Cosmic Rays Research Articles

Charging and Discharging Modeling of Inertial Sensors Based on Ultraviolet Charge Management

Inertial sensors act as inertial references in space gravitational wave detection missions, necessitating that their internal test mass (TM) maintains minimal residual acceleration noise. High-energy particles and cosmic rays in space, along with ion pumps in ground-based torsion pendulum experiments, can cause charge accumulation on the TM surface, leading to increased residual acceleration noise. Consequently, a charge management system was introduced to control the TM’s charge. The complex light path propagation within the electrode housing (EH) makes the TM’s charging and discharging process difficult to theoretically calculate and fully simulate. To address this issue, we propose a simulation method for charging and discharging inertial sensors within ultraviolet (UV) charge management systems. This method innovatively considers the impact of photoelectron emission angle and the TM’s position offset from symmetry on performance. The method also simulates charging and discharging rates over time under conditions of symmetry and preliminarily examines factors affecting the TM’s equilibrium potential. Simulation results indicate that this method effectively models the charge management system’s operation, providing a valuable reference for system design.

Theory and Observation of Winds from Star-Forming Galaxies

Galactic winds shape the stellar, gas, and metal content of galaxies. To quantify their impact, we must understand their physics. We review potential wind-driving mechanisms and observed wind properties, with a focus on the warm ionized and hot X-ray-emitting gas. Energy and momentum injection by supernovae (SNe), cosmic rays, radiation pressure, and magnetic fields are considered in the light of observations: ▪Emission and absorption line measurements of cool/warm gas provide our best physical diagnostics of galactic outflows.▪The critical unsolved problem is how to accelerate cool gas to the high velocities observed. Although conclusive evidence for no one mechanism exists, the momentum, energy, and mass-loading budgets observed compare well with theory.▪A model in which star formation provides a force ∼L/c, where L is the bolometric luminosity, and cool gas is pushed out of the galaxy's gravitational potential, compares well with available data. The wind power is ∼0.1 of that provided by SNe.▪The very hot X-ray-emitting phase may be a (or the) prime mover. Momentum and energy exchange between the hot and cooler phases is critical to the gas dynamics.▪Gaps in our observational knowledge include the hot gas kinematics and the size and structure of the outflows probed with UV absorption lines. Simulations are needed to more fully understand mixing, cloud–radiation, cloud–cosmic ray, andcloud–hot wind interactions, the collective effects of star clusters, and both distributed andclustered SNe. Observational works should seek secondary correlations in the wind data thatprovide evidence for specific mechanisms and compare spectroscopy with the column density–velocity results from theory.

Modeling hadronic interactions in ultra-high-energy cosmic rays within astrophysical environments: A parametric approach

Interactions of ultra-high energy cosmic-rays (UHECRs) accelerated in astrophysical environments have been shown to shape the energy production rate of nuclei escaping from the confinement zone. To address the influence of hadronic interactions, Hadronic Interaction Models (HIMs) come into play. In this context, we present a parameterization capable of capturing the outcomes of two distinct HIMs, namely EPOS-LHC and Sibyll2.3d, in terms of secondary fluxes, including escaping nuclei, nucleons, neutrinos, photons, and electrons. Our parameterization is systematically evaluated against the source codes, both at fixed energy and mass, as well as in a physical case scenario. The comparison demonstrates that our parameterization aligns well with the source codes, establishing its reliability as a viable alternative for analytical or fast Monte Carlo approaches dedicated to the study of UHECR propagation within source environments. This suggests the potential for utilizing our parameterization as a practical substitute in studies focused on the intricate dynamics of ultra-high energy cosmic rays.

