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70-472: The experiment detects scintillation and ionization signals produced when external particles interact in the liquid xenon volume, to search for an excess of nuclear recoil events against known backgrounds. The detection of such a signal would provide the first direct experimental evidence for dark matter candidate particles. The collaboration is currently led by Italian professor of physics Elena Aprile from Columbia University . The XENON experiment operates

140-579: A 30 GeV/ c WIMP mass. Due to nearly half of natural xenon having odd spin states (Xe has an abundance of 26% and spin-1/2; Xe has an abundance of 21% and spin-3/2), the XENON detectors can also be used to provide limits on spin dependent WIMP-nucleon cross sections for coupling of the dark matter candidate particle to both neutrons and protons. XENON10 set the world's most stringent restrictions on pure neutron coupling. The second phase detector, XENON100, contains 165 kg of liquid xenon, with 62 kg in

210-433: A p contact. Coaxial detectors with a central n contact are referred to as n-type detectors, while p-type detectors have a p central contact. The thickness of these contacts represents a dead layer around the surface of the crystal within which energy depositions do not result in detector signals. The central contact in these detectors is opposite to the surface contact, making the dead layer in n-type detectors smaller than

280-416: A certain particle (dE/dx), the "fast" and "slow" states are occupied in different proportions. The relative intensities in the light output of these states thus differs for different dE/dx. This property of scintillators allows for pulse shape discrimination: it is possible to identify which particle was detected by looking at the pulse shape. Of course, the difference in shape is visible in the trailing side of

350-419: A characteristic spectrum is emitted following the absorption of radiation . The scintillation process can be summarized in three main stages: conversion, transport and energy transfer to the luminescence center, and luminescence. The emitted radiation is usually less energetic than the absorbed radiation, hence scintillation is generally a down-conversion process. The first stage of scintillation, conversion,

420-526: A collision point in a particle accelerator can yield an accurate picture of what paths particles take. Silicon detectors have a much higher resolution in tracking charged particles than older technologies such as cloud chambers or wire chambers . The drawback is that silicon detectors are much more expensive than these older technologies and require sophisticated cooling to reduce leakage currents (noise source). They also suffer degradation over time from radiation , however, this can be greatly reduced thanks to

490-418: A dual phase time projection chamber (TPC), which utilizes a liquid xenon target with a gaseous phase on top. Two arrays of photomultiplier tubes (PMTs), one at the top of the detector in the gaseous phase (GXe), and one at the bottom of the liquid layer (LXe), detect scintillation and electroluminescence light produced when charged particles interact in the detector. Electric fields are applied across both

560-537: A few cases mass spectrometry was performed on low mass plastic samples. In doing so the design goal of <10 events/kg/day/keV was reached, realising the world's lowest background rate dark matter detector. The detector was installed at the Gran Sasso National Laboratory in 2008 in the same shield as the XENON10 detector, and has conducted several science runs. In each science run, no dark matter signal

630-474: A few millimeters, germanium can have a sensitive layer (depletion region) thickness of centimeters, and therefore can be used as a total absorption detector for gamma rays up to a few MeV. These detectors are also called high-purity germanium detectors (HPGe) or hyperpure germanium detectors. Before current purification techniques were refined, germanium crystals could not be produced with purity sufficient to enable their use as spectroscopy detectors. Impurities in

700-746: A fiducial volume of about 2 tons. The detector is housed in a 10 m water tank that serves as a muon veto. The TPC is 1 m in diameter and 1 m in height. The detector project team, called the XENON Collaboration, is composed of 135 investigators across 22 institutions from Europe, the Middle East, and the United States. The first results from XENON1T were released by the XENON collaboration on May 18, 2017, based on 34 days of data-taking between November 2016 and January 2017. While no WIMPs or dark matter candidate signals were officially detected,

770-650: A great number of secondary electron–hole pairs are produced until the hot electrons and holes have lost sufficient energy. The large number of electrons and holes that result from this process will then undergo thermalization , i.e. dissipation of part of their energy through interaction with phonons in the material The resulting large number of energetic charge carriers will then undergo further energy dissipation called thermalization. This occurs via interaction with phonons for electrons and Auger processes for holes. The average timescale for conversion, including energy absorption and thermalization has been estimated to be in

