We present the observation of a charge-sign dependent solar modulation of galactic cosmic rays (GCRs) with the Calorimetric Electron Telescope onboard the International Space Station over 6 yr, ...corresponding to the positive polarity of the solar magnetic field. The observed variation of proton count rate is consistent with the neutron monitor count rate, validating our methods for determining the proton count rate. It is observed by the Calorimetric Electron Telescope that both GCR electron and proton count rates at the same average rigidity vary in anticorrelation with the tilt angle of the heliospheric current sheet, while the amplitude of the variation is significantly larger in the electron count rate than in the proton count rate. We show that this observed charge-sign dependence is reproduced by a numerical “drift model” of the GCR transport in the heliosphere. This is a clear signature of the drift effect on the long-term solar modulation observed with a single detector.
Quasi horizontal showers produced by charged CR and gammas are constituted exclusively by muons, the other components being absorbed in the thick layer of the atmosphere they must cross to reach a ...detection system on the Earth surface. Their transverse dimensions are increased by the distance they must travel as well by the terrestrial magnetic field which extends muon cloud and separates positive muons from negative ones. The extended wide transverse dimensions allow increasing the rate of detection of EAS produced by high energy CR by means of a single detector which samples the muon density in the shower. This concept has been already applied in the NEVOD-DECOR experimental complex at MEPhI in Moscow that could detect local muon density (LMD) of showers produced by very high energy CR up to more than 10 super(18)eV. By adding to the LMD the measurement of the local energy density (LED) the determination of the primary energy E sub(0) can be substantially improved. A few embodiments of such a device can be envisaged and one of them is discussed. The substantial rate increase of the area explored by a multimuon detection system measuring LMD and LED allows to conceive an array constituted by a relatively small number of such stations for measuring UHECR up to 10 super(12)eV and higher.
The direct detection of high-energy cosmic rays up to the PeV region is one of the major challenges for the next generation of space-borne cosmic-ray detectors. The physics performance will be ...primarily determined by their geometrical acceptance and energy resolution. CaloCube is a homogeneous calorimeter whose geometry allows an almost isotropic response, so as to detect particles arriving from every direction in space, thus maximizing the acceptance. A comparative study of different scintillating materials and mechanical structures has been performed by means of Monte Carlo simulation. The scintillation-Cherenkov dual read-out technique has been also considered and its benefit evaluated.
This work discusses a variation of the Double Donut Schmidt Camera (DDSC), originally proposed for the EUSO-FF (EUSO on Free Flyer) project and devoted to the observation of UHECRs from space with a ...threshold of about 5 * 1019 eV for a 600 km altitude. Increasing the entrance pupil area by a factor ~3, and then lowering the energy threshold to about 8 EeV (assuming for the differential energy spectrum of UHECR’s the index −2.7), the proposed system will allow the observation of some ‘cosmogenic neutrino’ events in the 1018–1019 eV range, where most of their flux is expected. The scalability of the DDSC design and the high Technological Readiness Level (TRL5) reached in the last decade for ultra-light, deployable, active mirrors does not set conceptual limits on the possible diameter of the primary mirror. We then propose to scale up the optics until the UV light detector in the focal plane will fill the whole diameter of the fairing of the considered launcher (4.2 m diameter assumed as in EUSO-FF baseline for Ariane 5/6 class). This will make necessary to deploy the corrector plate in orbit, in order to accommodate it into the fairing. This technology is still to be evaluated, but as the plate has a small refractive power, its tolerances are much broader than those of the primary mirror and it should be technologically feasible. With this upgrade, EUSO-FF, in addition to detecting more UHECR events, could also act as a precursor of a UHE neutrino observatory from space, addressing the problems to be faced for its realization.
The satellite borne Pamela instrument is dedicated to the precise and high statistics study of cosmic-ray fluxes over a four decades energy range. Pamela experiment is the last step of the ...‘Russian-Italian Mission’ (RIM) program established in 1992 between several Italian and Russian institutes and with the participation of Sweden and Germany. Designed asa cosmic ray observatory at 1AU, its extensive program is made possible thanks to the outstanding performance of the instrument, the low energy threshold, the quasi-polar orbit and the 10years duration of the observation. The physics program pays particular attention to the study of particles and antiparticles fluxes and includes search for dark matter, primordial antimatter, new matter in the Universe, study of cosmic-ray propagation, solar physics and solar modulation, and terrestrial magnetosphere. Very important is the discovery of the anomalous increase of the positron flux at energies higher that 10GeV (the so called ‘Pamela anomaly’), and the abrupt spectral hardening of H and He, challenging the current paradigm of cosmic-ray acceleration and propagation in the Galaxy.
Homogeneous and isotropic calorimetry for space experiments Mori, N.; Adriani, O.; Basti, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Volume:
732
Journal Article
Peer reviewed
Calorimetry plays an essential role in experiments observing high energy gamma and cosmic rays in space. The observational capabilities are mainly limited by the geometrical dimensions and the mass ...of the calorimeter. Since deployable mass depends on the design of the detector and the total mass of the payload, it is important to optimize the geometrical acceptance of the calorimeter for rare events, its granularity for particle identification, and its absorption depth for the measurement of the particle energy. A design of a calorimeter that could simultaneously optimize these characteristics assuming a mass limit of about 1.6t has been studied. As a result, a homogeneous calorimeter instrumented with cesium iodide (CsI) crystals was chosen as the best compromise given the total mass constraint. The most suitable geometry found is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic CsI crystals. The total radiation length in any direction is very large, and allows for optimal electromagnetic particle identification and energy measurement, while the interaction length is at least sufficient to allow a precise reconstruction of hadronic showers. Optimal values for the size of the crystals and spacing among them have been studied. Two prototypes have been constructed and preliminary tests with high energy ion and muon beams are reported.
Shielding is arguably the main countermeasure for the exposure to cosmic radiation during interplanetary exploratory missions. However, shielding of cosmic rays, both of galactic or solar origin, is ...problematic, because of the high energy of the charged particles involved and the nuclear fragmentation occurring in shielding materials. Although computer codes can predict the shield performance in space, there is a lack of biological and physical measurements to benchmark the codes. An attractive alternative to passive, bulk material shielding is the use of electromagnetic fields to deflect the charged particles from the spacecraft target. Active shielding concepts based on electrostatic fields, plasma, or magnetic fields have been proposed in the past years, and should be revised based on recent technological improvements. To address these issues, the European Space Agency (ESA) established a Topical Team (TT) in 2002 including European experts in the field of space radiation shielding and superconducting magnets. The TT identified a number of open research questions to be addressed, including development and testing of novel shielding materials, studies on the angular distributions of energetic solar particles, and cooling systems for magnetic lenses in space. A detailed report to the ESA will be published within a few months. A summary of the TT conclusions and recommendations will be discussed in this paper, with emphasis on active shielding using superconducting magnets.
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