247 research outputs found

    Absolute Fluorescence Spectrum and Yield Measurements for a wide range of experimental conditions

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    For the JEM-EUSO CollaborationThe fluorescence yield is a key ingredient in cosmic ray energy determination. It is sensitive to pressure, temperature and humidity. Up to now the fluorescence yield of the brightest line at 337 nm has been measured in an absolute way in one set of conditions, whereas fluorescence yields at the other wavelengths have been relatively measured for different conditions. Thus, absolute calibration for all the lines is unclear. We will do all measurements at once using the same apparatus: all the lines will be measured absolutely and not relatively for all conditions. For that we will use the 3-5 MeV electron beam of the PHIL accelerator (Photon Injector at LAL), shooting in a box filled with air at varying pressures, temperatures and humidity. Delta rays resulting from the beam collisions with Nitrogen are responsible for the light yield. The light detection probability should be independent of its emission point especially at the delta ray stopping point. The idea is to use an integrating sphere, encapsulated in a vessel where pressure, temperature and humidity can be varied. This sphere will have two ports for the beam (in and out), one more port dedicated to a NIST photodiode for calibration and another port feeding optical fibers going to: A) a grating spectrometer equipped with cooled CCD. B) a photomultiplier with BG3 filters to measure directly the integrated yield. Calibrations at the percent level, will give each line spectrum yields with a precision between 2 to 5%. A special issue will be to estimate the leakage due to "high energy" delta rays. Thus, we the air density will be increased, the beam energy will be lowered until the beam stops inside the sphere. Then, the energy loss will be precisely derived from the Bethe-Bloch formula. We will present the set-up

    Antimatter and Matter Production in Heavy Ion Collisions at CERN (The NEWMASS Experiment NA52)

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    Besides the dedicated search for strangelets NA52 measures light (anti)particle and (anti)nuclei production over a wide range of rapidity. Compared to previous runs the statistics has been increased in the 1998 run by more than one order of magnitude for negatively charged objects at different spectrometer rigidities. Together with previous data taking at a rigidity of -20 GeV/c we obtained 10^6 antiprotons 10^3 antideuterons and two antihelium3 without centrality requirements. We measured nuclei and antinuclei (p,d,antiprotons, antideuterons) near midrapidity covering an impact parameter range of b=2-12 fm. Our results strongly indicate that nuclei and antinuclei are mainly produced via the coalescence mechanism. However the centrality dependence of the antibaryon to baryon ratios show that antibaryons are diminished due to annihilation and breakup reactions in the hadron dense environment. The volume of the particle source extracted from coalescence models agrees with results from pion interferometry for an expanding source. The chemical and thermal freeze-out of nuclei and antinuclei appear to coincide with each other and with the thermal freeze-out of hadrons.Comment: 12 pages, 8 figures, to appear in the proceedings of the conference on 'Fundamental Issues in Elementary Matter' Bad Honnef, Germany, Sept. 25-29, 200

    Progress on a spherical TPC for low energy neutrino detection

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    The new concept of the spherical TPC aims at relatively large target masses with low threshold and background, keeping an extremely simple and robust operation. Such a device would open the way to detect the neutrino-nucleus interaction, which, although a standard process, remains undetected due to the low energy of the neutrino-induced nuclear recoils. The progress in the development of the fist 1 m3^3 prototype at Saclay is presented. Other physics goals of such a device could include supernova detection, low energy neutrino oscillations and study of non-standard properties of the neutrino, among others.Comment: 3 pages, talk given at the 9th Workshop on Topics in Astroparticle and Underground Physics, Zaragoza, September 10-1

    Detecting ultra-high energy cosmic rays from space with unprecedented acceptance: objectives and design of the JEM-EUSO mission

