Proton Energy Spectra Research Articles

CALET results after three years on the International Space Station

The CALET (CALorimetric Electron Telescope) space experiment, which is currently conducting direct cosmic-ray observations onboard the International Space Station (ISS), is an all-calorimetric instrument optimized for cosmic-ray electron measurements with capability to measure hadrons and gamma-rays. Since the start of observation in October 2015, smooth and continuous operations have taken place. In this paper, we will give a brief summary of the CALET observations ranging from charged cosmic rays, gamma-rays, to space weather, while focusing on the energy spectra of electrons and protons.

Optimization of shielding to reduce cosmic radiation damage to packaged semiconductors during air transport using Monte Carlo simulation

BackgroundCosmic ray-induced particles can lead to failure of semiconductors packaged for export during air transport. This work performed MCNP 6.2 simulations to optimize shielding against neutrons and protons induced by cosmic radiation Methods and materialsThe energy spectra of protons and neutrons by incident angle at the flight altitude were determined using atmospheric cuboid model. Various candidates for the shielding materials and the geometry of the Unit Load Device Container were evaluated to determine the conditions that allow optimal shielding at all sides of the container. ResultsIt was found that neutrons and protons, at the flight altitude, generally travel with a downward trajectory especially for the particles with high energy. This indicated that the largest number of particles struck the top of the container. Furthermore, the simulation results showed that, among the materials tested, borated polyethylene and stainless steel were the most optimal shielding materials. The optimal shielding structure was also determined with the weight limit of the container in consideration. ConclusionsUnder the determined optimal shielding conditions, a significantly reduced number of neutrons and protons reach the contents inside the container, which ultimately reduces the possibility of semiconductor failure during air transport.

Simultaneous observation of ultrafast electron and proton beams in TNSA

The interaction of ultra-intense high-power lasers with solid-state targets has been largely studied for the past 20 years as a future compact proton and ion source. Indeed, the huge potential established on the target surface by the escaping electrons provides accelerating gradients of TV/m. This process, called target normal sheath acceleration, involves a large number of phenomena and is very difficult to study because of the picosecond scale dynamics. At the SPARC_LAB Test Facility, the high-power laser FLAME is employed in experiments with solid targets, aiming to study possible correlations between ballistic fast electrons and accelerated protons. In detail, we have installed in the interaction chamber two different diagnostics, each one devoted to characterizing one beam. The first relies on electro-optic sampling, and it has been adopted to completely characterize the ultrafast electron components. On the other hand, a time-of-flight detector, based on chemical-vapour-deposited diamond, has allowed us to retrieve the proton energy spectrum. In this work, we report preliminary studies about simultaneous temporal resolved measurements of both the first forerunner escaping electrons and the accelerated protons for different laser parameters.

Spectra of Protons and Subthreshold Pions for Collisions of Heavy Ions Using a Hydrodynamic Approach with a Nonequilibrium Equation of State

The nonequilibrium equation of state is studied in the context of the hydrodynamic approach. The compression stage, the expansion stage, and the freeze-out stage of the hot spot formed during the collisions of heavy ions are considered. The energy spectra of protons and subthreshold pions produced in collisions of heavy ions are calculated with inclusion of the nuclear viscosity effects and compared with experimental data for various combinations of colliding nuclei with energies of several tens of MeV per nucleon.

Proceedings to the 6th Annual Conference of the Particle Therapy Cooperative Group North America (PTCOG-NA): 14-16 October 2019, Hosted by Miami Cancer Institute, part of Baptist Health South Florida, Miami, FL, USA.

Proceedings to the 6th Annual Conference of the Particle Therapy Cooperative Group North America (PTCOG-NA): 14-16 October 2019, Hosted by Miami Cancer Institute, part of Baptist Health South Florida, Miami, FL, USA.

Nuclear Fragments in 12C + 9Be Interactions at an Energy of 2 GeV per Nucleon

Differential cross sections for the production of nuclear fragments at an angle of 3.5° in the fragmentation of 2-GeV/nucleon carbon ions on a beryllium target were measured in the FRAGM experiment performed at the ITEP-TWA heavy-ion accelerator-accumulator complex. The predictions of four Monte Carlo models of ion-ion interactions (BC, INCL, LAQGSM, and QMD) were tested on the basis of a comparison with the momentum spectra of fragments. Successes and drawbacks of these models are discussed. The energy spectra of protons and 3He nuclei in the cumulative region in the projectile rest frame are well described by an exponential dependence, which make it possible to estimate temperature parameters of their emission source.

