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The δ 13 C profile of Globigerinoides ruber , measured in the GT90/3 shallow-water Ionian sea core and dated with high precision, is presented and analyzed using the Singular Spectrum Analysis and the Wavelet Transform. This time series covers the period 200–1979 AD, with a resolution of 3.87 years. The δ 13 C of foraminifera depends on the photosynthetic activity of the symbiontic algae living on the shells, strictly related to the illumination of the sea-surface. Both spectral methods, besides an 11-years oscillation in phase with the Schwabe cycle of the solar activity, show the presence of a centennial cycle that is in phase with the amplitude modulation of the sunspot number series in the last 300 years. Moreover, another climatic record, the tree ring δ 13 C of a Japanese cedar covering the time interval 125–1952 AD, shows a similar centennial oscillation and therefore suggests that this climatic variation is global and in phase with the solar activity.

The evolution of the cosmic ray primary composition in the energy range 10 6 –10 7 GeV (i.e. the “knee” region) is studied by means of the e.m. and muon data of the Extensive Air Shower EAS-TOP array (Campo Imperatore, National Gran Sasso Laboratories). The measurement is performed through: (a) the correlated muon number ( N μ ) and shower size ( N e ) spectra, and (b) the evolution of the average muon numbers and their distributions as a function of the shower size. From analysis (a) the dominance of helium primaries at the knee, and therefore the possibility that the knee itself is due to a break in their energy spectrum (at E k He =(3.5±0.3)×10 6 GeV) are deduced. Concerning analysis (b), the measurement accuracies allow the classification in terms of three mass groups: light (p,He), intermediate (CNO), and heavy (Fe). At primary energies E 0 ≈10 6 GeV the results are consistent with the extrapolations of the data from direct experiments. In the knee region the obtained evolution of the energy spectra leads to: (i) an average steep spectrum of the light mass group ( γ p,He >3.1), (ii) a spectrum of the intermediate mass group harder than the one of the light component ( γ CNO ≃2.75, possibly bending at E k CNO ≈(6–7)×10 6 GeV), (iii) a constant slope for the spectrum of the heavy primaries ( γ Fe ≃2.3–2.7) consistent with the direct measurements. In the investigated energy range, the average primary mass increases from 〈ln A 〉=1.6–1.9 at E 0 ≃1.5×10 6 GeV to 〈ln A 〉=2.8–3.1 at E 0 ≃1.5×10 7 GeV. The result supports the standard acceleration and propagation models of galactic cosmic rays that predict rigidity dependent cut-offs for the primary spectra of the different nuclei. The uncertainties connected to the hadronic interaction model (QGSJET in CORSIKA) used for the interpretation are discussed.

We demonstrate the presence of solar flare as well as neutron capture effects in the isotopic composition of rare gases in the Fermo regolith breccia acquired on its parent body based on the measurements of tracks, rare gases and radionuclides. The track density along a 3.2 cm long core decreases by a factor of about 6 and by more than a factor of 13 within the meteorite, indicating small (2-9 cm) and asymmetrical ablation. Rare gases show a large trapped component; the isotopic ratios, particularly 20 Ne/ 22 Ne ≅ 11 and 20 Ne/ 36 Ar = 10 are indicative of a solar component. The galactic cosmic-ray exposure age is determined to be 8.8 Ma. Activities of a dozen radionuclides ranging in half-life from 16 day 48 V to 0.73 Ma 26 Al are consistent with their expected production rates. Track, rare gas and radionuclide data show that the meteoroid was a small body (≤ 120 kg) and had a simple, one-stage exposure history to cosmic rays in the interplanetary space. However, 82 Kr and 128 Xe show an excess due to neutron irradiation on the parent body of the meteorite. The presence of solar gases and the neutron capture effects indicate several stages of irradiation on the parent asteroid. The chemical composition of Fermo confirms that it belongs to the H group of ordinary chondrites with lithic clasts having varying compositions. δ 15 N is found to be 8.3 ± 1.2%0, close to the typical values observed in H chondrites.

A search for transient point sources of ultra-high-energy (UHE) γ-rays has been performed, based on the correlation of two extensive air shower arrays, BAKSAN (North Caucasus, 1700 m a.s.l., BAKSAN Neutrino Observatory, Russia) and EAS-TOP (Campo Imperatore, 2005 a.s.l., Laboratori Nazionali del Gran Sasso, Italy), which are located at very similar latitudes (φ≈43° N), and separated in longitude by Δλ≈33.7°. The search has been conducted at primary energy Eγ⩾5×1013 eV on the time scale of a daily source transit over the sky, observable in the northern hemisphere (19° The stability of the single detectors has been studied and verified up to high significance level. No coincident excess, not compatible with the expectations from statistical fluctuations, has been observed. The obtained upper limits to the rate of transient events, nγ, at 90% c.l., are • concerning the sky survey, in the declination band corresponding to the zenith, n γ /(Ωt) /(yr sr) with Φγ(Eγ>5×1013 eV)>2.0×10−11 cm −2 s−1 and duration Δt • concerning the candidate sources, e.g., for Markarian 421: nγ/t 5×1013 eV)>1.3×10−11 cm −2 s−1 and Δt A coincident episode from Markarian 421, observed on 15 January, 1994, with expected chance imitation rate nch= 0.01 is discussed.

The break observed in the electron shower size power law spectrum of Extensive Air Showers (EAS) at corresponding primary energy E-0 similar to (3 - 5)10(15) eV ("knee") is studied in different EAS components (electromagnetic and muonic) and at different atmospheric depths. A consistent description is obtained. The interpretation of data in terms of primary composition, and following the most accepted high energy interaction models, leads to an increasing average primary mass in this energy range. The study of such behaviour is expected to provide a crucial information for the understanding of the physical parameters that characterize the break for the different primaries.

