The NAVIgation DOsimetry System (NAVIDOS) comprises a complete readout system for a radiation detector, an air pressure sensor and a GPS receiver.The detector system DOSTEL uses silicon detectors which make NAVI-DOS light weighted and compact in size.Therefore, NAVI-DOS is well suited to be installed on board aircraft.The calibration of NAVIDOS in terms of ambient dose equivalent is done by an in-field comparison with the PTB reference instrument πDOS.We also show that the dependence of these results on the vertical cut-off rigidity can be explained by the low response of the silicon detectors for neutrons.Therefore, in-flight measurements have been performed together with the PTB reference instrument πDOS.The dose rates, calculated using the PTB code FDOScalc, were verified with these πDOS measurements.The calibration of NAVIDOS was done with FDOScalc and results in calibration factors between 3.4 in the polar and 2.4 in the equator region.
A method has been developed to correct in real- time the cosmic ray (CR) muon component, observed by the muon telescopes of different geometry, for temperature ef- fect.
. Spacecraft missions such as Wind and ACE can be used to determine magnetic correlation functions in the solar wind. From such data sets one can obtain spatial and temporal correlations of magnetic fields. Such correlations are fundamental in the theory of magnetic turbulence and are important to describe the statistics of magnetic field lines and the propagation of energetic particles such as cosmic rays. In the present article we compare analytical forms of correlation functions with measurements performed in the solar system. We obtain new values for the correlations length scales and we test our understanding of the turbulence dynamics.
In this study, first direct and circumstantial ev- idences of the effects of cosmic rays (CR) on biological systems are presented. A direct evidence of biological ef- fects of CR is demonstrated in experiments with three cellu- lar lines growing in culture during three events of Ground Level Enhancement (GLEs) in the neutron count rate de- tected by ground-based neutron monitor in October 1989. Various phenomena associated with DNA lesion on the cel- lular level demonstrate coherent dynamics of radiation ef- fects in all cellular lines coincident with the time of arrival of high-energy solar particles to the near-Earth space and with the main peak in GLE. These results were obtained in the course of six separate experiments, with partial overlapping of the time of previous and subsequent experiments, which started and finished in the quiet period of solar activity (SA). A significant difference between the values of multinuclear cells in all cellular lines in the quiet period and during GLE events indicates that the cause of radiation effects in the cell cultures is an exposure of cells to the secondary solar CR near the Earth's surface. The circumstantial evidence was obtained by statistical analysis of cases of congenital mal- formations (CM) at two sites in the Murmansk region. The number of cases of all classes of CM reveals a significant correlation with the number of GLE events. The number of cases of CM with pronounced chromosomal abnormalities clearly correlates with the GLE events that occurred a year before the birth of a child. We have found a significant corre- lation between modulations of the water properties and daily background variations of CR intensity. We believe that the effects of CR on biological systems can be also mediated by fluctuations in water properties, considered as one of possi- ble mechanisms controlling the effects of CRs on biological systems.
We report here on two proton energetic particle events observed by the Energetic and Relativistic Nuclei and Electron (ERNE) instrument on the Solar and Heliospheri- cal Observatory (SOHO). Both events were impulsive (SEP) events with intensities of > 10 3 cm 2 sr 1 s 1 MeV 1 at an energy range of tens of MeVs and were associated with CMEs of angular widths 800 kms 1 . In one of the events there was no associated solar flare, which indicates that the first injected protons were completely due to the associated CME and in the second event the associated solar flare was an impulsive M1.1 class flare and the calculated first injection time for protons of en- ergies 36 MeV and propagating along 1.2 AU path length, was close to the liftoff time of the CME. These observations are inconsistent with the view presented in some studies that narrow fast CME are not associated with SEP events.
The NuMoon project aims to study ultra-highenergy neutrinos and cosmic rays by using radio telescopes to search for short pulses from the Moon.These pulses are created when a neutrino or cosmic ray impinges on the Moon and interacts below the lunar surface.Part of the energy is converted into a hadronic shower, which emits radio emission in a process known as the Askaryan effect.In the first phase of the NuMoon project, 46 hrs of data were collected with the Westerbork Synthesis Radio Telescope in a low frequency band: 40 -80 MHz.This resulted in an upper limit on the neutrino flux above 10 22 eV which is an order of magnitude lower than previous limits.Additionally, an upper limit has been set on the ultra-high-energy cosmic-ray flux.The second phase of NuMoon will consist of observations with LOFAR.
The kinetic energy spectra of solar energetic particle (SEP) events contain information on the particle acceleration mechanisms.A novel approach is proposed to investigate the time evolution of the spectral shape for the 20 February 2002 SEP event.Proton differential fluxes recorded by the ERNE instrument aboard SOHO, in the energy range 1.67-112 MeV, are analyzed.The solar source is associated with this SEP event by studying solar and interplanetary conditions during the considered time period.The energy spectrum evolution is studied by evaluating the time history of Shannon's differential entropy derived from the SEP fluxes.Our findings suggest that particle acceleration in the considered event is produced by a perpendicular shock in the solar corona.Moreover, dropouts in the particle flux are clearly identified up to energies of at least ∼ 10 MeV.
