arXiv subjects

A. Picciotto

Publications and source records attributed to A. Picciotto.

17 recordsLinked to original sources

arXiv2026

CubeSats Reach the Millisecond X-Ray Domain: Crab Pulsar Timing with SpIRIT/HERMES

The High Energy Rapid Modular Ensemble of Satellites (HERMES) instrument is a compact X/$γ$-ray spectrometer operating on board the 6U (11 kg) SpIRIT CubeSat. The payload is particularly well suited for the observation of cosmic transients such as Gamma-Ray Bursts and bright pulsars thanks to its unique broadband sensitivity from a few keV to a few MeV and the temporal resolution down to half a microsecond. We report here the detection of the $\sim$33~ms Crab pulsar double-peaked pulse profile obtained by considering the canonical Crab ephemerides as provided by the Jodrell Bank catalog. We collected approximately 5.7$\cdot$10$^4$ photons from 730~s of observations, in the 3 keV -- 2 MeV energy band, during a single operation, and achieved a 5$σ$ pulse profile significance in the 3--11.5 keV energy band with binning at the ms scale. The results demonstrate that SpIRIT/HERMES can achieve millisecond timing accuracy at high energies and, thanks to its wide field of view and broad energy band, has the potential to contribute to GRB monitoring in the near future. Such capabilities were previously the domain of flagship observatories, underscoring the performance of the HERMES instrument with its compact form factor.

astro-ph.HE↗

arXiv2025

HERMES Pathfinder & SpIRIT: a progress report

HERMES Pathfinder is an in-orbit demonstration consisting of a constellation of six 3U cubesats hosting simple but innovative X-ray/gamma-ray detectors for the monitoring of cosmic high-energy transients. HERMES-PF, funded by ASI and by the EC Horizon 2020 grant, is scheduled for launch in Q1 2025. An identical X-ray/gamma-ray detector is hosted by the Australian 6U cubesat SpIRIT, launched on December 1st 2023. The main objective of HERMES-PF/SpIRIT is to demonstrate that high energy cosmic transients can be detected efficiently by miniatured hardware and localized using triangulation techniques. The HERMES-PF X-ray/gamma-ray detector is made by 60 GAGG:Ce scintillator crystals and 12 2x5 silicon drift detector (SDD) mosaics, used to detect both the cosmic X-rays directly and the optical photons produced by gamma-ray interactions with the scintillator crystals. This design provides a unique broad band spectral coverage from a few keV to a few MeV. Furthermore, the use of fast GAGG:Ce crystals and small SDD cells allows us to reach an exquisite time resolution better than a microsecond. We present a progress report on the missions focusing the discussion on the scientific innovation of the project and on the main lessons learned during the project development including: the importance and the challenges of using distributed architectures to achieve ambitious scientific objectives; the importance of developing critical technologies under science agreements for the realization of high-performing but low-cost payloads; best use of COTS technologies in scientific missions. We finally discuss the prospects of applying these concepts for the creation of an all-sky, all-time monitor to search for the high-energy counterparts of gravitational wave events that Advanced LIGO/Virgo/Kagra will find at the end of this decade and the Einstein Telescope during the 2030s.

astro-ph.IM↗

arXiv2024

The HERMES (High Energy Rapid Modular Ensemble of Satellites) Pathfinder mission

HERMES (High Energy Rapid Modular Ensemble of Satellites) Pathfinder is a space-borne mission based on a constellation of six nano-satellites flying in a low-Earth orbit (LEO). The 3U CubeSats, to be launched in early 2025, host miniaturized instruments with a hybrid Silicon Drift Detector/GAGG:Ce scintillator photodetector system, sensitive to X-rays and gamma-rays in a large energy band. HERMES will operate in conjunction with Australian Space Industry Responsive Intelligent Thermal (SpIRIT) 6U CubeSat, launched in December 2023. HERMES will probe the temporal emission of bright high-energy transients such as Gamma-Ray Bursts (GRBs), ensuring a fast transient localization in a field of view of several steradians exploiting the triangulation technique. HERMES intrinsically modular transient monitoring experiment represents a keystone capability to complement the next generation of gravitational wave experiments. In this paper we outline the scientific case, development and programmatic status of the mission