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840-611: A low background environment, usually achieved by enclosing the sample and detector in a lead shield known as a 'lead castle'. Automated systems have been developed to sequentially move a number of samples into and out of the lead castle for measurement. Due to the complexities of opening the shield and moving the samples, this automation has traditionally been expensive, but lower-cost autosamplers have recently been introduced. Semiconductor detectors especially HPGe are often integrated into devices for characterising packaged radioactive waste. This can be as simple as detectors being mounted on

910-491: A moveable platform to be brought to an area for in-situ measurements and paired with shielding to restrict the field-of-view of the detector to the area of interest for one-shot "open detector geometry" measurements, or for waste in drums, systems such as the Segmented Gamma Scanner (SGS) combine a semiconductor detector with integrated mechatronics to rotate the item and scan the detector across different sections. If

980-523: A product of π-orbitals . Organic materials form molecular crystals where the molecules are loosely bound by Van der Waals forces . The ground state of C is 1s 2s 2p . In valence bond theory, when carbon forms compounds, one of the 2s electrons is excited into the 2p state resulting in a configuration of 1s 2s 2p . To describe the different valencies of carbon, the four valence electron orbitals, one 2s and three 2p, are considered to be mixed or hybridized in several alternative configurations. For example, in

1050-824: A rather diverse detector as far as applications go. Cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detectors have been developed for use in X-ray spectroscopy and gamma spectroscopy . The high density of these materials means they can effectively attenuate X-rays and gamma-rays with energies of greater than 20 keV that traditional silicon -based sensors are unable to detect. The wide band gap of these materials also means they have high resistivity and are able to operate at, or close to, room temperature (~295K) unlike germanium -based sensors. These detector materials can be used to produce sensors with different electrode structures for imaging and high-resolution spectroscopy . However, CZT detectors are generally unable to match

1120-404: A tetrahedral configuration the s and p orbitals combine to produce four hybrid orbitals. In another configuration, known as trigonal configuration, one of the p-orbitals (say p z ) remains unchanged and three hybrid orbitals are produced by mixing the s, p x and p y orbitals. The orbitals that are symmetrical about the bonding axes and plane of the molecule (sp ) are known as σ-electrons and

1190-442: A variety of additional applications. High-purity germanium detectors are used by Homeland Security to differentiate between naturally occurring radioactive material (NORM) and weaponized or otherwise harmful radioactive material. They are also used in monitering the environment due to the concern of the use of nuclear power. Finally, high-purity germanium detectors are used for medical imaging and nuclear physics research, making them

1260-505: Is a constant that varies between 3 and 4, and E γ {\displaystyle E_{\gamma }} is the energy of the photon. At low X-ray energies, scintillator materials with atoms with high atomic numbers and densities are favored for more efficient absorption of the incident radiation. At higher energies ( E γ {\displaystyle E_{\gamma }} ≳ {\displaystyle \gtrsim } 60 keV) Compton scattering,

1330-528: Is designed to reach a sensitivity (in a small part of the mass-range probed) where neutrinos become a significant background. As of 2019, the upgrade was on-going and first light was expected in 2020. The XENONnT detector was under construction in March 2020. Even with the problems posed by COVID-19, the project was able to finish construction and move forwards into commissioning phase by mid 2020. Full detector operations commenced in late 2020. In September 2021, XENONnT

1400-457: Is measured by the number of charge carriers set free in the detector material which is arranged between two electrodes , by the radiation. Ionizing radiation produces free electrons and electron holes . The number of electron-hole pairs is proportional to the energy of the radiation to the semiconductor. As a result, a number of electrons are transferred from the valence band to the conduction band , and an equal number of holes are created in

1470-503: Is referred to as the S2 signal. This technique has proved sensitive enough to detect S2 signals generated from single electrons. The detector allows for a full 3-D position determination of the particle interaction. Electrons in liquid xenon have a uniform drift velocity. This allows the interaction depth of the event to be determined by measuring the time delay between the S1 and S2 signal. The position of

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1540-436: Is still often quoted in relative terms to a "standard" 3″ x 3″ NaI(Tl) scintillation detector. Crystal growth techniques have since improved, allowing detectors to be manufactured that are as large as or larger than commonly available NaI crystals, although such detectors cost more than €100,000 (US$ 113,000). As of 2012 , HPGe detectors commonly use lithium diffusion to make an n ohmic contact , and boron implantation to make