The cross section for large p t jet production for transverse momentum 10≤ p t ≤20 GeV/c and rapidity 1.6≤ η ≤2.6 in p – N ( p –`air') interactions is studied from the analysis of multicore Extensive Air Showers recorded in the EAS–TOP calorimeter. The projectiles are the leading particles interacting at atmospheric depths between 250 and 480 cm −2 , the CMS energy of interaction being s ≈500 GeV. The slope of the p t distribution agrees with the expected one from the p – p collider data at the same CMS energy. The measured jet production cross section in p – N interactions with respect to p – p interactions is (dσ/dp t ) pN jet =(dσ/dp t ) p p jet ·A α with α =1.56±0.07 for A =14.7 (average mass number of `air' nuclei). Such value is compatible within the experimental uncertainties with the one obtained in p –nucleus accelerator measurements at s ≃30 GeV in the same range of transverse momentum and rapidity. No indication of increase of α with energy, i.e. of the entity of the `Cronin effect', is found.

The amplitude and phase of the first harmonic of the sidereal anisotropy of cosmic rays at E 0 = 2·10 14 eV have been measured by the EAS-TOP experiment (Campo Imperatore, 2005 m a.s.l., LNGS, Italy) and are respectively (at the equatorial plane): A sid = (3.73±0.57)·10 −4 ; φ sid = 1.82±0.49 h lst, with significance 6.5 s.d. The result is supported by different consistency checks. From the comparison with lower energy data, it follows that the amplitude and the phase of the cosmic ray anisotropy are constant over the energy range 10 12 – 2·10 14 eV. This implies at these energies a constant influence of the local interstellar medium on the propagation of cosmic rays.

The cosmic ray energy spectrum in the range E-o = 10(15)-10(16) eV (including the region of the steepening, "knee") is studied by means of the EAS-TOP array (Campo Imperatore, Gran Sasso Laboratories, atmospheric depth 820 g cm(-2)). Measurements of the electromagnetic size (N-e = total number of charged particles at the observation level) are performed as a function of zenith angle with statistical accuracies of a few percent. The change of slope of the spectrum is observed in each bin of zenith angle at size values decreasing with increasing atmospheric depth. Its attenuation is compatible with the one of shower particles (Lambda(e) = 219 +/- 3 g cm(-2)). This observation provides a consistency check, supporting a normal behaviour of showers at the break, that make plausible astrophysical interpretations based on an effect on primaries occurring at a given primary energy. The break has a "sharp" shape (i.e., within experimental errors is compatible with two intersecting power laws) that represents a constraint with which any interpretation has to match. The change of slope of the power law index reproducing the size spectrum is Delta gamma = 0.40 +/- 0.09. The derived all particle energy spectrum is in good agreement with the extrapolation of the direct measurements at low energies and with other EAS data at and above the knee. Power laws fits to the energy spectrum below and above the knee give tin units of m(-2) s(-1) sr(-1) TeV-1) S(E-o) = (3.48 +/- 0.06) x 10(-10) (E-o/2300)(-2.76+/-0.03) for 900 TeV < E-o < 2300 TeV and S(E-o) = (3.77 +/- 0.08) x 10(-11) (E-o/5000)(-3.19+/-0.06) for 5000 TeV < E-o < 10(4) TeV. The systematic uncertainties connected to the interaction model and the primary composition are discussed. (C) 1999 Elsevier Science B.V.

We have previously shown that the very low activity of the cosmogenic 44Ti in meteorites records the galactic cosmic ray (GCR) flux over a century time-scale (Bonino et al., 1995). The heliospheric magnetic field (HMF) variations are the principal source of the GCR modulation in the heliosphere. We present here new measurements which extend our investigation over the last two centuries. The 44Ti activity at the time of fall has been obtained on the basis of the recently revised value of its half-life of 59.2 years. We basically confirm our earlier findings (Bonino et al., 1997). The 44Ti profile, with the time of fall of the meteorites, shows variations in phase in agreement with those expected. The magnitude of oscillations is ∼ 4 times higher than expected (∼ 6%) on the basis of the GCR flux over the past centuries deduced from sunspot number since 1700 and by the neutron monitor and balloon measurements in the last decades. The higher 44Ti production rate during prolonged solar quiet periods (Gleissberg minima) may imply that during these minima the HMF was weaker than during the recent minima of the 11-year solar cycle.

In this paper we present the δ18O profile of Globigerinoides ruber measured in the GT90/3 shallow water Ionian sea core, dated with high precision. The δ18O profile covers the period 1200–1900 AD, with a resolution of 3.87 years. This long record of 700 years of δ18O allows us to identify the imprint of the solar cycle in a climatic record. In fact, the spectral analysis of the time series performed with different methods shows a dominant periodicity of about 11 years with an amplitude of ≈0.07‰. The signal is in opposition to the sunspot number cycle. This component is identified at a high significance level by Monte Carlo Singular Spectrum Analysis (MC-SSA).

We report on a measurement of the ${}^{44}\mathrm{Ti}$ half-life aimed at lowering existing systematic uncertainties in this value, which is important to astrophysics. The half-life was measured by following the decay of ${}^{44}\mathrm{Ti}$ relative to ${}^{60}\mathrm{Co}$ for about 5 yr and the measurements were performed independently in three laboratories---Argonne, Jerusalem, and Torino. We suggest to combine our result, $59.0\ifmmode\pm\else\textpm\fi{}0.6$ yr, with the one from the accompanying Letter by G\"orres et al., $60.3\ifmmode\pm\else\textpm\fi{}1.3$ yr, to obtain a current ``best value'' for the half-life of ${}^{44}\mathrm{Ti}$ of $59.2\ifmmode\pm\else\textpm\fi{}0.6$ yr ( $1\ensuremath{\sigma}$ error).

