Search

HERMES (High Energy Rapid Modular Ensemble of Satellites) is a space-borne mission based on a constellation of nano-satellites flying in a low-Earth orbit (LEO). The six 3U CubeSat buses host new miniaturized instruments hosting a hybrid Silicon Drift Detector/GAGG:Ce scintillator photodetector system sensitive to X-rays and gamma-rays. HERMES will probe the temporal emission of bright high-energy transients such as Gamma-Ray Bursts (GRBs), ensuring a fast transient localization (with arcmin-level accuracy) in a field of view of several steradians exploiting the triangulation technique. With a foreseen launch date in late 2023, HERMES transient monitoring represents a keystone capability to complement the next generation of gravitational wave experiments. Moreover, the HERMES constellation will operate in conjunction with the Space Industry Responsive Intelligent Thermal (SpIRIT) 6U CubeSat, to be launched in early 2023. SpIRIT is an Australian-Italian mission for high-energy astrophysics that will carry in a Sun-synchronous orbit (SSO) an actively cooled HERMES detector system payload. On behalf of the HERMES collaboration, in this paper we will illustrate the HERMES and SpIRIT payload design, integration and tests, highlighting the technical solutions adopted to allow a wide-energy-band and sensitive X-ray and gamma-ray detector to be accommodated in a 1U Cubesat volume., arXiv admin note: substantial text overlap with arXiv:2101.03032

Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray (2022), Montreal, Jul 17-22, 2022.--Proceedings of SPIE - The International Society for Optical Engineering vol. 12181 Article number 1218126.-- Full list of authors: Amati, Lorenzo; Labanti, Claudio; Mereghetti, Sandro; Frontera, Filippo; Campana, Riccardo; Auricchio, Natalia; Baldazzi, Giuseppe; Bellutti, Pierluigi; Bertuccio, Giuseppe; Branchesi, Marica; Butler, Reginald C.; Caballero-Garcia, Maria D.; Camisasca, Anna E.; Castro-Tirado, Alberto J.; Cavazzini, Leo; Ciolfi, Riccardo; De Rosa, Adriano; Evangelisti, Federico; Farinelli, Ruben; Ferro, Lisa; Ficorella, Francesco; Fiorini, Mauro; Fuschino, Fabio; Gasent-Blesa, Jose L.; Ghirlanda, Giancarlo; Grassi, Marco; Guidorzi, Cristiano; Hedderman, Paul; Kuvvetli, Irfan; La Rosa, Giovanni; Lorenzi, Paolo; Malcovati, Piero; Marchesini, Ezequiel; Marisaldi, Martino; Melchiorri, Michele; Mele, Filippo; Mikhalska, Malgorzata; Orlandini, Mauro; Orleanski, Piotr; Pedersen, Soren M.; Pizzolla, Raffaele; Rachevski, Alexandre; Rashevskaya, Irina; Rosati, Piero; Reglero, Victor; Ronchini, Samuele; Santangelo, Andrea; Salvaterra, Ruben; Sarra, Paolo; Sortino, Francesca; Sottile, Giuseppe; Stratta, Giulia; Squerzanti, Stefano; Stephen, John B.; Tenzer, Chris; Terenzi, Luca; Trois, Alessio; Vacchi, Andrea; Virgilli, Enrico; Volpe, Angela; Winkler, Marek; Zampa, Gianluigi; Zampa, Nicola; Zdziarski, Andrzej, We describe the science case, design and expected performances of the X/Gamma-ray Imaging Spectrometer (XGIS), a GRB and transients monitor developed and studied for the THESEUS mission project, capable of covering an exceptionally wide energy band (2 keV – 10 MeV), with imaging capabilities and location accuracy, With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709

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.