1610-425: Is the rest mass of the electron and c {\displaystyle c} is the speed of light . Hence, at high γ-ray energies, the energy absorption depends both on the density and average atomic number of the scintillator. In addition, unlike for the photoelectric effect and Compton scattering, pair production becomes more probable as the energy of the incident photons increases, and pair production becomes

1680-406: Is the linear attenuation coefficient, which is the sum of the attenuation coefficients of the various contributions: At lower X-ray energies ( E γ ≲ {\displaystyle E_{\gamma }\lesssim } 60 keV), the most dominant process is the photoelectric effect, where the photons are fully absorbed by bound electrons in the material, usually core electrons in

1750-411: Is the physical process where a material, called a scintillator , emits ultraviolet or visible light under excitation from high energy photons ( X-rays or gamma rays ) or energetic particles (such as electrons , alpha particles , neutrons , or ions ). See scintillator and scintillation counter for practical applications. Scintillation is an example of luminescence , whereby light of

1820-570: Is the process where the energy from the incident radiation is absorbed by the scintillator and highly energetic electrons and holes are created in the material. The energy absorption mechanism by the scintillator depends on the type and energy of radiation involved. For highly energetic photons such as X-rays (0.1 keV < E γ {\displaystyle E_{\gamma }} < 100 keV) and γ-rays ( E γ {\displaystyle E_{\gamma }} > 100 keV), three types of interactions are responsible for

1890-445: The K- or L-shell of the atom, and then ejected, leading to the ionization of the host atom. The linear attenuation coefficient contribution for the photoelectric effect is given by: where ρ {\displaystyle \rho } is the density of the scintillator, Z {\displaystyle Z} is the average atomic number, n {\displaystyle n}

1960-565: The LZ experiment published its first results too excluding cross sections above 9.2 × 10 − 48 c m 2 {\displaystyle 9.2\times 10^{-48}cm^{2}} at 36 GeV with 90% confidence level. 42°25′14″N 13°30′59″E  /  42.42056°N 13.51639°E  / 42.42056; 13.51639 Scintillation (physics) In condensed matter physics , scintillation ( / ˈ s ɪ n t ɪ l eɪ ʃ ən / SIN -til-ay-shun )

2030-553: The Lazarus effect . Diamond detectors have many similarities with silicon detectors but are expected to offer significant advantages – in particular a high radiation hardness and very low drift currents. They are also suited to neutron detection. At present, however, they are much more expensive and more difficult to manufacture. Germanium detectors are mostly used for gamma spectroscopy in nuclear physics , as well as x-ray spectroscopy . While silicon detectors cannot be thicker than

2100-479: The Schrödinger wave equation are: where q is the orbital ring quantum number; the number of nodes of the wave-function. Since the electron can have spin up and spin down and can rotate about the circle in both directions all of the energy levels except the lowest are doubly degenerate. The above shows the π-electronic energy levels of an organic molecule. Absorption of radiation is followed by molecular vibration to

2170-408: The S 1 state. This is followed by a de-excitation to the S 0 state called fluorescence. The population of triplet states is also possible by other means. The triplet states decay with a much longer decay time than singlet states, which results in what is called the slow component of the decay process (the fluorescence process is called the fast component). Depending on the particular energy loss of

XENON - Misplaced Pages Continue

2240-624: The TPC measures 20 cm in diameter and 15 cm in height. An analysis of 59 live days of data, taken between October 2006 and February 2007, produced no WIMP signatures. The number of events observed in the WIMP search region is statistically consistent with the expected number of events from electronic recoil backgrounds. This result excluded some of the available parameter space in minimal Supersymmetric models , by placing limits on spin independent WIMP-nucleon cross sections down to below 10 × 10 cm for

2310-477: The XENON1T collaboration reported an excess of electron recoils: 285 events, 53 more than the expected 232 with a statistical significance of 3.5σ. Three explanations were considered: existence of to-date-hypothetical solar axions , a surprisingly large magnetic moment for neutrinos, and tritium contamination in the detector. Multiple other explanations were given later by others groups and in 2021 an interpretation of

2380-457: The bonds are called σ-bonds. The p z orbital is called a π-orbital. A π-bond occurs when two π-orbitals interact. This occurs when their nodal planes are coplanar. In certain organic molecules π-orbitals interact to produce a common nodal plane. These form delocalized π-electrons that can be excited by radiation. The de-excitation of the delocalized π-electrons results in luminescence. The excited states of π-electron systems can be explained by

