arXiv subjects

Francesco Ceraudo

Publications and source records attributed to Francesco Ceraudo.

7 recordsLinked to original sources

arXiv2026

Design and performance of the coded mask for the Lunar Electromagnetic Monitor in X-rays (LEM-X)

The Lunar Electromagnetic Monitor in X-rays (LEM-X) is a proposed wide-field X-ray observatory designed for deployment on the Moon's surface. Its primary scientific goal is to enhance multi-messenger astrophysics by detecting, localizing, and monitoring high-energy transient phenomena and variable X-ray sources across the sky. Building on the heritage of the eXTP and LOFT mission proposals, LEM-X employs pairs of coded-aperture cameras equipped with large-area linear Silicon Drift Detectors (SDDs), offering excellent spectral resolution ($\leq$350 eV at 6 keV) over the 2-50 keV energy range. Each camera provides a field of view of ~1 steradian at 25% effective area and achieves a Point-Source Location Accuracy (PSLA) of 1 arcminute, with an on-axis sensitivity better than 5 mCrab in 50 ks and 700 mCrab in 1 s. In this paper we describe the experiment and focus on the detailed design and optimization of the LEM-X coded mask, analyzing its scientific performance, imaging capabilities, and thermo-mechanical properties. We describe the mask code generation, decoding algorithms, and the trade-offs involved in achieving the required angular resolution, sensitivity, and structural integrity. Imaging simulations and mechanical analyses confirm the effectiveness of the proposed design, demonstrating its suitability for high-precision, wide-field X-ray imaging devoted to multi-messenger astrophysics and transient events detection.

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arXiv2025

Prediction of the SVOM MXT camera end of life spectral performance based on proton irradiation results

SVOM, the Space-based Variable astronomical Object Monitor, launched on June 22nd 2024, is a Chinese-French mission focused on exploring the brightest phenomena in the cosmos - Gamma-Ray Bursts. Among the four instruments on board is the Micro-channel X-ray Telescope (MXT). The MXT camera features a 256x256 pixel pnCCD detector to perform X-ray imaging and spectroscopy in the 0.2-10 keV energy range. Cruising in a low-Earth orbit (600 km) that crosses the South Atlantic Anomaly, the MXT focal plane is exposed to radiation, primarily protons, that will lead to performance degradation over time. The challenge for MXT, and possibly for future missions with similar mass and mechanical constraints, is to maintain spectral performance all along the mission duration. To assess the expected radiation-induced performance degradation, a spare flight model of MXT focal plane underwent an irradiation campaign with 50 MeV protons at the Arronax cyclotron facility in June 2022. Then, the proton irradiated spare model was characterized in detail at the X-ray Metrology beamline of the SOLEIL Synchrotron facility in June 2023, as well as with a laboratory X-ray fluorescence source. We find through the evaluation of key indicators of performance such as the charge transfer inefficiency (CTI) and the low energy threshold, that MXT will remain compliant to its requirements over the SVOM mission lifetime. We also report an unexpected effect of proton irradiation that is the inversion of the trend of CTI with energy, recovered with two different sources illuminating the detector, and never reported in literature so far.

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arXiv2024

The Wide Field Monitor (WFM) of the China-Europe eXTP (enhanced X-ray Timing and Polarimetry) mission

The eXTP mission is a major project of the Chinese Academy of Sciences (CAS), with a large involvement of Europe. Its scientific payload includes four instruments: SFA, PFA, LAD and WFM. They offer an unprecedented simultaneous wide-band Xray timing and polarimetry sensitivity. A large European consortium is contributing to the eXTP study, both for the science and the instrumentation. Europe is expected to provide two of the four instruments: LAD and WFM; the LAD is led by Italy and the WFM by Spain. The WFM for eXTP is based on the design originally proposed for the LOFT ESA M3 mission, that underwent a Phase A feasibility study. It will be a wide field of view X-ray monitor instrument working in the 2-50 keV energy range, achieved with large-area Silicon Drift Detectors (SDDs), similar to the ones used for the LAD but with better spatial resolution. The WFM will consist of 3 pairs of coded mask cameras with a total combined field of view (FoV) of 90x180 degrees at zero response and a source localisation accuracy of ~1 arc min. The main goal of the WFM is to provide triggers for the target of opportunity observations of the SFA, PFA and LAD, in order to perform the core science programme, dedicated to the study of matter under extreme conditions of density, gravity and magnetism. In addition, the unprecedented combination of large field of view and imaging capability, down to 2 keV, of the WFM will allow eXTP to make important discoveries of the variable and transient X-ray sky, and provide X-ray coverage of a broad range of astrophysical objects covered under 'observatory science', such as gamma-ray bursts, fast radio bursts, gravitational wave electromagnetic counterparts. In this paper we provide an overview of the WFM instrument, explaining its design, configuration, and anticipated performance.

