Design And Development Of An Autonomous Radar Receiver For The Detection Of Ultra High Energy Cosmic Rays

The detection of ultra-high energy cosmic rays is constrained by their flux, requiring detectors with apertures of hundreds or even thousands of square kilometers and close to one hundred percent duty cycle. The sheer scale that would be required of conventional detectors, to acquire sufficient statistics for energy, composition or anisotropy studies, means that new techniques that reduce manpower and financial resources are continually being sought. In this dissertation, the development of a remote sensing technique based observatory known as bistatic radar, which aims to achieve extensive coverage of the Earth's surface, cf. Telescope Array's 700 km2 surface detector, is discussed. Construction of the radar projects transmitter station was completed in the summer of 2013, and remote receiver stations were deployed in June and November of 2014. These stations accomplish radar echo detection using an analog signal chain. Subject to less radio interference, the remote stations add stereoscopic measurement capabilities that theoretically allow unique determination of cosmic ray geometry and core location. An FPGA is used as a distributed data processing node within the project. The FPGA provides triggering logic for data sampled at 200 MSa/s, detecting Cosmic Ray shower echoes chirping at -1 to -10 Megahertz/microsecond (depending on the geometry) for several microseconds. The data acquisition system with low power consumption at a cost that is also comparatively inexpensive is described herein

A Double Layered Water Cherenkov Detector Array for Gamma-Ray Astronomy

Ground-level particle detection is now a well-established approach to TeV gamma-ray astronomy. Detection of Cherenkov light produced in water-filled detection units is a proven and cost-effective method. Here we discuss the optimization of the units towards the future Southern Wide-field Gamma-ray Observatory (SWGO). In this context, we investigate a new type of configuration in which each water Cherenkov detector (WCD) unit in the array comprises two chambers with black or reflective walls and a single photomultiplier tube (PMT) in each chamber. We find that this is a cost-effective approach that improves the performance of the WCD array with respect to current approaches. A shallow lower chamber with a PMT facing downwards enables muon tagging and the identification of hadron-induced air showers, which are the primary source of background in gamma-ray astronomy. We investigate how gamma/hadron separation power and achievable angular resolution depend on the geometry and wall reflectivity of the detector units in this configuration. We find that excellent angular resolution, background rejection power and low-energy response are achievable in this double-layer configuration, with the aid of reflective surfaces in both chambers.Comment: 17 pages, 20 figure

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With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino ‘track’ events from the Northern Hemisphere, while the second analysis uses 2 years of ‘cascade’ events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than $10^{28}$ s at 90% CL for dark matter masses above 10 TeV

High Altitude Sites for Astroparticle Observatories in Peru

International audienceThis paper describes four high altitude sites in southern Peru that were visited, in March 2019, by members of the SGSO Alliance (currently the SWGO Collaboration). The sites are located above 4000 m.a.s.l. with access to water resources and are located between 1 to 4 hours drive from the closest airport. Peruvian authorities, local populations and universities offer support and encourage international collaborations to consider these sites for Astroparticle Observatories

Detector developments for a hybrid particle and radio array for cosmic-ray air-shower detection

Large-scale air-shower arrays could profit from a radio sub-detector as the radio emission in air showers is sensitive to the electromagnetic component. In particular, with an array of radio antennas in combination with particle detectors highly inclined EAS can be detected. This gives rise to new science cases, e.g. the search for PeV gamma rays coming from the Galactic Center at the South Pole, from where it is visible all over the year at an inclination of 61° degree. We report on progress and plans in the development of an optimized hybrid detector

Probing the Neutrino Mass Ordering with Atmospheric Neutrinos from Three Years of IceCube DeepCore Data

The Neutrino Mass Ordering (NMO) remains one of the outstanding questions in the field of neutrino physics. One strategy to measure the NMO is to observe matter effects in the oscillation pattern of atmospheric neutrinos above $\sim 1\,\mathrm{GeV}$, as proposed for several next-generation neutrino experiments. Moreover, the existing IceCube DeepCore detector can already explore this type of measurement. We present results of a first search for the signature of the NMO with three years of DeepCore data based on two independent analyses. These analyses include a full treatment of systematic uncertainties and a statistically-rigorous method to determine the significance for the NMO from a fit to the data. For the more sensitive analysis, we observe a preference for Normal Ordering with a $p$-value of $p_\mathrm{IO} = 15.3\%$ and $\mathrm{CL}_\mathrm{s}=53.3\%$ for the Inverted Ordering hypothesis, while the experimental results from both analyses are consistent within their uncertainties. Since the result is independent of the value of $\delta_\mathrm{CP}$ and obtained from energies $E_\nu \gtrsim 5\,\mathrm{GeV}$, it is complementary to recent results from long-baseline experiments. These analyses set the groundwork for the future of this measurement with more capable detectors, such as the IceCube Upgrade and the proposed PINGU detector

Search for neutrinos from decaying dark matter with IceCube

With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino ‘track’ events from the Northern Hemisphere, while the second analysis uses 2 years of ‘cascade’ events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than $10^{28}$ s at 90% CL for dark matter masses above 10 TeV

Detection of the temporal variation of the Sun's cosmic ray shadow with the IceCube detector

We report on the observation of a deficit in the cosmic ray flux from the directions of the Moon and Sun with five years of data taken by the IceCube Neutrino Observatory. Between May 2010 and May 2011 the IceCube detector operated with 79 strings deployed in the glacial ice at the South Pole, and with 86 strings between May 2011 and May 2015. A binned analysis is used to measure the relative deficit and significance of the cosmic ray shadows. Both the cosmic ray Moon and Sun shadows are detected with high statistical significance ($>10\sigma$) for each year. The results for the Moon shadow are consistent with previous analyses and verify the stability of the IceCube detector over time. This work represents the first observation of the Sun shadow with the IceCube detector. We show that the cosmic ray shadow of the Sun varies with time. These results open the possibility to study cosmic ray transport near the Sun with future data from IceCube

Formation of a Renewable Amine and an Alcohol via Transformations of 3‑Acetamido-5-acetylfuran

The reactivity of the renewable amide 3-acetamido-5-acetylfuran (3A5AF) was explored. Hydrolysis of the amido group to yield the amino-substituted furan, 2-acetyl-4-aminofuran (<b>1</b>), was achieved via NaOH catalysis. Reduction of the acetyl group could be achieved stoichiometrically using NaBH₄ or catalytically via transfer hydrogenation using an Ir catalyst. The product alcohol, 3-acetamido-5-(1-hydroxylethyl)­furan (<b>2</b>), underwent dehydration during analysis via GC-MS to yield an alkene (<b>3</b>). The potential reactivity of 3A5AF and <b>1</b> toward carbon dioxide was studied, but no reaction was observed due to the inherent acidity of 3A5AF and <b>1</b> despite the latter being an amine. The computationally determined p<i>K</i>_a values for 3A5AF and <b>1</b> are reported. Interestingly, in this work, tautomerism of 3A5AF was observed in CD₃OD as evidenced by H–D exchange within the acetyl group