2450-417: The conduction band, where they are free to respond to the electric field, producing too much electrical noise to be useful as a spectrometer. Cooling to liquid nitrogen temperature (77K) reduces thermal excitations of valence electrons so that only a gamma ray interaction can give an electron the energy necessary to cross the band gap and reach the conduction band. Cooling with liquid nitrogen is inconvenient, as

2520-442: The contribution from Rayleigh scattering is almost negligible and photonuclear reactions become relevant only at very high energies. After the energy of the incident radiation is absorbed and converted into so-called hot electrons and holes in the material, these energetic charge carriers will interact with other particles and quasi-particles in the scintillator (electrons, plasmons , phonons ), leading to an "avalanche event", where

2590-442: The crystals trap electrons and holes, ruining the performance of the detectors. Consequently, germanium crystals were doped with lithium ions (Ge(Li)), in order to produce an intrinsic region in which the electrons and holes would be able to reach the contacts and produce a signal. When germanium detectors were first developed, only very small crystals were available. Low efficiency was the result, and germanium detector efficiency

2660-416: The dead layer in p-type detectors. Typical dead layer thicknesses are several hundred micrometers for a Li diffusion layer and a few tenths of a micrometer for a B implantation layer. The major drawback of germanium detectors is that they must be cooled to liquid nitrogen temperatures to produce spectroscopic data. At higher temperatures, the electrons can easily cross the band gap in the crystal and reach

2730-467: The detector requires hours to cool down to operating temperature before it can be used, and cannot be allowed to warm up during use. Ge(Li) crystals could never be allowed to warm up, as the lithium would drift out of the crystal, ruining the detector. HPGe detectors can be allowed to warm up to room temperature when not in use. Commercial systems became available that use advanced refrigeration techniques (for example pulse tube refrigerator ) to eliminate

2800-454: The electrons produced from a charged particle interaction in the TPC. These electrons are drifted to the top of the liquid phase by the electric field. The ionization is then extracted into the gas phase by the stronger electric field in the gaseous phase. The electric field accelerates the electrons to the point that it creates a proportional scintillation signal that is also collected by the PMTs, and

2870-675: The electrons travel fast, the time resolution is also very good, and is dependent upon rise time . Compared with gaseous ionization detectors , the density of a semiconductor detector is very high, and charged particles of high energy can give off their energy in a semiconductor of relatively small dimensions. Most silicon particle detectors work, in principle, by doping narrow (usually around 100 micrometers wide) silicon strips to turn them into diodes , which are then reverse biased . As charged particles pass through these strips, they cause small ionization currents that can be detected and measured. Arranging thousands of these detectors around

XENON - Misplaced Pages Continue

2940-407: The energy conversion process in scintillation: photoelectric absorption , Compton scattering , and pair production , which only occurs when E γ {\displaystyle E_{\gamma }} > 1022 keV, i.e. the photon has enough energy to create an electron-positron pair. These processes have different attenuation coefficients , which depend mainly on the energy of

3010-404: The event in the x-y plane can be determined by looking at the number of photons seen by each of the individual PMTs. The full 3-D position allows for the fiducialization of the detector, in which a low-background region is defined in the inner volume of the TPC. This fiducial volume has a greatly reduced rate of background events as compared to regions of the detector at the edge of the TPC, due to

3080-463: The first direct observation of two-neutrino double electron capture in xenon-124 nuclei. The measured half-life of this process, which is several orders of magnitude larger than the age of the Universe, demonstrates the capabilities of xenon-based detectors to search for rare events and showcases the broad physics reach of even larger next-generation experiments. This measurement represents a first step in

3150-409: The incident radiation, measuring the number of electron-hole pairs allows the energy of the incident radiation to be determined. The energy required to produce electron-hole-pairs is very low compared to the energy required to produce paired ions in a gas detector. Consequently, in semiconductor detectors the statistical variation of the pulse height is smaller and the energy resolution is higher. As

3220-417: The incident radiation, the average atomic number of the material and the density of the material. Generally the absorption of high energy radiation is described by: where I 0 {\displaystyle I_{0}} is the intensity of the incident radiation, d {\displaystyle d} is the thickness of the material, and μ {\displaystyle \mu }

