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1.
Analysis Result of the High-Energy Cosmic-Ray Proton Spectrum from the ISS-CREAM Experiment
G. Choi, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment successfully recorded the data for about 539 days from August 2017 to February 2019. In this talk, we report the measurement of the cosmic-ray proton energy spectrum from the ISS-CREAM experiment in the energy range of 2.5 TeV - 650 TeV. For the analysis, we used the silicon charge detector (SCD) placed at the top of the ISS-CREAM payload to identify the incoming cosmic-ray charge. The SCD is finely segmented to minimize charge misidentification due to backscatter effects. The four-layer SCD consists of 10,752 silicon pixels, each of which is 1.37×1.57×0.05 cm^3 in size. The calorimeter (CAL) consists of 20 layers of tungsten/scintillating fibers preceded by carbon targets. It provided cosmic-ray tracking, energy determination, and the high-energy trigger. The Top and Bottom Counting detectors (T/BCD) are above and below the CAL, respectively, and provided the low energy trigger. Each T/BCD is composed of an array of 20×20 photodiodes on plastic scintillators. The measured proton spectral index of 2.67±0.02 between 2.5 and 12.5 TeV is consistent with prior CREAM measurements. The spectrum softens above ∼10 TeV consistent with the bump-like structure as reported by CREAM-I+III, DAMPE, and NUCLEON, but ISS-CREAM extends measurements to higher energies than those prior measurement
Ključne besede: ISS-CREAM, silicon charge detector, calorimeter, direct detection, cosmic rays, protons, energy spectrum
Objavljeno v RUNG: 26.09.2023; Ogledov: 546; Prenosov: 6
.pdf Celotno besedilo (2,06 MB)
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2.
Results from the Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment
E.S. Seo, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment took high-energy cosmic ray data for 539 days after its successful installation on the ISS in August 2017. The ISS-CREAM instrument is configured with complementary particle detectors capable of measuring elemental spectra for Z = 1 - 26 nuclei in the energy range 10^12 – 10^15 eV; as well as electrons at multi-TeV energies. The goal is to understand cosmic ray origin, acceleration, and propagation by extending direct measurements of cosmic rays to energies that overlap the energy region of air showers measurements. The four layers of finely segmented Silicon Charge Detectors provide precise charge measurements. They have been designed to minimize hits of accompanying backscattered particles in the same segment as the incident cosmic ray particle to avoid charge misidentification. The sampling tungsten/scintillating-fiber calorimeter, which is identical to the calorimeter for prior CREAM balloon flights, provides energy measurements. In addition, scintillator-based Top and Bottom Counting Detectors distinguish electrons from nuclei. Our analysis indicates that the data extend well above 100 TeV. Recent results from the ongoing analysis are presented.
Ključne besede: ISS-CREAM, silicon charge detector, calorimeter, direct detection, cosmic rays, electrons, energy spectrum, composition
Objavljeno v RUNG: 26.09.2023; Ogledov: 612; Prenosov: 6
.pdf Celotno besedilo (901,39 KB)
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3.
Cosmic-ray Heavy Nuclei Spectra Using the ISS-CREAM Instrument
S.C. Kang, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) was designed to study high-energy cosmic rays up to PeV and recorded data from August 22nd, 2017 to February 12th, 2019 on the ISS. In this analysis, the Silicon Charge Detector (SCD), CALorimeter (CAL), and Top and Bottom Counting Detectors (TCD/BCD) are used. The SCD is composed of four layers and provides the measurement of cosmic-ray charges with a resolution of ∼0.2e. The CAL comprises 20 interleaved tungsten plates and scintillators, measures the incident cosmic-ray particles' energies, and provides a high energy trigger. The TCD/BCDs consist of photodiode arrays and plastic scintillators and provide a low-energy trigger. In this analysis, the SCD top layer is used for charge determination. Here, we present the heavy nuclei analysis using the ISS-CREAM instrument.
Ključne besede: ISS-CREAM, silicon charge detector, calorimeter, direct detection, heavy nuclei, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 26.09.2023; Ogledov: 514; Prenosov: 5
.pdf Celotno besedilo (1,82 MB)
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4.
