Cosmic Ray Spectrum Research Articles

Congruents (COsmic ray, Neutrino, Gamma-ray, and Radio Non-Thermal Spectra) – I. A predictive model for galactic non-thermal emission

ABSTRACT The total luminosity and spectral shape of the non-thermal emission produced by cosmic rays depends on their interstellar environment, a dependence that gives rise to correlations between galaxies’ bulk properties – star-formation rate, stellar mass, and others – and their non-thermal spectra. Understanding the physical mechanisms of cosmic ray transport, loss, and emission is key to understanding these correlations. Here, in the first paper of the series, we present a new method to compute the non-thermal spectra of star-forming galaxies, and describe an open-source software package – congruents(COsmic ray, Neutrino, Gamma-ray, and Radio Non-Thermal Spectra) – that implements it. As a crucial innovation, our method requires as input only a galaxy’s effective radius, star-formation rate, stellar mass, and redshift, all quantities that are readily available for large samples of galaxies and do not require expensive, spatially resolved gas measurements. From these inputs we derive individual, galaxy-by-galaxy models for the background gas and radiation field through which cosmic rays propagate, from which we compute steady-state cosmic ray spectra for hadronic and leptonic particles in both the galactic disc and halo by solving the full kinetic equation. We invoke modern models for cosmic ray transport and include all significant emission and loss mechanisms. In this paper, we describe the model and validate it against non-thermal emission measured in nearby star-forming galaxies that span four orders of magnitude in star-formation rate.

Energy Spectrum of Primary Cosmic Rays According to the Data of the TAIGA Astrophysical Complex

Energy Spectrum of Primary Cosmic Rays According to the Data of the TAIGA Astrophysical Complex

The energy spectrum of cosmic rays measured by the Telescope Array using 10 years of fluorescence detector data

The Telescope Array (TA) Cosmic Ray Observatory is the largest cosmic ray detector in the northern hemisphere. TA was built to study ultra-high-energy cosmic rays (UHECRs), cosmic rays with energies above 1018eV. TA is a hybrid detector, employing two distinct detection methods: a surface detector array and a set of fluorescence telescopes. We will present a measurement of the cosmic ray energy spectrum for energies above 1017.5eV using only the fluorescence telescopes. A novel weather classification scheme using machine learning was used to select data parts with good weather to ensure the quality of the fluorescence data. The data from the Black Rock Mesa (BRM) and Long Ridge (LR) fluorescence telescope sites were analyzed separately in monocular mode, with the calculated fluxes combined into a single spectrum. The 10-year monocular combined cosmic ray energy spectrum is observed to be in excellent agreement with previous measurements from the northern hemisphere. We present fits of the combined spectrum to a series of broken power law models. The thrice-broken power law was observed to be the best fit considering the Poisson deviance per degrees of freedom. The three breaks suggest an additional feature of the spectrum between the previously observed Ankle feature at 1018.7eV and the GZK suppression at 1019.8eV.

Direct Measurement of the Cosmic-Ray Helium Spectrum from 40GeV to 250TeV with the Calorimetric Electron Telescope on the International Space Station.

We present the results of a direct measurement of the cosmic-ray helium spectrum with the CALET instrument in operation on the International Space Station since 2015. The observation period covered by this analysis spans from October 13, 2015, to April 30, 2022 (2392days). The very wide dynamic range of CALET allowed for the collection of helium data over a large energy interval, from ∼40 GeV to ∼250 TeV, for the first time with a single instrument in low Earth orbit. The measured spectrum shows evidence of a deviation of the flux from a single power law by more than 8σ with a progressive spectral hardening from a few hundred GeV to a few tens of TeV. This result is consistent with the data reported by space instruments including PAMELA, AMS-02, and DAMPE and balloon instruments including CREAM. At higher energy we report the onset of a softening of the helium spectrum around 30TeV (total kinetic energy). Though affected by large uncertainties in the highest energy bins, the observation of a flux reduction turns out to be consistent with the most recent results of DAMPE. A double broken power law is found to fit simultaneously both spectral features: the hardening (at lower energy) and the softening (at higher energy). A measurement of the proton to helium flux ratio in the energy range from 60 GeV/n to about 60 TeV/n is also presented, using the CALET proton flux recently updated with higher statistics.