astro-ph.IM↗

arXiv2024

HERMES: Gamma Ray Burst and Gravitational Wave counterpart hunter

Gamma Ray Bursts (GRBs) bridge relativistic astrophysics and multi-messenger astronomy. Space-based gamma/X-ray wide field detectors have proven essential to detect and localize the highly variable GRB prompt emission, which is also a counterpart of gravitational wave events. We study the capabilities to detect long and short GRBs by the High Energy Rapid Modular Ensemble of Satellites (HERMES) Pathfinder (HP) and SpIRIT, namely a swarm of six 3U CubeSats to be launched in early 2025, and a 6U CubeSat launched on December 1st 2023. We also study the capabilities of two advanced configurations of swarms of >8 satellites with improved detector performances (HERMES Constellations). The HERMES detectors, sensitive down to ~2-3 keV, will be able to detect faint/soft GRBs which comprise X-ray flashes and high redshift bursts. By combining state-of-the-art long and short GRB population models with a description of the single module performance, we estimate that HP will detect ~195^{+22}_{-21} long GRBs (3.4^{+0.3}_{-0.8} at redshift z>6) and ~19^{+5}_{-3} short GRBs per year. The larger HERMES Constellations under study can detect between ~1300 and ~3000 long GRBs per year and between ~160 and ~400 short GRBs per year, depending on the chosen configuration, with a rate of long GRBs above z>6 between 30 and 75 per year. Finally, we explore the capabilities of HERMES to detect short GRBs as electromagnetic counterparts of binary neutron star (BNS) mergers detected as gravitational signals by current and future ground-based interferometers. Under the assumption that the GRB jets are structured, we estimate that HP can provide up to 1 (14) yr^{-1} joint detections during the fifth LIGO-Virgo-KAGRA observing run (Einstein Telescope single triangle 10 km arm configuration). These numbers become 4 (100) yr^{-1}, respectively, for the HERMES Constellation configuration.

astro-ph.HE↗

arXiv2022

Design, integration, and test of the scientific payloads on-board the HERMES constellation and the SpIRIT mission

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.

astro-ph.IM↗

arXiv2022

X-Ray Silicon Drift Detector-CMOS Front-End System with High Energy Resolution at Room Temperature

We present a spectroscopic system constituted by a Silicon Drift Detector (SDD) coupled to a CMOS charge sensitive preamplifier, named SIRIO, specifically designed to reach ultimate low noise levels. The SDD, with an active area of 13 mm , has been manufactured by optimizing the production processes in order to reduce the anode current, successfully reaching current densities between 17 pA/cm and 25 pA/cm at 20 for drift fields ranging from 100 V/cm to 500 V/cm. The preamplifier shows minimum intrinsic noise levels of 1.27 and 1.0 electrons r.m.s. at 20 and 30 , respectively. At room temperature ( ) the 5.9 keV and the pulser lines have 136 eV and 64 eV FWHM, respectively, corresponding to an equivalent noise charge of 7.4 electrons r.m.s.; the noise threshold is at 165 eV. The energy resolution, as measured on the pulser line, ranges from 82 eV FWHM (9.4 electrons r.m.s.) at 30C down to 29 eV FWHM (3.3 electrons r.m.s.) at 30C .

physics.ins-det↗

arXiv2021

An innovative architecture for a wide band transient monitor on board the HERMES nano-satellite constellation

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.

astro-ph.IM↗

arXiv2018

HERMES: An ultra-wide band X and gamma-ray transient monitor on board a nano-satellite constellation

The High Energy Modular Ensemble of Satellites (HERMES) project is aimed to realize a modular X/gamma-ray monitor for transient events, to be placed on-board of a CubeSat bus. This expandable platform will achieve a significant impact on Gamma Ray Burst (GRB) science and on the detection of Gravitational Wave (GW) electromagnetic counterparts: the recent LIGO/VIRGO discoveries demonstrated that the high-energy transient sky is still a field of extreme interest. The very complex temporal variability of GRBs (up to the millisecond scale) combined with the spatial and temporal coincidence between GWs and their electromagnetic counterparts suggest that upcoming instruments require sub-ms time resolution combined with a transient localization accuracy lower than a degree. The current phase of the ongoing HERMES project is focused on the realization of a technological pathfinder with a small network (3 units) of nano-satellites to be launched in mid 2020. We will show the potential and prospects for short and medium-term development of the project, demonstrating the disrupting possibilities for scientific investigations provided by the innovative concept of a new "modular astronomy" with nano-satellites (e.g. low developing costs, very short realization time). Finally, we will illustrate the characteristics of the HERMES Technological Pathfinder project, demonstrating how the scientific goals discussed are actually already reachable with the first nano-satellites of this constellation. The detector architecture will be described in detail, showing that the new generation of scintillators (e.g. GAGG:Ce) coupled with very performing Silicon Drift Detectors (SDD) and low noise Front-End-Electronics (FEE) are able to extend down to few keV the sensitivity band of the detector. The technical solutions for FEE, Back-End-Electronics (BEE) and Data Handling will be also described.