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arXiv2024

STROBE-X High Energy Modular Array (HEMA)

The High Energy Modular Array (HEMA) is one of three instruments that compose the STROBE-X mission concept. The HEMA is a large-area, high-throughput non-imaging pointed instrument based on the Large Area Detector developed as part of the LOFT mission concept. It is designed for spectral timing measurements of a broad range of sources and provides a transformative increase in sensitivity to X-rays in the energy range of 2--30 keV compared to previous instruments, with an effective area of 3.4 m$^{2}$ at 8.5 keV and an energy resolution of better than 300 eV at 6 keV in its nominal field of regard.

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arXiv2018

The enhanced X-ray Timing and Polarimetry mission - eXTP

In this paper we present the enhanced X-ray Timing and Polarimetry mission - eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources. The paper provides a detailed description of: (1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload; (2) the elements and functions of the mission, from the spacecraft to the ground segment.

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arXiv2018

The Large Area Detector onboard the eXTP mission

The eXTP (enhanced X-ray Timing and Polarimetry) mission is a major project of the Chinese Academy of Sciences (CAS) and China National Space Administration (CNSA) currently performing an extended phase A study and proposed for a launch by 2025 in a low-earth orbit. The eXTP scientific payload envisages a suite of instruments (Spectroscopy Focusing Array, Polarimetry Focusing Array, Large Area Detector and Wide Field Monitor) offering unprecedented simultaneous wide-band X-ray spectral, timing and polarimetry sensitivity. A large European consortium is contributing to the eXTP study and it is expected to provide key hardware elements, including a Large Area Detector (LAD). The LAD instrument for eXTP is based on the design originally proposed for the LOFT mission within the ESA context. The eXTP/LAD envisages a deployed 3.4 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we provide an overview of the LAD instrument design, including new elements with respect to the earlier LOFT configuration.

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arXiv2016

Sensitivity Projections for Dark Matter Searches with the Fermi Large Area Telescope

The nature of dark matter is a longstanding enigma of physics; it may consist of particles beyond the Standard Model that are still elusive to experiments. Among indirect search techniques, which look for stable products from the annihilation or decay of dark matter particles, or from axions coupling to high-energy photons, observations of the $γ$-ray sky have come to prominence over the last few years, because of the excellent sensitivity of the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope mission. The LAT energy range from 20 MeV to above 300 GeV is particularly well suited for searching for products of the interactions of dark matter particles. In this report we describe methods used to search for evidence of dark matter with the LAT, and review the status of searches performed with up to six years of LAT data. We also discuss the factors that determine the sensitivities of these searches, including the magnitudes of the signals and the relevant backgrounds, considering both statistical and systematic uncertainties. We project the expected sensitivities of each search method for 10 and 15 years of LAT data taking. In particular, we find that the sensitivity of searches targeting dwarf galaxies, which provide the best limits currently, will improve faster than the square root of observing time. Current LAT limits for dwarf galaxies using six years of data reach the thermal relic level for masses up to 120 GeV for the $b\bar{b}$ annihilation channel for reasonable dark matter density profiles. With projected discoveries of additional dwarfs, these limits could extend to about 250 GeV. With as much as 15 years of LAT data these searches would be sensitive to dark matter annihilations at the thermal relic cross section for masses to greater than 400 GeV (200 GeV) in the $b\bar{b}$ ($τ^+ τ^-$) annihilation channels.

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