Comparison of Soil Water Content from SCATSAR-SWI and Cosmic Ray Neutron Sensing at Four Agricultural Sites in Northern Italy: Insights from Spatial Variability and Representativeness

Comparison of Soil Water Content from SCATSAR-SWI and Cosmic Ray Neutron Sensing at Four Agricultural Sites in Northern Italy: Insights from Spatial Variability and Representativeness

A common law in space for public health

Beyond the gravitational pull of Earth, space travel poses substantial public health hazards pertaining to the physical and mental well-being of astronauts and passengers, in addition to a possible threat to the populace of Earth upon re-entry. Exposure to cosmic radiation, cranial pressure from microgravity, weakened immunity to contagion, and the potential for depression and psychosis are all risks. Public health crises of this nature are to be expected as the duration of missions extends, as is the case with Mars settlement. In contrast to national space programmes, which have regarded these obstacles as human factors effecting the mission, public health law in common law British nations approaches them from the perspective of social justice and the preservation of human life and societal welfare. Countries including Australia, Canada, the United States, and the United Kingdom continue to apply traditional common law principles of public health law, which provide a sensible and enduring method for reconciling competing public and private interests. Common law permits the violation of civil liberties through the use of force in public health restraint, forced medication, and quarantine, but only if necessary, reasonable, and equitable. While the understanding of the health challenges associated with long-duration spaceflight may be in its infancy for national space programmes and civilian space ventures, the application of common law public health principles could aid in the establishment of health and safety protocols in which human reactions to crises in space resemble those observed on Earth. This may, nevertheless, necessitate the enactment of a more comprehensive federal public health statute. Embedded in both public health common law and international space law, the pre-eminence of preserving and respecting human life and well-being continues to be a cornerstone of humane justice despite the perilous conditions of space.

The MIZAR ASIC: 64-channel zone-sampling based ASIC for Cherenkov light detection from sub-orbital and orbital altitudes

This work describes the implementation of a 64-channel Application Specific Integrated Circuit (ASIC) developed in a commercial 65 nm CMOS technology to readout the signals collected by a camera plane made of Silicon Photo-Multipliers. The aim of the application is the identification of Extensive Air Showers (EASs) by detecting optical Cherenkov light generated by Ultra-High Energy Cosmic Rays (UHECRs) and Neutrinos (UHENUs) from sub-orbital and orbital altitudes. In this context, the ASIC is designed to store each event into an analog memory based on 256 configurable cells per channel. Then the chip forms a hitmap sent to an Field Programmable Gate Array (FPGA) to recognize a pattern of interest. If the signal is externally validated, the digital conversion can occur on-board using an array of 12-bits Wilkinson analog-to-digital converters (ADCs) at 200 MHz of clock. The readout is realized with two serializers running at 400 MHz in double data rate (DDR). Both the number of cells and the resolution can be configured into partitions of 32, 64 or 256 cells and in the range 8–12 bits respectively, becoming a key feature of this ASIC. The chip submission and testing are planned for the forthcoming months.

Studies on the temperature dependent drift velocity for the HELIX Drift Chamber Tracker

HELIX (High Energy Light Isotope eXperiment) is a ballon experiment designed to measure abundance of cosmic ray isotopes from hydrogen to neon, with a particular interest in abundances of beryllium isotopes. HELIX aim to provide essential data to study the cosmic ray propagation in our galaxy. The Drift Chamber Tracker (DCT) in HELIX is a multi-wire gas drift chamber designed to measure the position of incident cosmic rays. It is located inside a magnet, bending the trajectory of incoming particles through 72-layers of tracking, enabling the measurement of the momentum of incoming particles.Before the data can be used for scientific analysis, the background must be taken out, and the instrument must be well calibrated. In order to exclude electronic noise from the DCT data it was necessary to determine the maximum drift velocity of each wire over a short period of time. To do this I developed an algorithm to be able to identify the maximum drift velocity for each wire over each dataset. This revealed a position dependence of the data within the detector. In order to attempt to characterize this dependence, so it can be accounted for in the calibration stage, I preformed a study on the temperature dependence of the drift velocities analyzing at data from different time periods over the course of the flight. To characterize this dependence I built a predicted heat map of the gas within the detector over the course of the flight. This involved calibrating the thermistors based on data collected when the experiment was on the ground. This helped confirm that the predicted temperature was reasonable and that the variation was temperature dependent. This algorithms and this study can now be applied to the full data set to develop a calibration method.

