WorldWideScience

Sample records for chacaltaya

  1. Strangelets at Chacaltaya

    OpenAIRE

    Rybczynski, M.; Wlodarczyk, Z; Wilk, G.

    2000-01-01

    Comment: gz-compressed .tar file containing LaTeX file and 4 PS files with figures, 5 pages altogether (Nuovo Cimento cimento.cls style file attached) Presented at Chacaltaya Meeting On Cosmic Ray Physics, La Paz - Bolivia, 23-27 July 2000. To be published in Nuovo Cimento (Proc. Suppl.)

  2. Search for Gamma Ray Bursts at Chacaltaya

    CERN Document Server

    Vernetto, S

    2001-01-01

    A search for Gamma Ray Bursts in the GeV-TeV energy range has been performed by INCA, an air shower array working at 5200 m of altitude at the Chacaltaya Laboratory (Bolivia). The altitude of the detector and the use of the "single particle technique" allows to lower the energy threshold up to few GeVs. No significant signals are observed during the occurrence of 125 GRBs detected by BATSE, and the obtained upper limits on the energy fluence in the interval 1-1000(100) GeV range from 3.2(8.6) 10^-5 to 2.6(7.0) 10^-2 erg/cm^2 depending on the zenith angle of the events. These limits, thanks to the extreme altitude of INCA, are the lowest ever obtained in the sub-TeV energy region by a ground based esperiment.

  3. Measurement of cosmic ray chemical composition at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    BASJE group has measured the chemical composition of primary cosmic rays with energies around the knee with several methods. These measurements show that the averaged mass number of cosmic ray particles increases with energy up to the knee. In order to measure the chemical composition in much wider energy range, it was started a new experiment at Mt. Chacaltaya in 2000

  4. Study of hadronic component in air showers at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    An experiment to operate an air shower array, a burst detector (or a hadron calorimeter) and an emulsion chamber is under way at Mt. Chacaltaya (5,200 m, Bolivia), in order to study the hadron interactions and the primary cosmic rays in the energy region exceeding 1015 eV. The number of hadrons in the air shower, detected by the burst detector, indicates that the proton fraction among the primary cosmic rays exceeds 50 %

  5. A small air-shower array at Mount Chacaltaya

    International Nuclear Information System (INIS)

    We have operated a small air-shower array at Mount Chacaltaya in Bolivia since September 1987 and have observed air showers with primary energies above 2.0.1013 eV. This array consists of thirty-three unshielded scintillation detectors and a shielded scintillation detector. The unshielded detectors are installed over an almost flat field of approximately 8.103m2 area, while the shielded detector is located at the array center. In the present paper, we report both the details and the operation of this array and the analysis method for the observed data. Furthermore, we have simulated air showers with a Monte Carlo technique. Then, analyzing these air showers, we examine the performance of our array, that is, the accuracy in determination of the electron sizes and the arrival directions of observed air showers. (orig.)

  6. Study of hadronic component in air showers at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    An experiment of an air shower array, a hadron calorimeter (8 m2) and an emulsion chamber (8 m2, 15 cm Pb) is under way at Mt. Chacaltaya (5200 m above sea level, Bolivia), in order to study the hadron interactions and the primary cosmic rays in the energy region exceeding 1015 eV. The number of particles in the hadronic component in the air shower, which is detected by the hadron calorimeter, is not compatible with that obtained by simulations, indicating that violation of the Feynman scaling law is stronger at 1016 eV than the one assumed in the simulations. The average mass number of the primary cosmic rays, estimated from the distribution of the number of hadrons in the air shower, is = 2.8 ± 0.5 at 1016 eV

  7. Present experiment of BASJE group at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    A compact air shower array to observe primary cosmic rays above a few TeV has been installed at Mt. Chacaltaya in Bolivia since 1996. This array is available to observe the air showers above 6 TeV and the longitudinal development curves above 50 TeV. The purpose of the observations is to study the chemical composition and the energy spectrum of cosmic rays in the energy region including the knee of the energy spectrum. First, the consistency between direct measurements (balloon-borne experiments) and air shower observations in the energy region from 50 TeV to 80 TeV is examined and confirmed. Next, the chemical composition and the energy spectrum are derived from the air shower observations. In the study, the longitudinal developments of shower particles are calculated by Monte Carlo simulations, assuming different chemical compositions above 80 TeV. The characteristics of the present air shower array and the comparison of the preliminary observed results with that of the simulations are presented

  8. Combination of emulsion chamber and air shower array at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    Data of 34 familes with the accompanying air showers, observed by the combination of emulsion chamber and air shower array at Mt. Chacaltaya, are presented. Comparison with the simulation calculation concludes that a change is necessary in the characteristics of hadron interactions in E0≥1015 eV

  9. Study of nuclear interactions by observing family and air showers at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    It was operated an air shower array and an emulsion chamber simultaneously at Mt. Chacaltaya (5200 m, Bolivia), in order to study high energy nuclear interactions, induced by cosmic rays. It was showed that high energy electromagnetic component and hadronic component in the air shower are not described by the simulations, indicating that the energy spectrum of produced particles in multiple particle production is suppressed strongly in the forward region

  10. A systematic study of the hybrid experiment at Mt.Chacaltaya

    OpenAIRE

    Semba H.; Ohsawa A.; Ohmori N.; Ochi N.; Martinic N.; Kawasumi N.; Inoue N.; Honda K.; Aoki H; Tamada M.; Ticona R.

    2013-01-01

    In the hybrid experiment on Mt.Chacaltaya, we can observe three different components of airshowers, that is, air-shower size, burst-density and high energy families (a bundle of high energy particles). Burst-density in each block of hadron calorimeters are newly recalculated in simulations in oder to compare directly to the experimental data. Energy deposits in the scintillators of the hadron calorimeters are calculated using GEANT4 for every particle, incident upon the hadron calorimeter, in...

  11. Atmospheric interactions detected in both the upper and the lower chambers at Chacaltaya

    International Nuclear Information System (INIS)

    The cosmic ray interactions in the energy region 10 to the 13th power to 10 to the 17th power eV were studied by emulsion chambers exposed at Chacaltaya, 5220 m above sealevel. The chambers have a two-storied structure, and the events observed in both chambers give important informations on these phenomena. The first Centauro event was detected as a small shower at the bottom of the upper chamber and as a big fraction of energy deposit in the lower chamber, which indicates a high contribution of hadronic showers. Results of the events with continuation in the rather low energy region are described

  12. Cosmic ray nuclear interactions and EAS-triggered families observed by the Chacaltaya hybrid experiment

    International Nuclear Information System (INIS)

    Longitudinal and lateral characteristics of the families detected by emulsion chambers in the hybrid experiment with AS-array at Mt. Chacaltaya are studied in detail. Although many groups discuss about an increase of the heavy component in primary cosmic-rays beyond the knee region, it is shown that the observed characteristics of the families accompanied by large shower size, Ne>106, can not be explained by an increase of heavy primaries alone. It is necessary to assume some changes of nuclear interaction in order to explain the observed characteristics of the air-showers accompanied by families

  13. Atmospheric interactions detected in both the upper and the lower chambers at Chacaltaya

    Science.gov (United States)

    Amato, N. M.; Arata, N.; Maldonado, R. H. C.

    1985-01-01

    The cosmic ray interactions in the energy region 10 to the 13th power to 10 to the 17th power eV were studied by emulsion chambers exposed at Chacaltaya, 5220 m above sea-level. The chambers have a two-storied structure, and the events observed in both chambers give important informations on these phenomena. The first Centauro event was detected as a small shower at the bottom of the upper chamber and as a big fraction of energy deposit in the lower chamber, which indicates a high contribution of hadronic showers. Results of the events with continuation in the rather low energy region are described.