TRIPLE MULTIPLICATIVE THERMORESONANCES ON THE SPECTRA OF EXCHANGE INERTIAL RADIATION GENERATED IN NON-EQUILIBRIUM MEDIA WITH CONTACT GAPS IN ENGINEERING, COSMIC, PSEUDO-ELEMENTARY AND BIOLOGICAL SYSTEMS IN COMPLEX SPACE WITH TRIPLET VIOLATION OF ANTISYMMETRY

Calculated ratios that quantitatively describe the properties of resonance triplets of inertial radiation generated in non-equilibrium systems of various scales and levels of organization are given. The multiplicative nature of the energy of resonant components is revealed, which is significantly different from the additive principles of the formation of known triplet structures. The mechanism of triplet violation of the antisymmetry of the complex space is established, which ensures the avoidance of annihilation of the energy created according to the principle of Creatio ex nihilo in the topological contact gaps between the real and imaginary half-spaces. There is a marked dilution of the dominant energy cascades – direct in the imaginary and inverted in the real half-space. The analysis of resonant triads on nuclear and collider spectra was carried out, the components of these spectra were explained and quantitatively calculated. The muon structure of hadrons was confirmed and the parameters of this structure were calculated, as well as the parameters of the collider proton-muon plasma, alternative to the known models of the quark-gluon plasma. The calculation of the spectra of cosmic rays of low, medium, high and ultra-high energies was made, which quantitatively corresponds to natural data. Triple resonances in the spectra of the Sun’s radiation and the spectra of solar and geomagnetic activity were detected and quantified. It is shown that the solar spectrum is significantly different from the blackbody spectrum, and the main periods of the Sun’s activity are determined by resonant triads on the scale of the heliosphere. Calculated parameters of the cold outer photosphere at the periphery of the Solar System, the background microwave radiation of which is usually erroneously attributed to the account of a “relic” from the so-called Big bang. The analysis of resonant triplets on the spectra of acoustic disturbances in technical systems was carried out. Synchronization of gravitational and electromagnetic modes is noted, which leads to dangerous buffeting modes. The relationship between geodynamic, climatic and biological processes on the planet and the activity of cavitation topological gaps on the periphery of the Solar System has been established. The mechanism of contact capillary thermostabilization of the human body was revealed and the multiplicative triplet coronavirus destruction of this mechanism was noted.

Real-time monitoring of solar energetic particles outside the ISS with the AMS-02 instrument

Space human activities in the International Space Station (ISS) are always ongoing. The atmosphere and geomagnetic field in this environment only offer partial protection from radiation. Considering the whole energetic spectrum of cosmic rays (CR), the highest energy particles are the most dangerous, but the rarest: on the other hand, sporadic solar emissions of plasma, in the low end of the energetic spectrum, inject an intense and dangerous flux of charged particles called Solar Energetic Particles (SEPs) in the Sun-Earth environment. The experiment Alpha Magnetic Spectrometer (AMS-02) operates on the ISS since 2011, performing precision measurements of cosmic ray composition and flux. In this study we aim to verify if the low latency information provided by AMS-02 could be used to perform SEP and solar activity real-time monitoring in the ISS external environment. An algorithm has been developed to identify sudden increases in the AMS-02 trigger rate with respect to the quiet conditions, demonstrating the potency of AMS-02 low-latency data for this real-time application.