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 selection of the best Light Emitting Diode (LED) technologies for space application is a challenging issue, requiring a trade-off of several aspects starting from the intrinsic properties of the die. Starting from a previous evaluation of the LEDs for optocouplers by the team, the effects of proton-induced radiation damage on several types of more modern LEDs fabricated by different manufacturers and technologies are discussed in this paper. The test results have been validated by the supervising entity, according to their needs. The adopted methodology contemplated more than 150 devices, belonging to several technological options under comparison, irradiated unbiased. Electrical and electro-optical parameters were measured and analyzed by using dedicated advanced facilities and finally, the differences in output optical power emission and spectral emission and the degradation rate of the device families under comparison have been studied. Statistical analysis was performed, using a one-sided tolerance method for hardness assurance, on the LEDs’ optical power emission and spectral emission data in which the effects of different bias currents and particle fluences were investigated. Non-Ionizing Energy Loss model of the light sources was also applied in order to qualify the results. Finally, the comparative analysis clearly showed that one specific device family, i.e. R type, was the most efficient even after proton damage, with an outstanding performance if compared to all the others, and second best in relative terms, with N type was the one with the most reduced degradation dynamics. The comparative analysis allowed the device selection for the subsequent project phase, taking the obtained results into account.

The INFN CSN5 “TIMESPOT” project aims at the development and implementation of a complete integrated tracking system featuring very high precision both in space and in time for every pixel. Within this framework we are developing 3D pixel sensors optimized for timing, while retaining their usual advantages of low depletion voltage, extreme radiation hardness, and active edges. The pixel geometries are being optimized in terms of size, electrode configuration and shape. In particular, trenched electrodes are used instead of columns, so as to achieve more uniform electric and weighting field profiles. No established technology exists for 3D sensors with trenched electrodes, so we have developed and tested the necessary process steps. In this paper we report the main design and fabrication issues and selected results from TCAD simulations.

3D type of pixel sensors is a promising option for the innermost pixel layer at the High-Luminosity LHC. However, the required very high hit-rate capabilities, finer pixel granularity, extreme radiation hardness and reduced material budget call for a downscale of the pixel size as compared to existing 3D sensors, involving smaller pitch (e.g. 50 × 50 or 25 × 100 μ m 2 ), shorter inter-electrode spacing ( ∼ 30 μ m ), narrower electrodes ( ∼ 6 μ m diameter), and reduced active thickness ( ∼ 100 – 150 μ m ). Within a joint R&D effort with INFN, FBK has produced a new generation of 3D pixel sensors with these challenging features. In this talk preliminary results from the electrical and functional characterisation of the first prototypes are reported, included their behaviour after large radiation fluence, close to the ones expected in the High Luminosity LHC environment. Prospects for the next prototypes are also presented.

Fondazione Bruno Kessler (FBK, Trento, Italy) has recently delivered its first 50 μ m thick production of Ultra-Fast Silicon Detectors (UFSD), based on the Low-Gain Avalanche Diode design. These sensors use high resistivity Si-on-Si substrates, and have a variety of gain layer doping profiles and designs based on Boron, Gallium , Carbonated Boron and Carbonated Gallium to obtain a controlled multiplication mechanism. Such variety of gain layers will allow identifying the most radiation hard technology to be employed in the production of UFSD, to extend their radiation resistance beyond the current limit of ϕ ∼ 1015 n e q /cm 2 . In this paper, we present the characterisation, the timing performance, and the results on radiation damage tolerance of this new FBK production.

A new multielement X-ray fluorescence detector is presented, specifically designed to probe the chemical speciation of trace 3d elements down to the p.p.m. range., X-ray absorption fine-structure (XAFS) spectroscopy can assess the chemical speciation of the elements providing their coordination and oxidation state, information generally hidden to other techniques. In the case of trace elements, achieving a good quality XAFS signal poses several challenges, as it requires high photon flux, counting statistics and detector linearity. Here, a new multi-element X-ray fluorescence detector is presented, specifically designed to probe the chemical speciation of trace 3d elements down to the p.p.m. range. The potentialities of the detector are presented through a case study: the speciation of ultra-diluted elements (Fe, Mn and Cr) in geological rocks from a calcareous formation related to the dispersal processes from Ontong (Java) volcanism (mid-Cretaceous). Trace-elements speciation is crucial in evaluating the impact of geogenic and anthropogenic harmful metals on the environment, and to evaluate the risks to human health and ecosystems. These results show that the new detector is suitable for collecting spectra of 3d elements in trace amounts in a calcareous matrix. The data quality is high enough that quantitative data analysis could be performed to determine their chemical speciation.