Cosmic ray test of shashlik electromagnetic calorimeter modules for NICA-MPD

The electromagnetic calorimeter (ECal) plays a critical role in high-energy particle colliders, by measuring the energy of particles that interact primarily via the electromagnetic interaction such as electrons, positrons and photons. Fudan University has undertaken part of the mass production of ECal modules for the Multi-Purpose Detector (MPD) project of the Nuclotron-based Ion Collider fAcility (NICA). Preliminary tests on the ECal modules is an essential step in detector construction. This article introduces the cosmic ray testing of the ECal modules produced by Fudan University. We tested the cosmic ray under the conditions of horizontal and vertical placement of the module, calculated the average number of generated photons, and estimated the module’s energy resolution. Moreover we analyzed the time resolution performance of the device. The test results indicate that when cosmic rays vertically traverse the entire ECal, the number of photons produced can reach 834, with a potential energy resolution less than 5%/E. The time resolution is 189ps. Based on the comprehensive test results, the production of the ECal meets the design requirements.

Cancer risk among air transportation industry workers in Korea: a national health registry-based study

BackgroundFlight attendants face various risk factors in their working environments, particularly occupational exposure to cosmic radiation. This study aimed to assess cancer risk among air transportation industry workers, including flight attendants, in Korea by constructing a cohort using national health registry-based data and analyzing cancer incidence risk.MethodsWe used the Korea National Health Insurance Service database from 2002 to 2021 to construct a cohort of 37,011 workers in the air transportation industry. Cancer incidence was defined using the tenth version of the International Classification of Diseases. We calculated the age- and sex-specific standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) by applying the cancer incidence rate of the general population between 2002 and 2019.ResultsApproximately 5% of the cohort developed cancer. Overall, the cancer incidence in the cohort was similar to or lower than that of the general population, with the SIRs for all cancers being lower. However, significantly higher SIRs were observed for nasopharyngeal cancer (SIR, 3.21; 95% CI, 1.71–5.48) and non-Hodgkin lymphoma (SIR, 1.57; 95% CI, 1.02–2.32) in male workers and breast and genital cancer (SIR, 1.51; 95% CI, 1.34–1.70) and thyroid cancer (SIR, 1.25; 95% CI, 1.05–1.47) in female workers.ConclusionsThe lower overall cancer incidence among air transportation industry workers observed in this study could indicate the “healthy worker effect”; however, the incidences of certain cancers were higher than those in the general population. Given that these workers are exposed to multiple occupational and lifestyle-related risk factors, including cosmic radiation, further studies are necessary to determine radiation-induced cancer risk while considering potential confounding factors.

A 350 GHz array of LEKIDs for balloon-borne CMB observations

We present the design, optimization and laboratory characterization of an array of Lumped Element Kinetic Inductance Detectors sensitive in a frequency band centered at 350 GHz. The array consists of 313 feed-horn coupled pixels with resonant frequencies spread over 250 MHz. We present measured yield, quality factor, responsivity, quasiparticle lifetime, noise equivalent power and optical efficiency. The array is a prototype for one of the four frequency bands of OLIMPO, a balloon-borne instrument with a 2.6 m primary mirror proposed for an Antarctic flight to measure the Sunyaev–Zel’dovich effect in clusters of galaxies and their connecting filaments. Similar arrays could also be used with instruments studying the polarization of the cosmic microwave background radiation.