Astronaut Radiation Dose Calculation With a New Galactic Cosmic Ray Model and the AMS‐02 Data

AbstractWe present a new calculation of the astronaut dose rate from the galactic cosmic rays in free space at 1 AU. We use the unshielded isotropic fluence‐to‐dose conversion coefficients given in the International Commission on Radiological Protection publication 123. A new 3D and time‐dependent solar modulation model based on Parker's transport equation as originally developed in Song et al. (2021, https://doi.org/10.3847/1538-4365/ac281c) is used to calculate the galactic cosmic ray spectra at 1 AU. This model uses the recent local interstellar spectra of Corti et al. (2019, https://doi.org/10.3847/1538-4357/aafac4), M. J. Boschini et al. (2020, https://doi.org/10.3847/1538-4365/aba901, 2021a, https://doi.org/10.3847/1538-4357/abf11c) to reproduce the PAMELA and AMS‐02 observations between 2006 and 2019. The radiation dose calculated from our model and from the AMS‐02 spectra in the same rigidity region agrees better than 1% for proton and helium in a time‐dependent way, and at 2% level for six most contributing cosmic ray elements averaged over 7 or 8.5 years. The time‐dependent dose rate analysis over 13 years shows an effective dose equivalent rate of 55–58 cSv/yr at solar minimum (January 2010) and 26 cSv/yr at solar maximum (February 2014).

On the contribution of cosmic-ray interactions in the circumgalactic gas to the observed high-energy neutrino flux

Cosmic rays escaping the Milky-Way disk interact with circumgalactic gas which fills the virial volume of our Galaxy. These interactions should produce guaranteed fluxes of energetic diffuse neutrinos and photons observable at the Earth. This neutrino flux would be a plausible contribution to the spectrum measured by the IceCube neutrino observatory: the energy emitted in this way is weakly constrained from cascade gamma rays, since the cascades have no time to develop, but the arrival directions of the neutrinos do not point to the Galactic disk, in agreement with observations. However, previous studies reported very different estimates of the corresponding neutrino flux, so it was unclear if this contribution to the observed spectrum is essential. Here we readdress the calculation of this diffuse neutrino flux component under various assumptions about the cosmic-ray spectrum and propagation in the circumgalactic medium. We find that even with these variations, this contribution to the observed neutrino flux remains subleading provided multimessenger constraints are satisfied.

Time Dependence of 50–250 MeV Galactic Cosmic-Ray Protons between Solar Cycles 24 and 25, Measured by the High-energy Particle Detector on board the CSES-01 Satellite

Time-dependent energy spectra of galactic cosmic rays (GCRs) carry crucial information regarding their origin and propagation throughout the interstellar environment. When observed at the Earth, after traversing the interplanetary medium, such spectra are heavily affected by the solar wind and the embedded solar magnetic field permeating the inner sectors of the heliosphere. The activity of the Sun changes significantly over an 11 yr solar cycle—and so does the effect on cosmic particles; this translates into a phenomenon called solar modulation. Moreover, GCR spectra during different epochs of solar activity provide invaluable information for a complete understanding of the plethora of mechanisms taking place in various layers of the Sun’s atmosphere and how they evolve over time. The High-Energy Particle Detector (HEPD-01) has been continuously collecting data since 2018 August, during the quiet phase between solar cycles 24 and 25; the activity of the Sun is slowly but steadily rising and is expected to peak around 2025/2026. In this paper, we present the first spectra for ∼50–250 MeV galactic protons measured by the HEPD-01 instrument—placed on board the CSES-01 satellite—from 2018 August to 2022 March over a one-Carrington-rotation time basis. Such data are compared to the ones from other spaceborne experiments, present (e.g., EPHIN, Parker Solar Probe) and past (PAMELA), and to a state-of-the-art three-dimensional model describing the GCRs propagation through the heliosphere.

Connecting multi-lepton anomalies at the LHC and in Astrophysics with MeerKAT/SKA

Multi-lepton anomalies at the Large Hadron Collider (LHC) are reasonably well described by a two Higgs doublet model with an additional singlet scalar. Here we demonstrate that using this model, with parameters set by the LHC, we are also able to describe the excesses in gamma-ray flux from the galactic centre and the cosmic-ray spectra from AMS-02. This is achieved through Dark Matter (DM) annihilation via the singlet scalar. Of great interest is the flux of synchrotron emissions which results from annihilation of DM in Milky-Way satellites. We make predictions for MeerKAT/SKA observations of the nearby dwarf galaxy Reticulum II and we demonstrate the power of this instrument as a new frontier in indirect dark matter searches. Since the dark matter sector of the aforementioned two Higgs doublet model is unconstrained by current LHC data, we also demonstrate a synergy between particle and astrophysical searches in order to motivate further exploration of this promising model.

