Ultra-fast silicon detectors for 4D particle tracking development

In this contribution I will review the state-of-the-art and developments of the Ultra-Fast Silicon Detectors (UFSD) project, designed to provide accurate particle tracking in both space and time. Working principles, technology, measurements and TCAD (Technology Computer-Aided Design) simulations of Low-Gain Avalanche Detectors (LGAD) are described, highlighting the advantages of having large output signal without high-gain regimes as in standard APD structures, where also noise is typically enhanced

Modeling challenges for high-efficiency visible light-emitting diodes

In order to predict through numerical simulation the optical and carrier transport properties of GaN-based light-emitting diodes (LEDs), a genuine quantum approach should be combined with an atomistic description of the electronic structure. However, computational considerations have elicited the empirical inclusion of quantum contributions within conventional semiclassical drift-diffusion approaches. The lack of first-principles validation tools has left these \u201cquantum corrections\u201d largely untested, at least in the context of LED simulation. We discuss here the results obtained comparing state-of-the-art commercial numerical simulators, in order to assess the predictive capabilities of some of the most important quantum-based models complementing the drift-diffusion equations

First experimental results of the spatial resolution of RSD pad arrays read out with a 16-ch board

Resistive Silicon Detectors (RSD, also known as AC-LGAD) are innovative silicon sensors, based on the LGAD technology, characterized by a continuous gain layer that spreads across the whole sensor active area. RSDs are very promising tracking detectors, thanks to the combination of the built-in signal sharing with the internal charge multiplication, which allows large signals to be seen over multiple read-out channels. This work presents the first experimental results obtained from a 3$\times$4 array with 200~\mum~pitch, coming from the RSD2 production manufactured by FBK, read out with a 16-ch digitizer. A machine learning model has been trained, with experimental data taken with a precise TCT laser setup, and then used to predict the laser shot positions, finding a spatial resolution of ~ 5.5 um

Test of innovative silicon detectors for the monitoring of a therapeutic proton beam

Beam monitoring in particle therapy is a critical task that, because of the high flux and the time structure of the beam, can be challenging for the instrumentation. Recent developments in thin silicon detectors with moderate internal gain, optimized for timing applications (Ultra Fast Silicon Detectors, UFSD), offer a favourable technological option to conventional ionization chambers. Thanks to their fast collection time and good signal-to-noise ratio, properly segmented sensors allow discriminating and counting single protons up to the high fluxes of a therapeutic beam, while the excellent time resolution can be exploited for measuring the proton beam energy using time-of-flight techniques. We report here the results of the first tests performed with UFSD detector pads on a therapeutic beam. It is found that the signal of protons can be easily discriminated from the noise, and that the very good time resolution is confirmed. However, a careful design is necessary to limit large pile-up inefficiencies and early performance degradation due to radiation damage