The next generation magnetic spectrometer in space, AMS-100, is designed to have a geometrical acceptance of 100 m 2 sr and to be operated for at least ten years at the Sun–Earth Lagrange Point 2. ...Compared to existing experiments, it will improve the sensitivity for the observation of new phenomena in cosmic rays, and in particular in cosmic antimatter, by at least a factor of 1000. The magnet design is based on high temperature superconductor tapes, which allow the construction of a thin solenoid with a homogeneous magnetic field of 1 Tesla inside. The inner volume is instrumented with a silicon tracker reaching a maximum detectable rigidity of 100 TV and a calorimeter system that is 70 radiation lengths deep, equivalent to four nuclear interaction lengths, which extends the energy reach for cosmic-ray nuclei up to the PeV scale, i.e. beyond the cosmic-ray knee. Covering most of the sky continuously, AMS-100 will detect high-energy gamma-rays in the calorimeter system and by pair conversion in the thin solenoid, reconstructed with excellent angular resolution in the silicon tracker.
Cosmic-ray proton and helium spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass experiment flown for 42 days in Antarctica in the 2004-2005 austral summer season. ...High-energy cosmic-ray data were collected at an average altitude of ~38.5 km with an average atmospheric overburden of ~3.9 g cm--2. Individual elements are clearly separated with a charge resolution of ~0.15 e (in charge units) and ~0.2 e for protons and helium nuclei, respectively. The measured spectra at the top of the atmosphere are represented by power laws with a spectral index of --2.66 ? 0.02 for protons from 2.5 TeV to 250 TeV and --2.58 ? 0.02 for helium nuclei from 630 GeV nucleon--1 to 63 TeV nucleon--1. They are harder than previous measurements at a few tens of GeV nucleon--1. The helium flux is higher than that expected from the extrapolation of the power law fitted to the lower-energy data. The relative abundance of protons to helium nuclei is 9.1 ? 0.5 for the range from 2.5 TeV nucleon--1 to 63 TeV nucleon--1. This ratio is considerably smaller than the previous measurements at a few tens of GeV nucleon--1.
The forthcoming decades will see a rapid development of space programs aiming at the implementation of habitats on our satellite. Therefore it makes sense to evaluate the feasibility of a permanent ...cosmic-ray (CR) observatory on the Moon. Its large sensitive area would allow to carry out a very rich observational program over a time span of a few decades with an unprecedented energy reach. A thorough exploration of the energy region around the CR spectral anomaly located at a few PeV, also known as the “knee”, will become possible.
In this paper we propose an innovative concept of a modular lunar observatory designed to overcome the limitations of the present generation of cosmic-ray telescopes in Low Earth Orbit. It consists of an array of fully independent modules with limited individual size and weight. This would allow an ample flexibility in the gradual deployment of a progressively larger active volume, while ensuring the collection of meaningful scientific data during the intermediate stages of its implementation. Each independent module consists of three main instruments: a combined Charge and Time-of-Flight detector to identify individual elements from proton to nickel (and beyond), a tracker providing the direction and impact point of the incident particle, and a calorimeter to measure its kinetic energy. The design of each instrument contains innovative solutions that are well within the reach of the present technology.
CALET is an advanced experiment that will be installed on the Exposure Facility of the Japanese Experiment Module (JEM-EF) on the International Space Station (ISS) with a launch window in 2014. The ...instrument consists of three main sub-systems: a charge module using plastic scintillators to identify the charge of the particle, a thin imaging calorimeter (3X0) with tungsten plates interleaving scintillating fiber planes, and a thick calorimeter (27X0) composed of lead tungstate logs. It has sufficient depth, imaging capabilities and excellent energy resolution to allow for a clear separation between hadrons and electrons and between charged particles and gamma-rays. The charge module will be able to identify cosmic nuclei from H through Fe as well as trans-Fe elements at least up to Zr (Z=40). With extended observations, over a period of 5 years, CALET will be able to unveil the presence of possible nearby sources of high energy electrons, study the details of particle propagation in the galaxy and search for signatures of dark matter.
In this paper, we will review the main features of the CALET instrument and the present status of the mission.
► Charge identification of relativistic cosmic nuclei. ► High granularity imaging calorimeter. ► Electron–proton discrimination with calorimetric techniques.
We present new measurements of the energy spectra of cosmic-ray (CR) nuclei from the second flight of the balloon-borne experiment Cosmic-Ray Energetics And Mass (CREAM). The instrument included ...different particle detectors to provide redundant charge identification and measure the energy of CRs up to several hundred TeV. The measured individual energy spectra of C, O, Ne, Mg, Si, and Fe are presented up to ~1014 eV. The spectral shape looks nearly the same for these primary elements and it can be fitted to an E -2.66 +/- 0.04 power law in energy. Moreover, a new measurement of the absolute intensity of nitrogen in the 100-800 GeV/n energy range with smaller errors than previous observations, clearly indicates a hardening of the spectrum at high energy. The relative abundance of N/O at the top of the atmosphere is measured to be 0.080 +/- 0.025 (stat.)+/-0.025 (sys.) at ~800 GeV/n, in good agreement with a recent result from the first CREAM flight.
