The origin and nature of extreme energy cosmic rays (EECRs), which have energies above the
5
⋅
10
19
eV
—the Greisen-Zatsepin-Kuzmin (GZK) energy limit, is one of the most interesting and complicated ...problems in modern cosmic-ray physics. Existing ground-based detectors have helped to obtain remarkable results in studying cosmic rays before and after the GZK limit, but have also produced some contradictions in our understanding of cosmic ray mass composition. Moreover, each of these detectors covers only a part of the celestial sphere, which poses problems for studying the arrival directions of EECRs and identifying their sources. As a new generation of EECR space detectors, TUS (Tracking Ultraviolet Set-up), KLYPVE and JEM-EUSO, are intended to study the most energetic cosmic-ray particles, providing larger, uniform exposures of the entire celestial sphere. The TUS detector, launched on board the Lomonosov satellite on April 28, 2016 from Vostochny Cosmodrome in Russia, is the first of these. It employs a single-mirror optical system and a photomultiplier tube matrix as a photo-detector and will test the fluorescent method of measuring EECRs from space. Utilizing the Earth’s atmosphere as a huge calorimeter, it is expected to detect EECRs with energies above
10
20
eV
.
It will also be able to register slower atmospheric transient events: atmospheric fluorescence in electrical discharges of various types including precipitating electrons escaping the magnetosphere and from the radiation of meteors passing through the atmosphere. We describe the design of the TUS detector and present results of different ground-based tests and simulations.
Abstract
The violation of baryon number,
B
, is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. ...However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron–antineutron oscillation (
n
→
n
̄
) via mixing, neutron–antineutron oscillation via regeneration from a sterile neutron state (
n
→
n
′
,
n
̄
′
→
n
̄
), and neutron disappearance (
n
→
n
′); the effective
Δ
B
=
0
process of neutron regeneration (
n
→
n
′
,
n
̄
′
→
n
) is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis and the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches. The opportunity to make such a leap in sensitivity tests should not be squandered. The experiment pulls together a diverse international team of physicists from the particle (collider and low energy) and nuclear physics communities, while also including specialists in neutronics and magnetics.
TUS (Tracking Ultraviolet Set-up) is the world's first orbital detector of ultra-high-energy cosmic rays (UHECRs). It was launched into orbit on 28th April 2016 as a part of the scientific payload of ...the Lomonosov satellite. The main aim of the mission was to test the technique of measuring the ultraviolet fluorescence and Cherenkov radiation of extensive air showers generated by primary cosmic rays with energies above ∼100 EeV in the Earth atmosphere from space. During its operation for 1.5 years, TUS registered almost 80,000 events with a few of them satisfying conditions anticipated for extensive air showers (EASs) initiated by UHECRs. Here we discuss an event registered on 3rd October 2016. The event was measured in perfect observation conditions as an ultraviolet track in the nocturnal atmosphere of the Earth, with the kinematics and the light curve similar to those expected from an EAS. A reconstruction of parameters of a primary particle gave the zenith angle around 44ˆ but an extreme energy not compatible with the cosmic ray energy spectrum obtained with ground-based experiments. We discuss in details all conditions of registering the event, explain the reconstruction procedure and its limitations and comment on possible sources of the signal, both of anthropogenic and astrophysical origin. We believe this detection represents a significant milestone in the space-based observation of UHECRs because it proves the capability of an orbital telescope to detect light signals with the apparent motion and light shape similar to what are expected from EASs. This is important for the on-going development of the future missions KLYPVE-EUSO and POEMMA, aimed for studying UHECRs from space.
Analysis of Anomalous Events in TUS Data Lavrova, M. V.; Blinov, A. V.; Grinyuk, A. A. ...
Physics of atomic nuclei,
08/2023, Letnik:
86, Številka:
4
Journal Article
Recenzirano
The main goal of the TUS experiment was to search for and study extremely high-energy cosmic rays with energies
EeV. The TUS detector registered a number of unusual events, the origin of which is ...unclear. The analysis of not similar to EAS and unique anomalous events is the subject of the study presented in this paper.
