M. Melchiorri - Academia.edu (original) (raw)
Papers by M. Melchiorri
Review of Scientific Instruments, 2010
A holder to lodge and bend a silicon crystal to excite multivolume reflection of a high-energy pa... more A holder to lodge and bend a silicon crystal to excite multivolume reflection of a high-energy particle beam has been designed and fabricated. A mechanically robust and stable structure fastens a crystal at best condition for experiments. The holder has allowed the observation of 12-time repeated volume reflection with very high efficiency. We detail the most important features behind the construction of the holder together with the characterization of the crystal being bent by the holder.
IEEE International Conference on Group IV Photonics, 2005. @nd, 2005
... Mirko Melchiorri1, Nicola Daldosso1, Lorenzo Pavesi1, Georg Pucker2, Costantino Kompocholis2,... more ... Mirko Melchiorri1, Nicola Daldosso1, Lorenzo Pavesi1, Georg Pucker2, Costantino Kompocholis2, Pierluigi Bellutti2 and Alberto Lui2. 1Department of Physics, University of Trento, Via Sommarive 14, I-38050 Povo (Trento), Italy 2Istituto Trentino di Cultura, Centro per la Ricerca ...
IEEE International Conference on Group IV Photonics, 2005. @nd, 2005
ABSTRACT This paper reports on Er3+ absorption cross section measurement by transmission measurem... more ABSTRACT This paper reports on Er3+ absorption cross section measurement by transmission measurements in waveguide σabs measured value is 0.5-1.7 × cm at 1534 nm for all samples resulting very close to that of Er3+ in pure silica.
Applied Physics Letters, 2005
Experimental and theoretical investigations of photonic crystal (PhC) structures in silicon nitri... more Experimental and theoretical investigations of photonic crystal (PhC) structures in silicon nitride/silicon dioxide (Si3N4/SiO2) vertical waveguiding geometry are reported. One-dimensional patterns, either periodic or with cavity layers, are carved onto the channel waveguides by using focused ion beam lithography. Broadband transmittance spectroscopy in the visible and near-infrared frequency ranges is employed to show photonic band gap behavior up to the
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications, 2010
A small PET scanner is under development at the University of Pisa using Silicon Photomultipliers... more A small PET scanner is under development at the University of Pisa using Silicon Photomultipliers (SiPM) matrices as a photodetectors, fabricated at Fondazione Bruno Kessler (FBK). In this paper, we report on the first characterization of very large monolithic SiPMs matrices. The matrices feature 8 × 8 elements with a pitch of 1.5 mm. The elements are read out at the edges of the silicon die. We electrically characterized these devices at the wafer level by means of an automatic test procedure, consisting of current-voltage curves in forward and reverse bias. These tests allowed the selection of functioning devices and the evaluation of the uniformity of breakdown voltage and quenching resistance. Then, we performed first functional tests coupling the SiPM matrix to a slab of LYSO scintillator crystal. Finally, we measured the energy and spatial resolution exciting the detector with a 22Na source.
Physics Procedia, 2012
ABSTRACT SuperB is a super-flavor factory that will be built in Tor Vergata (Italy). The project,... more ABSTRACT SuperB is a super-flavor factory that will be built in Tor Vergata (Italy). The project, recently approved by the Italian Government, and classified as the flagship project of the Italian INFN, foresees the construction of a high intensity asymmetric electron-positron collider and of the related detector. The expected luminosity of 2x10(36)cm(-2) s(-1), a factor 100 higher than the last generation of B-factories, will allow the high statistic study of rare decays and, possibly, will allow a deeper insight in the field of new physics. Part of the SuperB apparatus is the Instrumented Flux Return (IFR). This detector exploits the flux return iron structure of the superconducting solenoid as absorber for the identification of muons and neutral hadrons. In more details, It consists of similar or equal to 92 cm of iron interleaved by 9 layers of highly segmented scintillators. The detection technique is based on relatively inexpensive extruded plastic scintillator bars produced at the FNAL-NICADD facility. The scintillation light is collected through Wave Length Shifting fibers and guided to recently developed devices called Silicon Photon Multipliers used as photodetectors. The use of plastic scintillator as active material ensures reliability, robustness and long term stability while the high granularity and the fast response guarantee a good space-time resolution, extremely important to cope with the expected high particles flux. The readout scheme under evaluation is this manuscript is the double coordinate readout ("BIRO readout") where two layers of orthogonal scintillator bars provide both, the polar and azimuthal coordinate. In order to deeply understand the performances and possible drawbacks of the above technique, a full depth prototype has been designed and built in Ferrara and Padova, and tested at the Fermilab Test Beam Facility (FBTF) in December 2010. In this paper a comprehensive description of the IFR related R& D studies will be presented. In particular, we will focus on the results of the Fermilab beam test, issues and future activities will also be outlined. (C) 2012 Published by Elsevier B. V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.
IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010
The existing muon detectors for high-energy physics experiments are mainly made of gas chambers s... more The existing muon detectors for high-energy physics experiments are mainly made of gas chambers such as Resistive Plate Chambers, Limited Streamer Tubes or Multi Wire Proportional Chambers. With the increasing luminosity of the new accelerators and the increment in dimensions of the experiments the development of a new detection technique, which is robust, cheap and capable to sustain high particle
MRS Proceedings, 2004
Rib-loaded silica waveguides containing Si nanocrystals were grown by quadruple implantation of S... more Rib-loaded silica waveguides containing Si nanocrystals were grown by quadruple implantation of Si ions into a 2 µm-thick thermally-grown SiO 2 layer. The thickness of the resulting flat-profile active region was about 300 nm, with a 9.5% Si excess (determined by X-ray photoelectron spectroscopy). Complete phase separation and nanocrystal formation was assured by annealing at 1100 ºC, and studied by means of optical tools such as Raman and luminescence. The rib-loaded structure of the waveguides was fabricated by photolithographic and reactive ion etching processes, with patterned rib widths ranging from 1 to 8 µm. Efficient light propagation was observed when end-fire coupling a probe signal both at 633 nm and 780 nm into the waveguides, with attenuation losses as low as 11 dB/cm. Signal amplification experiments, with pulsed and continuous wave (CW) top pumping, have shown increased signal absorption when the pump power is raised. This couples with the lack of any fast component in the time decay of the amplified spontaneous emissions as measured by ns pulsed pumping Variable Stripe Length (VSL) experiments. These two phenomena are interpreted as due to the lack of stimulated emission in these nanocrystalline systems.
MRS Proceedings, 2004
Pump and probe experiments have been performed on Er-doped rib-loaded waveguides containing Si na... more Pump and probe experiments have been performed on Er-doped rib-loaded waveguides containing Si nanoclusters grown by reactive magnetron sputtering. An Er 3+ absorption crosssection of about 5x10 -21 cm 2 has been found at 1534 nm by insertion losses measurements. Transmission measurements at 1310 nm under optical pumping (488 nm) shows a decreasing of the signal because of confined carrier absorption of the Si nanoclusters. Amplification experiments at 1535 nm evidence two pump power regimes: losses due to confined carrier absorption in the Si nanoclusters at low pump powers and signal amplification at high pump powers. For strong optical pumping, signal enhancement of about 1.2 dB/cm was observed.
Review of Scientific Instruments, 2010
A holder to lodge and bend a silicon crystal to excite multivolume reflection of a high-energy pa... more A holder to lodge and bend a silicon crystal to excite multivolume reflection of a high-energy particle beam has been designed and fabricated. A mechanically robust and stable structure fastens a crystal at best condition for experiments. The holder has allowed the observation of 12-time repeated volume reflection with very high efficiency. We detail the most important features behind the construction of the holder together with the characterization of the crystal being bent by the holder.
IEEE International Conference on Group IV Photonics, 2005. @nd, 2005
... Mirko Melchiorri1, Nicola Daldosso1, Lorenzo Pavesi1, Georg Pucker2, Costantino Kompocholis2,... more ... Mirko Melchiorri1, Nicola Daldosso1, Lorenzo Pavesi1, Georg Pucker2, Costantino Kompocholis2, Pierluigi Bellutti2 and Alberto Lui2. 1Department of Physics, University of Trento, Via Sommarive 14, I-38050 Povo (Trento), Italy 2Istituto Trentino di Cultura, Centro per la Ricerca ...
IEEE International Conference on Group IV Photonics, 2005. @nd, 2005
ABSTRACT This paper reports on Er3+ absorption cross section measurement by transmission measurem... more ABSTRACT This paper reports on Er3+ absorption cross section measurement by transmission measurements in waveguide σabs measured value is 0.5-1.7 × cm at 1534 nm for all samples resulting very close to that of Er3+ in pure silica.
Applied Physics Letters, 2005
Experimental and theoretical investigations of photonic crystal (PhC) structures in silicon nitri... more Experimental and theoretical investigations of photonic crystal (PhC) structures in silicon nitride/silicon dioxide (Si3N4/SiO2) vertical waveguiding geometry are reported. One-dimensional patterns, either periodic or with cavity layers, are carved onto the channel waveguides by using focused ion beam lithography. Broadband transmittance spectroscopy in the visible and near-infrared frequency ranges is employed to show photonic band gap behavior up to the
Astroparticle, Particle and Space Physics, Detectors and Medical Physics Applications, 2010
A small PET scanner is under development at the University of Pisa using Silicon Photomultipliers... more A small PET scanner is under development at the University of Pisa using Silicon Photomultipliers (SiPM) matrices as a photodetectors, fabricated at Fondazione Bruno Kessler (FBK). In this paper, we report on the first characterization of very large monolithic SiPMs matrices. The matrices feature 8 × 8 elements with a pitch of 1.5 mm. The elements are read out at the edges of the silicon die. We electrically characterized these devices at the wafer level by means of an automatic test procedure, consisting of current-voltage curves in forward and reverse bias. These tests allowed the selection of functioning devices and the evaluation of the uniformity of breakdown voltage and quenching resistance. Then, we performed first functional tests coupling the SiPM matrix to a slab of LYSO scintillator crystal. Finally, we measured the energy and spatial resolution exciting the detector with a 22Na source.