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 substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane sizes were developed using the microfabrication process. The performance of these devices was evaluated to predict their thermal and mechanical behaviors by using both experimental and theoretical approaches. Finally, a statistical method was employed to cross-correlate the thermal predictive model and the mechanical failure analysis, aiming at microheater design optimization for gas-sensing applications.

The system design and characterization of a compact single-SDD (Silicon Drift Detector) module for X-ray and electron spectroscopy in a windowless, room-temperature, vacuum environment is presented. The measured SDD leakage current density at +22° C is only 31 pA/cm 2 . The module, characterized at room temperature with 55 Fe X-rays, demonstrated state-of-the-art performance: an energy resolution of 136 eV FWHM at 5.9 keV has been obtained with 1 µs filter peaking time, and its count-rate capability has been tested up to 4.2 Mcps with a 32 ns filter peaking time while maintaining an energy resolution of less than 200 eV FWHM at 5.9 keV.

International audience; In view of the LHC upgrade phase towards the High Luminosity LHC (HL-LHC), the ATLAS experiment plans to upgrade the Inner Detector with an all-silicon system. The n-on-p silicon technology is a promising candidate to achieve a large area instrumented with pixel sensors, since it is radiation hard and cost effective. This paper reports on the last n-on-p pixel productions made by a collaboration between the FBK-CMM and the LPNHE in Paris, with some focus on the latest designs of thin sensors bump-bonded to the RD53A prototype chip, featuring a 100 × 25 and 50 × 50 µm^2 pixel cells. An overview of 2019–2020 test-beam results for the produced devices will be given, with a special perspective to the sensor design for the ATLAS ITk pixel construction. Preliminary results for new 50 µm thick n-on-p pixel sensors, still produced by LPNHE at FBK-CMM will be also presented.

This paper presents the principles of operation of Resistive AC-Coupled Silicon Detectors (RSDs) and measurements of the temporal and spatial resolutions using a combined analysis of laser and beam test data. RSDs are a new type of n-in-p silicon sensor based on the Low-Gain Avalanche Diode (LGAD) technology, where the $n^+$ implant has been designed to be resistive, and the read-out is obtained via AC-coupling. The truly innovative feature of RSD is that the signal generated by an impinging particle is shared isotropically among multiple read-out pads without the need for floating electrodes or an external magnetic field. Careful tuning of the coupling oxide thickness and the $n^+$ doping profile is at the basis of the successful functioning of this device. Several RSD matrices with different pad width-pitch geometries have been extensively tested with a laser setup in the Laboratory for Innovative Silicon Sensors in Torino, while a smaller set of devices have been tested at the Fermilab Test Beam Facility with a 120 GeV/c proton beam. The measured spatial resolution ranges between $2.5\; \mu m$ for 70-100 pad-pitch geometry and $17\; \mu m$ with 200-500 matrices, a factor of 10 better than what is achievable in binary read-out ($bin\; size/ \sqrt{12}$). Beam test data show a temporal resolution of $\sim 40\; ps$ for 200-$\mu m$ pitch devices, in line with the best performances of LGAD sensors at the same gain., Comment: 34 pages, 33 figures

This paper presents the front-end section of the X-/γ-ray detection instrument of the HERMES mission, whose goal is to observe and localize γ-ray bursts, through a constellation of more than one hundred nano-satellites. Considering the severe volume and power consumption constraints of the nano-satellites, in the HERMES X-/γ-ray detection instrument, silicon drift detectors are read out through a mixed-signal ASIC chipset, called LYRA, based on a peculiar architecture. In particular, a small front-end ASIC (LYRA-FE), placed close to each silicon drift detector, is connected, through a current-mode link, to a multi-channel back-end ASIC (LYRA-BE). The LYRA ASIC chipset, implemented in a 0.35µm CMOS technology, achieves less than $22{\text{e}}_{{\text{rms}}}^ - $ of equivalent noise charge, with a power consumption lower than 600µW/channel from a 3.3V power supply. Thanks to the current-mode link between the LYRA-FE and the LYRA-BE ASICs, no significant crosstalk among channels can be observed, in spite of the length of the interconnection wires as large as 12cm.