  14. A Halo Event observed by the Hybrid Experiment at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    An experiment using an air shower array, a hadron calorimeter and an emulsion chamber is under way at Mt. Chacaltaya (5200 m, Bolivia). One of the highest energy events, having a halo (∼ 1 cm) in the centre of the family together with many γ-ray and hadron showers, is analyzed in detail. Available data for the event are on the halo (Ehalo=750 TeV) and on the high energy particles of electron/photon components by the emulsion chamber, and on the characteristics of the accompanied air shower (Ne=7.0x107, s=0.59) by the air shower array. The diagram of the air shower size and the total energy of electron/photon components in the family, which shows discrepancy between the experimental data and simulated events (QGSJET code for nuclear collisions) in our previous reports, is discussed including the present event

  15. A halo event observed with an emulsion chamber and air shower array at Mt Chacaltaya

    International Nuclear Information System (INIS)

    A hybrid experiment to operate simultaneously an air shower array, a hadron calorimeter and an emulsion chamber is under way at Mt Chacaltaya (5200 m, Bolivia). An event with a halo, a blackened area of ∼1 cm on x-ray film of the emulsion chamber, was observed with the experiment. Information about the halo (Ehalo = 850 TeV) and on high energy particles of electromagnetic and hadronic components outside the halo (ΣEγ = 632.5 TeV and ΣE(γ)h = 278.8 TeV with a detection threshold of 2 TeV) was obtained from emulsion chamber data. Details about low energy hadrons were determined from the hadron calorimeter data, and characteristics of the accompanying air shower (Ne = 7.0 x 107, s = 0.59) were determined by the air shower array. We reconstruct the event, based on the observed data. The event is compared with simulated events, which supports the conclusion that nuclear interactions change their characteristics in the high energy region so as to result in stronger energy subdivision

  16. A halo event created at 200 m above the Chacaltaya emulsion chamber

    Science.gov (United States)

    Amato, N. M.; Arata, N.; Maldonado, R. H. C.

    1985-01-01

    The results of analysis on a cosmic-ray induced nuclear event with the total visible energy approx. = 1300 TeV which is characterized by the central (halo) part of a strong energy concentration and the outer part of a large lateral spread are presented. The event (named as P06) was detected in the 18th two-storied emulsion chamber exposed at Chacaltaya by Brasil-Japan Collaboration. As the nuclear emulsion plates were inserted at every layer of the concerned blocks in the upper and the lower chambers together with RR- and N-type X-ray films, it is possible to study the details of the event. Some results on P06 have already been reported 1 based on the general measurement of opacity on N-type X-ray films: (1) the total energy of halo is approx. = 1000 TeV; (2) the shower transition reaches its maximum at approx. 16 cu; and (3) the radius of halo is 6.5 mm (at the level of 10 to the 6th power electrons/sq.cm.). The results in more details will be described.

  17. A systematic study of the hybrid experiment at Mt.Chacaltaya

    International Nuclear Information System (INIS)

    In the hybrid experiment on Mt. Chacaltaya, we can observe three different components of air showers, that is, air-shower size, burst-density and high energy families (a bundle of high energy particles). Burst-density in each block of hadron calorimeters are newly recalculated in simulations in order to compare directly to the experimental data. Energy deposits in the scintillators of the hadron calorimeters are calculated using GEANT4 for every particle, incident upon the hadron calorimeter, in the air-showers simulated using CORSIKA, and are converted into burst-density, taking into consideration the exact structure of experimental hadron calorimeter. We study correlations among three observable components in the air-showers. Correlations between air-shower size and burst-density and those between air-shower size and accompanied family energy can be explained by model calculations by adjusting primary particle composition, the former correlation is in favor of proton-primaries but the latter iron-primaries. No model can describe well observed correlations between burst-density and family energy. That is, the observed family energy accompanied by the air-showers with larger burst-density is systematically smaller than that expected in the simulated events. Effects of a fluctuation in the cross-section of hadronic interactions are studied to settle the disagreement between experimental data and simulations. (authors)

  18. Aerosol composition at Chacaltaya, Bolivia, as determined by size-fractionated sampling

    Science.gov (United States)

    Adams, F.; van Espen, P.; Maenhaut, W.

    Thirty-four cascade-impactor samples were collected between September 1977 and November 1978 at Chacaltaya, Bolivia. The concentrations of 25 elements were measured for the six impaction stages of each sample by means of energy-dispersive X-ray fluorescence and proton-induced X-ray emission analysis. The results indicated that most elements are predominantly associated with a unimodal coarse-particle soil-dustdispersion component. Also chlorine and the alkali and alkaline earth elements belong to this group. The anomalously enriched elements (S, Br and the heavy metals Cu, Zn, Ga, As, Se, Pb and Bi) showed a bimodal size distribution. Correlation coefficient calculations and principal component analysis indicated the presence in the submicrometer aerosol mode of an important component, containing S, K, Zn, As and Br, which may originate from biomass burning. For certain enriched elements (i.e. Zn and perhaps Cu) the coarse-particle enrichments observed may be the result of the true crust-air fractionation during soil-dust dispersion.

  19. A systematic study of the hybrid experiment at Mt.Chacaltaya

    Directory of Open Access Journals (Sweden)

    Semba H.

    2013-06-01

    Full Text Available In the hybrid experiment on Mt.Chacaltaya, we can observe three different components of airshowers, that is, air-shower size, burst-density and high energy families (a bundle of high energy particles. Burst-density in each block of hadron calorimeters are newly recalculated in simulations in oder to compare directly to the experimental data. Energy deposits in the scintillators of the hadron calorimeters are calculated using GEANT4 for every particle, incident upon the hadron calorimeter, in the air-showers simulated using CORSIKA, and are converted into burst-density, taking into consideration the exact structure of experimental hadron calorimeter. We study correlations among three observable components in the air-showers. Correlations between air-shower size and burst-density and those between air-shower size and accompanied family energy can be explained by model calculations by adjusting primary particle composition, the former correlation is in favor of proton-primaries but the latter iron-primaries. No model can describe well observed correlations between burst-density and family energy. That is, the observed family energy accompanied by the air-showers with larger burst-density is systematically smaller than that expected in the simulated events. Effects of a fluctuation in the cross-section of hadronic interactions are studied to settle the disagreement between experimental data and simulations.

  20. Possible measurements of gamma ray astronomy through the detection of EAS particles in Chacaltaya (5220 m a.s.1.)

    International Nuclear Information System (INIS)

    Since the beginning of August'82 an array for measurements of cosmic ray variations is operating at the Chacaltaya Laboratory (Bolivia, 5220 m a.s.1.). The possibility of using the same detector for measurements of high energy Gamma-Ray Astronomy from the Galactic Center and the sources PSR 0833-45 and Centaurus A is discussed. In one year of continuous operation a flux: S(E0>2.5x104 GeV) = 10-11 Ph/cm2 sec can be detected from a point source within a confidence level of 3 s.d. (Author)

  1. Search for GeV Gamma Ray Bursts at Mount Chacaltaya

    Science.gov (United States)

    Vernetto, S.; Inca Collaboration

    2001-08-01

    INCA is an air shower array working at Mount Chacaltaya, Bolivia, at 5200 m above sea level, searching for GRBs in the range of energies ˜1 GeV 1 TeV. The altitude of INCA and the use of the "single particle" technique allows to work with a detection threshold as low as few GeVs. In this paper we present the results of a search for GRBs in coincidence with satellites events in the period 1996 December 2001 March. No significant signals are observed during the occurrences of 135 GRBs, and the obtained upper limits on the energy fluence in the interval 1-103 (1-102 ) GeV, range from 1.7 (4.6) 10-5 to 9.6 10-2 (2.6 10-1 ) erg cm-2 depending on the zenith angle of the events. These limits, thanks to the extreme altitude of INCA, are the lowest ever obtained in the sub-TeV energy region by a ground based experiment. 1 High energy Gamma Ray Bursts So far the radiation emitted by GRBs in the GeV-TeV energy band has been very poorly studied due to the extremely low fluxes. EGRET, the high energy detector aboard the satellite CGRO, during its life detected only few very intense events containing some GeV photons (Catelli et al., 1997). However many models predicts emissions in the GeV-TeV region and one cannot exclude the possibility that all GRBs contain a high energy component (Meszaros and Rees, 1994; Vietri, 1997; Baring, 1997; Totani, 1998; Dermer and Chiang, 1999; De Paolis et al., 2000). The low flux is not the only problem to face when studing the high energy component of the GRB spectrum. A major obstacle is the absorption of gamma rays in the intergalactic space. GeV and TeV gamma rays interact with the infrared photons emitted by stars and dust and produce electrons and positrons pairs. The flux of photons of energy E decreases as dN/dE = (dN0/dE)e-τ(E,z) , where z is the redshift of the source. The optical depth τ increases with E and z; due

  2. Frequent nucleation events at the high altitude station of Chacaltaya (5240 m a.s.l.), Bolivia

    Science.gov (United States)

    Rose, C.; Sellegri, K.; Velarde, F.; Moreno, I.; Ramonet, M.; Weinhold, K.; Krejci, R.; Ginot, Patrick; Andrade, M.; Wiedensohler, A.; Laj, P.