Search for Cosmic-Ray Boosted Sub-MeV Dark-Matter–Electron Scattering in PandaX-4T

We report the first search for the elastic scatterings between cosmic-ray boosted sub-MeV dark matter (DM) and electrons in the PandaX-4T liquid xenon experiment. Sub-MeV DM particles can be accelerated by scattering with electrons in the cosmic rays and produce detectable electron recoil signals in the detector. Using the commissioning data from PandaX-4T of 0.63 tonne·year exposure, we set new constraints on DM-electron scattering cross sections for DM masses ranging from 10 eV/c2 to 3 keV/c2. Published by the American Physical Society 2024

Cosmic radiation monitoring in aeronautics and astronautics

The growth of the aerospace industry has made the detection of cosmic radiation essential. That led to a proposal for the development of an optoelectronic detector of cosmic radiation. This will allow continuous measurement of acceptable levels of radiation. The device is currently in its initial development phase, focusing on the detection of ionising radiation. Tests have been carried out with high-energy radiation simulators in the form of natural radioactive sources, confirming the performance of the overall system. The cosmic ray sensor of the study has numerous potential applications, particularly in the aerospace industry. Crew safety could be enhanced by a miniature sensor that measures the absorbed dose of cosmic radiation. Existing passive methods of dose measurement have been ineffective because they provide information about radiation with a delay of several weeks. Active monitoring of irradiation levels enables ongoing control of the dose taken, which is crucial for employee health.

Improved model of large-field inflation with primordial black hole production in Starobinsky-like supergravity

Abstract A viable model of large-field (chaotic) inflation with efficient production of primordial black holes is proposed in Starobinsky-like (modified) supergravity leading to the ‘no-scale-type’ Kähler potential and the Wess-Zumino-type (‘renormalizable’) superpotential. The cosmological tilts are in good (within 1σ) agreement with Planck measurements of the cosmic microwave background radiation. In addition, the power spectrum of scalar perturbations has a large peak at smaller scales, which leads to a production of primordial black holes from gravitational collapse of large perturbations with the masses about 1017 g. The masses are beyond the Hawking (black hole) evaporation limit of 1015 g, so that those primordial black holes may be viewed as viable candidates for a significant part or the whole of the current dark matter. The parameters of the superpotential were fine-tuned for those purposes, while the cubic term in the superpotential is essential whereas the quadratic term should vanish. The vacuum after inflation (relevant to reheating) is Minkowskian. The energy density fraction of the gravitational waves induced by the production of primordial black holes and their frequency were also calculated in the second order with respect to perturbations.

Suppressed Cosmic-Ray Energy Densities in Molecular Clouds from Streaming Instability-regulated Transport

Cosmic rays (CRs) are the primary driver of ionization in star-forming molecular clouds (MCs). Despite their potential impacts on gas dynamics and chemistry, no simulations of star cluster formation following the creation of individual stars have included explicit cosmic-ray transport (CRT) to date. We conduct the first numerical simulations following the collapse of a 2000M ⊙ MC and the subsequent star formation including CRT using the STAR FORmation in Gaseous Environments framework implemented in the GIZMO code. We show that when CRT is streaming-dominated, the CR energy in the cloud is strongly attenuated due to energy losses from the streaming instability. Consequently, in a Milky Way–like environment the median CR ionization rate in the cloud is low (ζ ≲ 2 × 10−19 s−1) during the main star-forming epoch of the calculation and the impact of CRs on the star formation in the cloud is limited. However, in high-CR environments, the CR distribution in the cloud is elevated (ζ ≲ 6 × 10−18), and the relatively higher CR pressure outside the cloud causes slightly earlier cloud collapse and increases the star formation efficiency by 50% to ∼13%. The initial mass function is similar in all cases except with possible variations in a high-CR environment. Further studies are needed to explain the range of ionization rates observed in MCs and explore star formation in extreme CR environments.