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

In the past few years, there has been growing interest in the development of silicon sensors able to simultaneously measure accurately the time of passage and the position of impinging charged particles. In this contribution, a review of the progresses in the design of UFSD (Ultra-Fast Silicon Detectors) sensors, manufactured at the FBK (Fondazione Bruno Kessler) Foundry, aiming at tracking charged particles in 4 dimensions, is presented. The state-of-the-art UFSD sensors, with excellent timing capability, are planned to be used in both ATLAS and CMS experiments detector upgrade, in order to reduce the background due to the presence of overlapping events in the same bunch crossing. The latest results on sensors characterization including time resolution, radiation resistance and uniformity of the response are here summarized, pointing out the interplay between the design of the gain layer and the UFSD performances. The research is now focusing on the maximization of the sensor fill factor, to be able to reduce the pixel size, exploring the implementation of shallow trenches for the pixel isolation and the development of resistive AC-coupled UFSD sensors. In conclusion, a brief review on research paths tailored for detection of low energy X-rays or for low material budget applications is given.

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.

In this paper we present the numerical simulation of silicon detectors with internal gain as the main tool for 4-dimensional (4D) particle trackers design and optimization. The Low-Gain Avalanche Diode (LGAD) technology and its present limitations are reviewed with the aim of introducing the Resistive AC-Coupled Silicon Detectors (RSD) paradigm as a case study of our investigation. Authors here present Spice-like and 2D/3D Technological Computer-Aided Design (TCAD) simulations to characterize sensors in terms of both their electrostatic behavior, capacitive (dynamic) coupling and radiation-hardness performances, showing the methodological approach used in order to extract the set of layout rules allowing the release of RSD1, the incoming production run at Fondazione Bruno Kessler (FBK) of next-generation silicon detectors for 4D tracking with intrinsic 100% fill-factor.

HERMES (High Energy Rapid Modular Ensemble of Satellites) Technological and Scientific pathfinder is a space borne mission based on a LEO constellation of nano-satellites. The 3U CubeSat buses host new miniaturized detectors to probe the temporal emission of bright high-energy transients such as Gamma-Ray Bursts (GRBs). Fast transient localization, in a field of view of several steradians and with arcmin-level accuracy, is gained by comparing time delays among the same event detection epochs occurred on at least 3 nano-satellites. With a launch date in 2022, HERMES transient monitoring represents a keystone capability to complement the next generation of gravitational wave experiments. In this paper we will illustrate the HERMES payload design, highlighting the technical solutions adopted to allow a wide-energy-band and sensitive X-ray and gamma-ray detector to be accommodated in a CubeSat 1U volume together with its complete control electronics and data handling system., Comment: 12 pages, 13 figures. Proceedings of SPIE "Astronomical Telescopes and Instrumentation" 2020

We present a novel design of fine segmented low gain avalanche diodes (LGAD) based on trench-isolation technique. The proposed design reduces the width of the no-gain inter-pad region down to less than $10~\mu \text{m}$ , from the 20- $80~\mu \text{m}$ of the current LGAD technology, enabling the production of sensors with small pixel pitch and high fill-factor. Prototypes of this new technology were produced in the FBK laboratories. Their electrical characterization in terms of I-V, gain measurement and response to a focused laser, indicates that the trenches provide electrical isolation among pixels without any increase in the dark current level and without affecting the gain of the sensor. In addition, I-V measurements of p-i-n diodes with the same trench-isolation structure demonstrate that such termination scheme can withstand more than 500 Volts without reaching breakdown. This is well above the typical operating bias voltage of LGADs, thus confirming that trench-isolation is a promising solution for finely pixelated LGAD sensors.