    2015-02-01

    While nucleation may represent one of the major processes responsible for the total aerosol number burden in the atmosphere, and especially at high altitude, new particle formation (NPF) events occurring in the upper part of the troposphere are poorly documented in the literature, particularly in the southern hemisphere. NPF events were detected and analyzed at the highest measurement site in the world, Chacaltaya (5240 m a.s.l.), Bolivia between January 1 and December 31 2012, using a Neutral Aerosol and Ion Spectrometer (NAIS) that detects clusters down to 0.4 nm. NPF frequency at Chacaltaya is one of the highest reported so far (63.9%) and shows a clear seasonal dependency with maximum up to 100% during the dry season. This high seasonality of the NPF events frequency was found to be likely linked to the presence of clouds in the vicinity of the station during the wet season. Multiple NPF events are seen on almost 50% of event days and can reach up to 6 events per day, increasing the potential of nucleation to be the major contributor to the particle number concentrations in the upper troposphere. Ion-induced nucleation (IIN) was 14.8% on average, which is higher than the IIN fractions reported for boundary layer stations. The median formation rate of 2 nm particles computed for first position events is increased during the dry season (1.90 cm-3 s-1) compared to the wet season (1.02 cm-3 s-1), showing that events are more intense, on top of being more frequent during the dry season. On the contrary, particle growth rates (GRs) are on average enhanced during the wet season, which could be explained by higher amount of biogenic volatile organic compounds transported from the Amazon rainforest. The NPF events frequency is clearly enhanced when air masses originate from the oceanic sector, with a frequency of occurrence close to 1. However, based on the particle GRs, we calculate that particles most likely nucleate after the oceanic air masses reach the land and are

  3. Arrival directions of large air showers, low-mu showers and old-age low-mu air showers observed at St. Chacaltaya

    International Nuclear Information System (INIS)

    Arrival directions of air showers with primary energies in the range 10 to the 16.5 power eV to 10 to the 18th power eV show the first harmonic in right ascension (RA) with amplitude of 2.7 + or - 1.0% and phase of 13-16h. However, the second harmonic in RA slightly seen for showers in the range 10 to the 18th power eV to 10 to the 19th power eV disappeared by accumulation of observed showers. The distribution of arrival directions of low-mu air showers with primary energies around 10 to the 15th power eV observed at Chacaltaya from 1962 to 1967 is referred to, relating to the above-mentioned first harmonic. Also presented in this paper are arrival directions of old-age low-mu air showers observed at Chacaltaya from 1962 to 1967, for recent interest in gamma-ray air showers

  4. Arrival directions of large air showers, low-mu showers and old-age low-mu air showers observed at St. Chacaltaya

    Science.gov (United States)

    Hagiwara, K.; Yoshii, H.; Martinic, N.; Siles, L.; Miranda, P.; Kakimoto, F.; Obara, T.; Suga, K.; Kaneko, T.; Inoue, N.

    1985-01-01

    Arrival directions of air showers with primary energies in the range 10 to the 16.5 power eV to 10 to the 18th power eV show the first harmonic in right ascension (RA) with amplitude of 2.7 + or - 1.0% and phase of 13-16h. However, the second harmonic in RA slightly seen for showers in the range 10 to the 18th power eV to 10 to the 19th power eV disappeared by accumulation of observed showers. The distribution of arrival directions of low-mu air showers with primary energies around 10 to the 15th power eV observed at Chacaltaya from 1962 to 1967 is referred to, relating to the above-mentioned first harmonic. Also presented in this paper are arrival directions of old-age low-mu air showers observed at Chacaltaya from 1962 to 1967, for recent interest in gamma-ray air showers.

  5. Cosmic ray observations at Chacaltaya and Cerro la Negra combined with the Pierre Auger and Milagro observatories: GRBs and search for cosmic ray correlations

    International Nuclear Information System (INIS)

    We consider the possibility to search for cosmic ray phenomena time correlated among distant experiments that are currently running in the world. In particular we consider the correlations of events detected by four experiments: between Milagro, operating in USA, and Cerro La Negra Cosmic Ray Laboratory, under construction in Mexico, and between Chacaltaya, in Bolivia, and Auger Observatory, under construction in Argentina. Almost complete sky coverage with fairly uniform celestial exposure of the northern and the southern hemispheres by the above four experiments at the same time could provide important information on astrophysical phenomena. Search for Gamma Ray Bursts and search for non random coincidence between these experiments seem to be feasible under an international extensive air shower joint experiment with the main goal to watch GRBs and other astrophysical phenomena

  6. On mini-cluster observed by Chacaltaya emulsion chamber experiment

    Science.gov (United States)

    Tati, T.

    1985-01-01

    Bundles of electromagnetic showers with very small tranverse momenta (approx. 10 MeV) accompanied by decay products of Chiron-type fireballs, have been observed. These bundles are called Miniclusters. This phenomenon supports the picture of fireballs made up of hadronic matter and based on the theory of the finite degree of freedom.

  7. Faltung formulation of hadron halo event cascade at Mt. Chacaltaya

    CERN Document Server

    Tsui, K H; Navia, C E; Shigueoka, H; De Oliveira, L C S

    2007-01-01

    It is shown that the fundamental standard hadron cascade diffusion equation in the Mellin transform space is not rigorously correct because of the inconsistent double energy integral evaluation which generates the function $$ with its associated parametizations. To ensure an exact basic working equation, the Faltung integral representation is introduced which has the elasticity distribution function $u(\\eta)$ as the only fundamental input function and $$ is just the Mellin transform of $u(\\eta)$. This Faltung representation eliminates standard phenomenological parameters which serve only to mislead the physics of cascade. The exact flux transform equation is solved by the method of characteristics, and the hadron flux in real space is obtained by the inverse transform in terms of the simple and essential residues. Since the essential residues are given by the singularities in the elasticity distribution and particle production transforms that appear in the exponentials, these functions should not be parametiz...

  8. Size distributions of air showers accompanied with high energy gamma ray bundles observed at Mt. Chacaltaya

    Science.gov (United States)

    Matano, T.; Machida, M.; Tsuchima, I.; Kawasumi, N.; Honda, K.; Hashimoto, K.; Martinic, N.; Zapata, J.; Navia, C. E.; Aquirre, C.

    1985-01-01

    Size distributions of air showers accompanied with bundle of high energy gamma rays and/or large size bursts under emulsion chambers, to study the composition of primary cosmic rays and also characteristics of high energy nuclear interaction. Air showers initiated by particles with a large cross section of interaction may develop from narrow region of the atmosphere near the top. Starting levels of air showers by particles with smaller cross section fluctuate in wider region of the atmosphere. Air showers of extremely small size accompanied with bundle of gamma rays may be ones initiated by protons at lower level after penetrating deep atmosphere without interaction. It is determined that the relative size distribution according to the total energy of bundle of gamma rays and the total burst size observed under 15 cm lead absorber.

  9. Observation and analysis of cosmic electromagnetic cascades detected in lead photoemulsion chamber of the Brazil-Japan cooperation, exposed in Monte Chacaltaya, Bolivia (altitude 5200m, air pressure 550 gr.cm-2)

    International Nuclear Information System (INIS)

    The cosmic gamma radiations in the photoemulsion chamber for Brazil-Japan Cooperation are studied. These radiations reproduces the electromagnetic component of extensive air showers at the begining of its development through the atmosphere. The gamma radiations, which is 0Π meson decay products emitted in nuclear interaction, are detected by electromagnetic cascades which are developed when they reach the photoemulsion chamber. Cosmic gamma radiations is a set of parallel electromagnetic cascades proceeding from nuclear interactions. The information about high energy nuclear interactions making possible to study the structure of extensive air showers at the beginning of its development and multiple meson production are obtained. (M.C.K.)

