Characterization of the NNVT capillary plate collimators

In this paper, we report the results of the characterization campaign of two prototypes of Micro-Channel Plates (MCPs), designed as the X-ray collimators for the Large Area Detector on board the eXTP mission. The devices were developed ad-hoc by North Night Vision Technology Co., Ltd. (Nanjing, China). Measurements involved the study of the angular response (rocking curve) of each device to X-rays of different energies. The study evidenced how the angular response of a collimator changes with the energy of the incoming photons, with the onset of side lobes at high energy, which enlarge the effective field of view of the device, causing a potential contamination of the on-axis signal. Nevertheless, the magnitude of this effect is proven to be acceptable in most situations of astrophysical interest. On the lower hand of the energy spectrum, photons may also modify the angular response due to grazing reflection on the inner walls of the collimator, a phenomenon strongly dependent on the degree of roughness of the surfaces involved. The whole campaign took place at the INAF/IAPS laboratories in Rome

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 $\gamma$-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 $b\bar{b}$ ($\tau^+ \tau^-$) annihilation channels.Comment: Updated with a few additional and corrected references; otherwise, text is identical to previous version. Submitted on behalf of the Fermi-LAT collaboration. Accepted for publication in Physics Reports, 59 pages, 34 figures; corresponding author: Eric Charles ([email protected]

PixDD: a multi-pixel silicon drift detector for high-throughput spectral-timing studies

The Pixelated silicon Drift Detector (PixDD) is a two-dimensional multi-pixel X-ray sensor based on the technology of Silicon Drift Detectors, designed to solve the dead time and pile-up issues of photon-integrating imaging detectors. Read out by a two-dimensional self-triggering Application-Specific Integrated Circuit named RIGEL, to which the sensor is bump-bonded, it operates in the 0:5 — 15 keV energy range and is designed to achieve single-photon sensitivity and good spectroscopic capabilities even at room temperature or with mild cooling (< 150 eV resolution at 6 keV at 0 °C). The paper reports on the design and performance tests of the 128-pixel prototype of the fully integrated system

The large area detector onboard the eXTP mission

The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 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 will provide an overview of the LAD instrument design, its current status of development and anticipated performance

Caractérisation et optimisation des performances du plan focal du télescope X de la mission d’astronomie spatiale SVOM

SVOM is a Chinese-French astronomy mission due to launch at the end of 2021 for the study of Gamma-Ray Bursts (GRBs). SVOM will be composed of a network of ground telescopes along with a satellite. On board, the Micro-channel X-ray Telescope (MXT) will study the afterglow emission of GRBs in the 0.2-10 keV range and provide source localization within a 2 arcmin precision. At the focal plane of lobster-eye optics, MXT will mount a back-illuminated fully-depleted frame-store Charge Coupled Device based on silicon pn-junctions (pnCCD), heritage of XMM-Newton and eROSITA. In this work, the first laboratory tests on the MXT detector are presented. Special attention is dedicated to energy calibration, in terms of algorithms and setups for fast and reliable characterization of the detector, both on ground and in orbit. The evolution of the performance is of critical concern because of the harsh radiation environment of the low Earth orbit to which the detector will be exposed. This is the object of extensive Monte Carlo simulations, leading to predictions of the end-of-life performances as well as the planning of a proton irradiation campaign at a particle accelerator for the experimental validation of the predictions.SVOM est une mission Franco-Chinoise prévue pour fin 2021, pour l'étude des sursauts gamma (GRBs). SVOM sera composée par un réseau de télescopes au sol, ainsi que d'un satellite. À bord de celui-ci, le Télescope X à Micro-canaux (MXT) étudiera l’émission rémanente des GRBs dans la bande 0.2-10 keV et localisera les sources avec une précision de 2 arcmin. Au plan focal d’optiques à œil de langouste, MXT montera un Charge Coupled Device en silicium complétement dépleté et basé sur jonctions pn (pnCCD), hérité de XMM-Newton et eROSITA. Dans ce travail, les premiers essais de laboratoire sur le détecteur de MXT sont présentés. Une attention particulière est portée à l'étalonnage spectral par des méthodes instrumentales et d'analyse permettant une caractérisation rapide et fiable du détecteur, au sol et en vol. L’évolution des performances est critique en raison de l'environnement radiatif sévère de l’orbite terrestre basse auquel le détecteur sera exposé. Ceci fait l’objet de simulations Monte Carlo approfondies, amenant aux prédictions des performances à la fin de la mission, ainsi que à la planification d’une campagne d’essais d’irradiation de protons dans un accélérateur de particules pour une validation expérimentale des prédictions

