Conveners
LRT 2022 - presentations: Welcome / Global Underground Laboratories
- Sean Paling (Professor at Boulby Underground Laboratory in UK)
LRT 2022 - presentations: Global Underground Laboratories / Screening Facilities
- Richard Ford (SNOLAB)
LRT 2022 - presentations: Fabrication Methods
- Alvine Kamaha (University of California, Los Angeles)
LRT 2022 - presentations: Particle Background impacts on Quantum Information Systems and Quantum Computing
- Brianna Mount
LRT 2022 - presentations: Surface Contamination Control
- Juergen Reichenbacher (South Dakota School of Mines and Technology)
LRT 2022 - presentations: Purification Techniques for Solids / Radon Detector
- Eric Hoppe (Pacific Northwest National Laboratory)
LRT 2022 - presentations: Purification Techniques for Liquids & Gases, incl. Rn
- Markus Horn (SDSTA - Science)
LRT 2022 - presentations: Assay and Screening Techniques
- Andreas Piepke
LRT 2022 - presentations: Community Coordination and Databases / Cosmogenic Backgrounds & Material Activation
- Vitaly Kudryavtsev (University of Sheffield)
LRT 2022 - presentations: Cosmogenic Backgrounds & Material Activation / Experiment Backgrounds, Models & Simulations (1)
- Pia Loaiza (IJCLab, CNRS, Université Paris Saclay)
LRT 2022 - presentations: Experiment Backgrounds, Models & Simulations (2)
- Douglas Leonard (IBS Center for Underground Physics)
LRT 2022 - presentations: Experiment Backgrounds, Models & Simulations (3)
- Jaret Heise (Sanford Underground Research Facility)
Remembrance of late Stanley Howard, SD Mines professor in the Department of Materials and Metallurgical Engineering
Updates from underground laboratories in North & South America will be presented, with a focus on progress at the Sanford Underground Research Facility (SURF).
Deep underground laboratories in Asia continue to add locations, size, and facilities to support current and next generation rare-event experiments related to neutrino physics, nuclear astrophysics, searches for dark matter and neutrinoless double beta decay, and other science requiring low-background environments. I will present an overview and status of major underground labs in Asia...
Updates on underground laboratories in Europe will be presented, with a focus on the Boulby Underground Laboratory
Over the past few decades, the scale and mass of rare event search experiments have increased by several orders of magnitude. To maintain background-free large fiducial-volume searches, the radio-purity requirements of the materials from which these devices are constructed have improved by similar factors.
High-purity germanium spectroscopy has long-been the workhorse of material screening...
The Black Hills Underground Campus (BHUC) houses a low background counting facility on the 4850’ level of the Sanford Underground Research Facility. Currently there are five ultra-low background, high-purity germanium detectors operating inside of a class 1,000 cleanroom at the Davis Campus, with a sixth anticipated to be installed within a year. A robust nitrogen purge system and on-site...
Reducing radioactive backgrounds is key for the success of many rare-event searches such as neutrinoless double beta decay, dark matter, and nuclear astrophysics. For a given component used in a rare-event search, backgrounds may be due to intrinsic radiocontaminants within the material and radiocontaminants that are introduced during manufacturing. Advances in additive manufacturing...
Selective laser melting (SLM) method occupies a special place in powder bed fusion (PBF) technology. The growing widespread interest in this technique is due to its several benefits. The final near to net-shape product, which has up to 99.9% relative density is the key advantage and with the extensive applicable materials, PBF–SLM has feasible economic benefits. This talk covers all the...
As the background level of new detector systems is pushed ever lower the demand for radiopure materials continues to increase. Electroformed copper is playing an ever more central role in many experiments. That is due to its favorable electrical and thermal properties in addition to the extremely high radiopurity levels that can be obtained using electroformed copper leaving room in their...