The primary cosmic ray (CR) proton, helium and CNO fluxes in the energy range 80-300 TeV are studied at the National Gran Sasso Laboratories by means of EAS-TOP (Campo Imperatore, 2005 m a.s.l.) and MACRO (deep underground, 3100 m w.e., the surface energy threshold for a muon reaching the detector being Eμth~1.3 TeV). The measurement is based on: (a) the selection of primaries based on their energy/nucleon (i.e., with energy/nucleon sufficient to produce a muon with energy larger than 1.3 TeV) and the reconstruction of the shower geometry by means of the muons recorded by MACRO in the deep underground laboratories; (b) the detection of the associated atmospheric Cherenkov light (C.l.) signals by means of the C.l. detector of EAS-TOP. The C.l. density at core distance r>100 m is directly related to the total primary energy E0. Proton and helium (``p+He'') and proton, helium and CNO (``p+He+CNO'') primaries are thus selected at E0~=80 TeV, and at E0~=250 TeV, respectively. Their flux is measured: Jp+He(80TeV)=(1.8+/-0.4)×10-6 m-2s-1sr-1TeV-1, and Jp+He+CNO(250TeV)=(1.1+/-0.3)×10-7 m-2s-1sr-1TeV-1, their relative weights being: Jp+He/Jp+He+CNO(250TeV)=0.78+/-0.17. By using the measurements of the proton spectrum obtained from the direct experiments and hadron flux data in the atmosphere, we obtain for the relative weights of the three components at 250 TeV: Jp:JHe:JCNO=(0.20+/-0.08):(0.58+/-0.19):(0.22+/-0.17). This corresponds to the dominance of helium over proton primaries at 100-1000 TeV, and a possible non-negligible contribution from CNO. The lateral distribution of Cherenkov light in Extensive Air Showers (EASs), which is related to the rate of energy deposit of the primary in the atmosphere, is measured for a selected proton and helium primary beam, and good agreement is found when compared with the one calculated with the CORSIKA/QGSJET simulation model.

Production of cosmogenic radioisotopes in meteorites depends on the galactic cosmic ray flux, which is controlled by the heliospheric magnetic field (HMF), which, in turn, depends on the solar activity. The radioisotopes can, therefore, serve as proxy records of the behaviour of the heliosphere in the past, in particular over prolonged solar quiet periods, such as during Gleissberg or Maunder minima, when the production rate of radioisotopes is expected to change significantly. For this purpose we have measured the 44 Ti (T 1/2 =66.6 yr) in ten stony meteorites, which fell between 1840–1992. The results indicate that the production of 44 Ti was significantly higher when the solar activity was persistently low, indicating that the HMF was weak during such periods, enabling higher flux of cosmic rays to enter the inner heliosphere.

Different fluxes and spectra of galactic cosmic rays (GCR) and solar cosmic rays result in a wide variety of radioactive and stable-nuclides production rates. The records of cosmic-ray interactions, have been studied in terrestrial archives, in meteorites, cosmic dust and lunar samples. We present here some results obtained in our laboratory on the study of cosmogenic radionuclides produced in meteorites which fell in the last century. The laboratory is situated in the underground station of Monte dei Cappuccini, Torino, at a depth of 70 m water equivalent to reduce the cosmic-ray background level. To measure γ-activity in meteorites we have set up a highly efficient and selective Ge−NaI(Tl) γ-ray spectrometer surrounded by a passive shield. The solar modulation affects the intensity of GCR and therefore the isotopes production rates in meteorites. The 11 y solar cycle is well reproduced by the variations of22Na (T 1/2=2.6 y) in meteorites which fell during the past three solar cycles. The44Ti (T 1/2=66.6 y) activity measured in eight chondrites which fell in the last 110 y is qualitatively consistent with the century-scale solar-activity variation, called the Gleissberg cycle. The increase is roughly four times higher, than expected (about 5%) for a GCR flux calculated by a model in which the solar-activity modulation is determined solely by the sunspot number indexR. This result suggests a much weakened modulation of GCR during the prolonged Gleissberg minimum during which highly ordered magnetic fields set up in the heliosphere.

We have measured the thermoluminescence (TL) profile of the Mediterranean Sea core CT85.5 at the same depths where the cosmogenic-isotope10Be production peak at 35 ky BP was found. Strong TL peaks are evident at 37.5 ky and 35.6 ky BP. The Fourier analysis of the TL time series running from 32.5 ky to 42.6 ky at 100 y sampling interval shows 2500 y and 500 y periodicities. We suggest that the Sun was «active» at the time of the10Be enhancement.

A number of marine as well as continental K/T sections in India, particularly around the Deccan volcanic regime, have been analyzed to obtain concentration profiles of some platinum group and other trace elements, specifically to search for anomalous levels of iridium. Except for the Um Sohryngkew River (USR) section in Meghalaya, where iridium is found to occur at an anomalously high level in the K/T boundary layer, all other sections show low levels in the range of 10 to ∼120 pg/g. The iridium profile in the USR section is characterized by a sharp peak of 12.1 ng/g in a 1.5 cm thick limonitic layer, superimposed on a broad band of ∼0.2 ng/g extending over a 50±20 cm thick section, beyond which Ir decreases to the base level of ∼0.02 ng/g, both in the Tertiary as well as in the Cretaceous. High Ir is accompanied by high Os but the Os/Ir ratio in the peak (0.37) is different from the Os/Ir ratio of ∼2 measured in the broad band. The Ir profile in the USR section seems to be consistent with fallout of cometary debris preceding and following the main impact. The measurements at other sites in the Deccan suggest that the iridium inventory of the Deccan is too low to account for the high iridium observed in the KTB layer all over the world, but may be sufficient to give rise to its enhancement adjacent to the KTB peak.