Evidence of fresh cosmic ray in galactic plane based on DAMPE measurement of B/C and B/O ratios

More and more experiments have identified that the energy spectra of both primary and secondary cosmic-rays exhibit a hardening above ∼ 200 GV. More recently, the DAMPE experiment has reported a hardening of boron-to-carbon ratio at 200 GV. These signs call for modifications of the conventional cosmic-ray (CR) picture. In this work, we propose that the plethoric secondary cosmic rays, for example, boron, antiprotons, originate from the hadronic interactions of freshly accelerated cosmic rays with the interstellar gas near the sources. We find that secondary-to-primary ratios, for example, boron-to-carbon, boron-to-oxygen and antiproton-to-proton ratios, can be well described. The measurements of electrons and positrons can also be accounted for.

The AMS-02 detector on the ISS - Status and highlights after 11 years on orbit

The Alpha Magnetic Spectrometer, AMS-02, is a magnetic spectrometer detector operating on the International Space Station (ISS) since May the 19th, 2011. More than 200 billion events have been collected by the instrument in the first 11 years of data taking, providing detailed and novel insights on the composition and energy spectra of cosmic rays up to TeV energies. We review the most recent AMS-02 measurements and the advances in the understanding of cosmic ray origin, acceleration and propagation physics.

Current Status of the HERD Space Mission Design

HERD (High Energy Radiation Detector) is a future experiment for space-based detection of cosmic rays and gamma ray astronomy onboard the Chinese Space Station. Its most innovative feature will be the event collection from 5 sides, and with its large size it will result in a one-order-of-magnitude jump in acceptance with respect to current largest calorimetric experiments. This will make possible to investigate cosmic ray spectra for each species up to the so-called knee region at PeV energies. The all-electron spectrum will be also measured up to about 10 TeV (depending on the actual flux) and the gamma sky will be studied with a large effective area from a few hundreds MeV up to few TeV, also allowing for the search for possible signatures from dark matter particles in our galaxy.

Measurement of wide energy range neutrons with a CLYC(Ce) scintillator

The CLYC(Ce) (Cs2LiYCl6:Ce3+) scintillator can identify different particles with various specific energy losses and is capable of measuring the fast neutron energy via the 35Cl(n,p)35S reaction. Thus, it is rational to expect using this detector for monitoring the on-site neutron dose rate for astronauts or equipments working at a spacecraft, which may undergo the irradiation of cosmic rays of energetic protons or alpha particles that could induce the production of spallation neutrons. However, as the spallation neutrons, as well as the moderated neutrons, have an energy distribution from the thermal region to several hundred MeV, the direct measurement of the neutron spectrum, which helps calculate the exact value of dose rate in the spacecraft, requires that the energy response matrices should be known in advance. In this study, we calibrated a Φ38 mm × 38 mm CLYC(Ce) scintillator detector with the Back-n beamline at the China Spallation Neutron Source (CSNS), acquiring its energy response matrices (ERM) ranging from 0.1 MeV to 100 MeV. To verify the CLYC(Ce) scintillator detector's capability for measuring neutrons with such a wide region, using the ERM, the energy spectrum of the Back-n beamline was reconstructed and the result conformed to the CSNS-measured result well; a good conformation between the reconstructed spectrum and the standard Watt fission neutron spectrum of 252Cf was also observed. This calibrated detector then was used to measure the cosmic-ray induced neutron spectra at five different sites in China of various altitudes. The measured neutron fluxes at five different sites conformed to results predicted by the EXcel based Program Atmospheric Cosmic-ray Spectrum (EXPACS). The results presented in this study indicate that the CLYC(Ce) scintillator detector is promising to be used in spacecraft as a neutron monitor with a wide energy range.