Readout cables for signal sensors are a fundamental component of rare event searches for dark matter and neutrinoless double beta decay. While possessing unique electrical and mechanical properties, polyimide-based flexible cables can be a significant contributor to the total detector background, due to their relatively high content of natural radionuclides. Contaminations of 232Th and 238U in...
The presence of nonequilibrium quasiparticles (QPs) hinders the performance of superconducting qubits. This excess of nonequilibrium quasiparticles arise mainly from two primary sources: in the infrared photons that couple to qubits via photon-assisted quasiparticle generation, and the impact events in which ionizing radiation deposits large amounts of energy (keV) onto the qubit chip. The...
Quantum devices and light dark matter searches are scientifically active fields. I will discuss the complementarity in technology and research between these two fields. I will discuss recent observations of ionizing radiation backgrounds in leading quantum processors and the insights that can be gained from dark matter searches based on low temperature calorimetry. Extending this observation,...
Over the last 20 years, searches for dark matter above the proton mass have advanced significantly across direct and indirect searches, but sub-GeV dark matter has until recently been comparatively unprobed. In this talk, I will discuss prospects for applying quantum measurement techniques to lowering mass thresholds for new searches with event thresholds at the eV-scale. I will then discuss...
Athermal phonons are high-energy vibration modes in solid-state substrates. They are the signal channel for sub-GeV low-mass dark matter direct search, while they are also dangerous noises in quantum information systems. I'll first introduce the method of athermal phonon detection in particle detectors. Then I'll discuss three approaches to mitigate athermal phonons: isolation,...
Radioactivity was recently discovered as one of the main concerns for quantum processors based on superconducting circuits. Cosmic rays and radioactive isotopes naturally present in the environment can affect the coherence time of single qubits and induce correlated errors in qubit arrays, seriously affecting quantum error correction. We developed a GEANT-4 based simulation to study the...
Surface contamination with long-lived daughters of Rn-222 is of great interest for experiments looking for rare events. These include for example searches for neutrino-less double beta decay or interactions of dark matter particles. Decays of Pb-210, Bi-210 and finally Po-210 may contribute significantly to the experiments’ background, especially when they appear close or directly in the...
nEXO is a proposed search for neutrinoless double beta decay of $^{136}$Xe. The experiment is planning to utilize isotopically enriched xenon both as source and detection medium. Radon daughters produced by radon decays in the air can plate out on material surfaces during detector assembly and handling. The alpha particles they emit can interact with low-Z materials nearby and produce fast...
nEXO is a planned next-generation experiment to search for $^{136}$Xe neutrinoless double beta decay. The experiment will utilize a time projection chamber and 5000 kg of isotopically enriched liquid xenon. The projected 90% CL half-life sensitivity is 1.35·10$^{28}$ yr after 10 yr of exposure. Stringent radioactive background control and careful material selection are necessary to achieve...
Next-generation experiments searching for rare events must satisfy increasingly stringent requirements on the bulk and surface radioactive contamination of their active and structural materials. The measurement of surface contamination is particularly challenging, as no existing technology is capable of separately measuring those parts of the 232Th and 238U decay chains that are commonly found...
The relatively long-lived Pb-210 (half-life of 22 years) and its progeny can be problematic sources of background for rare-event physics experiments. Pb-210 can be present in the bulk of materials at detrimental levels and concentrated at the surfaces of detector components as a result of exposure to environmental radon, where its decay products (and those of its progeny such as Po-210) can...
The SABRE project aims to a model-independent search for dark matter through the annual modulation signature, with an unprecedented sensitivity to confirm or refute the DAMA/LIBRA claim. To achieve this goal, SABRE is working to produce NaI(Tl) crystals with a very low background in the (1-6) keV energy region, dominated by radioactive contaminants in the crystals. Direct counting of beta and...