3290-582: The inelastic scattering of photons by bound electrons, often also leading to ionization of the host atom, becomes the more dominant conversion process. The linear attenuation coefficient contribution for Compton scattering is given by: Unlike the photoelectric effect, the absorption resulting from Compton scattering is independent of the atomic number of the atoms present in the crystal, but linearly on their density. At γ-ray energies higher than E γ {\displaystyle E_{\gamma }} > 1022 keV, i.e. energies higher than twice

3360-416: The laboratory provides 3100 m of water-equivalent shielding. The detector was placed within a shield to further reduce the background rate in the TPC. XENON10 was intended as a prototype detector, to prove the efficacy of the XENON design, as well as verify the achievable threshold, background rejection power and sensitivity. The XENON10 detector contained 15 kg of liquid xenon. The sensitive volume of

3430-449: The liquid and gaseous phase of the detector. The electric field in the gaseous phase has to be sufficiently large to extract electrons from the liquid phase. Particle interactions in the liquid target produce scintillation and ionization . The prompt scintillation light produces 178 nm ultraviolet photons. This signal is detected by the PMTs, and is referred to as the S1 signal. The applied electric field prevents recombination of all

3500-399: The luminescent center, and then the electrons and hole recombine radiatively . The exact details of the luminescence phase also depend on the type of material used for scintillation. For photons such as gamma rays, thallium activated NaI crystals (NaI(Tl)) are often used. For a faster response (but only 5% of the output) CsF crystals can be used. In organic molecules scintillation is

3570-413: The material. This is probably one of the most critical phases of scintillation, since it is generally in this stage where most loss of efficiency occur due to effects such as trapping or non-radiative recombination . These are mainly caused by the presence of defects in the scintillator crystal, such as impurities, ionic vacancies, and grain boundaries . The charge transport can also become a bottleneck for

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3640-414: The most dominant conversion process above E γ {\displaystyle E_{\gamma }} ~ 8 MeV. The μ o c {\displaystyle \mu _{oc}} term includes other (minor) contributions, such as Rayleigh (coherent) scattering at low energies and photonuclear reactions at very high energies, which also contribute to the conversion, however

3710-536: The need for liquid nitrogen cooling. Germanium detectors with multi-strip electrodes, orthogonal on opposing faces, can indicate the 2-D location of the ionization trail within a large single crystal of Ge. Detectors like this have been used in COSI balloon-born astronomy missions (NASA, 2016) and will be used in an orbital observatory (NASA, 2025) Compton Spectrometer and Imager (COSI). Because germanium detectors are highly efficient in photon detection, they can be used for

3780-420: The order of 1 ps, which is much faster than the average decay time in photoluminescence . The second stage of scintillation is the charge transport of thermalized electrons and holes towards luminescence centers and the energy transfer to the atoms involved in the luminescence process. In this stage, the large number of electrons and holes that have been generated during the conversion process, migrate inside

3850-431: The perimeter free-electron model (Platt 1949). This model is used for describing polycyclic hydrocarbons consisting of condensed systems of benzenoid rings in which no C atom belongs to more than two rings and every C atom is on the periphery. The ring can be approximated as a circle with circumference l. The wave-function of the electron orbital must satisfy the condition of a plane rotator: The corresponding solutions to

3920-512: The pulse, since it is due to the decay of the excited states. Semiconductor detector#Germanium detectors A semiconductor detector in ionizing radiation detection physics is a device that uses a semiconductor (usually silicon or germanium ) to measure the effect of incident charged particles or photons. Semiconductor detectors find broad application for radiation protection , gamma and X-ray spectrometry , and as particle detectors . In semiconductor detectors, ionizing radiation

3990-535: The ratio of S2/S1 can be used as a discrimination parameter to distinguish electronic and nuclear recoil events. This ratio is expected to be greater for electronic recoils than for nuclear recoils. In this way backgrounds from electronic recoils can be suppressed by more than 99%, while simultaneously retaining 50% of the nuclear recoil events. The XENON10 experiment was installed at the underground Gran Sasso laboratory in Italy during March 2006. The underground location of

4060-587: The resolution of germanium detectors, with some of this difference being attributable to poor positive charge-carrier transport to the electrode. Efforts to mitigate this effect have included the development of novel electrodes to negate the need for both polarities of carriers to be collected. Semiconductor detectors are often commercially integrated into larger systems for various radiation measurement applications. Gamma spectrometers using HPGe detectors are often used for measurement of low levels of gamma-emitting radionuclides in environmental samples, which requires

