Wagner

The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) uses low-noise fully depleted charge-coupled devices (CCDs) with the goal of measuring low-energy recoils from coherent elastic scattering (CE$ν$NS) of reactor antineutrinos with silicon nuclei and testing nonstandard neutrino interactions (NSI). We report here the first results of the detector array deployed in 2016, considering an active mass 47.6 g (8 CCDs), which is operating at a distance of 30 m from the core of the Angra 2 nuclear reactor, with a thermal power of 3.8 GW. A search for neutrino events is performed by comparing data collected with reactor on (2.1 kg-day) and reactor off (1.6 kg-day). The results show no excess in the reactor-on data, reaching the world record sensitivity down to recoil energies of about 1 keV (0.1 keV electron-equivalent). A 95% confidence level limit for new physics is established at an event rate of 40 times the one expected from the standard model at this energy scale. The results presented here provide a new window to low-energy neutrino physics, allowing one to explore for the first time the energies accessible through the low threshold of CCDs. They will lead to new constrains on NSI from the CE$ν$NS of antineutrinos from nuclear reactors.