  10. Aligned interactions in cosmic rays

    Science.gov (United States)

    Kempa, J.

    2015-12-01

    The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.

  11. Aligned interactions in cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Kempa, J., E-mail: kempa@pw.plock.pl [Warsaw University of Technology Branch Plock (Poland)

    2015-12-15

    The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.

  12. Atmospheric Cerenkov light from large air showers observed at 5200m above sea level

    International Nuclear Information System (INIS)

    A preliminary result is presented on the arrival-time distribution of atmospheric Cerenkov light from air showers of 1017 eV observed at Chacaltaya. The rise time and the FWHM are consistent with those expected from high multiplicity models, indicating the very fast development of electrons at the early stage

  13. High-altitude stations and high energy cosmic rays

    International Nuclear Information System (INIS)

    The advantages of high-altitude ground-based cosmic ray station have been discussed in many past reports and conferences. It is very satisfying to observe this renewed attention to the research potentials of the Chacaltaya Laboratory. Specific research opportunities are reviewed, and possible future scenarios are noted

  14. Energetic delayed hadrons in large air showers observed at 5200m above sea level

    Science.gov (United States)

    Kaneko, T.; Hagiwara, K.; Yoshii, H.; Martinic, N.; Siles, L.; Miranda, P.; Kakimoto, F.; Tsuchimoto, I.; Inoue, N.; Suga, K.

    1985-01-01

    Energetic delayed hadrons in air showers with electron sizes in the range 10 to the 6th power to 10 to the 9th power were studied by observing the delayed bursts produced in the shield of nine square meter scintillation detectors in the Chacaltaya air-shower array. The frequency of such delayed burst is presented as a function of electron size, core distance and sec theta.

  15. High energy astrophysics and high-altitude laboratories

    International Nuclear Information System (INIS)

    These are some summary remarks given at the Chacaltaya meeting on cosmic ray physics, held in La Paz (Bolivia), July 23-27, 2000. The meeting covered a wide range of topics in cosmic ray physics and high energy astrophysics. This contribution briefly touches on some of the highlights of the meeting, and discusses the important role that high-altitude laboratories can have in the future of these fundamental fields

  16. Use of water-Cherenkov detectors to detect Gamma Ray Bursts at the Large Aperture GRB Observatory (LAGO)

    International Nuclear Information System (INIS)

    The Large Aperture GRB Observatory (LAGO) project aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique in ground-based water-Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Merida, 4765 m a.s.l.). We report on detector calibration and operation at high altitude, search for bursts in 4 months of preliminary data, as well as search for signal at ground level when satellites report a burst

  17. Galactic-disk enhancement of cosmic rays at E > 1012 eV

    International Nuclear Information System (INIS)

    It was observed an enhancement of cosmic rays from the Vela region with SAS array at Mt. Chacaltaya in Bolivia. It is not possible to conclude that this enhancement is caused by primary gamma-rays, since the observed events not limited with the less muons in the air showers show the same enhancement. In order to confirm this result with improved statistics and to investigate the energy dependence of this enhancement, it has been installed a new array, called MAS array. All the data with much higher statistics show the enhancement along the whole galactic disk

  18. Energy spectrum of primary cosmic rays from 1016eV to 1019eV determined from air showers observed at 5200 m a.s.l

    International Nuclear Information System (INIS)

    Energy spectra of primary cosmic rays from 1016eV to 1019eV have been determined from electron-sizes as well as from muon-sizes of the same air showers observed at Mt. Chacaltaya. The spectrum from electron-sizes is significantly higher than that from muon-sizes. The discrepancy is discussed and an explanation is given under the assumption of possible existence of copious direct production of photons besides the production of charged and neutral pions at these high energies. The spectra are also compared with those by other groups and the discrepancies are discussed. (author)

  19. What can we study through families and accompanied air showers?

    International Nuclear Information System (INIS)

    At mountain altitudes, high energy γ-ray bundles (γ-rays in parallel trajectories and with the same direction of an air shower) can be observed in the central part of air showers. These γ-ray bundles (≥ 1 TeV) and their associated air showers are observed simultaneously at Mt. Chacaltaya (5200 m) by our detectors. The γ-ray bundle in the air shower can give information on the primary composition and the characteristics of proton interaction. In this paper, we report on experimental results, simulations calculated for the present experiments, and also problems in simulations

  20. Giant mini-clusters as possible origin of halo phenomena observed in super-families

    Science.gov (United States)

    1985-01-01

    Among 91 mini-clusters from 30 high energy Chiron-type families in Chacaltaya emulsion chambers, there were observed several extremely large multiplicity clusters in the highest energy range, far beyond the average of ordinary type clusters. Some details of microscopic observation of those giant mini-clusters in nuclear emulsion plates and some phenomenological regularity found in common among them are described. Such giant mini-clusters are possible candidates for the origin of narrow symmetric single halo phenomena in X-ray films which are frequently observed in super-families of visible energy greater than 1,000 TeV.

  1. Description of gamma-hadron families on the basis of the quasiscaling model for a normal nuclear composition of primary cosmic rays

    International Nuclear Information System (INIS)

    The nuclear composition of primary cosmic rays is investigated in the energy range 1015-1016 eV. These investigations are performed by comparing the properties of the gamma-hadron families observed by the Pamir and the Pamir-Chacaltaya collaboration with the properties of families generated on the basis of the MC0 quasiscaling model for various nuclear compositions. It is shown that all properties of experimental families are in good agreement with the predictions of the MC0 model for a normal nuclear composition, but that these experimental results are at odds with the results of the calculations that assume a nuclear composition enriched in heavy nuclei

  2. γ-Hadron family description by quasi-scaling model at normal nuclear composition of primary cosmic rays

    International Nuclear Information System (INIS)

    Primary Cosmic Rays Nuclear Composition was investigated in energy region 1015-1016 eV. The study is based on comparison of γ hadron families observed by Pamir and Pamir-Chacaltaya collaborations with those generated by means of quasi-scaling model MC0 at different nuclear compositions. It was shown that all characteristics of the observed families (including their intensity) are in very good agreement with properties of simulated events MC0 at normal composition and are in disagreement at heavy dominant compositions

  3. The Large Aperture GRB Observatory

    CERN Document Server

    Allard, D; Asorey, H; Barros, H; Bertou, X; Castillo, M; Chirinos, J M; De Castro, A; Flores, S; González, J; Berisso, M Gomez; Grajales, J; Guada, C; Day, W R Guevara; Ishitsuka, J; López, J A; Martínez, O; Melfo, A; Meza, E; Loza, P Miranda; Barbosa, E Moreno; Murrugarra, C; Núñez, L A; Ormachea, L J Otiniano; Pérez, G; Perez, Y; Ponce, E; Quispe, J; Quintero, C; Rivera, H; Rosales, M; Rovero, A C; Saavedra, O; Salazar, H; Tello, J C; Peralda, R Ticona; Varela, E; Velarde, A; Villaseñor, L; Wahl, D; Zamalloa, M A

    2009-01-01

    The Large Aperture GRB Observatory (LAGO) is aiming at the detection of the high energy (around 100 GeV) component of Gamma Ray Bursts, using the single particle technique in arrays of Water Cherenkov Detectors (WCD) in high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). WCD at high altitude offer a unique possibility of detecting low gamma fluxes in the 10 GeV - 1 TeV range. The status of the Observatory and data collected from 2007 to date will be presented.

  4. Investigation of unusual phenomena in cosmic rays with Tien Shan and Pamir experimental setups at energy higher than 1 PeV - I

    International Nuclear Information System (INIS)

    Numerous unusual phenomena observed in cosmic ray experiments at energy > 1 PeV can be effectively studied with modern large-scale combined setups located at high mountain altitudes. Construction in the nearest future of the new setups at Chacaltaya, Tien Shan and Pamir Mountain Stations situated at different altitudes will provide physicists with important additional information on the nature of unusual phenomena. In this report, it is discussed the main physics problems that should be investigated by means of the mountain-level setups

  5. Alignment in hadronic interactions

    CERN Document Server

    Wibig, T

    2000-01-01

    The alignment of the products of very high energy interactions seen in mountain altitude experiments is one of the most puzzling phenomena in cosmic ray physics for quite a long time. The observations of the Pamir and Chacaltaya emulsion chamber groups and by the Tien-Shan extensive air shower experiment, together with a very clear event seen in the Concorde French-Japanese experiment in the stratosphere, makes the experimental basis very substantial. In the present paper a novel possible explanation is put forward.