The COSINE experiment has performed an extensive R&D to develop ultra-low background NaI(Tl) crystals for the next phase COSINE-200 experiment. A ton of radio-pure NaI powder should be prepared for the 200 kg NaI(Tl) detectors. A large-scale recrystallization facility was built and had been operating to mass-produce pure NaI powder. The successful reduction of radioactive contamination in the...
We report on inorganic crystal purification for double beta decay and cosmic dark matter search;
focusing on the NaI(Tl) and CaF$_{2}$ crystals.
The NaI(Tl) crystal will be applied to search for cosmic dark matter, verifying the annual modulating signal reported by DAMA/LIBRA collaboration.
The CaF$_{2}$ crystal will be applied to search for the neutrino-less double beta decay of...
Advanced Mo-based Rare process Experiment (AMoRE) is a series of experiments for the neutrinoless double beta decay of 100Mo using molybdate-based crystals, such as $^{40}$Ca$^{100}$MoO$_4$, Li$_2$$^{100}$MoO$_4$, or Na$_2$$^{100}$Mo$_2$O$_7$. AMoRE phase-II aims to reach the internal background level below 5 $\times$ $10^{-6}$ ckky (count/kg/keV/year) in ROI using ~200 kg of bolometric...
In the field of particle physics, various experiments have been designed in order to search for rare physics processes beyond the standard model. Radioactive noble gas radon is one of the major background sources below the MeV region in rare event search experiments. To precisely monitor radon concentration in purified gases, a radon detector with an electrostatic collection method is widely...
In 2017-2020, Jinping Neutrino 1-t prototype has detected numerous MeV radioactive background events, 343 high energy muon events and muon induced neutrons. By Bi-Po coincidence, the U238 contamination of liquid scintillator (LS) is measured as $(6.98 \pm 0.73) \times 10−13$ g/g, and Th232 upperlimit is $3.7 \times 10−13$ g/g (95% C.L., preliminary). On PMT glass, K40 contamination is $(5.73...
nEXO is a 5 tonne neutrino-less double beta (0vBB) experiment looking for this Standard Model forbidden decay in $^{136}Xe$. If this decay is observed it would mean that neutrinos are Majorana fermions, i.e. their own antiparticle, and that lepton number is not conserved. The nEXO experiment is designed to achieve a $1.35\times 10^{28}$ year half-life sensitivity (at 90% confidence level),...
Trace radioactive noble elements are a potential source of electron recoil backgrounds in liquid xenon-based detectors. Commercially available research-grade xenon contains krypton at a concentration of up to 10-7 g/g as a byproduct of its extraction from the atmosphere. About 1 part in 1012 of this residual krypton is krypton-85, a beta emitter with an endpoint energy of 687 keV and a...
The MicroBooNE liquid argon time projection chamber has proven to be an excellent detector to study physics at the MeV-scale. It employs a large-scale liquid argon filtration system, using copper-based filters, to remove electronegative impurities from liquid argon to achieve and maintain a high level of purity. One prevalent background in this energy range is the decay of radon and its decay...
The DarkSide-20k experiment will search for dark matter in the form of WIMPs and has the potential to set the best limits for the spin-independent interaction of heavy WIMPs with nucleons. The background requirement of this experiment is less than 0.1 events in 200 tonne years, which is the most stringent one ever set so far in the field of rare event searches and establishes rigorous...
The AMoRE experiment searches for the neutrinoless double-beta decay of $^{100}$Mo with cooled to milli-Kelvin temperature molybdate crystal scintillators. The maximum sensitivity for a given exposure is reached if a zero background in the region of interest is ensured. Therefore, various background reduction studies are ongoing to achieve the required background level for the experiment.
We...
The 20 kton liquid scintillator detector of the Jiangmen Neutrino Underground Observatory, currently under construction in Southern China, has a vast potential for new insights into various fields of (astro-)particle physics. Stringent limits on the liquid scintillator radiopurity are required for several physics goals of JUNO. For both $^{232}$Th and $^{238}$U, a radiopurity of $10^{-15}$ g/g...