Charge Composition of Cosmic Rays at Energies More Than 1 TeV Based on the Results of the NUCLEON Mission

The NUCLEON experiment is aimed to investigate the composition and energy spectra of high energy cosmic rays. Direct measurements of the energy spectra of cosmic ray protons and nuclei over the range of 1–100 TeV are very important for the solution of a general astrophysical problem of origin of cosmic rays. The satellite was launched on 26 December 2014. The measured charge composition is analyzed and compared with data obtained by other experiments at lower energies. The proton to helium ratio is close to constant over the wide magnetic rigidity area (3–100 TV). The charge composition dependence on magnetic rigidity can be explained by means of the single source model.

APPROXIMATION OF THE INTEGRAL ENERGY SPECTRUM OF PROTONS OF SCR IN THE RANGE OF > 1-850 MEV

This work is a continuation of the work (Isaeva E., 2018) in which a new approximation of the in- tegral energy spectrum of solar cosmic ray (SCR) protons was presented in the range > 1-100 MeV. In this work, the comments and wishes of colleagues working in this field were taken into account. First, the comments were taken into account on the form of the functional for approximat- ing the energy spectrum of protons, which must correspond in form to the functionals predicted by particle acceleration theories. Secondly, the previously obtained functional should be checked for high-energy protons with energies >1000 MeV. For the analysis, we used original records of the intensity of the flux of SCR protons according to the data from GOES. The studied sample contains 349 solar proton events (SPE) for the period from 03-02-1986 to 12-02-2018 years, accompanied by protons with energies in the range > 1-850 MeV. Of 349 SPE, 53 were accompanied by high- energy protons with energies > 850 MeV. In this paper, we present the results of approximation of the integral energy spectrum of SCR protons with energies > 1-850 MeV using a functional containing power and ex- ponential functions. A comparative analysis showed that this functional gives a very good approximation for SCR protons with energies in the range > 1-850 MeV.

Indication of nearby source signatures of cosmic rays from energy spectra and anisotropies

The origin of Galactic cosmic rays (GCRs) remains a mystery after more than one century of their discovery. The diffusive propagation of charged particles in the turbulent Galactic magnetic field makes us unable to trace back to their acceleration sites. Nevertheless, nearby GCR source(s) may leave imprints on the locally measured energy spectra and the anisotropies of the arrival direction. In this work we propose a simple but natural description of the GCR production and propagation, within a two-zone disk-halo diffusion scenario together with a nearby source, to understand the up-to-date precise measurements of the energy spectra and anisotropies of GCRs. We find that a common energy scale of ∼100 TeV appears in both energy spectra of protons and helium nuclei measured recently by CREAM and large-scale anisotropies detected by various experiments. These results indicate that one or more local sources are very likely important contributors to GCRs below 100 TeV . This study provides a probe to identify source(s) of GCRs by means of joint efforts of spectral and anisotropy measurements.

Inclusive Spectra of Protons and α Particles from the Interaction between α Particles with an Energy of 29 MeV and 27Al and 59Co Nuclei

The energy spectra of protons and α particles are obtained for a wide range of angles in reactions between α particles with an energy of 29 MeV and 27Al and 59Co nuclei. The contributions from different mechanisms that shape the inclusive proton and α-particle spectra of the studied reactions are determined by analyzing the experimental data with the PRECO-2006 code. The experimental results are added to the bank of data needed for the development of advanced nuclear technologies.

Energy Spectra of Cosmic Ray Protons and Helium Nuclei in the NUCLEON Experiment

The main aims of the NUCLEON satellite experiment are direct measurement of the energy spectra of cosmic ray protons and nuclei in the 2–500 TeV range of energies by two different methods (an ionization calorimeter and the new Kinematic Lightweight Energy Meter (KLEM) technique). The energy spectra of protons and helium nuclei are presented, and their characteristics are discussed.