An accurate dating of recent Ionian Sea sediment cores has been performed by the210Pb radiometric method and by a detailed tephroanalysis. The markers of the historical volcanic eruptions which occurred in the Campanian area (Vesuvius, Phlegrean Fields, Ischia) during the last two millenia have been identified along the cores. Among the others, the famous Plinian Vesuvius eruption of 79 AD, which buried the Roman town of Pompei, has been recognized. Direct210Pb dating is limited to the last two centuries. The tephroanalysis demonstrates that the sedimentation rate estimated by the210Pb method is correct and it is constant, at least for the last 2 ky. The presence of the137Cs peak due to the intense activity of nuclear-weapon testing in the atmosphere in 1963–64 AD assures that the top of the core is present and not disturbed. The high precision of the core dating allows to transform the depth scale into a time scale with an accuracy of ∼1%. The analysis of several cores taken in the same area demonstrates that the results presented here are of general validity, at least in this region. The carbonatic mud deposited in the last millennia in the Gallipoli Terrace can be successfully utilized for investigating the environmental conditions in the recent past.

We describe and discuss the operation, calibration and stability of the EAS-TOP calorimeter (Campo Imperatore, National Gran Sasso Laboratories), a large area hadron and muon detector devoted to cosmic-ray physics. It consists of iron slabs (for a total thickness of 818 g cm(-2)) and Iarocci tubes as sensitive layers, operating in the streamer mode and the "quasi proportional" regime. Using a model describing the operation of the "quasi proportional" chambers, we derive a calibration curve in the energy range 50-5000 GeV, whose reliability has been indirectly checked through on-site measurements, by means of an accelerator beam run (up to similar or equal to 600-700 GeV) and by comparing the model predictions on hadron shower transition curves with the data. (C) 1999 Elsevier Science B.V. All rights reserved.

We study the total carbonate profiles of three coastal cores extracted from the continental shelf in the Ionian Sea and of two deep-sea cores extracted from the Tyrrhenian abissal plane. An overall similarity between the two deep-sea profiles and among the three coastal profiles is observed, indicating the complete reproductibility of this type of experimental measurements. In the case of the coastal cores, a constant sedimentation rates=(0.0646±0.0007) cm/y has been determined by radiometric methods and by tephroanalysis. For the deep-sea cores, the spectra of the upper and lower halves of the carbonate depth profiles display the same periodic components, suggesting that the sedimentation rate is nearly the same along the entire deep cores as well. The use of a careful tephroanalysis, the recognition of the Ignimbrite layers of Campanian origin at the expected depths and the similarity between the upper part (5000y) of the carbonate profile of the deep-sea core with that of the coastal cores provide the indication that, on the average, 1 cm of sediment is deposited in about 100 y. We show that the trend of the carbonate record in the deep-sea core is well approximated by a signal obtained by linearly superposing the obliquity and the precession parameters of the Earth rotation axis. Since these astronomical factors contribute to the temporal variations of the Earth insolation, and since the CaCO3 content of the sediment is presumably affected by climatic factors, this result supports the evidence of astronomical control on the Earth's climate, as already pointed out by several authors who analysed the power spectra of δ18O, δD and CO2 temporal series from sediment and ice cores. After removal of the «astronomical» trend, the carbonate record displays a dominant periodicity at approximately 12000 y. The 12000 y wave, taken with the opposite sign, corresponds to the trend of the radiocarbon record in tree-rings. This result becomes particularly relevant in view of the existence of common periodicities of about 200 y waves (Suess wiggles) which have already been detected in the carbonate profiles of the coastal cores and in tree-ring radiocarbon data.

A large-volume HPGe gamma-ray spectrometer in a NaI(Tl) well has been set up underground at 70 m.w.e. depth for whole body counting of cosmogenic radionuclides in meteorites. The detectors are housed in a 20 cm thick lead shield with a lining of cadmium and OFHC copper. The scintillator is simultaneously operated in anticoincidence as well as in coincidence in selected energy channels to achieve low background levels (in the range of counts per day) and high specificity. In this way a large number of radionuclides such as26Al,44Ti,60Co,22Na,54Mn, and shorter-lived nuclides produced in extraterrestrial materials like meteorites and lunar rocks can be analysed. Results on Bouvante and Bereba achondrites and Dhajala and Torino chondrites are presented.

In the energy region 10 - 100 TeV both the c.r. composition from direct measurements and the cross section for high energy secondary production in the very forward region for p-air interactions are rather uncertain. Contemporaneous measurements of the total energy and of the threshold energy/nucleon of the primary particle can be provided by the atmospheric Cherenkov light and high energy muons. These measurements are performed by the combined operation of the Cherenkov array of the EAS-TOP experiment on the surface (810 gcm(2) atmospheric depth) and of the LVD experiment in the underground Gran Sasso Laboratories (3300 m w.e.; E-mu(th) = 1.3 TeV) leading to the measurement of < N-mu > (E-mu > 1.3 TeV, E-o) in the given energy range. The combined operation of the experiments and preliminary results are reported.

The attenuation length of proton primaries and the proton-air inelastic cross section are studied at energies E 0 ≈ 10 15 eV by using the EAS-TOP array data. Proton initiated Extensive Air Showers, in the energy range (2 ÷ 4) 10 15 eV and near maximum development, are selected from their N μ ( E μ > 1 GeV) and N e sizes. The experimental attenuation length A obs is compared with those obtained from simulations, including the full detector response. based on different interaction models (HDPM, VENUS, DPMJET, QGSJET and SIBYLL) in the frame of CORSIKA code. The proton-air inelastic cross section is also inferred by using the factor k = Λ obs sim /λ p —air sim obtained from each interaction model.

