Due to be launched in late 2021, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2–8 keV band, complemented with ...imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode.
In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis—particularly as far as the response to unpolarized radiation and the stability in time are concerned.
Due to be launched in late 2021, the Imaging X-Ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2-8 keV band, complemented with ...imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode. In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis -- particularly as far as the response to unpolarized radiation and the stability in time are concerned.
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.
The CALorimetric Electron Telescope (CALET) space experiment, developed by Japan in collaboration with Italy and the United States, is a high-energy astroparticle physics mission installed on the ...International Space Station (ISS). The primary goals of the CALET mission include investigating on the possible presence of nearby sources of high-energy electrons, studying the details of galactic particle propagation and searching for dark matter signatures. During a two-year mission, extendable to five years, CALET can measure the flux of cosmic-ray electrons (including positrons) to 20 TeV, gamma-rays to 10 TeV and nuclei with Z = 1 to 40 up to 1,000 TeV. The instrument consists of two layers of segmented plastic scintillators for cosmic-ray charge identification (CHD), a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 27 radiation length thick lead-tungstate calorimeter (TASC). CALET 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 instrument was launched on August 19, 2015 to the ISS with the H-II Transfer Vehicle 5 (HTV-5) and installed on the Japanese Experiment Module-Exposed Facility (JEM-EF) on August 25. Since the start of operations in mid-October, 2015, a continuous observation has been going on mainly by triggering high energy (>10 GeV) showers without any major interruption. The number of triggered events above 10 GeV is nearly 20 million per month. By using the data obtained during the first two years, we give a summary of CALET observations: (1) Electron + Positron energy spectrum, (2) Proton and Nuclei spectrum, (3) Gamma-ray observation, with results of the performance study on orbit. We also present the results of observations of the electromagnetic counterparts to LIGO-VIRGO gravitational wave events and high-energy counterparts to GRB events measured with the CALET Gamma-ray Burst Monitor (CGBM).
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.
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.
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.
This paper presents the results from the crosstalk and dark count rate (DCR) characterization of a 24 × 72 single photon avalanche diode (SPAD) array, fabricated in a 150 nm CMOS technology. The chip ...under test consists of a dual layer detection system developed in view of applications to charged particle tracking. A three step procedure, used for the crosstalk characterization, is presented. The crosstalk probability, taking place in 5 × 5 sub arrays built around noisy pixels, has been computed. Eventually, random telegraph signal (RTS) fluctuations in DCR, at different bias conditions, are briefly discussed.
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.
CALET is a space mission of the Japanese Aerospace Agency (JAXA) in collaboration with the Italian Space Agency (ASI) and NASA. The CALET instrument (CALorimetric Electron Telescope) is planned for a ...long exposure on the JEM-EF, an external platform of the Japanese Experiment Module KIBO, aboard the International Space Station (ISS). The main science objectives include high precision measurements of the inclusive electron (+positron) spectrum below 1 TeV and the exploration of the energy region above 1 TeV, where the shape of the high end of the spectrum might reveal the presence of nearby sources of acceleration. With an excellent energy resolution and low background contamination CALET will search for possible spectral signatures of dark matter with both electrons and gamma rays. It will also measure the high energy spectra and relative abundance of cosmic nuclei from proton to iron and detect trans-iron elements up to Z ~ 40. With a large exposure and high energy resolution, CALET will be able to verify and complement the observations of CREAM, PAMELA and AMS-02 on a possible deviation from a pure power-law of proton and He spectra in the region of a few hundred GeV and to extend the study to the multi-TeV region. CALET will also contribute to clarify the present experimental picture on the energy dependence of the boron/carbon ratio, below and above 1 TeV/n, thereby providing valuable information on cosmic-ray propagation in the galaxy. Gamma-ray transients will be studied with a dedicated Gamma-ray Burst Monitor (GBM).
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