Search for heavy neutral lepton production in K+ decays

A search for heavy neutral lepton production in K + decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10−7 to 10−6 level are established on the elements of the extended neutrino mixing matrix |Ue4| 2 and |Uμ4| 2 for heavy neutral lepton mass in the ranges 170–448 MeV/c2 and 250–373 MeV/c2, respectively. This improves on the previous limits from HNL production searches over the whole mass range considered for |Ue4|2 and above 300 MeV/c2 for |Uμ4|2

The Imaging X-ray Polarimetry Explorer (IXPE): Technical Overview

The Imaging X-ray Polarimetry Explorer (IXPE) will expand the information space for study of cosmic sources, by adding linear polarization to the properties (time, energy, and position) observed in x-ray astronomy. Selected in 2017 January as a NASA Astrophysics Small Explorer (SMEX) mission, IXPE will be launched into an equatorial orbit in 2021. The IXPE mission will provide scientifically meaningful measurements of the x-ray polarization of a few dozen sources in the 2-8 keV band, including polarization maps of several x-ray-bright extended sources and phase-resolved polarimetry of many bright pulsating x-ray sources

Design, Development, and Test of Data Acquisition Systems for Physics in Space

Development of novel detectors, readout, and data acquisition systems capable of operating in the space environment is paramount to properly support the ever-growing interest in astrophysics and astroparticle physics. The new physics detectors have increasing requirements of accuracy, resolution, and data throughput, that the data acquisition systems shall meet to reach the performance within the limited resources available for a typical space application. Besides, the electronics systems must operate in the space environment, which is made of thermal, vacuum, and radiation stresses. Each component of a physics experiment, from the detector to the data acquisition, equally contribute to the success of the mission, thus it is crucial that their synergy meets the expected performance. The activity I carried out focused on the design, development, and test of data acquisition systems for innovative physics missions in space, embedding novel physics detectors. In collaboration with the Istituto Nazionale di Fisica Nucleare (INFN) and international partners, I worked on two missions: IXPE (NASA) and PAN (project 862044 EU H2020 FETOPEN). For both missions, I designed and developed the custom data acquisition systems based on FPGA, including their simulation, tests, and characterization. I also designed the ancillary support electronics that helped throughout the development and verification process. Finally, IXPE was launched on 9 December 2021 and is collecting data since then

Real-time FPGA design for the L0-trigger of the RICH detector of the NA62 experiment at CERN SPS

The NA62 experiment aims at measuring rare kaon decays, in order to precisely test the standard model. The RICH (Ring Imaging CHerenkov) detector of the experiment is instrumental in charged-particle identification and in measurement of their crossing time, with a resolution better than 100 ps. Here we describe the design of the Level-0 trigger system for the RICH, which provides a precise time reference by counting the input hit multiplicity within programmable fine-time windows. Since the design does not use spatial information and stands the maximum input rate of TDC-based NA62 systems, it can be deployed also in other subdetectors

Lignocellulosic Ethanol Production from the Recovery of Stranded Driftwood Residues

This paper builds upon a research project funded by the Italian Ministry of Environment, and aims to recover stranded driftwood residues (SDRs), in order to transform a potential pollution and safety issue into valuable bio-resources. In particular, one of the experiments consisted of bioethanol production from lignocellulosic residues. The SDRs were gathered from the Italian coast (Abruzzo Region, Italy) after an intense storm. The biomass recalcitrance, due to its lignocellulosic structure, was reduced by a steam explosion (SE) pretreatment process. Four different pretreatment severity factors (R0) were tested (LogR0 3.65, 4.05, 4.24 and 4.64) in order to evaluate the pretreated material’s accessibility to enzymatic attack and the holocellulose (cellulose plus hemicellulose) recovery. A first enzymatic hydrolysis was performed on the pretreated materials by employing a solid/liquid (S/L) ratio of 1% (w/w) and an enzyme dosage of 30% (w enzyme/w cellulose), in order to estimate the maximum enzymatically accessible cellulose content. Since the primary goal of pretreatment and hydrolysis is to convert as much cellulose as possible into monomeric glucose and recover all the holocellulose, the two pretreated materials showing these features were selected for bioethanol production process. The pretreated materials underwent a semi-simultaneous saccharification and fermentation (SSSF). The SSSF process was performed into two lab-scale bioreactors (5 L) with an S/L ratio of 15% and an enzyme dosage of 15% for five days. The efficiency of the whole bioethanol production process was assessed as ethanol overall yields (g ethanol/100 g raw material). The best overall yield was achieved by sample BS04 (8.98 g ethanol/100 g raw material)

Production of Carbohydrates from Cardoon Pre-Treated by Acid-Catalyzed Steam Explosion and Enzymatic Hydrolysis

Cardoon (Cynara cardunculus) is a promising crop from which to obtain oilseeds and lignocellulosic biomass. Acid-catalyzed steam explosion is a thermochemical process that can efficiently pre-treat lignocellulosic biomass. The drawback is the production of a high number of carbohydrate degradation products in the liquid fraction that could inhibit microbial growth. In this work, the lignocellulosic biomass of cardoon, gathered from a dedicated field, were used as the raw material for the production of fermentable monosaccharides by employing acid-catalyzed steam explosion. The raw material was pre-soaked with a dilute 1% (w/w) sulfuric acid solution and then subjected to steam explosion under three different severity conditions. The recovered slurry was separated into solid and liquid fractions, which were individually characterized to determine total carbohydrate and inhibitor concentrations. The slurry and the washed solid fraction underwent enzymatic hydrolysis to release glucose and pentose monosaccharides. By conducting the pre-treatment at 175 °C for 35 min and hydrolyzing the obtained slurry, a yield of 33.17 g of monosaccharides/100 g of cardoon was achieved. At the same conditions, 4.39 g of inhibitors/100 g of cardoon were produced