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The development of a new generation of soft gamma-ray telescopes should allow polarimetric measurements of astrophysical sources to be associated with the results from spectroscopy and imaging due to the promising developments in polarimetry achieved over the last decade. In this perspective, the advanced surveyor of transient events and nuclear astrophysics mission which includes a narrow field telescope (NFT) that comprises a wide band Laue lens (60–600 keV) associated with a high performance thick and stacked CdZnTe focal plane operating as spectrometer, imager, and scattering polarimeter has been submitted for the ESA Voyage 2050 long term scientific planning preparation. In this context, and with the aim of optimizing the focal plane configuration of an instrument such as NFT, several studies are underway. In particular, with this work we study some performance issues such as polarimeters of segmented semiconductor detectors at room temperature, such as CdZnTe and cadmium telluride (CdTe), by means of a prototype based on two planar CdTe spectroimagers operating in coincidence. The two CdTe detectors are 2-mm-thick crystals with the anode segmented in $8\times8$ pixels with 2-mm pitch. This prototype configuration allows the Compton polarimetric performance of a spectroimager to be assessed by changing the distance between the two detection layers while operating in the 100–600-keV energy range, thereby allowing the analysis of Compton polarimetry 3-D dependence. The results obtained provide relevant input to the design of large sensitive volume multilayer and 3-D sensitive focal planes.

The ORION chipset, a full-custom multi-chip readout and processing electronics for the X-γ Imaging Spectrometer (XGIS) on-board the THESEUS space mission, is presented. The XGIS detection plane is arranged in a matrix of 10×10 detection modules, each one composed by 64 CsI(Tl) scintillation bars (4.5 mm×4.5 mm×30 mm) optically coupled at the top and bottom ends to two 8×8 monolithic Silicon Drift Detector matrices. The top SDD, exposed to the X-ray entrance window, performs the double function of low-energy X-ray detection as well as scintillator’s readout, together with the bottom SDD, providing a detection and spectroscopic energy range from 2 keV up to 20 MeV. The need to achieve a high energy resolution, as well as a high sensitive area on the detection plane, led to the development of a chipset organized to have a minimum-area analog readout chip placed in close proximity of the SDD (ORION-FE) and a mixed-signal back-end (ORION-BE) placed a few centimeters further on the back-end board for the additional signal processing and digitization. The multi-chip readout electronics integrates two dedicated analog processors for low-energy photons up to 30 keV (X-processor) and high-energy photons up to 5 MeV (γ-processor), allowing a spectroscopy-grade resolution in the 4 decades energy band (2 keV–20 MeV) of the XGIS, with a simulated power consumption of 1.55 mW/pixel. The ORION prototype was bonded to two ~25mm2 SDDs, and extensively characterized in terms of pulse shaping, pulse discrimination and stretching functionality, as well as linearity, dynamic range and spectroscopic resolution. An optimum Equivalent Noise Charge (ENC) at –20°C of 24.3 el. r.m.s. on the X-channel (212 eV FWHM on Si), and 39.6 el. r.m.s. on the γ-channel (3.7 keV FWHM on CsI(Tl)) has been recorded.

The measurement of the polarization of the high-energy photons from cosmic sources has now become a key observational parameter for understanding the emission mechanisms and the geometry of the active regions involved. Therefore, a mandatory requirement for new instrumentation in this energy regime will be to provide high sensitivity for polarimetric measurements. For several years, our group has studied the performance of CdTe/CZT pixel spectrometer used as a scattering polarimeter. To achieve the required sensitivity in the 100 keV-1 MeV range with the next generation of instrumentation, a challenging solution is offered by a broadband Laue lens telescope paired to a spectrometer with very good three dimensional spatial resolution (i.e. 3D spectroscopic imager). This configuration is proposed for the narrow field instrument of the ASTENA mission concept currently under study in the framework of the AHEAD project. Herein, we report on the results of a Monte Carlo study devoted to optimize the configuration and, in particular, the modulation factor (Q) of a 3D CZT detector for scattering polarimetry when placed in the focus of a Laue lens telescope with a passband of 50–600 keV. We also present results on the dependence of Q on the detector geometrical configuration (thickness and pixel/voxel scales), and from various event filters that can be implemented. Finally, in order to assess the reliability of the implemented numerical model, we compare Monte Carlo results with experimental data obtained using different CdTe spectroscopic imager prototypes.