Physics Procedia, 2012
ABSTRACT SuperB is a super-flavor factory that will be built in Tor Vergata (Italy). The project,... more ABSTRACT SuperB is a super-flavor factory that will be built in Tor Vergata (Italy). The project, recently approved by the Italian Government, and classified as the flagship project of the Italian INFN, foresees the construction of a high intensity asymmetric electron-positron collider and of the related detector. The expected luminosity of 2x10(36)cm(-2) s(-1), a factor 100 higher than the last generation of B-factories, will allow the high statistic study of rare decays and, possibly, will allow a deeper insight in the field of new physics. Part of the SuperB apparatus is the Instrumented Flux Return (IFR). This detector exploits the flux return iron structure of the superconducting solenoid as absorber for the identification of muons and neutral hadrons. In more details, It consists of similar or equal to 92 cm of iron interleaved by 9 layers of highly segmented scintillators. The detection technique is based on relatively inexpensive extruded plastic scintillator bars produced at the FNAL-NICADD facility. The scintillation light is collected through Wave Length Shifting fibers and guided to recently developed devices called Silicon Photon Multipliers used as photodetectors. The use of plastic scintillator as active material ensures reliability, robustness and long term stability while the high granularity and the fast response guarantee a good space-time resolution, extremely important to cope with the expected high particles flux. The readout scheme under evaluation is this manuscript is the double coordinate readout ("BIRO readout") where two layers of orthogonal scintillator bars provide both, the polar and azimuthal coordinate. In order to deeply understand the performances and possible drawbacks of the above technique, a full depth prototype has been designed and built in Ferrara and Padova, and tested at the Fermilab Test Beam Facility (FBTF) in December 2010. In this paper a comprehensive description of the IFR related R& D studies will be presented. In particular, we will focus on the results of the Fermilab beam test, issues and future activities will also be outlined. (C) 2012 Published by Elsevier B. V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.
IEEE Nuclear Science Symposuim & Medical Imaging Conference, 2010
The existing muon detectors for high-energy physics experiments are mainly made of gas chambers s... more The existing muon detectors for high-energy physics experiments are mainly made of gas chambers such as Resistive Plate Chambers, Limited Streamer Tubes or Multi Wire Proportional Chambers. With the increasing luminosity of the new accelerators and the increment in dimensions of the experiments the development of a new detection technique, which is robust, cheap and capable to sustain high particle
MRS Proceedings, 2004
Rib-loaded silica waveguides containing Si nanocrystals were grown by quadruple implantation of S... more Rib-loaded silica waveguides containing Si nanocrystals were grown by quadruple implantation of Si ions into a 2 µm-thick thermally-grown SiO 2 layer. The thickness of the resulting flat-profile active region was about 300 nm, with a 9.5% Si excess (determined by X-ray photoelectron spectroscopy). Complete phase separation and nanocrystal formation was assured by annealing at 1100 ºC, and studied by means of optical tools such as Raman and luminescence. The rib-loaded structure of the waveguides was fabricated by photolithographic and reactive ion etching processes, with patterned rib widths ranging from 1 to 8 µm. Efficient light propagation was observed when end-fire coupling a probe signal both at 633 nm and 780 nm into the waveguides, with attenuation losses as low as 11 dB/cm. Signal amplification experiments, with pulsed and continuous wave (CW) top pumping, have shown increased signal absorption when the pump power is raised. This couples with the lack of any fast component in the time decay of the amplified spontaneous emissions as measured by ns pulsed pumping Variable Stripe Length (VSL) experiments. These two phenomena are interpreted as due to the lack of stimulated emission in these nanocrystalline systems.
MRS Proceedings, 2004
Pump and probe experiments have been performed on Er-doped rib-loaded waveguides containing Si na... more Pump and probe experiments have been performed on Er-doped rib-loaded waveguides containing Si nanoclusters grown by reactive magnetron sputtering. An Er 3+ absorption crosssection of about 5x10 -21 cm 2 has been found at 1534 nm by insertion losses measurements. Transmission measurements at 1310 nm under optical pumping (488 nm) shows a decreasing of the signal because of confined carrier absorption of the Si nanoclusters. Amplification experiments at 1535 nm evidence two pump power regimes: losses due to confined carrier absorption in the Si nanoclusters at low pump powers and signal amplification at high pump powers. For strong optical pumping, signal enhancement of about 1.2 dB/cm was observed.