Horizontal Air Showers, i.e. events observed at “quasi” horizontal incidence, are studied from EAS-TOP at Campo Imperatore (National Gran Sasso Laboratories). The “reality” of such events as due to deeply penetrating particles is discussed from the experimental point of view. We deduce: • -the measurement of the HE muon flux at E μ = 20 TeV : F μ (> 20 TeV ) = (1.3 ± 0.4) × 10 −11 cm −2 s −1 sr −1 , • -the upper limit to the extraterrestrial HE neutrino flux: I ν (> 10 5 GeV ) −9 cm −2 s −1 sr −1 . • The possibility to develop the technique for UHE ν detection is discussed.

The authors confirm and extend the results previously reported on the carbonate profile of the GT14 Ionian Sea core (Cini Castagnoli et al., 1990). A second, much longer core (2.81 meters) named GT89/3, has been taken about 1 km apart from the previous one. The carbonate profiles of the two cores are impressively similar; the details of the CaCO{sub 3} variations in the two sediments match on the scale of the sampling interval {Delta}d = 2.5 mm used for both cores. The authors show that {Delta}d corresponds to the mud deposited in a time interval {Delta}t = 3.87 {plus minus} 0.04 years, a value which is constant throughout the entire length of the cores. This precision is achieved by the tephroanalysis of the two cores. In this approach the markers of well-known historical eruptions in the Vesuvius area are recognized (Pompei, AD 79, Pollena, AD 472, Ischia, AD 1301), providing a precise dating which accurately tunes that obtained by the radiometric method. The correlation between the carbonate profile of the GT14 core and the tree-ring radiocarbon record has been discussed in (Cini Castagnoli et al., 1990); here the authors extend these results and show that the same correlation holds atmore » least up to 1690 BC. Due to the longer length of the GT89/3 time series, they also show that three periodic components at about 206 yr, 228 yr and 179 yr may now be resolved in the carbonate series, in close agreement with the results already found for the radiocarbon record.« less

The calcium carbonate (CaCO{sub 3}) profile of a recent sediment core, drilled in the Ionian Sea in 1979, is studied. The CaCO{sub 3} content of the sediment has been measured at regularly spaced intervals of {Delta}d=0.25 cm corresponding to {Delta}t=3.87 yr from AD 170 to the present. The CaCO{sub 3} profile of the core closely resembles the radiocarbon time series as deduced from tree ring data. The two records have a correlation coefficient of about 0.8 and show strikingly similar long-term variations. This result presumably follows from the fact that both systems take part in the carbon cycle. The spectral analysis of the CaCO{sub 3} time series reveals the presence of the well known periodicity with period ca: 200 years, characteristic of the {Delta}{sup 14}C record. Since the CaCO{sub 3} content of sea sediments is governed by biological, physical and chemical processes in surface sea waters, which in turn are strongly influenced by climatic conditions, and since the {approx}200 yr {Delta}{sup 14}C wave is known to be governed by solar modulation of galactic cosmic rays, the tuning of these two records on the same frequencies suggests a strong Sun-climate relationship.

The heliospheric magnetic field (HMF) is controlled by solar activity, as established by measurements over the last few decades, but its characteristics when the sun was quiet for prolonged periods, such as during Gleissberg or Maunder minima, are not known. Titanium-44, produced in meteorites, provides a monitor of the galactic cosmic ray (GCR) flux and allows estimation of the modulation effect of the sun for the period 1883 to 1992. The titanium-44 activity is consistent with the expected value, but the increase, due to the last Gleissberg minimum, is four times greater than expected for a GCR modulation based solely on sunspot numbers. This result implies that the HMF was weaker than at present and as a result the GCR flux (for energy greater than 1 gigaelectron volt) was higher between 2.2 to 3.6 protons per square centimeter per second per 4π steradians at 1 to 3 astronomical units in solar cycles 12 to 15.

The flux of cosmic ray hadrons at the atmospheric depth of 820 g/cm^2 has been measured by means of the EAS-TOP hadron calorimeter (Campo Imperatore, National Gran Sasso Laboratories, 2005 m a.s.l.). The hadron spectrum is well described by a single power law : S(E_h) = (2.25 +- 0.21 +- 0.34(sys)) 10^(-7)(E_h/1000)^(-2.79 +- 0.05) m^(-2) s^(-1) sr^(-1) GeV^(-1) over the energy range 30 GeV-30 TeV. The procedure and the accuracy of the measurement are discussed. The primary proton spectrum is derived from the data by using the CORSIKA/QGSJET code to compute the local hadron flux as a function of the primary proton spectrum and to calculate and subtract the heavy nuclei contribution (basing on direct measurements). Over a wide energy range E_0 = 0.5-50 TeV its best fit is given by a single power law : S(E_0) = (9.8 +- 1.1 +- 1.6(sys)) 10^(-5) (E_0/1000)^(-2.80 +- 0.06) m^(-2) s^(-1) sr^(-1) GeV^(-1). The validity of the CORSIKA/QGSJET code for such application has been checked using the EAS-TOP and KASCADE experimental data by reproducing the ratio of the measured hadron fluxes at the two experimental depths (820 and 1030 g/cm^2 respectively) at better than 10% in the considered energy range., Comment: 16 pages, 9 figures, accepted for publication in Astroparticle Physics