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

Journal of Instrumentation 16(07), P07057 (2021). doi:10.1088/1748-0221/16/07/P07057, We present ARDESIA-16, an X-ray spectrometer based on a monolithic 16-element Silicon Drift Detector (SDD) matrix specifically designed for synchrotron applications. In this work, we describe the main design guidelines which we followed concerning the signal throughput, the energy efficiency, the energy resolution and the overall solid angle covered by detector elements. The characterization of the spectrometer has been made both with radioactive sources in a laboratory environment and with synchrotron light at the P06 beamline (DESY, Hamburg). Experimental results showed an average energy resolution at the optimum peaking time equal to 125 eV (FWHM at Mn Kα), a maximum achieved Output Count Rate (OCR) equal to 17 Mcps, an increase of the energy efficiency above 10 keV thanks to the 1 mm-thick SDD and an overall solid angle equal to 0.4 sr. Finally, we report the first X-ray fluorescence microscopy (XFM) images acquired with an ARDESIA spectrometer., Published by Inst. of Physics, London

The development of new generations of synchrotron light sources aims at increasing their beam in term of flux and brightness. To cope with extremely high-brilliance sources, fluorescence detectors must go beyond their nowadays maximum throughput while keeping almost unchanged the performance. This paper has been carried out within the framework of the ARDESIA (ARray of DEtectors for Spectroscopy and Imaging Applications) project, whose primary aim is to develop a spectrometer with count-rate capability for applications like Xray absorption spectroscopy (XAS) and X-ray fluorescence (XRF). ARDESIA is a Silicon Drift Detector (SDD)-based, multichannel X-ray spectrometer, optimized for synchrotron applications requiring a high-count rate (>1Mcps per channel) and a high-resolution (e.g. below 150 eV of Full Width Half Maximum at peaking times faster than 200 ns) for X-ray fluorescence detection. This paper describes improvements made for the ARDESIA spectrometer on detection efficiency and overall counting rate capability to better match requirements of synchrotron experiments. These improvements have been obtained by increasing the number of channels, from 4 to 16, and the SDD thickness from 450 μm to 800 μm and 1000 μm. The new detection module and the new complete spectrometer are described in detail. The first 16-channel detection module prototype has been developed with an average resolution of 128 eV at the Mn-Kα at long peaking times (i.e. > 2 μs) and 183.5 eV at short peaking time (i.e. 32 ns). Then, the qualification of the 4channel 1mm-thick detector at the PETRA (Positron-Elektron-Tandem-Ring-Anlage) P65 beamline in DESY (Deutsches Elektronen-Synchrotron) is reported.

Resistive AC-Coupled Silicon Detectors (RSD) represent a new frontier in 4D particle tracking through silicon detectors with intrinsic gain. In this work we present the experimental characterization done on the first run of sensors, RSD1, produced at Fondazione Bruno Kessler (FBK) in Trento, Italy.

We designed, produced, and tested RSD (Resistive AC-Coupled Silicon Detectors) devices, an evolution of the standard LGAD (Low-Gain Avalanche Diode) technology where a resistive ${n}$ -type implant and a coupling dielectric layer have been implemented. The first feature works as a resistive sheet, freezing the multiplied charges, while the second one acts as a capacitive coupling for readout pads. We succeeded in the challenging goal of obtaining very fine pitch (50, 100, and $200~\mu \text{m}$ ) while maintaining the signal waveforms suitable for high timing and 4D-tracking performances, as in the standard LGAD-based devices.

Recent advances in segmented low-gain avalanche detectors (LGADs) make them promising for the position-sensitive detection of low-energy X-ray photons thanks to their internal gain. LGAD microstrip sensors fabricated by Fondazione Bruno Kessler have been investigated using X-rays with both charge-integrating and single-photon-counting readout chips developed at the Paul Scherrer Institut. In this work it is shown that the charge multiplication occurring in the sensor allows the detection of X-rays with improved signal-to-noise ratio in comparison with standard silicon sensors. The application in the tender X-ray energy range is demonstrated by the detection of the sulfur K α and K β lines (2.3 and 2.46 keV) in an energy-dispersive fluorescence spectrometer at the Swiss Light Source. Although further improvements in the segmentation and in the quantum efficiency at low energy are still necessary, this work paves the way for the development of single-photon-counting detectors in the soft X-ray energy range.

