Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934%. It is more than twice as abundant as water vapor, 23 times as abundant as carbon dioxide, and more than 500 times as abundant as neon. Argon is the most abundant noble gas in Earth's crust, comprising 0.00015% of the crust.
In physics, a time projection chamber (TPC) is a type of particle detector that uses a combination of electric fields and magnetic fields together with a sensitive volume of gas or liquid to perform a three-dimensional reconstruction of a particle trajectory or interaction.
The ArDM Experiment was a particle physics experiment based on a liquid argon detector, aiming at measuring signals from WIMPs, which may constitute the Dark Matter in the universe. Elastic scattering of WIMPs from argon nuclei is measurable by observing free electrons from ionization and photons from scintillation, which are produced by the recoiling nucleus interacting with neighbouring atoms. The ionization and scintillation signals can be measured with dedicated readout techniques, which constituted a fundamental part of the detector.
Astroparticle physics, also called particle astrophysics, is a branch of particle physics that studies elementary particles of astrophysical origin and their relation to astrophysics and cosmology. It is a relatively new field of research emerging at the intersection of particle physics, astronomy, astrophysics, detector physics, relativity, solid state physics, and cosmology. Partly motivated by the discovery of neutrino oscillation, the field has undergone rapid development, both theoretically and experimentally, since the early 2000s.
DEAP is a direct dark matter search experiment which uses liquid argon as a target material. DEAP utilizes background discrimination based on the characteristic scintillation pulse-shape of argon. A first-generation detector (DEAP-1) with a 7 kg target mass was operated at Queen's University to test the performance of pulse-shape discrimination at low recoil energies in liquid argon. DEAP-1 was then moved to SNOLAB, 2 km below Earth's surface, in October 2007 and collected data into 2011.
The Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) is a collaboration of European experimental particle physics groups involved in the construction of cryogenic detectors for direct dark matter searches. The participating institutes are the Max Planck Institute for Physics (Munich), Technical University of Munich, University of Tübingen (Germany), University of Oxford, the Comenius University Bratislava (Slovakia) and the Istituto Nazionale di Fisica Nucleare.
Fabrizio de Miranda was an Italian bridges and structural engineer and university professor.
The Oscillation Project with Emulsion-tRacking Apparatus (OPERA) was an instrument used in a scientific experiment for detecting tau neutrinos from muon neutrino oscillations. The experiment is a collaboration between CERN in Geneva, Switzerland, and the Laboratori Nazionali del Gran Sasso (LNGS) in Gran Sasso, Italy and uses the CERN Neutrinos to Gran Sasso (CNGS) neutrino beam.
Borexino is a deep underground particle physics experiment to study low energy (sub-MeV) solar neutrinos. The detector is the world's most radio-pure liquid scintillator calorimeter and is protected by 3,800 meters of water-equivalent depth. The scintillator is pseudocumene and PPO which is held in place by a thin nylon sphere. It is placed within a stainless steel sphere which holds the photomultiplier tubes (PMTs) used as signal detectors and is shielded by a water tank to protect it against external radiation. Outward pointing PMT's look for any outward facing light flashes to tag incoming cosmic muons that manage to penetrate the overburden of the mountain above. Neutrino energy can be determined through the number of photoelectrons measured in the PMT's. While the position can be determined by extrapolating the difference in arrival times of photons at PMT's throughout the chamber.
The DarkSide collaboration is an international affiliation of universities and labs seeking to directly detect dark matter in the form of weakly interacting massive particles (WIMPs). The collaboration is planning, building and operating a series of liquid argon time projection chambers (TPCs) that are employed at the Gran Sasso National Laboratory in Assergi, Italy. The detectors are filled with liquid argon from underground sources in order to exclude the radioactive isotope 39
Ar, which makes up one in every 1015 (quadrillion) atoms in atmospheric argon. The Darkside-10 (DS-10) prototype was tested in 2012, and the Darkside-50 (DS-50) experiment has been operating since 2013. Darkside-20k (DS-20k) with 20 tonnes of liquid argon is being planned as of 2019.