Understanding the High-energy Hardening in Cosmic Ray Spectra

Abstract Recently, precise measurements on cosmic rays have been provided by various space experiments. A hardening at a few hundred GV has been observed in cosmic ray spectra both for primary and secondary particles. However, the reason for this hardening remains unclear. In this work, we employ the data measured by PAMELA, AMS02, ACE-CRIS and VOYAGER-1 to investigate this question. We study two different scenarios: the diffusion-reacceleration (DR) framework and the diffusion-convection (DC) framework. For each configuration, we investigate both the injection effects and the transport properties which may relate to the hardening. At the low-to-medium energy range, the diffusion slope δL are estimated to be 0.41 to 0.48. It is found that the value of δL estimated in the DR model is lower than that in the DC model. This infers that the reacceleration mechanism can result in steeper shapes in the (Li, Be, B)/C ratios than the convection process. At high energies, a variation in diffusion slope with Δδ ∼ −0.16 is favoured to explain the high-energy hardening structures observed in (Li, Be, B)/C ratios. Recent B/C data measured by DAMPE infers an even stronger high-energy diffusion break with Δδ ∼ −0.19.

Implications of Solar Wind Disturbances on Forbush Decrease

This study investigated the role of solar wind disturbances on variations in cosmic ray intensity. To conduct the study, use was made of the data on cosmic rays from the SOPO, CLMX, and MOSC neutron stations, as well as solar wind speed data from 2000 to 2005. The source Forbush decrease (FD) dates were generated from onset journal publications, specifically the FD list of Dumbovi ́c et al., (2011). The manual method of FD selection was used to identify FDs. The FD dates, computed magnitudes, and solar wind speed data were recorded and presented. From the study, FDs were generated, some of which were of the same date as those in the source table, while others were not observed in the source table. FDs not observed in the source table were generated and catalogued by this research. It was also observed that the magnitude of FDs generally depends on the coordinates of the observing neutron stations. A strong correlation with a value of cc = 0.93 was observed between FDs of SOPO and MOSC stations, followed by FDs of CLMX and MOSC stations of value cc = 0.89, and lastly, FDs of SOPO and CLMX stations of value cc = 0.74. This implies that observed FDs from neutron stations are coordinate-dependent. The correlation between FD magnitudes and solar activities shows that solar wind had a high and significant correlation with FD magnitude to the tune of cc = 0.54. Based on the findings, the study concludes that solar wind disturbances play a crucial role in causing a sharp decrease in the intensity of cosmic rays known as Forbush decrease.

Evidence for hybrid gamma-ray emission from the supernova remnant G150.3+4.5

The supernova remnant (SNR) G150.3+4.5 was first identified in radio, exhibiting a hard GeV spectrum and a ~1.5º radius. Radio observations revealed a bright arc with an index of ~−0.40, which stands in contrast to the index of ~−0.69 for the rest. This arc is coincident with the point-like Fermi source 4FGL J0426.5+5434 and KM2A source 1LHAASO J0428+5531. The rest of the SNR has a hard GeV spectrum and a soft TeV spectrum, implying a spectral cut-off or break near 1 TeV. Since there is no X-ray counterpart and no pulse signal detected, the gamma-ray (γ-ray) emission mechanism from the SNR and the point-like source appear puzzling. In this work, we reanalyse the γ-ray emission using 14 yr data recorded by Fermi Large Area Telescope and find that the spectrum of the northern half-sphere is compatible with a broken power law with a break at 146 ± 11 eV and photon indices of ΓNorthlobe = 1.54 ± 0.04stat ± 0.07syst (2.28 ± 0.08stat ± 0.12syst) below (above) the break. In addition, the southern half-sphere can be described well with a single power law with ΓSouthlobe =1.95 ± 0.07stat ± 0.09syst. Since the southern half-sphere is well correlated with CO emission, we propose that the γ-ray emission of the northern half-sphere could be dominated by relativistic electrons via inverse-Compton processes, while the southern half-sphere is dominated by cosmic rays via hadronic processes. 4FGL J0426.5+5434 may result from the illumination of a cloud by escaping cosmic rays or recent shock-cloud interaction. Observations from LHAASO-KM2A thus favour the possibility of a cosmic-ray PeVatron candidate, however, leptonic scenarios cannot be ruled out. Further multi-wavelength observations are warranted to confirm the hadronic nature of 1LHAASO J4028+5531.

