Localisation of gamma-ray bursts from the combined SpIRIT+HERMES-TP/SP nano-satellite constellation

Multi-messenger observations of the transient sky to detect cosmic explosions and counterparts of gravitational wave mergers critically rely on orbiting wide-FoV telescopes to cover the wide range of wavelengths where atmospheric absorption and emission limit the use of ground facilities. Thanks to continuing technological improvements, miniaturised space instruments operating as distributed-aperture constellations are offering new capabilities for the study of high energy transients to complement ageing existing satellites. In this paper we characterise the performance of the upcoming joint SpIRIT + HERMES-TP/SP nano-satellite constellation for the localisation of high-energy transients through triangulation of signal arrival times. SpIRIT is an Australian technology and science demonstrator satellite designed to operate in a low-Earth Sun-synchronous Polar orbit that will augment the science operations for the equatorial HERMES-TP/SP. In this work we simulate the improvement to the localisation capabilities of the HERMES-TP/SP when SpIRIT is included in an orbital plane nearly perpendicular (inclination = 97.6$^\circ$) to the HERMES orbits. For the fraction of GRBs detected by three of the HERMES satellites plus SpIRIT, the combined constellation is capable of localising 60% of long GRBs to within ~ 30 deg$^2$ on the sky, and 60% of short GRBs within ~ 1850 deg$^2$. Based purely on statistical GRB localisation capabilities (i.e., excluding systematic uncertainties and sky coverage), these figures for long GRBs are comparable to those reported by the Fermi GBM. Further improvements by a factor of 2 (or 4) can be achieved by launching an additional 4 (or 6) SpIRIT-like satellites into a Polar orbit, which would both increase the fraction of sky covered by multiple satellite elements, and enable $\geq$ 60% of long GRBs to be localised within a radius of ~ 1.5$^\circ$ on the sky.Comment: 17 pages, 10 figures, 1 table. Accepted for publication in PAS

Evolution of Arsenic nanometric distributions in Silicon under advanced ion implantation and annealing processes

The study presented in this thesis is focused on the investigation of Arsenic ultra-shallow distributions in Si for applications as source-drain extension dopant in CMOS technology. Using the Ultra-low energy SIMS measurements the evolution of arsenic shallow distribution was investigated with reference to the metastable electrical activation and the successive deactivation under moderate thermal treatment (550-700°C). Three different approaches to form As USJ were investigated to understand their physical mechanisms to verify their possible application in next generation microelectronics devices. First two activation approaches were based on low energy beamline ion implanted material. The first one is the low temperature (550°C) solid-phase epitaxial re-growth and the second activation approach is a sub-melt laser annealing at different temperatures. A range of deactivation studies was performed using these two classes of material with more attention given to the laser annealed ones. Plasma ion immersion implantation together with the LA was considered as the third approach of arsenic ultra-shallow junction formation. Samples created by AsH3+ plasma were investigated with respect to arsenic distribution, silicon oxide thickness and arsenic local order using SIMS, INAA, and EXAFS analysis

Research by Fondazione Bruno Kessler on Strategies to Improve the Yield in Plasma Focused Ion Beam Circuit Editing

This contribution explores the potential of PFIB for the post-production circuit editing of custom ASICs. The reworking of integrated circuits with ion beam is an effective tool for testing design modifications rapidly, and in small-volume productions, it proves to be a valuable substitute for the microfabrication of chips with a revised layout, thus reducing the cost and lead time. In the case study in this work, the PFIB intervention resulted in the recovery of ~90% of defective channels in a multichannel ASIC design by disconnecting some parts of the internal circuit. This contribution describes several implemented optimization strategies and their statistical effectiveness

Development of nano-topography during SIMS characterization of Ge1-xSnx alloy

none5Ge1-xSnx is a semiconductor alloy, compatible with silicon technology, with a bandgap tunable with Sn concentration (3%<x<7% can change the Ge bandgap from indirect to direct) [1], high electron and hole mobility [2,3]. For all those applications, it is mandatory to define analytical approaches able to provide accurate measurements of Sn content. SIMS can be a valuable choice but quantification and matrix issues due to the high Sn content need to be addressed. Therefore, we developed a SIMS protocol using Sn ion implants on Ge as reference samples. Ion implantation was carried out at liquid nitrogen temperature, in order to avoid the well-known phenomenon of Ge nanostructuration under heavy ion implantation at room temperature [4,5]. Implant fluences varied between 1x10^14 at/cm2 and 5x10^15 at/cm2 and implant energy was set at 45keV. SIMS characterization was performed in different configurations, i.e. using O2+ as primary beam and collecting positive secondary ions, Cs+ and negative secondary ions, Cs+ collecting MCs+ ions; the final results were compared with quantitative measurements obtained by RBS, revealing a good accuracy for the MCs+ protocol. However, it was observed that the applied sputtering conditions (Cs+ 1 keV, 55° incidence vs. normal) induced an early formation of surface topography resulting in a variation of sputtering yield. AFM images will be reported showing the peculiar topography developed on Ge and corrections to improve depth calibration accuracy will be discussed. The obtained protocol was then used to quantify also SIMS profiles of room temperature Sn implants, i.e. nanostructured Ge samples, with good accuracy. [1] S. Gupta et al., IEDM 2011. [2] G. He and H.A. Atwater, Phys. Rev. Lett., 79, (2007), 1937. [3] J.D. Sau and M.L. Cohen, Phys. Rev. B, 75, (2007), 045208. [4] I.H. Wilson, J. Appl. Phys. 53(3), (1982), 1698. [5] N.G. Rudawski and K.C. Jones, J. Mater. Res. 28(13), 1633, 2013M. Secchi; E. Demenev; D. Giubertoni; E. Iacob; M. BersaniM. Secchi; E. Demenev; D. Giubertoni; E. Iacob; M. Bersan