astro-ph.IM↗

arXiv2018

Characterization of a novel pixelated Silicon Drift Detector (PixDD) for high-throughput X-ray astrophysics

Multi-pixel fast silicon detectors represent the enabling technology for the next generation of space-borne experiments devoted to high-resolution spectral-timing studies of low-flux compact cosmic sources. Several imaging detectors based on frame-integration have been developed as focal plane devices for X-ray space-borne missions but, when coupled to large-area concentrator X-ray optics, these detectors are affected by strong pile-up and dead-time effects, thus limiting the time and energy resolution as well as the overall system sensitivity. The current technological gap in the capability to realize pixelated silicon detectors for soft X-rays with fast, photon-by-photon response and nearly Fano-limited energy resolution therefore translates into the unavailability of sparse read-out sensors suitable for high throughput X-ray astronomy applications. In the framework of the ReDSoX Italian collaboration, we developed a new, sparse read-out, pixelated silicon drift detector which operates in the energy range 0.5-15 keV with nearly Fano-limited energy resolution ($\leq$150 eV FWHM @ 6 keV) at room temperature or with moderate cooling ($\sim$0 °C to +20 °C). In this paper, we present the design and the laboratory characterization of the first 16-pixel (4$\times$4) drift detector prototype (PixDD), read-out by individual ultra low-noise charge sensitive preamplifiers (SIRIO) and we discuss the future PixDD prototype developments.

astro-ph.IM↗

arXiv2018

The Wide Field Monitor 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 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.

astro-ph.IM↗

arXiv2018

Response to the authors of 'On the (un)effectiveness of Proton Boron Capture in Proton Therapy'

This manuscript provides a response to a recent report by Mazzone et al. available online on arXiv that, in turn, tentatively aims at demonstrating the inefficacy of proton boron capture in hadrotherapy. We clarify that Mazzone et al. do not add any scientific or technical insights to the points extensively discussed in the original manuscript by Cirrone et al., and/or in the series of iterations had with the Referee, which ultimately lead to the publication of our original and pioneering experimental work. Here we summarize some of the key points of the long scientific debate we had during the review process of paper by Cirrone et al., which are very similar to the considerations presented by Mazzone et al.. In conclusion, no quantitative explanation of our robust experimental achievements presented in Cirrone et al. is provided in Mazzone et al.

physics.med-ph↗

arXiv2018

The X-Gamma Imaging Spectrometer (XGIS) onboard THESEUS

A compact and modular X and gamma-ray imaging spectrometer (XGIS) has been designed as one of the instruments foreseen on-board the THESEUS mission proposed in response to the ESA M5 call. The experiment envisages the use of CsI scintillator bars read out at both ends by single-cell 25 mm 2 Silicon Drift Detectors. Events absorbed in the Silicon layer (lower energy X rays) and events absorbed in the scintillator crystal (higher energy X rays and Gamma-rays) are discriminated using the on-board electronics. A coded mask provides imaging capabilities at low energies, thus allowing a compact and sensitive instrument in a wide energy band (~2 keV up to ~20 MeV). The instrument design, expected performance and the characterization performed on a series of laboratory prototypes are discussed.

astro-ph.IM↗

arXiv2017

A compact and modular X and gamma-ray detector with a CsI scintillator and double-readout Silicon Drift Detectors

A future compact and modular X and gamma-ray spectrometer (XGS) has been designed and a series of prototypes have been developed and tested. The experiment envisages the use of CsI scintillator bars read out at both ends by single-cell 25 mm2 Silicon Drift Detectors. Digital algorithms are used to discriminate between events absorbed in the Silicon layer (lower energy X rays) and events absorbed in the scintillator crystal (higher energy X rays and gamma-rays). The prototype characterization is shown and the modular design for future experiments with possible astrophysical applications (e.g. for the THESEUS mission proposed for the ESA M5 call) are discussed.