. During my long scientific career of about 60 years (from 1951), I was happy to meet and cooperate with Academician S. N. Vernov. During the first step (1950–1952), S. N. Vernov together with N. V. Pushkov organized the first Soviet network of cosmic ray (CR) stations equipped by large automatically operating ionization chambers of A. Compton type shielded by 10 cm of Pb. This was the beginning of the CR variations research in the former USSR. In the present paper I consider step by step the development of experimental and theoretical basis of CR variations research in the former USSR and the great role of S. N. Vernov in this process.
It has recently been suggested that neutron stars inside the shells of young supernova remnants (SNR) are the sources of PeV cosmic rays and that the interaction of the particles with the radiation field in the SNR causes electron pair production, which has relevance to recent observations of 'high' positron fluxes. Furthermore, the character of the interaction is such that the well-known knee in the cosmic ray energy spectrum can be explained. Our examination of the mechanism leads us to believe that the required parameters of SN and pulses are so uncommon that the knee and positron fraction can only be explained if a single, local and recent SN - and associated pulsar - are concerned.
Electromagnetic cascades in matter, photon fields, and magnetic fields are solved by a standard numerical method, integrating the diffusion equations of respective cascade processes numerically.Our results and those of Aharonian and Plyasheshnikov agree very well for cascades in matter and magnetic fields, though they show some slight discrepancies for cascades in photon fields of high incident energies.Transport properties of electron and photon spectra are also investigated by solving differential-difference equations for cascades with simplified cross-sections, and the spectra under the electron cooldown process are well explained quantitatively.
Measurements of the underground atmospheric muon flux are important in order to determine accurately the overburden in mwe (meter water equivalent) of an un- derground laboratory for appreciating which kind of exper- iments are feasible for that location. Slanic- Prohava is one of the 7 possible locations for the European large un- derground experiment LAGUNA (Large Apparatus studying Grand Unification and Neutrino Astrophysics). A mobile de- vice consisting of 2 scintillator plates ( 0.9 m 2 , each) one above the other and measuring in coincidence, was set-up for determining the muon flux. The detector it is installed on a van which facilitates measurements on different positions at the surface or in the underground and it is in operation since autumn 2009. The measurements of muon fluxes pre- sented in this contribution have been performed in the under- ground salt mine Slanic-Prahova, Romania, where IFIN-HH has built a low radiation level laboratory, and at the surface on different sites of Romania, at different elevations from 0 m a.s.l up to 655 m a.s.l. Based on our measurements we can say that Slanic site is a feasible location for LAGUNA in Unirea salt mine at a water equivalent depth of 600 mwe. The results have been compared with Monte-Carlo simula- tions performed with the simulation codes CORSIKA and MUSIC.
Recent results from the Pierre Auger Observatory and the Hi-Res array have been analysed hoping to derive a strong statement about the mass composition in the region of the ankle, where the change from Galactic to ExtraGalactic cosmic ray flux should take place, at least according to some theoretical predictions. It is shown that there are problems in reconciling the data with expectation.
We have developed a self powered stand alone par- ticle detector array dedicated to the observation of horizontal tau air showers induced by high energy neutrinos interacting in mountain rock. Air shower particle detection reaches a 100% duty cycle and is practically free of background when compared to Cherenkov light or radio techniques. It is thus better suited for rare neutrino event search. An appropriate mountain to valley topological configuration has been identi- fied and the first array will be deployed on an inclined slope at an elevation of 1500 m facing Southern Alps near the city of Grenoble (France). A full simulation has been performed. A neutrino energy dependent mountain tomography chart is obtained using a neutrino and tau propagation code together with a detailed cartography and elevation map of the region. The array acceptance is then evaluated between 1 PeV and 100 EeV by simulating decaying tau air showers across the valley. The effective detection surface is determined by the shower lateral extension at array location and is hence much larger than the array geometrical area. The array exposure will be 10 14 cm 2 sr s at 100 PeV. Several independent arrays can be deployed with the aim of constituting a large distributed observatory. Some other sites are already under study. At last, special care is dedicated to the educational and outreach aspects of such a cosmic ray detector.
Using the Tibet-III air shower array, we search for steady TeV γ -rays from 18 pulsars in the Fermi Large Area Telescope pulsar catalog.Among them, we observe 8 sources including the Crab instead of the expected Published by Copernicus Publications on behalf of the Arbeitsgemeinschaft Extraterrestrische Forschung e.V. 212 M. Amenomori et al.: Observation of the Fermi pulsar catalog at TeV energies with the Tibet airshower experiment 0.41 sources at a significance of 2 σ or more excess.Under the assumption of Poisson distribution, the chance probability is estimated to be 1.4 × 10 -8 .When the Crab is excluded, it becomes 1.8 × 10 -7 .These low chance probabilities clearly show that the Fermi pulsars have a statistically significant correlations with TeV γ -ray excesses.
