Simulation and experimental qualification of the response of microstrip detectors to ion beams
In the framework of the construction of a novel Femtoscope Array for Correlation and Spectroscopy, named FARCOS, aiming at the identification in charge and mass even of particles stopping in the first detection layer, we are performing a thorough characterization of the silicon detector layers in terms of the collection properties as a function of the point of incidence. We have experimental evidence - as previously observed also in the literature for other strip detectors - that interstrip incidence alters the signal shape not only for the trivial effect of charge sharing but also because of induction effects on neighbor strips. In order to clarify this issue we developed a custom simulation suite of the electron-hole transport and signal formation able to properly describe 3-D Coulomb interaction and thermal diffusion in semiconductor detectors. We ran a batch of significant and representative simulations presenting the qualitative correct interpretation and the quantitative validation as proved by the comparison of the simulation results with the experimental data.
Development of double-sided silicon strip detectors (DSSD) for a Compton telescope
Abstract The low noise double-sided silicon strip detector (DSSD) technology is used to construct a next generation Compton telescope which is required to have both high-energy resolution and high-Compton reconstruction efficiency. In this paper, we present the result of a newly designed stacked DSSD module with high-energy resolution in highly packed mechanical structure. The system is designed to obtain good P-side and N-side noise performance by means of DC-coupled read-out. Since there are no decoupling capacitors in front-end electronics before the read-out ASICs, a high density stacked module with a pitch of 2 mm can be constructed. By using a prototype with four-layer of DSSDs with an area of 2.56 cm × 2.56 cm , we have succeeded to operate the system. The energy resolution at 59.5 keV is measured to be 1.6 keV (FWHM) for the P-side and 2.8 keV (FWHM) for the N-side, respectively. In addition to the DSSD used in the prototype, a 4 cm wide DSSD with a thickness of 300 μ m is also developed. With this device, an energy resolution of 1.5 keV (FWHM) was obtained. A method to model the detector energy response to properly handle split events is also discussed.
Evidence for an anticorrelation effect in the production of hard photons and preequilibrium protons in heavy ion collisions.
An exclusive study of the hard photon production in the reaction $^{40}\mathrm{Ar}$+$^{51}\mathrm{V}$ at 44 MeV/nucleon has been carried on with the $4\ensuremath{\pi}$ multidetector MEDEA. An anticorrelation effect in the emission of very energetic photons and protons has been observed for the first time. This is a strong indication for the first-chance $n\ensuremath{-}p$ bremsstrahlung production mechanism.