Beam Test Results of the ISS-CREAM Calorimeter
H.G. Zhang, Jon Paul Lundquist, 2022, objavljeni znanstveni prispevek na konferenci

Opis: The Cosmic Ray Energetics And Mass experiment for the International Space Station (ISS-CREAM) was installed on the ISS to measure high-energy cosmic-ray elemental spectra for the charge range Z=1 to 26. The ISS-CREAM instrument includes a tungsten scintillating-fiber calorimeter preceded by carbon targets for energy measurements. The carbon targets induces hadronic interactions, and showers of secondary particles develop in the calorimeter. The calorimeter was calibrated with electron beams at CERN. This beam test included position, energy, and angle scans of electron and pion beams together with a high-voltage scan for calibration and characterization. Additionally, an attenuation effect in the scintillating fibers was studied. In this paper, beam test results, including corrections for the attenuation effect, are presented.
Ključne besede: ISS-CREAM, calorimeter, particle accelerator, CERN, electron beam, direct detection, cosmic rays, energy spectrum, composition
Objavljeno v RUNG: 26.09.2023; Ogledov: 563; Prenosov: 4
.pdf Celotno besedilo (1003,73 KB)
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5.
6.
Search for Physics beyond the Standard Model with the CRESST Experiment
2017, magistrsko delo

Opis: In spite of the successes of observational astro- and particle physics and cosmology very much of the universe remains unknown. The Standard Model of particle physics is a theory describing the electromagnetic, weak, and strong nuclear interactions, as well as classifying all the subatomic particles known. But there is overwhelming evidence, that all the known particles, the ordinary (baryonic) matter, the building blocks of planets, stars and ourselves, only make up about 4.9% of the energy content of the universe. The standard model of cosmology (CDM) indicates that the total mass-energy of the universe contains beside the 4.9% ordinary matter two other components: 26.8% dark matter and 68.3% dark energy. The accelerating expansion of the Universe is the result of the effect of the dark energy with its most simple form given by a cosmological constant in Einstein's Equation. Dark matter is an unidentified type of matter that is not accounted for by dark energy and neutrinos and is generally believed to be a non-relativistic, charge neutral and non-baryonic new form of matter. Although dark matter has not been directly observed yet, its existence and properties are inferred from its gravitational effects such as the motions of visible matter, gravitational lensing, its influence on the universe's large-scale structure, and its effects in the cosmic microwave background. Thus the search for Dark Matter is the search for physics beyond the standard model. Although the nature of dark matter is yet unknown, its presence is crucial to understanding the future of the universe. The CRESST experiment is searching for direct evidence in the form of a nuclear recoil induced on a scintillating CaWO4 crystal by a dark matter particle, and is installed and taking data underground at Laboratory Nazionali del Gran Sasso (LNGS) in Italy. While both, dark energy and dark matter, have not been detected directly, a class of dark matter particles that interact only via gravity and the weak force, referred to asWeakly Interacting Massive Particles (WIMPs), has been established as the leading candidate among the dark matter community. For this thesis a special model of dark matter was studied, namely the dark photon. This thesis provides a detailed description of the calculation of the 90% upper limit on the dark photon kinetic mixing based on data from the second phase of the CRESST experiment. The analysis was carried out in a frequentist approach based on the (unbinned) maximum-likelihood method and likelihood ratios. To make a statement about the calculated result and its quality, the used algorithm had to be tested, what was done with Monte Carlo simulations (pseudo data).
Ključne besede: astro physics, particle physics, cosmology, universe, Standard Model of particle physics, standard model of cosmology, matter, ordinary matter, dark matter, dark energy, accelerating expansion of the Universe, non-baryonic, new form of matter, gravitational lensing, cosmic microwave background, search for physics beyond the standard model, CRESST experiment, direct detection, CaWO4 crystal, underground laboratory, Laboratory Nazionali del Gran Sasso, Weakly Interacting Massive Particles, WIMP, dark photon, 90% upper limit, upper limit, kinetic mixing, frequentist approach, unbinned, maximum likelihood
Objavljeno v RUNG: 13.10.2017; Ogledov: 4435; Prenosov: 0
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