astro-ph.IM↗

arXiv2017

Nuclear fusion enhances cancer cell killing efficacy in a protontherapy model

Protontherapy is hadrontherapy fastest-growing modality and a pillar in the battle against cancer. Hadrontherapy superiority lies in its inverted depth-dose profile, hence tumour-confined irradiation. Protons, however, lack distinct radiobiological advantages over photons or electrons. Higher LET (Linear Energy Transfer) $^{12}$C ions can overcome cancer radioresistance: DNA lesion complexity increases with LET, resulting in efficient cell killing, i.e. higher Relative Biological Effectiveness (RBE). However, economic and radiobiological issues hamper $^{12}$C-ion clinical amenability. Thus, enhancing proton RBE is desirable. To this end, we exploited the p + $^{11}$B $\rightarrow$3$α$ reaction to generate high-LET alpha particles with a clinical proton beam. To maximize the reaction rate, we used sodium borocaptate (BSH) with natural boron content. Boron-Neutron Capture Therapy (BNCT) uses $^{10}$B-enriched BSH for neutron irradiation-triggered alpha-particles. We recorded significantly increased cellular lethality and chromosome aberration complexity. A strategy combining protontherapy ballistic precision with the higher RBE promised by BNCT and $^{12}$C-ion therapy is thus demonstrated.

physics.med-ph↗

arXiv2016

Prompt gamma ray diagnostics and enhanced hadron-therapy using neutron-free nuclear reactions

We propose a series of simulations about the potential use of Boron isotopes to trigger neutron-free (aneutronic) nuclear reactions in cancer cells through the interaction with an incoming energetic proton beam, thus resulting in the emission of characteristic prompt gamma radiation (429 keV, 718 keV and 1435 keV). Furthermore assuming that the Boron isotopes are absorbed in cancer cells, the three alpha-particles produced in each p-11B aneutronic nuclear fusion reactions can potentially result in the enhancement of the biological dose absorbed in the tumor region since these multi-MeV alpha-particles are stopped inside the single cancer cell, thus allowing to spare the surrounding tissues. Although a similar approach based on the use of 11B nuclei has been proposed in [1], our work demonstrate, using Monte Carlo simulations, the crucial importance of the use of 10B nuclei (in a solution containing also 11B) for the generation of prompt gamma-rays, which can be applied to medical imaging. In fact, we demonstrate that the use of 10B nuclei can enhance the intensity of the 718 keV gamma-ray peak more than 30 times compared to the solution containing only 11B nuclei. A detailed explanation of the origin of the different prompt gamma-rays, as well as of their application as real-time diagnostics during a potential cancer treatment, is here discussed.

physics.med-ph↗

arXiv2016

Avalanche boron fusion by laser picosecond block ignition with magnetic trapping for clean and economic reactor

After the very long consideration of the ideal energy source by fusion of the protons of light hydrogen with the boron isotope 11 (boron fusion HB11) the very first two independent measurements of very high reaction gains by lasers basically opens a fundamental breakthrough. The non-thermal plasma block ignition with extremely high power laser pulses above petawatt of picosecond duration in combination with up to ten kilotesla magnetic fields for trapping has to be combined to use the measured high gains as proof of an avalanche reaction for an environmentally clean, low cost and lasting energy source as potential option against global warming. The unique HB11 avalanche reaction is are now based on elastic collisions of helium nuclei (alpha particles) limited only to a reactor for controlled fusion energy during a very short time within a very small volume.

physics.plasm-ph↗

arXiv2014

Characterization of the VEGA ASIC coupled to large area position-sensitive Silicon Drift Detectors

Low-noise, position-sensitive Silicon Drift Detectors (SDDs) are particularly useful for experiments in which a good energy resolution combined with a large sensitive area is required, as in the case of X-ray astronomy space missions and medical applications. This paper presents the experimental characterization of VEGA, a custom Application Specific Integrated Circuit (ASIC) used as the front-end electronics for XDXL-2, a large-area (30.5 cm^2) SDD prototype. The ASICs were integrated on a specifically developed PCB hosting also the detector. Results on the ASIC noise performances, both stand-alone and bonded to the large area SDD, are presented and discussed.

astro-ph.IM↗