Massive star clusters as the an alternative source population of galactic cosmic rays

Extended gamma -ray emissions in the vicinity of young star clusters are believed to be produced by the interaction of CRs accelerated therein with the ambient gas. The detailed spatial analysis reveals 1/r type distribution of CRs, which indicates a continuous injection of CRs in these objects. The hard, propto E^{-2.3} type power-law energy spectra of parent protons continue up to sim 1 PeV. The efficiency of conversion of kinetic energy of powerful stellar winds to CRs can be as high as 10%. This implies that the young massive stars can operate as effective proton PeVatrons with a major or even dominant contribution to the flux of highest-energy galactic CRs.

Imprint of the stochastic nature of photon emission by electrons on the proton energy spectra in the laser-plasma interaction

The impact of stochasticity effects (SEs) in photon emissions on the proton energy spectra during laser-plasma interaction is theoretically investigated in the quantum radiation-dominated regime. We calculate the photon emissions quantum mechanically and the plasma dynamics semiclassically via two-dimensional particle-in-cell simulations. An ultrarelativistic plasma generated and driven by an ultraintense laser pulse head-on collides with another strong laser pulse, which decelerates the electrons due to radiation-reaction effect and results in a significant compression of the proton energy spectra because of the charge separation force. In the considered regime the SEs are demonstrated in the shift of the mean energy of the protons up to hundreds of MeV. This effect is robust with respect to the laser and target parameters and measurable in soon available strong laser facilities.

Evolution of the Suprathermal Proton Population at Interplanetary Shocks

Abstract We investigate the evolution of the suprathermal (ST) proton population as interplanetary shocks cross 1 au. The variability of the ST proton intensities and energy spectra upstream of the shocks is analyzed in terms of the shock parameters, upstream magnetic field configurations, and preexisting upstream populations. Propitious conditions for the observation of ST particles at distances far upstream from the shock occur in parallel shock configurations when particles can easily escape from the shock vicinity. In this situation, ST intensity enhancements show onsets characterized by velocity dispersion effects and energy spectra that develop into a “hump” profile peaking around ∼10 keV just before the arrival of the shock. The observation of field-aligned proton beams at low energies (5–10 keV) is possible under conditions that facilitate the scatter-free propagation of the particles streaming out of the shock. Upstream of perpendicular shocks, ST intensity enhancements are only observed in close proximity to the shock. Power-law proton spectra develop downstream of the shocks. The functional form for the downstream phase-space density proportional to v −5 is observed only over a limited range of ST energies. The absence of ST populations observed far upstream of interplanetary shocks raises questions about whether ST protons contribute as a seed particle population in the processes of particle acceleration at shocks.

Expected energy spectrum of cosmic ray protons and helium below 4 PeV measured by LHAASO * * Supported by the National Key R&D Program of China (2018YFA0404201, 2018YFA0404202), the Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, CAS (Y5113D005C) and National Natural Science Foundation (NSFC) (11563004, 11775248)

The Large High Altitude Air Shower Observatory (LHAASO) is a composite cosmic ray observatory consisting of three detector arrays: kilometer square array (KM2A), which includes the electromagnetic detector array and muon detector array, water Cherenkov detector array (WCDA) and wide field-of-view Cherenkov telescope array (WFCTA). One of the main scientific objectives of LHAASO is to precisely measure the cosmic rays energy spectrum of individual components from eV to eV. The hybrid observation will be employed by the LHAASO experiment, in which the lateral and longitudinal distributions of extensive air shower can be observed simultaneously. Thus, many kinds of parameters can be used for primary nuclei identification. In this paper, high purity cosmic ray simulation samples of the light nuclei component are obtained using multi-variable analysis. The apertures of 1/4 LHAASO array for pure proton and mixed proton and helium (H&He) samples are and , respectively. Prospect of obtaining proton and H&He spectra from 100 TeV to 4 PeV is discussed.