No robust detection of prompt electromagnetic counterparts to fast radio bursts (FRBs) has yet been obtained, in spite of several multi-wavelength searches carried out so far. Specifically, X/gamma-ray counterparts are predicted by some models. We planned on searching for prompt gamma-ray counterparts in the Insight-Hard X-ray Modulation Telescope (Insight-HXMT) data, taking advantage of the unique combination of large effective area in the keV-MeV energy range and of sub-ms time resolution. We selected 39 FRBs that were promptly visible from the High-Energy (HE) instrument aboard Insight-HXMT. After calculating the expected arrival times at the location of the spacecraft, we searched for a significant excess in both individual and cumulative time profiles over a wide range of time resolutions, from several seconds down to sub-ms scales. Using the dispersion measures in excess of the Galactic terms, we estimated the upper limits on the redshifts. No convincing signal was found and for each FRB we constrained the gamma-ray isotropic-equivalent luminosity and the released energy as a function of emission timescale. For the nearest FRB source, the periodic repeater FRB180916.J0158+65, we find $L_{\gamma,iso}, Comment: 15 pages, 3 figures, 6 tables, accepted by A&A

The HERMES-TP/SP mission, based on a nanosatellite constellation, has very stringent constraints of sensitivity and compactness, and requires an innovative wide energy range instrument. The instrument technology is based on the "siswich" concept, in which custom-designed, low-noise Silicon Drift Detectors are used to simultaneously detect soft X-rays and to readout the optical light produced by the interaction of higher energy photons in GAGG:Ce scintillators. To preserve the inherent excellent spectroscopic performances of SDDs, advanced readout electronics is necessary. In this paper, the HERMES detector architecture concept will be described in detail, as well as the specifically developed front-end ASICs (LYRA-FE and LYRA-BE) and integration solutions. The experimental performance of the integrated system composed by scintillator+SDD+LYRA ASIC will be discussed, demonstrating that the requirements of a wide energy range sensitivity, from 2 keV up to 2 MeV, are met in a compact instrument., Comment: 12 pages, 10 figures. Proceedings of SPIE "Astronomical Telescopes and Instrumentation" 2020

A link between magnetars and fast radio burst (FRB) sources has finally been established. In this context, one of the open issues is whether/which sources of extra galactic FRBs exhibit X/gamma-ray outbursts and whether it is correlated with radio activity. We aim to constrain possible X/gamma-ray burst activity from one of the nearest extragalactic FRB sources currently known over a broad energy range, by looking for bursts over a range of timescales and energies that are compatible with being powerful flares from extragalactic magnetars. We followed up the as-yet nearest extragalactic FRB source at a mere 149 Mpc distance, the periodic repeater FRB180916.J0158+65, during the active phase on February 4-7, 2020, with the Insight-Hard X-ray Modulation Telescope (HXMT). Taking advantage of the combination of broad band, large effective area, and several independent detectors available, we searched for bursts over a set of timescales from 1 ms to 1.024 s with a sensitive algorithm, that had previously been characterised and optimised. Moreover, through simulations we studied the sensitivity of our technique in the released energy-duration phase space for a set of synthetic flares and assuming different energy spectra. We constrain the possible occurrence of flares in the 1-100 keV energy band to E, 10 pages, 3 figures, accepted by A&A

Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray; Virtual, Online; United States; 14 December 2020 through 18 December 2020; Code 166330.--Proceedings of SPIE - The International Society for Optical Engineering Volume 11444, 2020, Article number 114442K.--Full list of authors: Labanti, C.; Amati, L.; Frontera, F.; Mereghetti, S.; Gasent-Blesa, J. L.; Tenzer, C.; Orleanski, P.; Kuvvetli, I.; Campana, R.; Fuschino, F.; Terenzi, L.; Virgilli, E.; Morgante, G.; Orlandini, M.; Butler, R. C.; Stephen, J. B.; Auricchio, N.; De Rosa, A.; Da Ronco, V.; Evangelisti, F. Melchiorri, M.; Squerzanti, S.; Fiorini, M.; Bertuccio, G.; Mele, F.; Gandola, M.; Malcovati, P.; Grassi, M.; Bellutti, P.; Borghi, G.; Ficorella, F.; Picciotto, A.; Zanini, V.; Zorzi, N.; Demenev, E.; Rashevskaya, I.; Rachevski, A.; Zampa, G.; Vacchi, A.; Zampa, N.; Baldazzi, G.; La Rosa, G.; Sottile, G.; Volpe, A.; Winkler, M.; Reglero, V.; Connell, P. H.; Pinazo-Herrero, B.; Navarro-González, J.; Rodríguez-Martínez, P.; Castro-Tirado, A. J.; Santangelo, A.; Hedderman, P.; Lorenzi, P.; Sarra, P.; Pedersen, S. M.; Tcherniak, D.; Guidorzi, C.; Rosati, P.; Trois, A.; Piazzolla, R., THESEUS (Transient High Energy Sky and Early Universe Surveyor) is one of the three missions selected by ESA as fifth medium class mission (M5) candidates in its Cosmic Vision science program, currently under assessment in a phase A study with a planned launch date in 2032. THESEUS is designed to carry on-board two wide and deep sky monitoring instruments for X/gamma-ray transients detection: a wide-field soft X-ray monitor with imaging capability (Soft X-ray Imager, SXI, 0.3 - 5 keV), a hard X-ray, partially-imaging spectroscopic instrument (X and Gamma Imaging Spectrometer, XGIS, 2 keV - 10 MeV), and an optical/near-IR telescope with both imaging and spectroscopic capability (InfraRed Telescope, IRT, 0.7 - 1.8 µm). The spacecraft will be capable of performing fast repointing of the IRT to the error region provided by the monitors, thus allowing it to detect and localize the transient sources down to a few arcsec accuracy, for immediate identification and redshift determination. The prime goal of the XGIS will be to detect transient sources, with monitoring timescales down to milliseconds, both independently of, or following up, SXI detections, and identify the sources performing localisation at, The Phase A study of the THESEUS/XGIS instrument is supported by ASI-INAF Agreement n. 2018-29-HH.0, OHB Italia/ - INAF-OASBo Agreement n.2331/2020/01, by the European Space Agency ESA through the M5/NPMC Programme and by the AHEAD2020 project funded by UE through H2020-INFRAIA-2018-2020. By the Spanish Ministerio de Ciencia e Innovación, PID2019-109269RB-C41. By Polish National Science Center, Project 2019/35/B/ST9/03944 and Foundation for Polish Science, Project POIR.04.04.00-00-5C65/17-00.