  6. Simultaneous Observation of Solar Neutrons from the ISS and High Mountain Observatories in association with a flare on July 8, 2014

    CERN Document Server

    Muraki, Y; Koga, K; Kakimoto, F; Goka, T; Gonzalez, L X; Masuda, S; Matsubara, Y; Matsumoto, H; Miranda, P; Okudaira, O; Obara, T; Salinas, J; Sako, T; Shibata, S; Ticona, R; Tsunesada, Y; Valdes-Galicia, J F; Watanabe, K; Yamamoto, T

    2015-01-01

    An M6.5-class flare was observed at N12E56 of the solar surface at 16:06 UT on July 8, 2014. In association with this flare, solar neutron detectors located on two high mountains, Mt. Sierra Negra and Chacaltaya and at the space station observed enhancements in the neutral channel. The authors analysed these data and a possible scenario of enhancements produced by high-energy protons and neutrons is proposed, using the data from continuous observation of a solar surface by the ultraviolet telescope onboard the Solar Dynamical Observatory (SDO).

  7. On exotic fireballs

    International Nuclear Information System (INIS)

    Exotic fireballs found by Brazil-Japan Collaboration of Chacaltaya Emulsion Chamber Experiment are interpreted in terms of a model of hadronic matter (of which hadrons are made) based on the theory of finite degree of freedom. It is considered in our picture that exotic fireballs reveal the part left undefined in the renormalization theory of quantum field and nonappearance of exotic fireballs (of relatively small mass, i.e. Mini-Centauro and Geminion) in CERN SPS collider experiment is possibly due to the existence of universal time realized by the cutoff of momentum degree of freedom of the field of basic particles. (Author)

  8. Physics of ion acceleration in the solar flare on 2005 September 7 determines gamma-ray and neutron production

    International Nuclear Information System (INIS)

    Relativistic neutrons were observed by the neutron monitors at Mt. Chacaltaya and Mexico City and by the solar neutron telescopes at Chacaltaya and Mt. Sierra Negra in association with an X17.0 flare on 2005 September 7. The neutron signal continued for more than 20 min with high statistical significance. Intense emissions of gamma-rays were also registered by INTEGRAL, and during the decay phase by RHESSI. We analyzed these data using the solar-flare magnetic-loop transport and interaction model of Hua et al. [Hua, X.-M., Kozlovsky, B., Lingenfelter, R.E. et al. Angular and energy-dependent neutron emission from solar flare magnetic loops, Astrophys. J. Suppl. Ser. 140, 563-579, 2002], and found that the model could successfully fit the data with intermediate values of loop magnetic convergence and pitch-angle scattering parameters. These results indicate that solar neutrons were produced at the same time as the gamma-ray line emission and that ions were continuously accelerated at the emission site. (authors)

  9. FUNCIÓN EMPÍRICA DE DISTRIBUCIÓN LATERAL MUÓNICA

    Directory of Open Access Journals (Sweden)

    R. Bustos

    2011-01-01

    Full Text Available Se estudió la componente muónica de los Chubascos Atmosféricos Extendidos (EAS comprendidos entre los rangos de 10(14 y 10(16 eV con los datos del arreglo BASJE (Bolivian Air Shower Joint Experiment ubicado en el Monte Chacaltaya, Bolivia. Mediante el análisis de los datos de esta componente se logró obtener una función de distribución lateral muónica y su dependencia con los rangos de energía que tiene dicho arreglo. El empleo de simulaciones AIRES y su modelo QGSJET01c ha servido para comparar nuestros resultados, encontrándose interesantes coincidencias así como discrepancias. La simulación hecha con CORSIKA y su modelo PLOTHS2 sirvió únicamente para ilustrar cualitativamente el comportamiento acumulativo muónico del chubasco hacia el centro de su eje. Los resultados del experimento Tien-Shan corroboran los resultados del experimento BASJE, haciendo de la función de distribución lateral muónica del BASJE una buena candidata para el estudio del cosmos a través de los EAS detectados en el observatorio de Chacaltaya. Finalmente se realizó una aplicación rápida con la función empírica obtenida.

  10. Nuclear interactions of super high energy cosmic-rays observed in mountain emulsion chambers

    Energy Technology Data Exchange (ETDEWEB)

    Bayburina, S.G.; Borisov, A.S.; Cherdyntseva, K.V.; Guseva, Z.M.; Denisova, V.G.; Dunaevskii, A.M.; Kanevskaya, E.A.; Maximenko, V.M.; Pashkov, S.V.; Puchkov, V.S. (AN SSSR, Moscow. Fizicheskij Inst.)

    1981-11-09

    Here we present a summary of joint discussions on the results of three mountain experiments with large-scale emulsion chambers, at Pamir, Mt. Fuji and Chacaltaya. Observations cover gamma quanta, hadrons and their clusters (called families). The following topics are covered, concerning the characteristics of nuclear interactions the energy region 10/sup 14/-10/sup 16/ eV: (i) rapid dissipation seen in atmospheric diffusion of high-energy cosmic-rays; (ii) multiplicity and Psub(t) increase in produced pi-mesons in the fragmentation region; (iii) existence of large-Psub(t) jets, (iv) extremely hadron-rich family of the Centauro type; (v) exotic phenomena in the extremely high energy region beyond 10/sup 16/ eV.

  11. Arrival time distribution of muons in large air showers observed at 900m above sea level

    International Nuclear Information System (INIS)

    The arrival time distribution of muons (>1GeV) in large air showers above 1017 eV has been measured at core distances from 100m to 250m in the Akeno air shower array (900m a.s.1.) using four 2m2 scintillation detectors and an equipment with a time response of 3.5ns in rise time and 7.0ns in FWHM. The time from 20% to 70% in integral arrival time distribution (tsub(20-70)) suggests a very fast development of muons expected from the enhanced Esup(1/2) multiplicity law and the rising cross section for primary protons. This result is consistent with thoose obtained from the measurement of arrival time distribution of muons and the equi-intensity cuts of muon-size spectra at Chacaltaya (5200m a.s.1.)

  12. Simultaneous Observation of Solar Neutrons from the International Space Station and High Mountain Observatories in Association with a Flare on July 8, 2014

    Science.gov (United States)

    Muraki, Y.; Lopez, D.; Koga, K.; Kakimoto, F.; Goka, T.; González, L. X.; Masuda, S.; Matsubara, Y.; Matsumoto, H.; Miranda, P.; Okudaira, O.; Obara, T.; Salinas, J.; Sako, T.; Shibata, S.; Ticona, R.; Tsunesada, Y.; Valdés-Galicia, J. F.; Watanabe, K.; Yamamoto, T.

    2016-04-01

    An M6.5-class flare was observed at N12E56 on the solar surface at 16:06 UT on July 8, 2014. In association with the flare, two neutron detectors located at high mountains, Mt. Sierra Negra in Mexico and Mt. Chacaltaya in Bolivia, recorded two neutron pulses, separated approximately by 30 min. Moreover, enhancements were also observed by the solar neutron detector onboard the International Space Station. We analyzed these data combined with solar images from Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory. From these we noticed that the production mechanism of neutrons cannot be explained by a single model; at least one of the enhancements may be explained by an electric field generated by the collision of magnetic loops and the other by the shock acceleration mechanism at the front side of the CME.

  13. Lateral distribution of Cherenkov light in extensive air showers at high mountain altitude produced by different primary particles in wide energy range

    CERN Document Server

    Mishev, A

    2005-01-01

    The general aim of this work is to obtain the lateral distribution of atmospheric Cherenkov light in extensive air showers produced by different primary particles precisely by. protons, Helium, Iron, Oxygen, Carbon, Nitrogen, Calcium, Silicon and gamma quanta in wide energy range at high mountain observation level of Chacaltaya cosmic ray station. The simulations are divided generally in two energy ranges 10GeV-10 TeV and 10 TeV-10 PeV. One large detector has been used for simulations, the aim being to reduce the statistical fluctuations of the obtained characteristics. The shape of the obtained lateral distributions of Cherenkov light in extensive air showers is discussed and the scientific potential for solution of different problems as well.