4130-465: The rest-mass energy of the electron, pair production starts to occur. Pair production is the relativistic phenomenon where the energy of a photon is converted into an electron-positron pair. The created electron and positron will then further interact with the scintillating material to generate energetic electron and holes. The attenuation coefficient contribution for pair production is given by: where m e {\displaystyle m_{e}}

4200-547: The results not as dark matter particles but of as dark energy particles candidates called chameleons has also been discussed. In July 2022 a new analysis by XENONnT discarded the excess. XENONnT is an upgrade of the XENON1T experiment underground at LNGS. Its systems will contain a total xenon mass of more than 8 tonnes. Apart from a larger xenon target in its time projection chamber the upgraded experiment will feature new components to further reduce or tag radiation that otherwise would constitute background to its measurements. It

4270-415: The search for the neutrinoless double electron capture process, the detection of which would provide insight into the nature of the neutrino and allow to determine its absolute mass. As of 2019, the XENON1T experiment has stopped data-taking to allow for construction of the next phase, XENONnT. The XENON1T detector operated 2016–2018, with the detector operations ending at the end of 2018. In June 2020,

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4340-403: The self-shielding properties of liquid xenon. This allows for a much higher sensitivity when searching for very rare events. Charged particles moving through the detector are expected to either interact with the electrons of the xenon atoms producing electronic recoils, or with the nucleus, producing nuclear recoils. For a given amount of energy deposited by a particle interaction in the detector,

4410-452: The sensitivity to WIMPs . In September 2018 the XENON1T experiment published its results from 278.8 days of collected data. A new record limit for WIMP-nucleon spin-independent elastic interactions was set, with a minimum of 4.1 × 10 cm at a WIMP mass of 30 GeV/ c . In April 2019, based on measurements performed with the XENON1T detector, the XENON Collaboration reported in Nature

4480-494: The spin dependent WIMP-nucleon cross section. An axion result was published in 2014, setting a new best axion limit. XENON100 operated the then-lowest background experiment, for dark matter searches, with a background of 50 mDRU (1 mDRU=10 events/kg/day/keV). Construction of the next phase, XENON1T, started in Hall B of the Gran Sasso National Laboratory in 2014. The detector contains 3.2 tons of ultra radio-pure liquid xenon, and has

4550-424: The target region and the remaining xenon in an active veto. The TPC of the detector has a diameter of 30 cm and a height of 30 cm. As WIMP interactions are expected to be extremely rare events, a thorough campaign was launched during the construction and commissioning phase of XENON100 to screen all parts of the detector for radioactivity. The screening was performed using high-purity Germanium detectors . In

4620-456: The team did announce a record low reduction in the background radioactivity levels being picked up by XENON1T. The exclusion limits exceeded the previous best limits set by the LUX experiment , with an exclusion of cross sections larger than 7.7 × 10 cm for WIMP masses of 35 GeV/ c . Because some signals that the detector receives might be due to neutrons, reducing the radioactivity increases

4690-423: The timing of the scintillation process. The charge transport phase is also one of the least understood parts of scintillation and depends strongly on the type material involved and its intrinsic charge conduction properties. Once the electrons and holes reach the luminescence centers, the third and final stage of scintillation occurs: luminescence. In this stage the electrons and holes are captured potential paths by

4760-460: The valence band. Under the influence of an electric field , electrons and holes travel to the electrodes, where they result in a pulse that can be measured in an outer circuit , as described by the Shockley-Ramo theorem . The holes travel in the opposite direction and can also be measured. As the amount of energy required to create an electron-hole pair is known, and is independent of the energy of

4830-454: Was observed above the expected background, leading to the most stringent limit on the spin independent WIMP-nucleon cross section in 2012, with a minimum at 2.0 × 10 cm for a 65 GeV/ c WIMP mass. These results constrain interpretations of signals in other experiments as dark matter interactions, and rule out exotic models such as inelastic dark matter, which would resolve this discrepancy. XENON100 has also provided improved limits on

4900-449: Was taking science data for its first science run, which was ongoing at the time. On 28 July 2023 the XENONnT published the first results of its search for WIMPs, excluding cross sections above 2.58 × 10 − 47 c m 2 {\displaystyle 2.58\times 10^{-47}cm^{2}} at 28 GeV with 90% confidence level, jointly on the same date

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