We show the δ 13 C profile of Globigerinoides ruber measured in the GT90/3 shallow-water Ionian sea core. This core is dated with high accuracy (better than 1%) using radiometric and tephroanalysis methods, for the last 2000 years. The core, extracted from the Gallipoli platform, was sampled at contiguous steps of thickness 2.5 mm, corresponding to 3.87 years. The δ 13 C profile covers the period 1147–1975 AD. During the first seven centuries it appears fairly flat, while it shows a steep increase between 1760 and 1950 of ∼0.3‰. The analysis of the time series performed using different methods shows a dominant decadal periodicity throughout the record. The 11-year component is identified at high significance level by Monte Carlo singular spectrum analysis (MC-SSA); the SSA-reconstructed-11-year component is in phase with the sunspot solar cycle. The average amplitude of this component is A 11y =0.04‰. It is commonly accepted that δ 13 C variations in symbiontic foraminifera mainly record the effects of symbiont density and of photosynthetic activity, varying with ambient light level. The δ 13 C peak-to-trough 11-year variation (0.08‰) can be related to solar irradiance variation of 0.1% on decadal time scale, like that measured in space in the last 20 years. By supposing that the observed δ 13 C modern increase of ∼0.3‰ is also produced by a solar irradiance variability on a longer time scale, through the same mechanisms, we estimate a secular increase of the total solar irradiance between 1760 and 1950 of (0.3/0.08)∗0.1% ≅ 0.37%. This value is at the higher limit of the long term variability estimates (0.25%–0.35%) that are currently proposed. Finally, in the light of the available experimental evidences, we discuss possible ways in which direct solar forcing can be modified by atmospheric processes in order to give the observed δ 13 C signal.

Portales Valley is an unusual meteorite with H6 chondritic matrix, interspersed by heterogeneous distribution of metallic veins. Four fragments with different abundances of veins, as determined by their bulk densities (3.49–4.86 gcm −3 ) were analysed for measurement of the cosmogenic radionuclides 57 Co, 54 Mn, 22 Na, 60 Co, 44 Ti and 26 Al using a gamma ray spectrometer. Chondritic and metallic proportions were estimated for each fragment. One sample was essentially free of metal veins. The shielding depth of each fragment (14 to 81 gcm −2 ) was estimated using cosmic ray heavy nuclei tracks which varied by more than two orders of magnitude in the four fragments, ranging between 4 to 1.7×10 6 cm −2 . The activity ratio 22 Na/ 26 Al was found to be similar (1.53±0.03) in the four fragments, independent of shielding depth and consistent with the expected activity at the time of fall during the beginning phase of the solar cycle 23.

We present measurements and data analysis of the oarbon stable isotopes (delta^13C) in the planktonic Globigerinoides ruber extracted from the GT9O/3 shallow water lonian sea core, dated with high precision. It is commonly accepted that delta^13C variations in symbiontic foraminifera mainly record the effects of productivity and of photosynthetic activity, varying with the ambient light level. Therefore from this time series we can deduce information on the sea surface illumination at the time of the planktonic foraminifera growth. The profile (359 points) covers the period 590-1979 AD, with a resolution of 3.87 years and it is an extension of the time series (215 points) previously published in this journal. The spectral analysis of the longer time series confirms the presence of the 11 y signal, with amplitude —0.08 per mille (peak-to-trough), found in the shorter time series in phase with the sunspot solar cycle; furthermore it shows the presence of two centennial cycles of 100 and 200 years, with amplitude 0.08 per mille and 0.02 per mille respectively. These components are identified at high significance level by Monte Carlo singular spectrum analysis (MC-SSA). A comparison between the delta^13C profile and the historical aurorae series (600-1500 AD) shows that the long-term delta^13C variations are at least partially generated by the solar activity modulation and in phase with the solar output, as represented by the solar wind interaction with the magnetosphere.

We present evidence for a dependence of the average deep underground muon energies on shower size in the coincident EAS-TOP and LVD data at the Gran Sasso laboratories. The measured relation agrees with a mixed chemical composition of the cosmic ray primary spectrum at energies around 10(15) eV. (C) 1998 Elsevier Science B.V.

In this letter, we report the profiles (∼160 samples) of 10Be, 9Be, Zn in a Mediterranean sediment core spanning the last 60 kyr. We show the existence of a 10Be peak, whose absolute age is estimated to be 34±3 kyr BP, based on its stratigraphic position between two tephra layers originating from two volcanic eruptions (Campanian Ignimbrite and Citara), dated by K-Ar, 40Ar-39Ar and 14C methods. This peak is similar to the increase in the 10Be concentration observed in Vostok and Dome C ice cores at the same age. The increase with approximately similar amplitude in both ice and sediment cores at different latitudes and hemispheres cannot be explained by changes in the archives. The present result supports the view of a well defined global enhancement of the 10Be flux, related to an increase of the 10Be production rate and not to a redistribution of the 10Be fallout between different latitudes.

Extensive Air Shower (EAS) experiments with high granularity have reported the detection of multicore events. On the other hand, multicluster and double-core events have been observed with emulsion chambers (EC) at mountain altitudes since the late '70s. A striking characteristic of these events is the large transverse momentum of the clusters. At accelerator energy region, it is known that jet production in deep inelastic hadronic processes is associated with the emission of large-P T particles. In this paper we analyse the possibility that both EAS and EC events represent the same physical process, discussing the physical consequences of this fact and the possibilities offered by both techniques in integrating the accelerators data.

In this paper, we compare the carbonate record obtained by us (Cini-Castagnoliet al., Nuovo Cimento C,15 (1992) 547) in the CT85-5 Tyrrhenian deep-sea core with that obtained by Kegwin and Jones (J. Geophys. Res. C,99 (1994) 12397) in the western North Atlantic GPC-9 Bahama core, during the period of climate stage 3 (20–62 ky BP). Both time series are radiocarbon tested. An overall similarity between the two carbonate profiles is observed. The Tyrrhenian and the Bahama records show a maximum correlation coefficientr2=0.6 for a time shift of 900 y, the latter preceding the former. By using the method of superposition of epochs, we show that the two series display a similar variability on the time scale between 2000 and 5000 y. Periods and phases of the oscillations agree within experimental errors. We have recently found in CT85-5 the10Be peak discovered in Vostok ice core at about 35 ky BP; so this marker could be searched in GPC-9 in order to synchronize in absolute way the past ocean conditions.