  14. The energy spectrum of cosmic rays in the region 2.1016-4.1017 eV

    International Nuclear Information System (INIS)

    The four triggering detectors of the Haverah Park array impose a well defined threshold energy of 2.1017 eV (rho(600) = 0.3 m-2). To investigate the spectrum at lower energies an inner group of detectors, spaced at 150 m, has been used to generate a separate trigger and data recorded over a period of almost two years have now been analysed. The most directly determined ground parameter for such showers is the density at 150 m from the axis (rho(150)) and conversion to a primary energy spectrum has assumed a constant ratio of rho(150)/rho(600). Comparison is made with the Chacaltaya experiment at similar energies. (orig.)

  15. Analysis of the hadronic energy spectrum in high-energy cosmic-ray families detected by emulsion chambers

    International Nuclear Information System (INIS)

    We analyze the hadronic energy spectrum for cosmic-ray families detected by emulsion chambers in the high-energy region, by means of the solution of diffusion equations for the hadronic cascade induced by one single nucleon in the atmosphere, assuming three different models for the energy distribution function in multiple pion production. We describe the experimental data for the energy of three high-energy families detected in emulsion chamber of Brazil-Japan Colloboration (BJC) at Mt. Chacaltaya and of two families detected by Pamir Collaboration (PC). We look also for consistency of the rapidity-density distribution, obtained for the different hypotheses for multiple pion production above, with accelerator data in the ISR and Collider regions. Finally, the Models are analysed with respect to the energy dependence of the mean inelasticity

  16. New-particle search in very-high-energy nuclear interactions of cosmic rays

    International Nuclear Information System (INIS)

    Systematic analyses for new-particle search are carried out by using cosmic-ray data (E0 approx. 105 GeV) obtained from the Brazil-Japan two-story emulsion-chamber experiment exposed on Mt. Chacaltaya. Twelve events, selected by two different ways from 127 carbon-jet (C-jet) events with summationE/sub γ/ > or = 5 x 103 GeV and N/sub γ/ > or = 4, are measured by geometrical arrival-direction measurement. Five abnormal cores that are not emitted directly from C jets are observed. An estimation on X-particle production as a possible origin of abnormal cores gives very high production frequencies. Various sources for possible backgrounds are discussed and their rates are found to be negligibly small

  17. Changes in BOLD and ADC weighted imaging in acute hypoxia during sea-level and altitude adapted states

    DEFF Research Database (Denmark)

    Rostrup, Egill; Larsson, Henrik B.W.; Born, Alfred P.;

    2005-01-01

    possible structural changes as measured by diffusion weighted imaging. Eleven healthy sea-level residents were studied after 5 weeks of adaptation to high altitude conditions at Chacaltaya, Bolivia (5260 m). The subjects were studied immediately after return to sea-level in hypoxic and normoxic conditions......, and the examinations repeated 6 months later after re-adaptation to sea-level conditions. The BOLD response, measured at 1.5 T, was severely reduced during acute hypoxia both in the altitude and sea-level adapted states (50% reduction during an average S(a)O(2) of 75%). On average, the BOLD response...... magnitude was 23% lower in altitude than sea-level adaptation in the normoxic condition, but in the hypoxic condition, no significant differences were found. A small but statistically significant decrease in the apparent diffusion coefficient (ADC) was seen in some brain regions during acute hypoxia...

  18. On the 'Geminion'

    International Nuclear Information System (INIS)

    The ''binocular'' events newly observed by the Chacaltaya emulsion chamber experiment are discussed on the basis of the theory of hadronic matter proposed previously. Hadronic matter (hadrons, fireballs etc.) consists of a large number of pairs of basic particles (''bare'' quarks) and its mass density is approximately uniform and nearly common to all hadronic matter. It is possible and even probable, in our picture, that the ''binocular'' event, at least some of them, is a fission of the SH-quantum (a fireball of the mass 20 - 30 GeV) into a ''physical'' quark and a ''physical'' anti-quark (the mass of the ''physical quark is assumed to be 10 GeV). The possibility of finding ''physical'' quarks through the intermediate state of the SH-quantum in a future high energy colliding beams (e.g. 200 GeV x 200 GV) is mentioned. (author)

  19. Nuclear interactions of super high energy cosmic-rays observed by mountain emulsion chambers

    International Nuclear Information System (INIS)

    Here is presented a summary of joint discussions on the results of three mountain experiments with large-scale emulsion chambers, at Pamir, Mt. Fuji and Chacaltaya. The observation covers gamma-quanta, hadrons and their clusters (called ''families''). Following topics are covered concerning on characteristics of nuclear interactions in energy region of 1014 - 1016 eV: 1) rapid dissipation seen in atmospheric diffusion of high energy cosmic-rays, 2) multiplicity and p sub(t) increase in produced pimesons in the fragmentation region, 3) existence of large p sub(t) jets, 4) extremely-hadron-rich family of Centauro type, 5) exotic phenomena at extremely high energy region beyond 1016 eV. (author)

  20. Observation of intensity of cosmic rays and daily magnetic shifts near meridian 70° in the South America

    Science.gov (United States)

    Cordaro, E. G.; Gálvez, D.; Laroze, D.

    2016-05-01

    In analysis of experiments carried during September 2008 using secondary cosmic ray detectors located in Chacaltaya (Bolivia) and Niteroi (Brazil), Augusto et al. (2010) showed an increase in the intensity of charged particles which takes place 3 h after sunrise and lasts until 1 h after sunset, furthermore they said that during this period the solar magnetic field lines overtake the Earth‧s surface. These stations are located within the South Atlantic Magnetic Anomaly (SAMA), having both different magnetic rigidities. To reproduce data from the Niteroi and Chacaltaya stations, we record data during the same hours and days using our neutron monitors, muon telescopes and magnetometers within the stations Putre and Los Cerrillos. Our observation stations in Putre and Cerrillos are located at 18°11‧47.8″S, 69°33‧10.9″W at an altitude of 3600 m and 33°29‧42.3″S, 70°42‧59.81″W with 570 m height above sea level, respectively. These stations are located within the South Atlantic Anomaly (SAMA) and are separated approximately 1700 km from each other and 1700 km from the center of the anomaly. Our network is composed furthermore by two auxiliary Cosmic Ray and/or Geomagnetic stations located at different latitudes along 70°W meridian, LARC and O'Higgins stations, which are located within Antarctic territory, covering a broad part of the Southern Hemisphere. Our magnetometer data shows that for each of the components, shifts in the magnetic field intensity for every station (even for those out of the SAMA) lasted between 3 and 4 h after sunrise and 1 and 2 h past sunset, which are the periods when the geomagnetic field is modulated by the transit of the dayside to nightside and nightside to dayside. We believe that, although the magnetometric data indicates the magnetic reconnection for the Chilean region, there is no direct influence from the SAMA other than the lower rigidity cut-off that leads to an increased count rate. Other details about the

  1. New air Cherenkov light detectors to study mass composition of cosmic rays with energies above knee region

    Energy Technology Data Exchange (ETDEWEB)

    Tsunesada, Yoshiki, E-mail: tsunesada@cr.phys.titech.ac.jp [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8550 Japan (Japan); Katsuya, Ryoichi, E-mail: katsuya@cr.phys.titech.ac.jp [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8550 Japan (Japan); Mitsumori, Yu; Nakayama, Keisuke; Kakimoto, Fumio; Tokuno, Hisao [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo 152-8550 Japan (Japan); Tajima, Norio [RIKEN, Wako, Saitama 351-0198 (Japan); Miranda, Pedro; Salinas, Juan; Tavera, Wilfredo [Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, La Paz (Bolivia, Plurinational State of)