Arrays of single photon avalanche diodes (SPADs) fabricated in a 150 nm CMOS technology have been exposed to neutrons up to fluences of about <inline-formula> <tex-math notation="LaTeX">4.3 \times ...10^{10}~1 </tex-math></inline-formula> MeV neutron equivalent cm<inline-formula> <tex-math notation="LaTeX">^{-2} </tex-math></inline-formula>, with fluxes around <inline-formula> <tex-math notation="LaTeX">3 \times 10^{6}~1 </tex-math></inline-formula> MeV neutron equivalent cm<inline-formula> <tex-math notation="LaTeX">^{-2}\text{s}^{-1} </tex-math></inline-formula>. Dark count rate (DCR) was monitored during irradiation and for some time, from 5 to 23 min, depending on the irradiation step, at the end of the irradiation interval to investigate the dynamics of defect formation and short-term annealing. Measurements were performed both on single- and on dual-layer devices, where SPAD arrays are face to face bonded and read out in coincidence. A range of different DCR behaviors were detected after single neutron interaction with the device substrate, including in particular partial performance recovery following a logarithmic relaxation process, but also damped oscillation phenomena, sudden step-shaped changes, and the emergence of RTS-like fluctuations, pointing to different defect reordering dynamics.
We report on the measurements performed with relativistic ions from Be to Fe, at the Fragment Separator (FRS) of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, to test the ...performance of charge-sensitive detectors that were designed to separate – via multiple dE/dx measurements – fully stripped nuclei of cosmic origin in the experiment CALET. The latter is a space mission by the Japanese Space Agency (JAXA) scheduled to be launched to the International Space Station (ISS) in 2013. The CALET instrument is managed by an international collaboration and it is scheduled to take data for 5 years on the Exposure Facility (JEM-EF) of the Japanese module KIBO on the ISS.
The aim of the test was to accurately measure the response of the scintillator to different nuclear species and parametrize the saturation of the scintillation light in order to assess the impact of this effect on the charge resolution of the instrument.
► Charge identification of relativistic cosmic nuclei. ► Saturation of scintillation light from ionization by heavy nuclei. ► Charge resolution with scintillators with high Z ionizing radiation.
We present measurements of the relative abundances of cosmic-ray nuclei in the energy range of 500-3980 GeV/nucleon from the second flight of the Cosmic Ray Energetics And Mass balloon-borne ...experiment. Particle energy was determined using a sampling tungsten/scintillating-fiber calorimeter, while particle charge was identified precisely with a dual-layer silicon charge detector installed for this flight. The resulting element ratios C/O, N/O, Ne/O, Mg/O, Si/O, and Fe/O at the top of atmosphere are 0.919 {+-} 0.123{sup stat} {+-} 0.030{sup syst}, 0.076 {+-} 0.019{sup stat} {+-} 0.013{sup syst}, 0.115 {+-} 0.031{sup stat} {+-} 0.004{sup syst}, 0.153 {+-} 0.039{sup stat} {+-} 0.005{sup syst}, 0.180 {+-} 0.045{sup stat} {+-} 0.006{sup syst}, and 0.139 {+-} 0.043{sup stat} {+-} 0.005{sup syst}, respectively, which agree with measurements at lower energies. The source abundance of N/O is found to be 0.054 {+-} 0.013{sup stat} {+-} 0.009{sup syst+0.010esc} {sub -0.017}. The cosmic-ray source abundances are compared to local Galactic (LG) abundances as a function of first ionization potential and as a function of condensation temperature. At high energies the trend that the cosmic-ray source abundances at large ionization potential or low condensation temperature are suppressed compared to their LG abundances continues. Therefore, the injection mechanism must be the same at TeV/nucleon energies as at the lower energies measured by HEAO-3, CRN, and TRACER. Furthermore, the cosmic-ray source abundances are compared to a mixture of 80% solar system abundances and 20% massive stellar outflow (MSO) as a function of atomic mass. The good agreement with TIGER measurements at lower energies confirms the existence of a substantial fraction of MSO material required in the {approx}TeV per nucleon region.
Single-photon avalanche diode (SPAD) arrays fabricated in a 180-nm CMOS technology with a high-voltage option have been exposed to calibrated neutron and X-ray sources to evaluate their radiation ...tolerance. The technology is being investigated in view of the design of low material budget detectors for charged particle tracking based on the coincidence of the signals coming from two or more overlapping layers of SPAD sensors. Each element in the array is a monolithic detector including the processing electronics together with the diode in the same substrate. Different sensor dimensions and structures have been implemented in the test chip to thoroughly explore the technology features. This paper will present and discuss the results from the characterization, in terms of dark count rate, of SPAD arrays irradiated with X-ray doses reaching 1 Mrad(SiO 2 ) and with neutron fluences up to <inline-formula> <tex-math notation="LaTeX">10^{11}~1 </tex-math></inline-formula>-MeV neutron equivalent cm<inline-formula> <tex-math notation="LaTeX">^{-2} </tex-math></inline-formula>.
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