Quantifying the High Early Solar Cosmic-Ray Flux with Cosmogenic Neon Isotopes in Refractory Minerals

An enhancement in the activity of the early young Sun resulting in a high charged particle flux has been invoked to explain excesses in spallation-induced nuclides in primitive planetary materials. Astronomical observations of energetic outbursts of young stellar objects (YSOs) also support the idea of an active young Sun. However, the early solar cosmic-ray (SCR) flux has not been well constrained. Here we use measured concentrations of SCR-produced nuclides that formed and are preserved in meteoritical hibonite and spinel, some of the solar system’s oldest solids, and physical models for dust transport in the early protoplanetary disk to determine the magnitude of the early SCR flux. We focus our attention on cosmogenic neon, which cannot have been inherited from precursors and can only be produced in situ in solids. Our modeled effective exposure time to SCRs for these solids is very short, on the order of years. This indicates that the young Sun’s SCR flux recorded in refractory mineral hibonite was up to ∼7 orders of magnitude higher than the contemporary level. Our flux estimate is consistent with the >105× enhanced flux inferred from astronomical observations of greatly enhanced flare activities of YSOs.

Effect of solar wind disturbances on small-amplitude simultaneous Forbush events during solar cycle 23

The transient and rapid reduction in galactic cosmic ray (GCR) flux intensity, commonly referred to as Forbush decrease (FD), is widely used as a mediator variable in searching for solar-terrestrial weather linkages. Whereas literature in the field is replete with high-amplitude (FD(%) ⩾3) FD-based analyses, the empirical connections between low-amplitude (FD(%) ⩽3) events and Sun-Earth variables are seldom tested. It is recently observed that the dearth of such studies might be due to the daunting task of accurate detection/precise timing of FDs and other transient astrophysical events. Using a sensitive version of the FD detection algorithm, we selected 264, 267, and 206 low amplitude (FD(%) ⩽3) FDs from the daily GCR data of Hermanus (HRMS), Newark (NWRK) and Oulu (OULU) neutron monitor stations respectively during solar cycle 23. A total of 80 simultaneous small-amplitude FDs were identified from the three stations with a simple coincident computer code. Statistically significant correlations at 95% confidence level exist between the planetary K-index (Kp), disturbance storm time index (Dst), planetary A-index (Ap), and the corresponding simultaneous small-amplitude FDs at OULU station, but not found in HRMS and NWRK data. These significant links between the weak FDs and the geomagnetic indices (Kp, Dst, and Ap) at OULU station suggest that the parameters (Kp, Dst, and Ap) are likely connected with some common solar activities.

Study of solar activities associated with a Halo CME on 17 Feb 2023 event

In the present work, propagation of an earth directed fast and wide Coronal Mass Ejection event on 17 February 2023 is studied in detail. The complex magnetic configuration in the Active Region (AR) 13229 at N25E64 caused an intensive X2.3 flare with a peak at 19:38 UT. It is followed by a massive halo CME event observed in the LASCO C3 coronagraph with a linear speed of 930 km/s and shock speed of 1300 km/s. A low frequency Type II emission was detected in the frequency range 10 MHz – 180 kHz during 20:30 UT-04:45 UT on 18 Feb 2023 by space borne Wind/WAVES instrument. From the OMNI data, the IP shock and the ICME reached earth's magnetosphere on 20 Feb 2023. A fast forward type shock was observed using OMNI high resolution data. The IP shock and ICME affected the Galactic Cosmic ray (GCR) detection. This event caused large magnetic turbulences in sheath region caused a major geomagnetic storm (∼-100 nT).