The Cryogenic AntiCoincidence detector for ATHENA X-IFU: a scientific assessment of the observational capabilities in the hard X-ray band

ATHENA is a large X-ray observatory, planned to be launched by ESA in 2028 towards an L2 orbit. One of the two instruments of the payload is the X-IFU: a cryogenic spectrometer based on a large array of TES microcalorimeters, able to perform integral field spectrography in the 0.2-12 keV band (2.5 eV FWHM at 6 keV). The X-IFU sensitivity is highly degraded by the particle background expected in the L2 orbit, which is induced by primary protons of both galactic and solar origin, and mostly by secondary electrons. To reduce the particle background level and enable the mission science goals, the instrument incorporates a Cryogenic AntiCoincidence detector (CryoAC). It is a 4 pixel TES based detector, placed <1 mm below the main array. In this paper we report a scientific assessment of the CryoAC observational capabilities in the hard X-ray band (E>10 keV). The aim of the study has been to understand if the present detector design can be improved in order to enlarge the X-IFU scientific capability on an energy band wider than the TES array. This is beyond the CryoAC baseline, being this instrument aimed to operate as anticoincidence particle detector and not conceived to perform X-ray observations.Comment: Accepted for publication on Experimental Astronom

I dati archeologici nella società dell’informazione

[Italiano]: Lo studio della relazione tra i dati digitali e la metodologia archeologica costituisce uno dei principali campi di interesse dell’Archeologia Digitale, una disciplina che si è affermata recentemente, in parallelo alla trasformazione digitale della società. L’introduzione di strumenti e metodi digitali nel campo della ricerca storica e archeologica ha cambiato l’approccio degli studiosi alla ricostruzione del mondo antico. Il volume si propone di indagare la composizione della nuova cassetta degli attrezzi dell’archeologo che ha affiancato alla tradizionale cazzuola sofisticate attrezzature che producono dati digitali di alta qualità. La crescita esponenziale dei documenti digitali generati dalla ricerca (testi, immagini, audio e video) richiede la messa a punto di procedure e strategie innovative per la conservazione e, soprattutto, per la condivisione degli archivi. Le tecnologie semantiche forniscono un importante contributo in tale direzione, consentendo di standardizzare informazioni testuali, geografiche e geometriche, rendendole, così, accessibili e riutilizzabili in rete. La scienza reclama, oggi, una maggiore collaborazione e interazione tra i ricercatori; la prospettiva di saperi, dati e metodi, disponibili liberamente in rete, diviene una realtà concreta che supera ogni barriera disciplinare. Il libro delinea gli scenari inaugurati dai principi dell’Open Science, introducendo il lettore alle più recenti sfide che coinvolgono il settore delle scienze archeologiche./[English]: The study of the relationship between digital data and archaeological methodology is one of the main fields of interest of Digital Archaeology, a discipline that has recently emerged in parallel with the digital transformation of society. The introduction of digital tools and methods into the field of historical and archaeological research has changed scholars’ approach to reconstructing the ancient cultures. This volume aims to investigate the composition of the archaeologist's new toolbox, which has complemented the traditional trowel with sophisticated equipment producing high-quality digital data. The exponential growth of research-generated digital documents (text, images, audio, and video) requires the development of innovative procedures and strategies for preservation and, above all, for sharing archives. Semantic technologies make an important contribution in this direction, allowing textual, geographic, and geometric information to be standardized, thus making it accessible and reusable on the Web. Science claims, today, greater collaboration and interaction among researchers; the prospect of knowledge, data, and methods, freely available on the Web, becomes a concrete reality that crosses all disciplinary barriers. The book outlines the scenarios inaugurated by the principles of Open Science, introducing the reader to the latest challenges involving the field of archaeological sciences

Time resolved multi-photon effects in the fluorescence spectra of two-level systems at rest and in motion

We study the time-resolved fluorescence spectrum in two-level systems interacting with an incident coherent field, both in the weak and intermediate coupling regimes. For a single two-level system in the intermediate coupling case, as time flows, the spectrum develops distinct features, that are not captured by a semi-classical treatment of the incident field. Specifically, for a field on resonance with the atomic transition energy, the usual Mollow spectrum is replaced by a four peak structure, and for a frequency that is half of the atomic transition energy, the time-dependent spectrum develops a second harmonic peak with a superimposed Mollow triplet. In the long-time limit, our description recovers results previously found in the literature. After analyzing why a different behavior is observed in the quantum and classical dynamics, the reason for the occurrence of a second harmonic signal in a two-level system is explained via a symmetry analysis of the total (electron and photon) system, and in terms of a three level system operating in limiting regimes. We find an increased second harmonic signal in an array of two-level systems, suggesting a superradiance-like enhancement for multiple two-level systems in cavity setups. Finally, initial explorative results are presented for two-level model atoms entering and exiting a cavity, which hint at an interesting interplay between cavity-photon screening and atomic dynamics effects.Comment: 19 pages, 11 figures. To be published in Phys. Rev.

Compressed sensing in fluorescence microscopy.

Compressed sensing (CS) is a signal processing approach that solves ill-posed inverse problems, from under-sampled data with respect to the Nyquist criterium. CS exploits sparsity constraints based on the knowledge of prior information, relative to the structure of the object in the spatial or other domains. It is commonly used in image and video compression as well as in scientific and medical applications, including computed tomography and magnetic resonance imaging. In the field of fluorescence microscopy, it has been demonstrated to be valuable for fast and high-resolution imaging, from single-molecule localization, super-resolution to light-sheet microscopy. Furthermore, CS has found remarkable applications in the field of mesoscopic imaging, facilitating the study of small animals' organs and entire organisms. This review article illustrates the working principles of CS, its implementations in optical imaging and discusses several relevant uses of CS in the field of fluorescence imaging from super-resolution microscopy to mesoscopy