The advent of commercial atomic ICP-MS/MS has made it possible to measure low levels of actinides and other analytes without the need for extensive sample preprocessing. The instrument utilizes inline gas phase chemistry that either eliminates or reacts the analyte away from matrix derived interferences that otherwise need to be removed through separation techniques such as ion exchange column...
Measuring the argon purity is critical for all Ar-based rare event research experiments. Mass spectrometry is typically used to measure U and Th contamination in samples of the materials used to build a low-background detector; however, this technique has the potential to provide other valuable information that is typically not exploited. At CIEMAT, we have shown that, by ICPMS, it is possible...
Radon emanation is projected to account for ≈66% of the electron recoil (ER) background in the WIMP region of interest for the LUX ZEPLIN (LZ) experiment. The relatively long half-life of 222Rn leads to mixing within the target volume and an internal ER background with a beta-spectrum up to 1019 keV from its 214Pb progeny. To mitigate the amount of radon inside the detector volume, materials...
The Stawell Underground Physics Laboratory (SUPL) is a newly built underground facility in regional Victoria, Australia. The laboratory is be located 1024 m underground (~2900 m water equivalent) within the Stawell Gold Mine and construction will be completed in May 2022. The laboratory will house rare event physics searches, including the upcoming SABRE dark matter experiment, as well as...
Astroparticle physics experiments searching for rare events, such as neutrinoless double beta decay and dark matter particle interactions, must be shielded from background radiation and must exhibit a radioactive background as low as reasonably achievable. The material selection for the next generation of low-background experiments is becoming crucial to inform the final design of the...
Low background gamma spectrometry, specifically in the support of rare-event experiment material assays, presents a unique set of challenges and considerations from those found in traditional production counting facilities. A general overview of these challenges will be presented, along with some practical methods and approaches that vary in sophistication. Topics to be discussed include...
The 2021 particle physics community study, known as “Snowmass 2021,” has brought together particle physicists around the world to create a unified vision for the field over the next decade. One of the areas of focus is the Underground Facilities (UF) frontier, which addresses underground infrastructure and the scientific programs and goals of underground-based experiments. To this effect, the...
When located on surface, rare event searches face various background sources. While most of them can be reduced by different shielding approaches, cosmogenic radiation is high enough in energy to still penetrate the experiments. Therefore, the only feasible solution remains to locate experiments deep underground. In my talk I will give an overview how germanium-based experiments handle this...
Muon-induced neutrons can lead to potentially irreducible backgrounds in rare event search experiments. We have investigated the implication of laboratory depth on the muon induced background in a future dark matter experiment capable of reaching the so-called neutrino floor. Our
simulation study focuses on a xenon-based detector with 70 tonnes of active mass, surrounded by additional veto...
Borexino was a liquid scintillator detector situated underground in the Laboratori Nazionali del Gran Sasso in Italy, officially decommissioned in October 2021. Its successful and renowned physics program covers the study of solar neutrinos and spans also across geo-neutrinos and neutrino physics. Within its solar program, Borexino successfully measured neutrinos from the fusion processes in...
nEXO is a planned ton-scale search for the neutrinoless double beta decay of 136Xe. nEXO intends to use 5000 kg of isotopically enriched liquid xenon as source and detector. In this talk I will discuss the approach nEXO has chosen to estimate, control and manage the experiment background, a subject important for all double beta decay experiments.
The ${\rm M{\scriptsize AJORANA}~D{\scriptsize EMONSTRATOR}}$ is a neutrinoless double-beta decay ($0{\rm \nu\beta\beta}$) experiment containing ~30 kg of p-type point contact germanium detectors enriched to 88% in ${^{76}{\rm Ge}}$ and ~14 kg of natural germanium detectors. The detectors are housed in two electroformed copper (EFCu) cryostats and surrounded by a graded passive shield with...
