[en] The recent years saw the implementation and deployment of a new generation of instruments flown in space or on stratospheric balloons. They are targeted at the study of a variety of energetic cosmic particles, including protons and nuclei, electrons, antimatter particles (positrons and antiprotons), secondary nuclei (including isotopes), ultraheavy nuclei, all complementing gamma-ray studies. Thus a new wealth of data is providing fresh insights on high-energy phenomena in the Galaxy. The instruments are large and deployed for long exposures, providing for an energy reach that permits direct cross-comparisons with ground-based measurements. We briefly review the state of the field, focusing on present and near future efforts.

[en] The Cosmic Ray Energetics And Mass (CREAM) instrument flew on a high altitude balloon in Antarctica in 2004-2005 for a record breaking 42 days. An array of detectors was deployed to identify cosmic rays and measure their energies up to several hundred TeV. A major science goal is the measurement of secondary nuclei at high energy (produced by spallation reactions of heavier cosmic rays in the interstellar medium). This is done with a transition radiation detector using xenon-filled proportional tubes, and charge identification devices comprising plastic scintillator and Cherenkov counters. Accurate and stable performance of these detectors is necessary for the reliable identification of the secondary nuclei. The design of these detectors and their performance in flight are discussed, and preliminary data presented

[en] We present a new measurement of the cosmic-ray positron fraction at energies between 5 and 15 GeV with the balloon-borne HEAT-p-bar instrument in the spring of 2000. The data presented here are compatible with our previous measurements, obtained with a different instrument. The combined data from the three HEAT flights indicate a small positron flux of nonstandard origin above 5 GeV. We compare the new measurement with earlier data obtained with the HEAT-e^± instrument, during the opposite epoch of the solar cycle, and conclude that our measurements do not support predictions of charge sign dependent solar modulation of the positron abundance at 5 GeV

[en] We present a targeted search for blazar flux-correlated high-energy (${\mathrm{\epsilon <!--\; ??\; -->}}_{\mathrm{\nu <!--\; ??\; -->}}$ ≳ 1 TeV) neutrinos from six bright northern blazars, using the public database of northern hemisphere neutrinos detected during “IC40” 40-string operations of the IceCube neutrino observatory (2008 April to 2009 May). Our six targeted blazars are subjects of long-term monitoring campaigns by the VERITAS TeV γ-ray observatory. We use the publicly available VERITAS light curves to identify periods of excess and flaring emission. These predefined intervals serve as our “active temporal windows” in a search for an excess of neutrinos, relative to Poisson fluctuations of the near-isotropic atmospheric neutrino background, which dominates at these energies. After defining the parameters of an optimized search, we confirm the expected Poisson behavior with Monte Carlo simulations prior to testing for excess neutrinos in the actual data. We make two searches: one for excess neutrinos associated with the bright flares of Mrk 421 that occurred during the IC40 run, and one for excess neutrinos associated with the brightest emission periods of five other blazars (Mrk 501, 1ES 0806+524, 1ES 1218+304, 3C 66A, and W Comae), all significantly fainter than the Mrk 421 flares. We find no significant excess of neutrinos from the preselected blazar directions during the selected temporal windows. We derive 90% confidence upper limits on the number of expected flux-associated neutrinos from each search. These limits are consistent with previous point-source searches and Fermi GeV flux-correlated searches. Our upper limits are sufficiently close to the physically interesting regime that we anticipate that future analyses using already-collected data will either constrain models or yield discovery of the first blazar-associated high-energy neutrinos.

