A Facility for Low-Radioactivity Underground Argon

Henning O. Back, Walter Bonivento, Mark Boulay, Eric Church, Steven R. Elliott, Federico Gabriele, Cristiano Galbiati, Graham K. Giovanetti, Christopher Jackson, Art McDonald, Andrew Renshaw, Roberto Santorelli, Kate Scholberg, Marino Simeone, Rex Tayloe, Richard Van de Water

The DarkSide-50 experiment demonstrated the ability to extract and purify argon from deep underground sources and showed that the concentration of $^{39}$Ar in that argon was greatly reduced from the level found in argon derived from the atmosphere. That discovery broadened the physics reach of argon-based detector and created a demand for low-radioactivity underground argon (UAr) in high-energy physics, nuclear physics, and in environmental and allied sciences. The Global Argon Dark Matter Collaboration (GADMC) is preparing to produce UAr for DarkSide-20k, but a general UAr supply for the community does not exist. With the proper resources, those plants could be operated as a facility to supply UAr for most of the experiments after the DarkSide 20k production. However, if the current source becomes unavailable, or UAr masses greater than what is available from the current source is needed, then a new source must be found. To find a new source will require understanding the production of the radioactive argon isotopes underground in a gas field, and the ability to measure $^{37}$Ar, $^{39}$Ar, and $^{42}$Ar to ultra-low levels. The operation of a facility creates a need for ancillary systems to monitor for $^{37}$Ar, $^{39}$Ar, or $^{42}$Ar infiltration either directly or indirectly, which can also be used to vet the $^{37}$Ar, $^{39}$Ar, and $^{42}$Ar levels in a new UAr source, but requires the ability to separate UAr from the matrix well gas. Finding methods to work with industry to find gas streams enriched in UAr, or to commercialize a UAr facility, are highly desirable.

US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report

Marco Battaglieri, Alberto Belloni, Aaron Chou, Priscilla Cushman, Bertrand Echenard, Rouven Essig, Juan Estrada, Jonathan L. Feng, Brenna Flaugher, Patrick J. Fox, Peter Graham, Carter Hall, Roni Harnik, JoAnne Hewett, Joseph Incandela, Eder Izaguirre, Daniel McKinsey, Matthew Pyle, Natalie Roe, Gray Rybka, Pierre Sikivie, Tim M. P. Tait, Natalia Toro, Richard Van De Water, Neal Weiner, Kathryn Zurek, Eric Adelberger, Andrei Afanasev, Derbin Alexander, James Alexander, Vasile Cristian Antochi, David Mark Asner, Howard Baer, Dipanwita Banerjee, Elisabetta Baracchini, Phillip Barbeau, Joshua Barrow, Noemie Bastidon, James Battat, Stephen Benson, Asher Berlin, Mark Bird, Nikita Blinov, Kimberly K. Boddy, Mariangela Bondi, Walter M. Bonivento, Mark Boulay, James Boyce, Maxime Brodeur, Leah Broussard, Ranny Budnik, Philip Bunting, Marc Caffee, Sabato Stefano Caiazza, Sheldon Campbell, Tongtong Cao, Gianpaolo Carosi, Massimo Carpinelli, Gianluca Cavoto, Andrea Celentano, Jae Hyeok Chang, Swapan Chattopadhyay, Alvaro Chavarria, Chien-Yi Chen, Kenneth Clark, John Clarke, Owen Colegrove, Jonathon Coleman, David Cooke, Robert Cooper, Michael Crisler, Paolo Crivelli, Francesco D'Eramo, Domenico D'Urso, Eric Dahl, William Dawson, Marzio De Napoli, Raffaella De Vita, Patrick DeNiverville, Stephen Derenzo, Antonia Di Crescenzo, Emanuele Di Marco, Keith R. Dienes, Milind Diwan, Dongwi Handiipondola Dongwi, Alex Drlica-Wagner, Sebastian Ellis, Anthony Chigbo Ezeribe, Glennys Farrar, Francesc Ferrer, Enectali Figueroa-Feliciano, Alessandra Filippi, Giuliana Fiorillo, Bartosz Fornal, Arne Freyberger, Claudia Frugiuele, Cristian Galbiati, Iftah Galon, Susan Gardner, Andrew Geraci, Gilles Gerbier, Mathew Graham, Edda Gschwendtner, Christopher Hearty, Jaret Heise, Reyco Henning, Richard J. Hill, David Hitlin, Yonit Hochberg, Jason Hogan, Maurik Holtrop, Ziqing Hong, Todd Hossbach, T. B. Humensky, Philip Ilten, Kent Irwin, John Jaros, Robert Johnson, Matthew Jones, Yonatan Kahn, Narbe Kalantarians, Manoj Kaplinghat, Rakshya Khatiwada, Simon Knapen, Michael Kohl, Chris Kouvaris, Jonathan Kozaczuk, Gordan Krnjaic, Valery Kubarovsky, Eric Kuflik, Alexander Kusenko, Rafael Lang, Kyle Leach, Tongyan Lin, Mariangela Lisanti, Jing Liu, Kun Liu, Ming Liu, Dinesh Loomba, Joseph Lykken, Katherine Mack, Jeremiah Mans, Humphrey Maris, Thomas Markiewicz, Luca Marsicano, C. J. Martoff, Giovanni Mazzitelli, Christopher McCabe, Samuel D. McDermott, Art McDonald, Bryan McKinnon, Dongming Mei, Tom Melia, Gerald A. Miller, Kentaro Miuchi, Sahara Mohammed Prem Nazeer, Omar Moreno, Vasiliy Morozov, Frederic Mouton, Holger Mueller, Alexander Murphy, Russell Neilson, Tim Nelson, Christopher Neu, Yuri Nosochkov, Ciaran O'Hare, Noah Oblath, John Orrell, Jonathan Ouellet, Saori Pastore, Sebouh Paul, Maxim Perelstein, Annika Peter, Nguyen Phan, Nan Phinney, Michael Pivovaroff, Andrea Pocar, Maxim Pospelov, Josef Pradler, Paolo Privitera, Stefano Profumo, Mauro Raggi, Surjeet Rajendran, Nunzio Randazzo, Tor Raubenheimer, Christian Regenfus, Andrew Renshaw, Adam Ritz, Thomas Rizzo, Leslie Rosenberg, Andre Rubbia, Ben Rybolt, Tarek Saab, Benjamin R. Safdi, Elena Santopinto, Andrew Scarff, Michael Schneider, Philip Schuster, George Seidel, Hiroyuki Sekiya, Ilsoo Seong, Gabriele Simi, Valeria Sipala, Tracy Slatyer, Oren Slone, Peter F Smith, Jordan Smolinsky, Daniel Snowden-Ifft, Matthew Solt, Andrew Sonnenschein, Peter Sorensen, Neil Spooner, Brijesh Srivastava, Ion Stancu, Louis Strigari, Jan Strube, Alexander O. Sushkov, Matthew Szydagis, Philip Tanedo, David Tanner, Rex Tayloe, William Terrano, Jesse Thaler, Brooks Thomas, Brianna Thorpe, Thomas Thorpe, Javier Tiffenberg, Nhan Tran, Marco Trovato, Christopher Tully, Tony Tyson, Tanmay Vachaspati, Sven Vahsen, Karl van Bibber, Justin Vandenbroucke, Anthony Villano, Tomer Volansky, Guojian Wang, Thomas Ward, William Wester, Andrew Whitbeck, David A. Williams, Matthew Wing, Lindley Winslow, Bogdan Wojtsekhowski, Hai-Bo Yu, Shin-Shan Yu, Tien-Tien Yu, Xilin Zhang, Yue Zhao, Yi-Ming Zhong