The thermoluminescence (TL) and carbonate profiles are measured in shallow water Ionian Sea cores, dated precisely by radiometric and tephroanalysis methods. Their time series, covering the last 4000 years, are obtained at time intervals of 3.096 and 3.87 years. We show that the 10.8 yr cyclicity is always present in each of time series analysed. A study of the amplitudes and phases of the wave is performed by the method of superposition of epochs. The phase shift of the TL and of the CaCO3 waves is ∼π. The persistency of the wave is assured in the last 3000 years by the cyclogram analysis. The power involved in this component of the signals is however small. Since the time series which we have extracted from the Ionian Sea cores bear some relation to the climatic factors forcing the deposition of the coastal carbonatic mud, these results may be interpreted as a proof that the Schwabe cycle of the Sun, associated with the irradiance variability, is directly involved in the climatic changes of the terrestrial archives.

Abbiamo analizzato i profili della concentrazione del carbonato di calcio (CaCO3) in quattro cores di sedimenti recenti del Mar Ionio, che coprono un intervallo di ∼5000 anni, ed il profilo della termoluminescenza (TL) in uno di questi cores che copre un intervallo di ∼2000 anni. La velocita di sedimentazione e stata determinata con grande precisione utilizzando metodi radiometrici e di tefroanalisi e si e dimostrata costante ed identica per i quattro cores. I profili di CaCO3 e di TL sono stati cosi trasformati in serie temporali. La precisione delle scale temporali ha permesso l'analisi accurata di significative ciclicita presenti nelle serie temporali ottenute e di individuare la loro possibile origine solare. Le serie di CaCO3 sono perfettamente riproducibili e rivelano, in particolare, le periodicita di circa 90 anni (ciclo di Gleissberg) e di circa 200 anni presenti anche nel14C degli anelli degli alberi. Questa periodicita e accompagnata da due bande laterali che suggeriscono che l'onda di 200 anni e modulata da una componente con periodo di ∼2000 anni, come si trova anche nel radiocarbonio. L'analisi della serie temporale di TL rivela ben definite periodicita a 137.7 a, 59 a, 28.5 a, 22 a, 12.06 a, 10.8 a, che hanno notevoli corrispondenze con le periodicita trovate nelle macchie solari e nelle aurore. Inoltre, il battimento delle due onde con periodo decennale produce un treno d'onda con periodo di 11.4 a ed una modulazione d'ampiezza di 206 a gia citata, ed i nodi del treno d'onda coincidono con i minimi delle macchie solari. I risultati ottenuti indicano un possibile meccanismo comune, di origine solare e/o climatica che controlla indici differenti in reservoirs terrestri.

This paper presents data on the sidereal variation of muons recorded at 570 hg/cm 2 , corresponding to primary rigidities around 1.8 TV. The record investigated covers a period of five years, from September 1985, near solar minimum, to September 1990, near solar maximum. The features of the observed sidereal variation histogram are related to the changing heliospheric conditions. Three conclusions emerge: (1) The Fourier reconstruction of the 24-h histogram requires a large number of harmonics, since the first and the second (diurnal and semidiurnal) are often outranked by higher order Fourier harmonics; (2) the anisotropy observed during the period of minimum solar activity has galactic origin; (3) as the level of solar activity increases the information on this anisotropy is altered by solar modulation processes.

The thermoluminescence (TL) profile of the GT14 Ionian Sea core has been recently analyzed in connection with other records of solar activity. Phenomenological similarities among the TL profile, the radiocarbon record in tree-rings and the variations of the mean anuual sunspot number Rz suggest a solar control of the TL signal. In this paper we consider new readings of the TL profile of the GT14 core which were obtained at different glow temperatures. While the main spectral peaks discussed in previous papers are observed in all readings, a few new significant periodic components may now be separated from the noise background. Among these, a strong 22 yr (Hale) cycle is evident, together with a periodicity of 28.5 yr which has already been detected in the spectrum of the sunspot number series. We finally test the temporal persistency of the main TL periodic components by using a cyclogram method and we explore the effects of background noise by considering the TL profile of bleached samples.

The EAS-TOP extensive air shower array has been operating since 1992 in the search for gamma-ray bursts at primary energies E(1) greater than or equal to 10 GeV and E(2) greater than or equal to 80 TeV. The study is performed by searching for short transients in the cosmic-ray intensity in the single particle (E(1)) and extensive air shower (E(2)) counting rates at mountain altitude (2005 m above sea level). We discuss the method and the results obtained both in sky survey and in correlation with BATSE events. In both energy ranges, the observed fluctuations in the event rate obtained in the sky survey during similar to 800 days of live time are compatible with the statistical fluctuations of the cosmic-ray background. A single candidate of time duration Delta t similar to 2 s and energy fluence F(10 < E < 100 GeV) = 1.7 x 10(-4)/(cos theta)(10.5) ergs cm(-2) (where theta is the unknown zenith angle) has been observed on 1992 July 15 at 13:22:26 UT in the energy range E(1) greater than or equal to 10 GeV with significance 10.6 and 20.1 sigma in two measurement channels. In the analysis made in correlation with similar to 50 events detected by BATSE, no burst candidate was found in time coincidence or in the 2 hr interval, around the BATSE detection time. The following ranges of upper limits F-max to the energy fluence in the time interval Delta t(90) in which BATSE detected 90% of the counts are obtained: F-max = 2.3 x 10(-5)-7.4 x 10(-3) ergs cm(-2) (10 < E < 100 GeV) F-max = 1.6 x 10(-6)-3.3 x 10(-5) ergs cm(-2) (100 < E < 1000 TeV).