On behalf of the ARGO-YBJ Collaboration Abstract. We report on the search for Gamma Ray Bursts (GRBs) in the energy range 1 100 GeV in coincidence with the prompt emission detected by satellites, using the Astro- physical Radiation Ground-based Observatory at YangBa- Jing (ARGO-YBJ). With its big active surface ( 6700 m 2 ) and large field of view ( 2 sr) the ARGO-YBJ air shower detector is particularly suitable to detect unpredictable and short duration events such as GRBs. The search has been performed using the single particle technique in time coinci- dence with satellite detections both for single events and for the piling up of all the GRBs in time and in phase. Between November 2004 and June 2010 115 GRBs, de- tected by different satellites (mainly Swift and Fermi), oc- curred within the field of view of ARGO-YBJ. For 94 of these we searched for a counterpart in the ARGO-YBJ data finding no statistically significant emission. Search methods and results are discussed.
A stacking analysis performed with data from the IceCube neutrino observatory is presented in this paper. In general, the stacking technique is sensitive to a cumulative signal from a generic source class. This can lead to a sig- nificant signal for the most luminous sources of the class, even if the individual sources cannot be detected. Here, the final data set of the AMANDA-II experiment, which is the predecessor of the IceCube, is used for an analysis. In a second analysis, data from a quarter of the IceCube detec- tor is used. IceCube consists of so called stings, these are steel cables with photo multipliers hooked up which are de- ployed into the Antarctic ice to depths between 1450 m and 2450 m. This analysis covers data taken with 22 strings of IceCube (IC-22) within one year. For the first time, a sam- ple of Starburst Galaxies was analyzed. In addition, sev- eral AGN catalogs are used as well as a catalog of pul- sars. The analysis did not reveal a significant neutrino sig- nal for any of the analyzed source classes, neutrino flux lim- its were improved. The strongest limit was received for the class of Gigahertz Peaked / Compact Steep Spectrum sources (GPS/CSS), E 2 dN /dE GPS <8.2·10 12 GeV/s/sr per source, assuming an E 2 shaped spectrum. This corre- sponds to an improvement of a factor of 2.5 compared with the average point source limit for single sources. In photon-hadron interactions, or in interactions of the cos- mic rays with matter in the vicinity of the source, neutrinos are mainly produced via charged pion decays. Neutrinos are dominantly produced in hadronic interactions and are not ex- pected to come from leptonic interactions. Therefore, a neu- trino detection from an extraterrestrial source is an unam- biguous sign for cosmic ray acceleration. Several sources and source classes have been proposed as neutrino emitters, see e.g. Becker (2008). The IceCube experiment is currently being constructed close to the geographic South Pole, using the Antarctic ice for neutrino detection. IceCube uses digital optical modules (DOMs) to detect Cherenkov light emitted by muons which where produced in neutrino-nucleon inter- actions in the ice. When completed in 2011 IceCube will consist of 5160 DOMs arranged along 86 strings deployed in depths between 1450 m and 2450 m in the antarctic ice. The seven source classes presented in this analysis were analyzed aiming for a high energy neutrino signal.
For the purposes of a study of hadron component of an extended air shower (EAS), two detectors of cosmic rays (CR) were joined at the Baksan Neutrino Observatory.They are an EAS array detector (the "Carpet") and a neutron monitor (NM).Due to the versatility of a new recording system a master-pulse, which comes from the "Carpet" and marks to occurring of EAS, is joined to NM data.After processing of the huge data set it is found that the time of EAS influence on NM is less than 1 ms.The distribution of time intervals between pulses in the first millisecond after EAS onset is essentially different from the background and shows presence of two processes with characteristic times 45 and 230 µs.
A brief description of the developed structural electric diagrams of 16-channel scintillation module for the underground EMMA experiment, the basic characteristics and parameters of the electrical diagrams of this module are presented. Multi-pixel photodiodes operating in a limited Geiger mode are used for photoreadout of the scintillator de- tectors in 16-channel scintillation module. The method of the automatic tuning of the photosensors gain based on the sta- bilization of an average counting rate of the scintillation de- tectors from gamma rays of a natural radioactive background is described.
Strong variations of the intensity of secondary cosmic rays during thunderstorms are found to be accompanied in some cases by very clear pulsations of the geomagnetic field. The experiment is carried out in the Baksan Valley, North Caucasus, the Carpet air shower array being used as a particle detector. Magnetic field measurements are made with high-precision magnetometers located deep underground in the tunnel of the Baksan Neutrino Observatory, several kilometers apart from the air shower array.
A new type of solar neutron detector (NEM) was launched by the space shuttle Endeavour on 16 July 2009 and it began collecting data on 25 August 2009 at the International Space Station (ISS).In this paper we introduce preliminary results obtained by the NEM.