Application of CORSIMA (Cosmic Ray Spectrum and Intensity in Middle Atmosphere) Model for Solar Cosmic Rays. Case Study of the Extremes GLE 05 and GLE 69

The new model CORSIMA (COsmic Ray Spectrum and Intensity in Middle Atmosphere) is presented. The spectra and intensities of solar cosmic rays (SCR) from GLE (Ground Level Enhancement) 05 on 23 February 1956 and GLE 69 on 20 January 2005 at different altitudes are calculated. For this purpose, the operational CORSIMA model is applied. In the final version of the CORSIMA program, an approximation in 6 characteristic energy intervals of the Bohr–Bethe–Bloch function is used, including the charge decrease interval. Analytical expressions for the contributions of the energy intervals are provided.
 For the first time we present a quantitative and qualitative appreciation of the impact of Solar Cosmic Rays (SCRs) from the Solar Particle Events (SPEs) on the ionosphere and middle atmosphere (30–80 km). These altitudes are above the Regener–Pfotzer maximum.
 Unlike Galactic Cosmic Rays (GCR), the differential spectra of SCR essentially vary in time. The SCR fluxes also differ from each other during the different events. The spectrum and intensity behaviour is explained considering the structure of the CORSIMA program. The calculation results are in agreement with the experimental data and show characteristic features of the propagation process for different altitudes and geomagnetic latitudes. The calculations are performed for geomagnetic latitudes 90° (cusp region). The development of this research is important for the processes and mechanisms of space weather.

URANOS v1.0 – the Ultra Rapid Adaptable Neutron-Only Simulation for Environmental Research

Abstract. The understanding of neutron transport by Monte Carlo simulations led to major advancements towards precise interpretation of measurements. URANOS (Ultra Rapid Neutron-Only Simulation) is a free software package which has been developed in the last few years in cooperation with particle physics and environmental sciences, specifically for the purposes of cosmic-ray neutron sensing (CRNS). Its versatile user interface and input/output scheme tailored for CRNS applications offers hydrologists straightforward access to model individual scenarios and to directly perform advanced neutron transport calculations. The geometry can be modeled layer-wise, whereas in each layer a voxel geometry is extruded using a two-dimensional map from pixel images representing predefined materials and allowing for the construction of objects on the basis of pixel graphics without a three-dimensional editor. It furthermore features predefined cosmic-ray neutron spectra and detector configurations and also allows for a replication of important site characteristics of study areas – from a small pond to the catchment scale. The simulation thereby gives precise answers to questions like from which location do neutrons originate? How do they propagate to the sensor? What is the neutron's response to certain environmental changes? In recent years, URANOS has been successfully employed by a number of studies, for example, to calculate the cosmic-ray neutron footprint, signals in complex geometries like mobile applications on roads, urban environments and snow patterns.

Cosmogenic activation of sodium iodide

The production of radioactive isotopes by interactions of cosmic-ray particles with sodium iodide (NaI) crystals can produce radioactive backgrounds in detectors used to search for rare events. Through controlled irradiation of NaI crystals with a neutron beam that matches the cosmic-ray neutron spectrum, followed by direct counting and fitting the resulting spectrum across a broad range of energies, we determined the integrated production rate of several long-lived radioisotopes. The measurements were then extrapolated to determine the sea-level cosmogenic neutron activation rate, including the first experimental determination of the tritium production rate: $(80\ifmmode\pm\else\textpm\fi{}21)\text{ }\text{ }\mathrm{atoms}/\mathrm{kg}/\mathrm{day}$. These results will help constrain background estimates and determine the maximum time that NaI-based detectors can remain unshielded above ground before cosmogenic backgrounds impact the sensitivity of next-generation experiments.