    2014-11-01

    We have installed a hybrid detection system for air showers generated by cosmic rays with energies greater than 3×10{sup 15}eV at Mount Chacaltaya (5200 m above the sea level), in order to study the mass composition of cosmic rays above the knee region. This detection system comprises an air shower array with 49 scintillation counters in an area of 500 m×650 m, and seven new Cherenkov light detectors installed in a radial direction from the center of the air shower array with a separation of 50 m. It is known that the longitudinal development of a particle cascade in the atmosphere strongly depends on the type of the primary nucleus, and an air shower initiated by a heavier nucleus develops faster than that by a lighter primary of the same energy, because of the differences in the interaction cross-section and the energy per nucleon. This can be measured by detecting the Cherenkov radiation emitted from charged particles in air showers at higher altitudes. In this paper we describe the design and performance of our new non-imaging Cherenkov light detectors at Mount Chacaltaya that are operated in conjunction with the air shower array. The arrival directions and energies of air showers are determined by the shower array, and information about the primary masses is obtained from the Cherenkov light data including the time profiles and lateral distributions. The detector consists of photomultiplier tube (PMT), high-speed ADCs, other control modules, and data storage device. The Cherenkov light signals from an air shower are typically 10–100 ns long, and the waveforms are digitized with a sampling frequency of 1 GHz and recorded in situ without long-distance analog signal transfers. All the Cherenkov light detectors record their time-series data by receiving a triggering signal transmitted from the trigger module of the air shower array, which is fired by a coincidence of shower signals in four neighboring scintillation counters. The optical characteristics of the

  2. Observation of very high energy cosmic-ray families in emulsion chambers at high mountain altitudes. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Baradzei, L.T.; Borisov, A.S.; Cherdyntseva, K.V.; Guseva, Z.M.; Denisova, V.G.; Dobrotin, N.A.; Dunaevsky, A.M.; Kanevskaya, E.A.; Karpova, S.A.; Maximenko, V.M.; Nam, R.A.; Puchkov, V.S.; Slavatinsky, S.A.; Smirnova, M.D.; Smorodin, Yu.A.; Uryson, A.V.; Zelevinskaya, N.G.; Zimin, M.V.; Zhdanov, G.B. (Lebedev Physical Inst., Academy of Sciences, Moscow (USSR)); Mikhailova, I.A.; Mukhamedshin, R.A.; Doroshenko, O.E.; Nikolaeva, L.P.; Sukhov, L.V.; Zatsepin, G.T. (Inst. for Nuclear Research, Academy of Sciences, Moscow (USSR)); Amineva, T.P.; Fedorova, G.F.; Ivanenko, I.P.; Iljina, N.P.; Kopenkin, V.V.; Managadze, A.K.; Popova, E.G.; Rakobolskaya, I.V.; Roganova, T.M.; Strogova, O.P.; Sveshnikova, L.G. (Inst. of Nuclear Physics, Moscow Univ. (USSR)); Chadranyan, L.Kh.; Khisanishvili, L.A.; Roinishvili, N.N.; Svanidze, M.S. (Inst. of Physics, Academy of Sciences, Georgia, Tbilisi (USSR)); Azimov, Z.A.; Bobodjanov, I.B.; Gubar, N.E.; Gulov, Yu.A.; Normuradov, F. (Inst. of Physics and; Chacaltaya Collaboration; Pamir Collaboration

    1992-02-17

    Characteristics of cosmic-ray hadronic interactions in the 10{sup 15}-10{sup 17} eV range are studied by observing a total of 429 cosmic-ray families of visible energy greater than 100 TeV found in emulsion chamber experiments at high mountain altitudes, Chacaltaya (5300 m above sea level) and the Pamirs (4300 m above sea level). Extensive comparisons were made with simulated families based on models so far proposed, concentrating on the relation between the observed family flux and the behaviour of high-energy showers in the families, hadronic and electromagnetic components. It is concluded that there must be global change in characteristics of hadronic interactions at around 10{sup 16} eV deviating from those known in the accelerator energy range, specially in the forwardmost angular region of the collision. A detailed study of a new shower phenomenon of small-p{sub T} particle emissions, p{sub T} being of the order of 10 MeV/c, is carried out and its relation to the origin of huge 'halo' phenomena associated with extremely high energy families is discussed as one of the possibilities. General characteristics of such super-families are surveyed. (orig.).

  3. Systematic analysis of γ-ray families, 1

    International Nuclear Information System (INIS)

    Atmospheric nuclear interactions caused by cosmic rays are observed in the Chacaltaya emulsion chamber experiment. A systematic analysis is made on 106 events (γ-ray families) with visible energy in the range of 100 - 300 TeV. A new method called 'decascading' is introduced to pick up a cluster of γ-rays and electrons in a family, so that the cluster is an air cascade from one parent γ-ray. The application of 'decascading' method to the family data gives information on original γ-rays produced at the atmospheric interactions. The results are compared with data from the traget interactions at lower energy range ΣEsub(γ)=20 - 100 TeV). The conclusion is that the characteristics of nuclear interactions at the concerned family energy range (E deg approximately equal to 1,000 TeV) are in accordance with those at the target interaction range (E deg approximately equal to 100 TeV), with increased ratio of frequencies of a heavy fire-ball (SH-quantum) to a small and usual fire-ball (H-quantum). (author)

  4. LAGOVirtual: A Collaborative Environment for the Large Aperture GRB Observatory

    CERN Document Server

    Camacho, R; Diaz, G; Guada, C; Hamar, V; Hoeger, H; Melfo, A; Nunez, L A; Perez, Y; Quintero, C; Rosales, M; Torrens, R

    2009-01-01

    We present the LAGOVirtual Project: an ongoing project to develop platform to collaborate in the Large Aperture GRB Observatory (LAGO). This continental-wide observatory is devised to detect high energy (around 100 GeV) component of Gamma Ray Bursts, by using the single particle technique in arrays of Water Cherenkov Detectors (WCD) at high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). This platform will allow LAGO collaboration to share data, and computer resources through its different sites. This environment has the possibility to generate synthetic data by simulating the showers through AIRES application and to store/preserve distributed data files collected by the WCD at the LAGO sites. The present article concerns the implementation of a prototype of LAGO-DR adapting DSpace, with a hierarchical structure (i.e. country, institution, followed by collections that contain the metadata and data files), for the captured/simulate...

  5. PREFACE: Second School on Cosmic Rays and Astrophysics

    Science.gov (United States)

    Zepeda, Arnulfo

    2008-02-01

    The physics of cosmic rays, gamma rays and neutrinos has become nowadays a subject of fast development. On the other hand present and planed experimental facilities installed in the American continent, attract and facilitate the involvement of local young researchers. For these reasons Professor Oscar Saavedra and his team of the high altitude cosmic ray Chacaltaya laboratory and the Universidad Mayor de San Andres in La Paz Bolivia, conceived the idea of organizing the First School on Cosmic Rays and Astrophysics in La Paz 9-20 August 2004. That school was possible, in spite of the scarcity of funds, thanks to the solidary participation of several distinguish lecturers who paid their travel and local expenses. Their lectures were made available on a CD by the local students. It was then decided that a second school be organized for 2006 in Mexico. It was held from 28 August to 15 September 15. Some of the lecturers in this Second School on Cosmic Rays and Astrophysics were too busy to write their lectures, but here we put at the disposal of the interested community the contributions of Roberto Battiston, Karen S Caballero, Edgar Casimiro, David Delepine, Giorgio Giacomelli, Gonzalo Rodríguez and Luis Villaseñor. This School was possible thanks to the financial assistance of CONACyT (Mexico), the Benemerita Universidad Autonoma de Puebla, Centro de Investigacion y de Estudios Avanzados (Cinvestav), the University of Torino and the Centro Latino Americano de Fisica. Arnulfo Zepeda The editors of these proceedings are: Rebeca López Rodrigo Pelayo Oscar Saavedra Arnulfo Zepeda

  6. New results from Ooty EAS array for cosmic sources at PeV energies: Cygnus X-3, Crab pulsar and Sco X-1

    International Nuclear Information System (INIS)

    Ooty group has reported detection of a steady signal from Cyg X-3 based on observations made during 1984-86 through detection of a directional excess. Further analysis of data has revealed a significant flux enhancement during April 1986, confirming observations reported by the CYGNUS group at Los Alamos and the Baksan group. These results show conclusively that the flux from Cyg X-3 is variable over a time scale of few weeks. We also report here the details of an unusual burst from Cyg X-3, consisting of 5 showers in 13 minutes, on June 19, 1985, which shows the variability of the flux from Cyg X-3 on a much shorter time scale of few minutes. Our analysis of showers arriving from the direction of the Crab pulsar has shown only a small time-averaged excess. But these data, when folded with the Crab pulsar period, show a very significant excess at the expected phase of the optical interpulse. This is the first detection of 33 ms pulsation in the PeV energy flux from the Crab pulsar. The exact alignment of the phase of emission over nearly 20 decades of energy, from meter wavelengths to PeV, makes the Crab pulsar a really unique source to study and understand details of mechanisms for emission and acceleration of particles in compact sources. We also present here a discussion of our observations on another X-ray binary, Sco X-1. Ooty data show a very significant excess in the number of showers from the direction of Sco X-1 during a two month period in 1986, in agreement with observations reported by the Mt. Chacaltaya group. These observations establish this X-ray binary as another important source of PeV energy radiation. (orig.)