The X and Gamma Imaging Spectrometer instrument on-board the THESEUS mission (selected by ESA in the framework of the Cosmic Vision M5 launch opportunity, currently in phase A) is based on a detection plane composed of several thousands of single active elements. Each element comprises a 4.5x4.5x30 mm 3 CsI(Tl) scintillator bar, optically coupled at both ends to Silicon Drift Detectors (SDDs). The SDDs acts both as photodetectors for the scintillation light and as direct X-ray sensors. In this paper the design of the XGIS detection plane is reviewed, outlining the strategic choices in terms of modularity and redundancy of the system. Results on detector-electronics prototypes are also described. Moreover, the design and development of the low-noise front-end electronics is presented, emphasizing the innovative architectural design based on custom-designed Application-Specific Integrated Circuits (ASICs)., Comment: Proceedings of the SPIE 2020, paper 11444-277

The development of wide band Laue lens imaging technology is challenging, but has important potential applications in hard X- and γ-ray space instrumentation for the coming decades. The Italian Space Agency has funded a project dedicated to the development of a reliable technology to assemble a wide band Laue lens for use in space. The ground support equipment (GSE) for this project was fundamental to its eventual success... The GSE was implemented in a hard X-ray beam line built at the University of Ferrara and had the main purpose of controlling the assembly of crystals onto the Laue lens petal and to verify its final performance. The GSE incorporates the management and control of all the movements of the beam line mechanical subsystems and of the precision positioner (based on a Hexapod tool) of crystals on the petal, as well as the acquisition, storing and analysis of data obtained from the focal plane detectors (an HPGe spectrometer and an X-ray flat panel imager). The GSE is based on two PC’s connected through a local network: one, placed inside the beam line, to which all the movement subsystems and the detector I/O interface and on which all the management and acquisition S/W runs, the other in the control room allows the remote control and implements the offline analysis S/W of the data obtained from the detectors. Herein we report on the GSE structure with its interface with the beam line mechanical system, with the fine crystal positioner and with the focal plane detector. Furthermore we describe the SW developed for the handling of the mechanical movement subsystems and for the analysis of the detector data with the procedure adopted for the correct orientation of the crystals before their bonding on the lens petal support.

We present the results obtained with the new Laue lens prototype built in the LARIX facility in the Physics Department of University of Ferrara. Following the results of the first prototype presented at the SPIE conference in Marseille, and also thanks to the methods adopted for improving the prototype (SPIE conference in San Diego, Ferrari et al. 2009) here we present the results of the new prototype with improved performances in terms of point spread function (PSF) and spectral response., 9 pages,8 figures. Paper presented at the SPIE conference in San Diego, August 2011, on "Optics for EUV, X-ray, and Gamma-Ray Astronomy". To be published in the Proceedings of SPIE, vol. 8147, 2011

GrailQuest (Gamma-ray Astronomy International Laboratory for Quantum Exploration of Space-Time) is an ambitious astrophysical mission concept that uses a fleet of small satellites whose main objective is to search for a dispersion law for light propagation in vacuo. Within Quantum Gravity theories, different models for space-time quantization predict relative discrepancies of the speed of photons w.r.t. the speed of light that depend on the ratio of the photon energy to the Planck energy. This ratio is as small as 10-23 for photons in the γ- ray band (100 keV). Therefore, to detect this effect, light must propagate over enormous distances and the experiment must have extraordinary sensitivity. Gamma-Ray Bursts, occurring at cosmological distances, could be used to detect this tiny signature of space-time granularity. This can be obtained by coherently combine a huge number of small instruments distributed in space to act as a single detector of unprecedented effective area. This is the first example of high-energy distributed astronomy: a new concept of modular observatory of huge overall collecting area consisting in a fleet of small satellites in low orbits, with sub-microsecond time resolution and wide energy band (keV-MeV). The enormous number of collected photons will allow to effectively search these energy dependent delays. Moreover, GrailQuest will allow to perform temporal triangulation of impulsive events with arc-second positional accuracies: an extraordinary sensitive X-ray/Gamma all-sky monitor crucial for hunting the elusive electromagnetic counterparts of Gravitational Waves, that will play a paramount role in the future of Multi-messenger Astronomy. A pathfinder of GrailQuest is already under development through the HERMES (High Energy Rapid Modular Ensemble of Satellites) project: a fleet of six 3U cube-sats to be launched by the end of 2022.