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    The Extreme Universe Space Observatory on the Japanese Experiment Module (JEM-EUSO) of the Interna- tional Space Station (ISS) is the first mission that will study from space Ultra High-Energy Cosmic Rays (UHECR). JEM-EUSO will observe Extensive Air Showers (EAS) pro- duced by UHECRs traversing the Earth's atmosphere from above. For each event, the detector will make accurate mea- surements of the energy, arrival direction and nature of the primary particle using a target volume far greater than what is achievable from ground. The corresponding increase in statistics will help to clarify the origin and sources of UHE- CRs as well as the environment traversed during production and propagation. Possibly this will bring new light onto par- ticle physics mechanisms operating at energies well beyond those achievable by man-made accelerators. The spectrum of scientific goals of the JEM-EUSO mission includes as ex- ploratory objectives the detection of high-energy gamma ray

    The JEM-EUSO Instruments

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    For the JEM-EUSO CollaborationJEM-EUSO mission with a large and wide-angle telescope to be mounted on the International Space Station has been planned to open up "particle astronomy" through the investigation of extreme-energy cosmic rays by detecting fluorescence and Cherenkov photons generated by air showers in the earth's atmosphere. The JEM-EUSO telescope consists of 3 light-weight optical Fresnel lenses with a diameter of about 2.5m, 300k channels of MAPMTs, front-end readout electronics, trigger electronics, and system electronics. An infrared camera and a LIDAR system will be also used to monitor the earth's atmosphere. Status of the JEM-EUSO instruments will be reported

    Global Description of EUSO-Balloon Instrument

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    For the JEM-EUSO CollaborationThe EUSO-Balloon is a pathfinder of the JEM-EUSO mission, designed to be installed on-board the International Space Station before the end of this decade. The EUSO-Balloon instrument, conceived as a scaleddown version of the main mission, is currently developed as a payload of a stratospheric balloon operated by CNES, and will, most likely, be launched during the CNES flight campaign in 2014. Several key elements of JEM-EUSO have been implemented in the EUSO-Balloon. The instrument consists of an UV telescope, made of three Fresnel lenses, designed to focus the signal of the UV tracks, generated by highly energetic cosmic rays propagating in the earth's atmosphere, onto a finely pixelized UV camera. In this contribution, we review the main stages of the signal processing of the EUSO-Balloon instrument: the photodetection, the analog electronics, the trigger stages, which select events while rejecting random background, the acquisition system performing data storage and the monitoring, which allows the instrument control during operation

    The LBNO long-baseline oscillation sensitivities with two conventional neutrino beams at different baselines

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    The proposed Long Baseline Neutrino Observatory (LBNO) initially consists of 20\sim 20 kton liquid double phase TPC complemented by a magnetised iron calorimeter, to be installed at the Pyh\"asalmi mine, at a distance of 2300 km from CERN. The conventional neutrino beam is produced by 400 GeV protons accelerated at the SPS accelerator delivering 700 kW of power. The long baseline provides a unique opportunity to study neutrino flavour oscillations over their 1st and 2nd oscillation maxima exploring the L/EL/E behaviour, and distinguishing effects arising from δCP\delta_{CP} and matter. In this paper we show how this comprehensive physics case can be further enhanced and complemented if a neutrino beam produced at the Protvino IHEP accelerator complex, at a distance of 1160 km, and with modest power of 450 kW is aimed towards the same far detectors. We show that the coupling of two independent sub-MW conventional neutrino and antineutrino beams at different baselines from CERN and Protvino will allow to measure CP violation in the leptonic sector at a confidence level of at least 3σ3\sigma for 50\% of the true values of δCP\delta_{CP} with a 20 kton detector. With a far detector of 70 kton, the combination allows a 3σ3\sigma sensitivity for 75\% of the true values of δCP\delta_{CP} after 10 years of running. Running two independent neutrino beams, each at a power below 1 MW, is more within today's state of the art than the long-term operation of a new single high-energy multi-MW facility, which has several technical challenges and will likely require a learning curve.Comment: 21 pages, 12 figure