Solar Modulation of the Galactic Electron and Proton Intensity near the Activity Minimum of 2009

A model of galactic cosmic ray modulation is presented that satisfactorily describes long-period variations in the intensity of the proton and electron components in the waning phase of the solar activity of the 23rd cycle (2006–2009). A distinctive feature of the model is its description of the temporal behavior of energy spectra of both electrons and protons at the same fixed values of model parameters. Model calculations are compared to measurement data obtained on the PAMELA spectrometer for spectra of the proton and electron components of galactic cosmic rays.

Solar Activity and Cosmic Ray Variations in September 2017

The results are presented from an analysis of data on solar activity and cosmic ray variations observed in September 2017. This period is characterized by a sharp increase in the solar flare activity in the active region AR 12673 during the late descending phase of the 24th solar activity cycle. Solar protons are recorded by the particle instruments aboard the GOES-13 satellite, in the atmosphere, and by the ground-based neutron monitor network. A moderate Forbush decrease in the cosmic ray flux during September 6–10 is also recorded by a number of neutron monitors. Several solar proton energy spectra during September 10, 2017, (GLE72 event) are evaluated using the results from satellite measurements, balloon observations, and neutron monitor records.

An online beam profiler for laser-accelerated protons.

The design and operation of an online energy and spatially resolving detector based on three different scintillators for laser-driven protons are described. The device can be used for a multi-Hertz recording rate. The spatial resolution is <0.5 mm, allowing to retrieve details of the proton beam which is of interest, e.g., for radiographic applications. At the same time, the particle energy is divided into three energy bands between 1 MeV and 5 MeV to retrieve the proton energy spectrum. The absolute response of the detector was calibrated at a conventional proton accelerator.

Massive stars as major factories of Galactic cosmic rays

The identification of the main contributors to the locally observed fluxes of cosmic rays is a prime objective in the resolution of the long-standing enigma of the source of cosmic rays. We report on a compelling similarity of the energy and radial distributions of multi-TeV cosmic rays extracted from observations of very-high-energy γ-rays towards the Galactic Centre and two prominent clusters of young massive stars, Cygnus OB2 and Westerlund 1. We interpret this resemblance as evidence that cosmic rays responsible for the diffuse very-high-energy γ-ray emission from the Galactic Centre are accelerated by the ultracompact stellar clusters located in the heart of the Galactic Centre. The derived 1/r decrement of the cosmic ray density with the distance from a star cluster is a distinct signature of continuous cosmic ray injection into the interstellar medium over a few million years. The lack of brightening of the γ-ray images towards the stellar clusters excludes the leptonic origin of γ-ray radiation. The hard, ∝E−2.3-type, power-law energy spectra of parent protons continues up to ~1 PeV. The efficiency of conversion of the kinetic energy of stellar winds to cosmic rays can be as high as 10%, implying that young massive stars may operate as proton PeVatrons with a dominant contribution to the flux of the highest-energy Galactic cosmic rays. Ultracompact stellar clusters in the Galactic Centre are likely to be major contributors to the Galactic cosmic ray flux in the multi-TeV energy range. Observations of the diffuse gamma-ray emission from the Galactic Centre and two young massive star clusters correlate with the cosmic-ray distribution.

The high-energy particle package onboard CSES

The China Seismo-Electromagnetic Satellite (CSES) aims to monitor space electromagnetic fields, ionospheric plasma, high-energy charged particles and other features of the global space environment. The high-energy particle package (HEPP), which can effectively detect the energy spectrum, flux and pitch angle distribution of space electrons and protons, and soft X-ray emission from solar flares, is one of the main payloads of CSES. In this study, we designed, developed and calibrated the high-energy particle package and launched it into orbit with CSES. HEPP consists of the high-energy detector (HEPP-H), the low-energy detector (HEPP-L), and the solar X-ray monitor (HEPP-X). The three sub-detectors mainly use silicon detector and crystal calorimeter detection technology. Before launching, we calibrated the three sub-detectors in detail by using radiation source and accelerator beam. All the three sub-detectors have good energy linearity. After launching into orbit, the space energetic particles and X-ray distribution detected by HEPP are consistent with expectations. The performance indices of the detector reach the advanced level of the same kind of detector in the world. HEPP has a wide energy detection range, good energy resolution and high angular resolution ability for electrons and protons. It will play an important role in the study of space particle response and space physics of seismic activity.