[en] The Cosmic Ray Energetics And Mass (CREAM) mission is planned for launch in 2015 to the International Space Station (ISS) to research high-energy cosmic rays. Its aim is to understand the acceleration and propagation mechanism of high-energy cosmic rays by measuring their compositions. The Top Counting Detector and Bottom Counting Detector (T/BCD) were built to discriminate electrons from protons by using the difference in cascade shapes between electromagnetic and hadronic showers. The T/BCD provides a redundant instrument trigger in flight as well as a low-energy calibration trigger for ground testing. Each detector consists of a plastic scintillator and two-dimensional silicon photodiode array with readout electronics. The TCD is located between the carbon target and the calorimeter, and the BCD is located below the calorimeter. In this paper, we present the design, assembly, and performance of the T/BCD

[en] Primary cosmic-ray elemental spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment since 2004. The third CREAM payload (CREAM-III) flew for 29 days during the 2007–2008 Antarctic season. Energies of incident particles above 1 TeV are measured with a calorimeter. Individual elements are clearly separated with a charge resolution of ∼0.12 e (in charge units) and ∼0.14 e for protons and helium nuclei, respectively, using two layers of silicon charge detectors. The measured proton and helium energy spectra at the top of the atmosphere are harder than other existing measurements at a few tens of GeV. The relative abundance of protons to helium nuclei is 9.53 ± 0.03 for the range of 1 TeV/n to 63 TeV/n. This ratio is considerably smaller than other measurements at a few tens of GeV/n. The spectra become softer above ∼20 TeV. However, our statistical uncertainties are large at these energies and more data are needed.

[en] We present a new measurement of atmospheric muons made during an ascent of the High Energy Antimatter Telescope balloon experiment. The muon charge ratio μ⁺/μ^- as a function of atmospheric depth in the momentum interval 0.3-0.9 GeV/c is presented. The differential μ^- intensities in the 0.3-50 GeV/c range and for atmospheric depths between 4-960 g/cm² are also presented. We compare these results with other measurements and model predictions. We find that our charge ratio is ∼1.1 for all atmospheric depths and is consistent, within errors, with other measurements and the model predictions. We find that our measured μ^- intensities are also consistent with other measurements, and with the model predictions, except at shallow atmospheric depths

[en] The HEAT (high-energy antimatter telescope) instrument has been developed for a series of observations in cosmic-ray astrophysics that require the use of a superconducting magnet spectrometer. This paper describes the first configuration of HEAT which is optimized for the detection of cosmic-ray electrons and positrons below 100 GeV. In addition to the spectrometer, a combination of time-of-flight scintillators, a transition radiation detector, and an electromagnetic shower counter, provides particle identification, energy measurement, and powerful discrimination against the large background of protons. The instrument was successfully flown aboard high-altitude balloons in 1994 and 1995. The design and construction of the spectrometer and of the detector systems are described, and the performance of the instrument is demonstrated with data obtained in flight. (orig.)

[en] The balloon-borne Cosmic Ray Energetics And Mass experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here, we report results from the first two flights of ∼70 days, which indicate hardening of the elemental spectra above ∼200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at ∼10¹⁵ eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible explanations should also be investigated.

[en] Cosmic-ray proton and helium spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass experiment flown for 42 days in Antarctica in the 2004-2005 austral summer season. High-energy cosmic-ray data were collected at an average altitude of ∼38.5 km with an average atmospheric overburden of ∼3.9 g cm^-2. Individual elements are clearly separated with a charge resolution of ∼0.15 e (in charge units) and ∼0.2 e for protons and helium nuclei, respectively. The measured spectra at the top of the atmosphere are represented by power laws with a spectral index of -2.66 ± 0.02 for protons from 2.5 TeV to 250 TeV and -2.58 ± 0.02 for helium nuclei from 630 GeV nucleon^-1 to 63 TeV nucleon^-1. They are harder than previous measurements at a few tens of GeV nucleon^-1. The helium flux is higher than that expected from the extrapolation of the power law fitted to the lower-energy data. The relative abundance of protons to helium nuclei is 9.1 ± 0.5 for the range from 2.5 TeV nucleon^-1 to 63 TeV nucleon^-1. This ratio is considerably smaller than the previous measurements at a few tens of GeV nucleon^-1.