LEGEND (Large Enriched Germanium Experiment for Neutrinoless double beta Decay) uses High Purity Germanium detectors to search for lepton number violation in the neutrino sector with a multi-stage strategy. The HPGe detectors are isotopically enriched with Ge76 and immersed in high purity liquid argon, which serves simultaneously as a coolant, radiation shield and scintillation...
In recent years, the search for dark matter with sub-GeV masses has been targeted by a variety of novel experiments that have reached the low-energy thresholds required for detection. Most of the experiments working in this unexplored kinematical regime have observed a large amount of excess events of unknown origin. In this talk, we show that Cherenkov radiation and luminescence originating...
A number of low mass dark matter direct detection experiments have observed an excess rate of events, rising sharply below energies of around 100 eV. A similar source of background energy has been observed to shorten the coherence time of superconducting quantum bits by creating excess quasiparticles in the qubit circuit. The relaxation of stress in detector materials has been shown to cause...
Highly-pixelated solid-state detectors offer outstanding capabilities in the identification and rejection of backgrounds from natural radioactivity. I will present the background identification techniques developed for the DAMIC experiment, which employs silicon CCDs to search for dark matter. DAMIC has demonstrated the capability to disentangle and measure the activities of every $\beta$...
The Jiangmen Underground Neutrino Observatory (JUNO) is a massive multi-purpose underground liquid scintillator detector whose primary scientific goal is the determination of the neutrino mass ordering by measuring the spectrum of the oscillated antineutrinos originating from two nuclear power plants at about 53 km distance. The JUNO detector consists of a central liquid scintillator detector...
Sensitivity of underground experiments searching for rare events due to dark matter or neutrino interactions is often limited by the background caused by neutrons from spontaneous fission and (alpha,n) reactions. A number of codes exist to calculate neutron yields and energy spectra due to these processes. Here we present the calculations of neutron production using the modified SOURCES4 code...
The far detector of the Deep Underground Neutrino Experiment (DUNE) will be located 1500m underground at the Ross campus of the Sanford Underground Research Facility (SURF). The excavation of the two detector halls, that will house together four 17.5kt scale DUNE modules, has commenced. External radiological neutron and gamma-ray backgrounds from the rock, shotcrete and concrete have been...
39Ar and 42Ar are irreducible backgrounds for several argon-based dark matter and neutrino experiments. The use of low-radioactivity underground argon (UAr) could be a solution to the problem. The DarkSide-50 experiment demonstrated that argon derived from underground sources can be highly depleted of 39Ar. Following this success, the Global Argon Dark Matter Collaboration (GADMC) is procuring...
The next-generation Enriched Xenon Observatory (nEXO) is a planned experiment utilizing 5 tonnes of isotopically-enriched liquid xenon (LXe) and a time projection chamber (TPC) to search for neutrinoless double beta decay of $^{136}$Xe. The large, monolithic design of the nEXO TPC provides excellent shielding from the dominant background source - $\gamma$ rays that originate from external...
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for 0νββ decay that has been able to reach the one-tonne mass scale. The detector, located at the LNGS in Italy, consists of an array of 988 TeO2 crystals arranged in a compact cylindrical structure of 19 towers. CUORE began its first physics data run in 2017 at a base temperature of...
CUPID-Mo, located in the Laboratoire Souterrain de Modane, in France, was a demonstrator for CUPID, the next generation neutrinoless double beta decay experiment. CUPID-Mo consisted of 20 enriched Li$_{2}$$^{100}$MoO$_{4}$ bolometers and 20 Ge light detectors, and aimed to demonstrate that the technology of particle identification based on scintillating bolometers is mature for a ton-scale...
Lowering detection limits for materials assay is an ever-growing requirement in ultra-trace detection of analytes via inductively coupled plasma mass spectrometry (ICP-MS). The need for reliable assay methods capable of reaching sub pg·g-1 detection limits for a variety of analytes has necessitated the development of creative approaches for analyte preconcentration and purification in...
