141 research outputs found
The Scintillator Upgrade of IceTop: Performance of the prototype array
The IceCube Collaboration foresees to upgrade IceTop, the present surface
array, with scintillator detectors augmented by radio antennas. As one of
several goals the scintillator detectors will be used to measure and mitigate
the effects of snow accumulation on the IceTop tanks: the increasing energy
threshold and efficiency loss are nowadays the sources of the largest
systematic uncertainties in shower reconstruction and mass composition
analysis. In addition, the upgrade will provide useful experience for the
development of next generation neutrino detectors proposed for the South Pole.
In the Austral summer season, 2017-2018 two full "stations" were installed near
the center of the IceTop array. Each station features custom-designed
electronics and consists of seven detectors, each having an active area of
1.5m plastic scintillator and wavelength shifting fibers read out by a
Silicon Photomultiplier. In this contribution we review the detector design and
performance, and show results from more than one year of operation of the
prototype stations. During that year several thousand air shower events have
been measured in coincidence with IceTop.Comment: Presented at the 36th International Cosmic Ray Conference (ICRC
2019). See arXiv:1907.11699 for all IceCube contribution
Magnetically-coupled piston pump for high-purity gas applications
Experiments based on noble elements such as gaseous or liquid argon or xenon
utilize the ionization and scintillation properties of the target materials to
detect radiation-induced recoils. A requirement for high light and charge
yields is to reduce electronegative impurities well below the ppb level. To
achieve this, the target material is continuously circulated in the gas phase
through a purifier and returned to the detector. Additionally, the low
backgrounds necessary dictate low-Rn-emanation rates from all components that
contact the gas.
Since commercial pumps often introduce electronegative impurities from
lubricants on internal components or through small air leaks, and are not
designed to meet the radiopurity requirements, custom-built pumps are an
advantageous alternative. A new pump has been developed in Muenster in
cooperation with the nEXO group at Stanford University and the nEXO/XENON group
at Rensselaer Polytechnic Institute based on a magnetically-coupled piston in a
hermetically sealed low-Rn-emanating vessel. This pump delivers high
performance for noble gases, reaching more than 210 standard liters per minute
(slpm) with argon and more than 170 slpm with xenon while maintaining a
compression of up to 1.9 bar, demonstrating its capability for noble gas
detectors and other applications requiring high standards of gas purity.Comment: 11 pages, 18 figure
Multi-messenger searches via IceCube’s high-energy neutrinos and gravitational-wave detections of LIGO/Virgo
We summarize initial results for high-energy neutrino counterpart searches coinciding with gravitational-wave events in LIGO/Virgo\u27s GWTC-2 catalog using IceCube\u27s neutrino triggers. We did not find any statistically significant high-energy neutrino counterpart and derived upper limits on the time-integrated neutrino emission on Earth as well as the isotropic equivalent energy emitted in high-energy neutrinos for each event
In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory
The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p
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