    Simulations studies for the Mini-EUSO detector

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    Mini-EUSO is a mission of the JEM-EUSO program flying onboard the International Space Station since August 2019. Since the first data acquisition in October 2019, more than 35 sessions have been performed for a total of 52 hours of observations. The detector has been observing Earth at night-time in the UV range and detected a wide variety of transient sources all of which have been modelled through Monte Carlo simulations. Mini-EUSO is also capable of detecting meteors and potentially space debris and we performed simulations for such events to estimate their impact on future missions for cosmic ray science from space. We show here examples of the simulation work done in this framework to analyse the Mini-EUSO data. The expected response of Mini-EUSO with respect to ultra high energy cosmic ray showers has been studied. The efficiency curve of Mini-EUSO as a function of primary energy has been estimated and the energy threshold for Cosmic Rays has been placed to be above 10^{21} eV. We compared the morphology of several transient events detected during the mission with cosmic ray simulations and excluded that they can be due to cosmic ray showers. To validate the energy threshold of the detector, a system of ground based flashers is being used for end-to-end calibration purposes. We therefore implemented a parameterisation of such flashers into the JEM-EUSO simulation framework and studied the response of the detector with respect to such sources

    Effects of charged Higgs bosons in the deep inelastic process \nu_{\tau} {\cal N} \to \tau^- X and the possibility of detecting tau-neutrinos at cosmic neutrino detectors

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    We study the deep inelastic process ντ+Nτ+X\nu_{\tau} + {\cal N} \to \tau^{-} + X (with N(n+p)/2{\cal N} \equiv (n+p)/2 an isoscalar nucleon), in the context of the two Higgs doublet model type II (2HDM(II)). We discuss the contribution to the total cross section of diagrams, in which a charged Higgs boson is exchanged. We present results which show the strong dependence of such contribution on tanβ\tan\beta and MH±M_{H^{\pm}}. We show that in the region 50tanβ20050 \leq \tan\beta \leq 200 and 90 GeV MH±\leq M_{H^{\pm}}\leq 600 GeV with the additional experimental constraint on the involved model parameters MH±1.5×tanβM_{H^{\pm}} \geq 1.5 \times \tan\beta GeV, the contribution of the charged Higgs boson exchange diagrams to the cross section of the charged current inclusive ντN\nu_{\tau} {\cal N} collision can become important. We obtain that this contribution for an inclusive dispersion generated through the collision of an ultrahigh energy tau-neutrino with Eν1020E_{\nu} \approx 10^{20} eV on a target nucleon can be larger than the value of the contribution of the W±W^{\pm} exchange diagrams, provided that MH±300M_{H^{\pm}} \approx 300 GeV and tanβ200\tan\beta \approx 200. Such enhancement and the induced variation on the mean inelasticity CC^{CC} could lead to sizeable effects in the acceptance of cosmic tau-neutrino detectors at experiments such as HiRes, PAO, and the CRTNT, which are anchored to the ground, and at experiments such as EUSO and OWL, which are proposed to orbit around the Earth.Comment: 18 pages, 2 figures, 8 table

    Mini-EUSO experiment to study UV emission of terrestrial and astrophysical origin onboard of the International Space Station

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    International audienceMini-EUSO will observe the Earth in the UV range (300 - 400 nm) offering the opportunity to study a variety of atmospheric events such as Transient LuminousEvents (TLEs), meteors and marine bioluminescence. Furthermore it aims to search for Ultra High Energy Cosmic Rays (UHECR) above 102110^{21} eV and Strange Quark Matter (SQM).The detector is expected to be launched to the International Space Station in August 2019 and look at the Earth in nadir mode from the UV-transparent window of the Zvezda module of the International Space Station. The instrument comprises a compact telescope with a large field of view (4444^{\circ}), based on an optical system employing two Fresnel lenses for lightcollection. The light is focused onto an array of 36 multi-anode photomultiplier tubes (MAPMT), for a total of 2304 pixels and the resulting signal is converted into digital, processed and stored viathe electronics subsystems on-board. In addition to the main detector, Mini-EUSO contains two ancillary cameras for complementary measurements in the near infrared (1500 - 1600 nm) and visible (400 - 780 nm) range and also a 8×88 \times 8 SiPM imaging array
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