Antonio Ereditato is an Italian physicist, currently Research Professor at the University of Chicago, associate researcher at Fermilab, Batavia, USA, and Emeritus professor at the University of Bern, Switzerland, where he has been Director of the Laboratory for High Energy Physics from 2006 to 2020. From 2021 to 2022 Ereditato has been Visiting Professor at the Yale University, USA. He carried out research activities in the field of experimental neutrino physics, of weak interactions and strong interactions with experiments conducted at CERN, in Japan, at Fermilab in United States and at the LNGS in Italy. Ereditato has accomplished several R&D studies on particle detectors: wire chambers, calorimeters, time projection chambers, nuclear emulsions, detectors for medical applications.
In 2011, the Oscillation Project with Emulsion-tRacking Apparatus (OPERA) experiment mistakenly observed neutrinos appearing to travel faster than light. Even before the source of the error was discovered, the result was considered anomalous because speeds higher than that of light in vacuum are generally thought to violate special relativity, a cornerstone of the modern understanding of physics for over a century.
ICARUS is a physics experiment aimed at studying neutrinos. It was located at the Laboratori Nazionali del Gran Sasso (LNGS) where it started operations in 2010. After completion of its operations there, it was refurbished at CERN for re-use at Fermilab, in the same neutrino beam as the MiniBooNE, MicroBooNE and Short Baseline Near Detector (SBND) experiments. The ICARUS detector was then taken apart for transport and reassembled at Fermilab, where data collection is expected to begin in fall 2021.
Paolo Cotta-Ramusino has been Secretary General of Pugwash Conferences on Science and World Affairs since August 2002. He is also Professor of Mathematical Physics at the University of Milan (Italy) and Senior Researcher at the Italian National Institute of Nuclear Physics. Cotta-Ramusino is an adjunct Professor, Centre of International Politics, Organization and Disarmament, School of International Studies, Jawaharlal Nehru University, New Delhi and an Associate with the Project on Managing the Atom, Belfer Center for Science and International Affairs, John F. Kennedy School of Government, Harvard University. He is a member of the International Institute for Strategic Studies, and the World Academy of Art and Sciences.
AEgIS, AD-6, is an experiment at the Antiproton Decelerator facility at CERN. Its primary goal is to measure directly the effect of Earth's gravitational field on antihydrogen atoms with significant precision. Indirect bounds that assume the validity of, for example, the universality of free fall, the Weak Equivalence Principle or CPT symmetry also in the case of antimatter constrain an anomalous gravitational behavior to a level where only precision measurements can provide answers. Vice versa, antimatter experiments with sufficient precision are essential to validate these fundamental assumptions. AEgIS was originally proposed in 2007. Construction of the main apparatus was completed in 2012. Since 2014, two laser systems with tunable wavelengths and synchronized to the nanosecond for specific atomic excitation have been successfully commissioned.
Muon g − 2 is a particle physics experiment at Fermilab to measure the anomalous magnetic dipole moment of a muon to a precision of 0.14 ppm, which is a sensitive test of the Standard Model. It might also provide evidence of the existence of new particles.
Ettore Fiorini was an Italian experimental particle physicist. He studied the physics of the weak interaction and was a pioneer in the field of double beta decay. He served as a professor of nuclear and subnuclear physics at the University of Milano-Bicocca.
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The Laboratori Nazionali di Legnaro is one of the four major research centers of the Italian National Institute for Nuclear Physics (INFN). The primary focus of research at this laboratory is in the fields of nuclear physics and nuclear astrophysics, where five accelerators are currently used. It is one of the most important facilities in Italy for research in these fields. The main future project of the laboratory is the Selective Production of Exotic Species (SPES), in which various radionuclides will be produced for research and medicinal purposes.
Luisa Cifarelli FInstP is a Professor of Experimental Particle Physics at the University of Bologna. She is the Director of the La Rivista del Nuovo Cimento.