Solar Neutrino Measurements

A. B. McDonald

A review of solar neutrino experiments is provided, including experimental measurements to date and proposed future measurements. Experiments to date have provided a clear determination that solar neutrinos are undergoing flavor transformation and that the dominant mechanism for this transformation is oscillation. The mixing parameters are well defined and limits are placed on sub-dominant modes. The measurements also provide strong confirmation of solar model calculations. New experiments under development will study neutrino oscillation parameters and sub-dominant modes with greater precision and will investigate solar fluxes further, concentrating primarily on the low energy pp, $^7$Be, pep and CNO reactions.

Sudbury Neutrino Observatory Results

A. B. McDonald

The Sudbury Neutrino Observatory uses 1000 tonnes of heavy water in an ultra-clean Cherenkov detector situated 2 km underground in Ontario, Canada to study neutrinos from the Sun and other astrophysical sources. The Charged Current (CC) reaction on deuterium is sensitive only to electron neutrinos whereas the Neutral Current (NC) is equally sensitive to all active neutrino types. By measuring the flux of neutrinos from 8B decay in the Sun with the CC and NC reactions it has been possible to establish clearly, through an appearance measurement, that electron neutrinos change to other active neutrino types, properties that are beyond the Standard Model of elementary particles. The observed total flux of active neutrinos agrees well with solar model flux calculations for 8B. This provides a clear answer to the "Solar Neutrino Problem". When these results are combined with other measurements, the oscillation of massive neutrinos is strongly defined as the primary mechanism for flavor change and oscillation parameters are well constrained.

Evidence for Neutrino Oscillations I: Solar and Reactor Neutrinos

A. B. McDonald

This paper discusses evidence for neutrino oscillations obtained from measurements with solar neutrinos and reactor neutrinos.

Astrophysical Neutrino Telescopes

A. B. McDonald, C. Spiering, S. Schoenert, E. T. Kearns, T. Kajita

This review describes telescopes designed to study neutrinos from astrophysical sources. These sources include the Sun and Supernovae emitting neutrino energies up to tens of MeV, atmospheric neutrino sources caused by cosmic ray interactions and other sources generating neutrino energies ranging up to $1\times 10^{20}$ eV. Measurements with these telescopes also provide information on neutrino properties including clear evidence for neutrino flavor change. Telescopes in operation in the past and present are described, along with plans for future instruments to expand this rapidly growing field of particle astrophysics.

Neutrino Properties from Measurements using Astrophysical and Terrestrial Sources

A. B. McDonald

The current knowledge of neutrino properties has been derived from measurements performed with both astrophysical and terrestrial sources. Observations of neutrino flavor change have been made with neutrinos generated in the solar core, through cosmic ray interactions in the atmosphere and in nuclear reactors. A summary is presented of the current knowledge of neutrino properties and a description is provided for future measurements that could provide more complete information on neutrino properties.