Characterization and performance optimization of the focal plane of the Micro-channel X-ray Telescope on-board the space astronomy mission SVOM

SVOM est une mission Franco-Chinoise prévue pour fin 2021, pour l'étude des sursauts gamma (GRBs). SVOM sera composée par un réseau de télescopes au sol, ainsi que d'un satellite. À bord de celui-ci, le Télescope X à Micro-canaux (MXT) étudiera l’émission rémanente des GRBs dans la bande 0.2-10 keV et localisera les sources avec une précision de 2 arcmin. Au plan focal d’optiques à œil de langouste, MXT montera un Charge Coupled Device en silicium complétement dépleté et basé sur jonctions pn (pnCCD), hérité de XMM-Newton et eROSITA. Dans ce travail, les premiers essais de laboratoire sur le détecteur de MXT sont présentés. Une attention particulière est portée à l'étalonnage spectral par des méthodes instrumentales et d'analyse permettant une caractérisation rapide et fiable du détecteur, au sol et en vol. L’évolution des performances est critique en raison de l'environnement radiatif sévère de l’orbite terrestre basse auquel le détecteur sera exposé. Ceci fait l’objet de simulations Monte Carlo approfondies, amenant aux prédictions des performances à la fin de la mission, ainsi que à la planification d’une campagne d’essais d’irradiation de protons dans un accélérateur de particules pour une validation expérimentale des prédictions.SVOM is a Chinese-French astronomy mission due to launch at the end of 2021 for the study of Gamma-Ray Bursts (GRBs). SVOM will be composed of a network of ground telescopes along with a satellite. On board, the Micro-channel X-ray Telescope (MXT) will study the afterglow emission of GRBs in the 0.2-10 keV range and provide source localization within a 2 arcmin precision. At the focal plane of lobster-eye optics, MXT will mount a back-illuminated fully-depleted frame-store Charge Coupled Device based on silicon pn-junctions (pnCCD), heritage of XMM-Newton and eROSITA. In this work, the first laboratory tests on the MXT detector are presented. Special attention is dedicated to energy calibration, in terms of algorithms and setups for fast and reliable characterization of the detector, both on ground and in orbit. The evolution of the performance is of critical concern because of the harsh radiation environment of the low Earth orbit to which the detector will be exposed. This is the object of extensive Monte Carlo simulations, leading to predictions of the end-of-life performances as well as the planning of a proton irradiation campaign at a particle accelerator for the experimental validation of the predictions

Reading an ancient vicus with non-invasive techniques: integrated terrestrial, aerial and geophysical surveys at Aequum Tuticum (Ariano Irpino-Av)

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Traumatic subarachnoid hemorrhage related to ophthalmic artery avulsion: a case report

We present a case of ophthalmic artery (OA) traumatic avulsion, leading to a post-traumatic subarachnoid hemorrhage (SAH) with ventricular blood invasion and hydrocephalus, mimicking an internal carotid aneurysm rupture. This is the third case of such an event reported in literature and the first without orbital fractures and optic nerve avulsion. Conservative treatment was sufficient for the avulsion, but surgery was needed for the coexisting eye luxation. Traumatic OA avulsion is a rare but possible event and should be suspected in case of basal cisterns SAH, evidence of orbital trauma and CT angiogram or angiographic absence of opacification of the OA

Reading an ancient vicus with non-invasive techniques: integrated terrestrial, aerial and geophysical surveys at Aequum Tuticum (Ariano Irpino-Av)

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