Some results of studies of cosmic rays obtained during the NUCLEON space experiment in 2015–2017 are presented. This experiment was intended for direct measurements of the energy spectra and chemical ...composition of cosmic rays (
Z
= 1−30) in the energy range 2–500 TeV. Results presented include energy spectra for various abundant nuclei measured using the new Kinematic Lightweight Energy Meter (KLEM). The primary energies are established using the spatial densities of secondary particles produced in inelastic interactions with a carbon target.
Graphite nanoplatelets (GNPs), with a thickness of 3–10 graphene layers and lateral linear dimensions varying from 2 to 10 μm, were used to enhance the conductivity of polytetrafluoroethylene (PTFE) ...films. Ten composite films with the (GNPs) content of 0, 2, 3, 4, 5, 6, 8, 10, 15 and 20 wt% were obtained. These films were characterised using X-ray diffraction, infrared and Raman spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). The conductivity the conductivity of the composite film increases with an increase in GNP content from 0.00095 S cm
−1
at 2% wt% of GNPs to 20.4 S cm
−1
at 20% wt% of GNPs. Further, a chemical bond is formed between the graphite nanoplates and polymer chains according to the XPS spectra.
Study of Anomalous Events in the TUS Experiment Lavrova, M. V.; Blinov, A. V.; Grinyuk, A. A. ...
Bulletin of the Russian Academy of Sciences. Physics,
07/2023, Letnik:
87, Številka:
7
Journal Article
Recenzirano
The results of the TUS experiment on search and study ultra high-energy cosmic rays with energies
E
> 70 EeV are analyzed. The TUS detector registered several unusual events of the unclear origin. ...The analysis of not similar to EAS and unique anomalous events is the subject of the study presented in this paper.
As part of the preparation of the TAIGA gamma ray observatory (Republic of Buryatia, Russian Federation) and the TUS space experiment on the Mikhailo Lomonosov satellite, 1400 PMTs of XP1911 type, ...1020 PMTs of XP1911/UV type, and 290 PMTs of R1463 type were tested for their main and additional specifications (nominal (operating) voltage, dark current at nominal voltage, quantum efficiency of the photocathode at a wavelength of 480 nm, cathode chamber resistivity, and quality parameters of the dynode system). The number of PMTs that did not meet the selection criteria is 3.9% for XP1911, 15.8% for XP1911/UV, and 4.8% for R1463 of the corresponding number of PMTs of this type. The parameters of 856 PMTs of XP1911/UV type, which successfully passed the selection criteria and turned out to be ready for use in the TAIGA experiment, were compared with the corresponding parameters of the new 1250 PMTs of R7877 type (Hamamatsu) previously measured for the ATLAS hadron scintillation calorimeter at the LHC (CERN, Geneva, Switzerland).
The structure of the newly synthesized palladium(
ii
) 3,5-di(
tert
-butyl)-2-oxyazobenzene, PdL
2
, was determined by X-ray diffraction. The metal chelate was found to adopt an unusual domed ...conformation, with the
trans
-planar coordination unit at the top. This is the first complex of this class, the domed structure of which was confirmed by X-ray diffraction and in which the planes of the ligands are
cis
with respect to the coordination unit. Quantum chemical calculations were performed to examine the possibility of the existence in the gas phase of the compound PdL
2
with this unusual structure and of related Pd- and Ni-based model complexes.
The NUCLEON satellite experiment is designed to investigate directly the energy spectra of galactic cosmic ray (CR) nuclei and its charge composition before the “knee”: in the energy interval from ...100 GeV to 100 TeV and the charge range
Z
= 1–30 respectively. The “knee” energy range of 10
11
–10
16
eV is a crucial region for the understanding of the cosmic-ray acceleration and propagation in the interstellar medium. The NUCLEON detector has been data taken since December, 2014. The NUCLEON trigger system and CR event selection are described, including the beam tests at the SPS CERN, flight tests in orbit and the Monte-Carlo simulation.
PDF