Development of nano-topography during SIMS characterization of Ge1-xSnx alloy

Ge1-xSnx is a semiconductor alloy, compatible with silicon technology, with a bandgap tunable with Sn concentration (3%<x<7% can change the Ge bandgap from indirect to direct) [1], high electron and hole mobility [2,3]. For all those applications, it is mandatory to define analytical approaches able to provide accurate measurements of Sn content. SIMS can be a valuable choice but quantification and matrix issues due to the high Sn content need to be addressed. Therefore, we developed a SIMS protocol using Sn ion implants on Ge as reference samples. Ion implantation was carried out at liquid nitrogen temperature, in order to avoid the well-known phenomenon of Ge nanostructuration under heavy ion implantation at room temperature [4,5]. Implant fluences varied between 1x1014 at/cm2 and 5x1015 at/cm2 and implant energy was set at 45keV. SIMS characterization was performed in different configurations, i.e. using O2+ as primary beam and collecting positive secondary ions, Cs+ and negative secondary ions, Cs+ collecting MCs+ ions; the final results were compared with quantitative measurements obtained by RBS, revealing a good accuracy for the MCs+ protocol. However, it was observed that the applied sputtering conditions (Cs+ 1 keV, 55° incidence vs. normal) induced an early formation of surface topography resulting in a variation of sputtering yield. AFM images will be reported showing the peculiar topography developed on Ge and corrections to improve depth calibration accuracy will be discussed. The obtained protocol was then used to quantify also SIMS profiles of room temperature Sn implants, i.e. nanostructured Ge samples, with good accuracy. [1] S. Gupta et al., IEDM 2011. [2] G. He and H.A. Atwater, Phys. Rev. Lett., 79, (2007), 1937. [3] J.D. Sau and M.L. Cohen, Phys. Rev. B, 75, (2007), 045208. [4] I.H. Wilson, J. Appl. Phys. 53(3), (1982), 1698. [5] N.G. Rudawski and K.C. Jones, J. Mater. Res. 28(13), 1633, 201

A 500 × 500 Pixel Image Sensor with Arbitrary Number of RoIs per Frame and Image Filtering for Center of Mass Estimation

This paper reports on a 500 x 500 pixel CMOS image sensor allowing multiple Regions of Interest (RoI) per frame with programmable number and size, aimed at minimizing the amount of data to be delivered off-chip and at reducing its power consumption. The proposed sensor architecture offers large flexibility to face different use case scenarios and it is suitable to any pixel array. The sensor embeds image background subtraction capability and integrates a computing layer which pre-filters the pixels to estimate the Center of Mass (CoM) of the RoIs up to a maximum size of 128 x 128 pixels. The 8 μm pixel sensor is manufactured in a 110 nm 1P4M CMOS technology and occupies 25 mm2. The chip, operating in standard imaging mode, consumes 4.9 mW at 30 fps

Synthesis of Light-Emitting Polymers via Heck coupling reactions

Conjugated polymers represent a very promising class of organic materials for photonics and electronics, which exhibits a unique combination of optical and electrical properties typical of semiconductors with processing advantages and mechanical features of polymers. Light-emitting devices (LED) were first fabricated from small organic molecule, having the main disadvantage that they can re-crystallize during device operation, leading to poor device stability. The use of conjugated polymers, potentially more stable, in such devices was first realized in the early 1990. The most efficient polymeric systems are actually based on poly(p-phenylenevinylene) (PPV) films, which emit basically green 1ight. However, there is still a big challenge in obtaining highly efficient blue-light-emitting devices. Among the several methods reported for the synthesis of PPV, the Heck coupling between an organic halide and an olefin, giving a carbon-carbon double bond, shows to have a great potential. In the present paper we reported on the palladium catalyzed synthesis of PPV starting from p-di-iodobenzene and an olefin

Formates for green catalytic reductions via CO2hydrogenation, mediated by magnetically recoverable catalysts

Precious metal catalyst has been prepared by conventional wet impregnation method followed by precipitation and reduction with hydrogen finally passivated with water in air. The magnetically recoverable catalyst has been prepared starting from a stoichiometric Fe3O4and ZrO2-Fe3O4as supports prepared following a sequential precipitation procedure. Precious metal catalysts supported on carbon, alumina, magnetite and zirconia-magnetite nanocomposite has been used in the reduction of nitrobenzenes and acetophenone by using sodium and potassium formate as reducing agent in the presence and in absence of an aqueous phase. In addition, the same catalysts has been tested in CO2and NaHCO3hydrogenation, for verifying their potentiality in the CO2as hydrogen carrier for hydrogenation processes