We present the design and characterization of a detection unit for simultaneous and combined XRF and XRD analysis of powder mineralogical samples. Arrays of 32 silicon microstrips are coupled to two 16-channel CUBE preamplifiers targeting an energy resolution below 200 eV at 6 keV with moderate cooling. The compact detection module will be mounted on a goniometer inside a suitcase-sized analyzer to be operated in mining sites.

An X-ray spectroscopic system composed of a novel Pixel Drift Detector (PixDD) and SIRIO charge sensitive preamplifier is presented. The PixDD prototype is a 4 × 4 matrix of 500 μ m × 500 μ m pixels, manufactured on a 450 μ m thick, 9 k Ω cm silicon wafer. The anode current of a pixel is 0.7 pA at +20 °C and decreases down to tens of fA for temperatures lower than 0 °C. The low current together with the low pixel capacitance (30 fF independent of the pixel area), make PixDD an extremely low noise detector. When PixDD is coupled to the ultra-low noise SIRIO CMOS preamplifier, intrinsic spectral line widths (pulser) of 51 eV FWHM (5.9 electrons r.m.s.) and 130 eV FWHM at 5.9 keV ( 55Fe) are obtained at +20 °C. If the system is slightly cooled down to 0 °C, the FWHMs decrease down to 38.5 eV (4.5 electrons r.m.s) and 127 eV for the pulser and the 5.9 keV line respectively. The high energy resolution of PixDD joined with its intrinsic position sensitivity and the possibility to sustain high photon fluxes open new perspectives in X-ray spectroscopic imaging in the 0.1 keV–20 keV energy range.

ARDESIA is an SDD-based, X-ray spectrometer, optimized for synchrotron measurements that require high count rates (>1 Mcounts/s/channel) and good energy resolution (

Low Gain Avalanche Diodes (LGADs) are now considered a viable solution for 4D-tracking thanks to their excellent time resolution and good resistance to high radiation fluence. However, the currently available LGAD technology is well suited only for applications that require coarse space precision, pixels with pitch in the range 500 µm–1 mm, due to the presence of a no-gain region between adjacent pixels of about 50 μ m , in which the gain is completely suppressed. In this paper, we will discuss the segmentation issues in the LGAD technology and we will present two new segmentation strategies aimed at producing LGADs with high spatial resolution and high fill factor. The first presented design is the so-called Trench-Isolated LGAD (TI-LGAD). Here, the pixel isolation is provided by trenches, physically etched in the silicon and then filled with silicon oxide. The second design is the Resistive AC-coupled Silicon Detector (RSD), an evolution of LGADs, where the segmentation is obtained by means of AC-coupled electrodes. Prototypes of both designs have been produced at FBK and characterized at the Laboratories for Innovative Silicon Sensors (INFN and University of Turin) by means of a laser setup to estimate the space resolution and the fill factor. The functional characterization shows that both the technologies yield fully working small pixel LGADs (down to 50 µm), providing the first examples of sensors able to concurrently measure space and time with excellent precision.