  7. Glacial recession in the Tropical Andes from the Little Ice Age: the case of Ampato Volcanic Complex (Southern Peru

    Science.gov (United States)

    Alcalá, J.; Palacios, D.; Zamorano, J. J.

    2010-03-01

    Data published over the last decade reveal substantial glacial recession in the tropical Andes since the Little Ice Age (LIA), (Ramirez, et al., 2001; Rabatel, et al., 2005; Rabatel, et al., 2008; Vuille, et al., 2008; Hastenrath, 2009; Jomelli, et al., 2009), and a growing rate of recession since the 1980’s caused by global warming (Ramirez, et al., 2001; Vuille, et al., 2008). Today there is great interest in the evolution of these ice masses due to heightened awareness of climate change and of the strategic importance that glaciers have as a hydrologic resource for communities in arid climate zones in the tropical Andes (Mark, 2008; Vuille et al., 2008). Cordillera Blanca forms part of the Andes Mountains of northern Peru, and is a chosen site for many studies on glacier evolution. Vuille et al. 2008 determined that a considerable area of ice mass was lost at Huascarán-Chopicalqui glacier (18% from 1920-1970) and Astesonraju glacier (20% from 1962-2003). Studies at Coropuna volcano, which has the most extensive glacier field in the western range of southern Peru, also report a strong melting trend that began with only minimal recession from 1955-1986 (4%), but increased to 14% from 1986-2007 (Úbeda et al., 2009). Only a few of the Andes glaciers are consistently monitored, and the most comprehensive data are for Chacaltaya and Zongo glaciers (16º S) in Bolivia. Since the maximum LIA, Chacaltaya has lost 89% of its surface area, particularly in recent years. By 1983, the totaled loss was five times the shrinkage for the period 1940-1963 (Ramirez, et al., 2001). Zongo glacier maintained equilibrium from 1956-1975, but later experienced a period dominated by continuous recession (Soruco, et al., 2009). This study expands current knowledge of glacier evolution since the LIA in the Central Volcanic Zone (CVZ; 14º - 27º S) (Stern, 2004) of the Andes. The study site was chosen in an area that had never been used for preliminary research of this type, concretely

  8. The LAGO Collaboration: Searching for high energy GRB emissions in Latin America

    Science.gov (United States)

    Barros, H.; Lago Collaboration

    2012-02-01

    During more than a decade Gamma Ray Bursts (GRB a cosmological phenomena of tremendous power) have been extensively studied in the keV - MeV energy range. However, the higher energy emission still remains a mystery. The Large Aperture GRB Observatory (L.A.G.O.) is an international collaboration started in 2005 aiming at a better understanding of the GRB by studying their emission at high energies (> 1 GeV), where the fluxes are low and measurements by satellites are difficult. This is done using the Single Particle Technique, by means of ground-based Water Cherenkov Detectors (WCD) at sites of high altitude. At those altitudes it is possible to detect air showers produced by high energy photons from the GRB, i. e. a higher rate of events on a short time scale, of the order of the second. The Pierre Auger Observatory could detect such GRB given its large number of detectors, but at 1400 m.a.s.l. the expected signal is quite small. At higher altitudes, similar performance is expected with only a very small number of WCD. As of 2011, high altitude WCD are in operation at Sierra Negra (Mexico, 4650 m.a.s.l.), Chacaltaya (Bolivia, 5200 m.a.s.l.), Maracapomacocha (Peru, 4200 m.a.s.l.), and new WCDs are being installed in Venezuela (Pico Espejo, 4750 m.a.s.l.), Argentina, Brazil, Chile, Colombia and Guatemala. Most of the new WCDs will not be at high enough altitude to detect GRB, never the less it will allow obtaining valuable measurements of secondaries at ground level, which are relevant for solar physics. The LAGO sensitivity to GRB is determined from simulations (under a sudden increase of 1 GeV - 1 TeV photons from a GRB) of the gamma initiated particle shower in the atmosphere and the WCD response to secondaries. We report on WDC calibration and operation at high altitude, GRB detectability, background rates, search for bursts in several months of preliminary data, as well as search for signals at ground level when satellite burst is reported, all these show the

  9. Physicochemical effects of cosmic rays in solids: analyses by mass spectrometry and by infrared spectroscopy

    International Nuclear Information System (INIS)

    Full text: Cosmic Rays (CR) are studied since their discovery by Victor Hess in the years 1911-1913. Interestingly, the beginning of research in Physics in Brazil started with experiments on CR. B. Gross (INT/ Rio), G. Wataghin and G. Occhialini (USP) started their investigation on CR in 1934. F.X. Roser, the founder of the Physics Institute of PUC-Rio, worked with Hess when he got the Nobel Prize in 1936. C. Lattes got in 1947 the experimental data in Chacaltaya that conducted to the discovery of the meson pi (C. Powell, Nobel Prize in 1950). Nowadays, the Auger Project deals with extremely high energy extragalactic particles. Except for these ones, the origin, the energy and mass distributions of CR constituents and their capability of producing elementary particles are well known. Nevertheless, there is an enormous lack of information on the effects caused by the CR on inorganic and biological materials. This motivates measurements of relevant physicochemical data, such as sputtering yields, cross sections for inducing chemical reactions and crystalline structure parameters. A fascinating question about CR is if they are/were the responsible for the transformation of inorganic into organic material, synthesizing therefore pre-biotic molecules in whole Universe. Nuclear Physics instrumentation is well suited to answer this question, providing ion sources and ion accelerators from keV to GeV. Time-of-flight mass spectrometry and FTIR infrared spectroscopy are techniques able to monitor the physicochemical modifications induced by the RC beam analogs. Data obtained in the GANIL (France) and Van de Graaff (PUC-Rio) accelerators are presented. Abundant inorganic molecular species in space, such as H2O, CO, CO2 and NH3, are condensed in laboratory and bombarded by H to Fe ions, from 10-3 to 103 MeV/u, covering the CR range. New chemical species are identified; sputtering yields (Y), formation (σf ) and destruction (σd) cross sections are measured. An important

  10. Cosmic rays: an in-flight hazard?

    International Nuclear Information System (INIS)

    muons and electrons makes up about 10% of the natural background at sea level. Some years ago, the European Union expressed concern at the patchy knowledge available on the radiation field at aircraft altitudes. It funded a major investigation during the last minimum in solar activity between 1995 and 1998. These investigations have recently received further significant support and a major European study will be continued through the solar maximum between 2000 and 2003. But why the sudden interest in the situation now? After all, we have been travelling at altitudes up to 17 km for decades, and few of us seem to care about being bombarded by high-energy particles. One of the main reasons is concern that the relative biological damage caused by neutrons may have been underestimated in the past. In addition, there is an increasing trend for subsonic aircraft to fly at higher cruising altitudes. And the International Commission on Radiological Protection (ICRP) has recently made a series of recommendations concerning exposure to cosmic rays. Neutrons are the major source of concern because they occur in significant numbers at aircraft altitudes. An improved understanding of their role in the radiation field is therefore important. Following the ICRP recommendations, the European Union has revised its basic safety-standards directive to include, for the first time, exposure to naturally occurring sources of ionizing radiation including cosmic radiation as an occupational hazard. The revised directive is being incorporated into the laws of the EU member states this month, and monitoring of aircrew will soon become mandatory. The research team has developed several different types of detector for the project, some of which have operated at high altitude on the Zugspitze mountain in Germany and Chacaltaya in Bolivia. In addition, the detectors were placed in high-energy beams at particle accelerators at Uppsala University in Sweden, the GSI laboratory in Germany and at CERN in