Revisiting GeV-scale annihilating dark matter with the AMS-02 positron fraction

Antimatter cosmic-rays are used to probe new phenomena in physics, including dark matter annihilation. We use the cosmic-ray positron fraction spectrum by the Alpha Magnetic Spectrometer, to search for such an annihilation signal in the Galaxy. We focus on dark matter with mass between 5 and 120 GeV, producing high-energy electrons and positrons. In these cosmic-ray energies the interplay of multiple astrophysical sources and phenomena, makes this search highly sensitive to the underlying astrophysical background assumptions. We use a vast public library of astrophysical models for the cosmic-ray positron fraction background, to derive robust upper limits on the dark matter's annihilation cross section for a number of annihilation channels. This library accounts for different types of cosmic-ray sources and uncertainties on their distribution in space and time. Also, it accounts for uncertainties on those sources' output, their injected into the interstellar medium cosmic-ray spectra and for uncertainties on cosmic-ray propagation. For any given dark matter particle mass and annihilation channel, upper limits on the annihilation cross section are given by bands that stretch a full order of magnitude in its value. Our work provides weaker limits compared to earlier results, that are however robust to all the relevant astrophysical uncertainties. Between 5 and 15 GeV, we find indications for a possible excess flux of cosmic-ray electrons and positrons. That excess is found for most, but not all of our astrophysical background parameter space, and its significance can vary appreciably. Further scrutiny is necessary to improve the understanding of these lower energy cosmic rays. Finally, we note that even if an excess signal is found in these energies, the current background uncertainties do not allow us to accurately deduce its underlying particle properties.

Development towards 53Mn Accelerator Mass Spectrometry capabilities at the University of Notre Dame

Accelerator Mass Spectrometry (AMS) with 53Mn has geological applications as a chronometer for exposure and burial times for discontinuously deposited sediments. It has also been used to search for evidence of recent supernovae events, and proposed as a proxy to monitor the variation in the galactic cosmic ray spectrum over time. The current sensitivity limit amongst active facilities is 53Mn/ 55Mn = 3×10−13 while a sensitivity of 53Mn/ 55Mn = 1×10−13 is necessary to fully exploit 53Mn’s capabilities. At the University of Notre Dame’s Nuclear Science Laboratory (NSL), a 10 MV tandem accelerator and a Browne–Buechner Spectrograph operated as a gas-filled magnet were used to separate 53Mn from 53Cr. Samples covering ranges of 53Mn/ 55Mn = 10−10−10−8 were measured for the first time at the NSL using various settings resulting in a background level of 53Mn/ 55Mn =6.2(3)×10−11. Analysis of the results, descriptions of experimental settings, and further explorations will be presented in this paper.

Cosmic Ray Spectrum and Intensity in Middle Atmosphere (CORSIMA) model. Use and Application for Solar Cosmic Rays

The new model CORSIMA (COsmic Ray Spectrum and Intensity in Middle Atmosphere) is presented. The spectra and intensities of solar cosmic rays (SCR) from GLE (Ground Level Enhancement) 05 on 23 February 1956 and GLE 69 on 20 January 2005 at different altitudes are calculated. For this purpose, the operational CORSIMA model is applied. In the final version of the CORSIMA program, an approximation in 6 characteristic energy intervals of the Bohr-Bethe-Bloch function is used, including the charge decrease interval. Analytical expressions for the contributions of the energy intervals are provided. For the first time we present a quantitative and qualitative appreciation of the impact of Solar Cosmic Rays (SCRs) from the Solar Particle Events (SPEs) on the ionosphere and middle atmosphere (30 - 80 km). These altitudes are above the Regener – Pfotzer maximum. Unlike Galactic Cosmic Rays (GCR), the differential spectra of SCR essentially vary in time. The SCR fluxes also differ from each other during the different events. The spectrum and intensity behavior is explained considering the structure of the CORSIMA program. The calculation results are in agreement with the experimental data and show characteristic features of the propagation process for different altitudes and geomagnetic latitudes. The calculations are performed for geomagnetic latitudes 90o (cusp region). The development of this research is important for the processes and mechanisms of space weather.