The recent development in the design of Ultra Fast Silicon Detector (UFSD), aimed at combining radiation resistance up to fluences of 1015 neq/cm2 and fine read-out segmentation, makes these sensors suitable for high energy physics applications. UFSD is an evolution of standard silicon sensor, optimized to achieve excellent timing resolution (~30 ps), thanks to an internal low gain (~20). UFSD sensors are n in p Low Gain Avalanche Diode (LGAD) with an active thickness of ~5 μm. The internal gain in LGAD is obtained by implanting an appropriate density of acceptors (of the order of ~ 1016/cm3) close to the p-n junction, that, when depleted, locally generates an electric field high enough to activate the avalanche multiplication; this layer of acceptors is called gain layer. The two challenges in the development of UFSD for high energy physics detectors are the radiation hardness and the fine segmentation of large area sensors. Irradiation fluences of the order of 1015 neq/cm2 have a dramatic effect on the UFSD: neutrons and charged hadrons reduce the active acceptor density forming the gain layer; this mechanism, called initial acceptor removal, causes the complete disappearance of the internal gain above fluence of 1015 neq/ cm2. For the segmentation of UFSDs, the crucial point is the electrical insulation of pads and the extension of the inactive area between pads. In this paper we present the latest results on radiation resistance of LGADs with different gain layer designs, irradiated up to 3⋅1015 neq/ cm2. Three different segmentation technologies, developed by Fondazione Bruno Kessler in Trento, will also be discussed in detail in the second part of the paper.

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 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 Wide Field Monitor (WFM). The WFM instrument for eXTP is based on the design originally proposed for the LOFT mission within the ESA context. The eXTP/WFM envisages a wide field X-ray monitor system in the 2-50 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors. 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 localization accuracy of ~1 arcmin. In this paper we provide an overview of the WFM instrument design, including new elements with respect to the earlier LOFT configuration, and anticipated performance., Comment: 16 pages, 15 figures, to appear in proceedings of SPIE, Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray

The properties of 60-{\mu}m thick Ultra-Fast Silicon Detectors (UFSD) detectors manufactured by Fondazione Bruno Kessler (FBK), Trento (Italy) were tested before and after irradiation with minimum ionizing particles (MIPs) from a 90Sr \b{eta}-source . This FBK production, called UFSD2, has UFSDs with gain layer made of Boron, Boron low-diffusion, Gallium, Carbonated Boron and Carbonated. The irradiation with neutrons took place at the TRIGA reactor in Ljubljana, while the proton irradiation took place at CERN SPS. The sensors were exposed to a neutron fluence of 4*10e14, 8*1014, 1.5*10e15, 3*10e15, 6*10e15 neq/cm2 and to a proton fluence of 9.6*10e14 p/cm2, equivalent to a fluence of 6*10e14 neq/cm2. The internal gain and the timing resolution were measured as a function of bias voltage at -20C. The timing resolution was extracted from the time difference with a second calibrated UFSD in coincidence, using the constant fraction method for both., Comment: arXiv admin note: text overlap with arXiv:1803.02690

In this paper, we report on the radiation resistance of 50-micron thick LGAD detectors manufactured at the Fondazione Bruno Kessler employing several different doping combinations of the gain layer. LGAD detectors with gain layer doping of Boron, Boron low-diffusion, Gallium, Carbonated Boron and Carbonated Gallium have been designed and successfully produced. These sensors have been exposed to neutron fluences up to $\phi_n \sim 3 \cdot 10^{16}\; n/cm^2$ and to proton fluences up to $\phi_p \sim 9\cdot10^{15}\; p/cm^2$ to test their radiation resistance. The experimental results show that Gallium-doped LGADs are more heavily affected by initial acceptor removal than Boron-doped LGAD, while the presence of Carbon reduces initial acceptor removal both for Gallium and Boron doping. Boron low-diffusion shows a higher radiation resistance than that of standard Boron implant, indicating a dependence of the initial acceptor removal mechanism upon the implant width. This study also demonstrates that proton irradiation is at least twice more effective in producing initial acceptor removal, making proton irradiation far more damaging than neutron irradiation., Comment: 22 pages, 17 figures

This work reports the results of the measurements using ARDESIA X-ray spectrometer in synchrotron measurements. ARDESIA is an SDD-based, multichannel X-ray spectrometer, optimized for synchrotron applications that require a high-count rate (> 1Mcps/channel) and high-resolution (

This paper presents a new European optocoupler type. This component has been developed by Optoi in the framework of ESA’s European Component Initiative (Phase 2). The most recent results are reported, specifically related to a full ESCC Evaluation Testing.