K.Yoshida

The CALET, CALorimetric Electron Telescope, mission for the International Space Station

Abstract The CALorimetric Electron Telescope, CALET, mission is proposed for the Japanese Experiment Module Exposure Facility of the International Space Station. Major goals of the mission are precise measurements of the electrons in a few GeV - 10 TeV and the gamma-rays in 100 MeV - several TeV, keeping an energy resolution of a few % over 100 GeV. From the measurements, a systematic investigation of high-energy electromagnetic process in universe will be performed. A detection of SUSY particle which is a candidate of the dark matter would also be expected. The detector is composed of an imaging calorimeter of scintillating fibers and a total absorption calorimeter. Total thickness of the absorber is 45 r.1 for electro-magnetic particles and 2.1 m.f.p for protons. Total weight of the payload is nearly 2,200 kg, and the effective geometrical factor should be ∼ 1.0 m 2 sr. The hadron rejection power can be 10 6 for electrons.

A Pb-SciFi imaging calorimeter for high energy cosmic electrons

The BETS (balloon-borne electron telescope with scintillating fiber) detector has been developed for high-altitude balloon flights to observe high-energy cosmic-electrons. The detector consists of an imaging calorimeter and a trigger system for particle identification and energy measurement. The calorimeter is composed of scintillating fibers and leads of a total thickness of ∼8 r.l. Two sets of an image-intensifier and CCD camera system are adopted for read-out of 10,080 scintillating fibers. The accelerator tests were carried out to study performance of the detector by the CERN-SPS electron and proton beams. It is demonstrated in the flight data that a reliable identification of the electron component has been successfully achieved up to 100 GeV, and the energy spectrum has been measured.

The LHCf experiment at LHC

— High Energy Cosmic Ray experiments are providing useful information to understand high energy phenomena in the Universe. However, the uncertainty caused from the poor knowledge of the interaction between very high energy primary cosmic ray and the Earth’s atmosphere prevents the precise deduction of astrophysical parameters from the observational data. The Large Hadron Collider (LHC) provides the best opportunity for calibrating the hadron interaction models in the most interesting energy range, between 10 eV and 10 eV. To constrain the models used in the extensive air shower simulations the measurements of very forward particles are mandatory. Among the LHC experiments, the LHCf experiment has been designed to reach this goal and its capability to measure forward neutral particle produced in p-p interaction will result crucial for a better interpretation of cosmic ray studies. In this paper, the status of the LHCf experiment and preliminary results for 900 GeV data taking are discussed.

The LHCf experiment at the LHC accelerator

The claimed discovery of atmospheric shower induced by cosmic‐ray with energy beyond the GZK cutoff by the AGASA experiment in 1994–1995, although not confirmed by other important experiments like Fly’s Eye and Hi‐Res, together with the poor knowledge of the composition of cosmic rays around and beyond the Knee region, have highlighted the necessity of new experiments that should increase our present knowledge of HECR and UHECR. For this reason big efforts have been addressed to the development of new experiments, like Auger, TA and EUSO, for a systematic study of the UHE atmospheric showers with increased capabilities with respect to the previous experiments. Moreover complementary experiments should allow a precise calibration of the methods used for the reconstruction of cosmic‐ray showers in atmosphere. Their aim is the measurement of quantities that are used in these procedures and that are not yet precisely known. Under this perspective the LHCf experiment is a compact experiment which has been prop...

Measurement of TeV electrons on ISS/JEM

By using the JEM (Japanese Experiment Module) facility on ISS, we are planning to carry out a precise measurement of the flux and energy spectrum of cosmic-ray electrons of 10 GeV to several TeV. Since the electrons over several 100 GeV could be contributed only from the nearby sources within a distance less than 1 kpc, it is expected in the high energy region that the energy spectrum has a structural component and the distribution of the arrival directions presents anisotropy. By helping to localize and identify the nearest cosmic ray sources, these data should help to resolve the long-term puzzle. The instrument used for the observation is a kind of scintilating-fiber/lead imaging calorimeter that has been used for the balloon observations. We are developing an improved detector having a geometrical factor of 0.5 m2sr and a higher rejection power against the background protons (⩾104). It is expected to observe nearly 500 electrons over 1 TeV during the one-year observation.