The authors investigate the fractal and statistical properties of underground muons recorded at 570 hg/cm{sup 2} and study their response to solar activity variations in the second part of solar cycle 21. A constant feature detected throughout the whole period considered is the self-affine nature of the underground muon fluctuations which display a scaling range extending approximately from a few hours to more than 2 months. An important result of the study is that the scaling and spectral exponents are positively correlated with the sunspot cycle. In addition, the intensity distribution shows a more marked presence of short- and long-term fluctuations near solar maximum. The presence of solar modulation in the muon record suggests dimensions of the heliosphere at least as large as a few scattering mean free paths of the 1.8-TV primaries.

In order to investigate the extent to which 10Be concentrations in polar ice record solar activity on the level of individual Schwabe solar cycles, we have measured 10Be concentrations over the interval from 1180 to 1800 A.D. in an ice core from Greenland, using the accelerator mass spectrometer of the ETH Zurich. The data were analysed using the cyclogram method of time series analysis which showed that 10Be concentrations varied with a period which ranged between 9 and 11.4 y. Schwabe-type 10Be variations were visible even during the Maunder Minimum (1645–1715 A.D.), an interval of almost no visible sunspots. During this period 10Be concentrations varied with a periodicity which slowly increased from 9 to 11 y. 10Be concentrations were higher during the Maunder Minimum than during minima in the 11 y Schwabe cycle. This suggests the presence of residual solar modulation even during Schwabe solar cycle minima.

The thermoluminescence profile of an Ionian Sea recent sedimentary core, constructed with 467 equispaced data points and spanning 18 centuries from 170 to 1974 A.D. is studied. Several time series analysis methods reveal two evident periodicities on the centennial time scale, at 137 years and 118 years, both with their second harmonics. Together with these slow cyclic variations two sharp periodicities appear on the decennial time scale, at 12.1 years and 10.8 years. In the present study the amplitude and phase of these waves have been determined and it is shown that their summation accounts for more than 50% of the standard deviation of the whole time series and that they correctly reproduce the basic characteristics of the data.

A meteorite shower fell at Torino, Italy on May 18, 1988. Petrographic studies indicate that the stone is an H6 chondrite having features of moderate to severe shock. Chemical analyses of the meteorite are reported. Cosmic ray produced He-3, Ne-21 and Xe-126 yield an exposure age of about 48 Ma. The cosmic ray track densities in three fragments range between 1.8 to 5 x 10 to the 5th/sq cm suggesting about 99 percent mass ablation in the atmosphere,. Twelve radioisotopes with half lives ranging between 5.6 days to 7.3 x 10 to the 5th years have been measured with high precision. Marginal signals were observed for several short-lived nuclides and upper limits were obtained for the activity levels of eight radionuclides, some of which have not been hitherto detected in fresh falls. The data are generally consistent with the nuclide production by galactic cosmic rays when modulation due to the solar cycle is taken into consideration. 23 refs.

Thermoluminescence from the different layers of a recent core drilled in the Tyrrhenian Sea has been measured. The sedimentation rate of 0.115 cm y−1 previously determined by the210Pb−226Ra method allows the profile of TL to be obtained in the last 1500 years. We notice that sharp peaks in the TL intensity appear during the years in which records of hystorical supernovae explosions are given. A working model of the process based on the irradiation of dust in the upper atmosphere by γ-rays produced in the SN burst allows a satisfactory energy estimate of the observations to be done. Moreover, the profile shows the modulation of the irradiations of the Earth environment produced by the Sun in the past.

The integral response functions for cosmic-ray muons, at different muon threshold energies, are calculated by taking into account the nuclear composition of the primary cosmic radiation, and showing their contribution also at large zenith angles.

The Zurich sunspot relative number R z series has been analysed by the cyclogram method. The amplitude and the frequency variations of the Fourier 11 yr component between 1700–1983 A.D., were determined in a continuous way. Four distinct time intervals with significantly different characteristics of the periodicities are observed and discussed. Their second harmonics are also considered. The periodicity changes are contemporary to those of the 11 yr cycles. Around the year 1903 it seems that an important event has happened in the Sun. In fact the 11.4 yr cycle periodicity, that was very stable since at least 1825 started to change gradually to smaller values and similarly it happened to the second harmonic which also stopped and abruptly changed of phase of 90°.

The results of the spectral analysis of the time variations of the thermoluminescence (TL) intensity measured at 4 y intervals in a recent Ionian Sea sediment core from 1500 A.D. to 1974 A.D. are presented. The presence of an 11 y wave is clearly demonstrated not only by the power spectral density analysis but also by two other methods:a) the superposition of the 11 y epochs andb) the stretching index of the 11 y cyclogram. Moreover, the fan map of the stretching index of the cyclograms at different perioditities shows that the oscillations in the band (11±0.5) y are regularly frequency-modulated on a time scale around 90 y. The two kind of periodicities could be related to the Schwabe and the Gleissberg cycles of solar activity which appear in phase with the TL cycles. We confirm, therefore, our previous suggestion that the TL profiles from sea sediments could be a useful tool for monitoring the solar-terrestrial effects in the past.

The profiles of the concentration of210Pb precipitated from the atmosphere are measured in Tyrrhenian Sea cores, all collected in about the same region. From the disequilibrium226Ra−210Pb the sedimentation rate has been found and its uniformity has been tested. The measured activities of210Pb unsupportedin situ in the different layers show an exponential behaviour as a function of depth, thus demonstrating that the sedimentation rate is constant. Moreover the fall-out has been estimated in two different cores, and the agreement is excellent (respectively 62 and 58 atoms/cm2 min). A case of mixing in the top layers during collection mishandling is also presented: the fluctuations in the activity measurements are evident and prevent the sedimentation rate to be univocally determined.