A. Vacchi | Università degli Studi di Udine / University of Udine (original) (raw)
Papers by A. Vacchi
Optical Engineering, 1997
The concept of a new bidimensional photon-counting, MCPbased detector is presented together with ... more The concept of a new bidimensional photon-counting, MCPbased detector is presented together with estimates of imaging and dynamic range performances. The first results of tests on the position readout system, a silicon drift chamber, are also presented.
Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray, 2012
LOFT (Large Observatory For x-ray Timing) is one of the four missions selected in 2011 for assess... more LOFT (Large Observatory For x-ray Timing) is one of the four missions selected in 2011 for assessment study for the ESA M3 mission in the Cosmic Vision program, expected to be launched in 2024. The LOFT mission will carry two instruments with their prime sensitivity in the 2-30 keV range: a 10 m 2 class large area detector (LAD) with a <1° collimated field of view and a wide field monitor (WFM) instrument based on the coded mask principle, providing coverage of more than 1/3 of the sky. The LAD will provide an effective area ~20 times larger than any previous mission and will by timing studies be able to address fundamental questions about strong gravity in the vicinity of black holes and the equation of state of nuclear matter in neutron stars. The prime goal of the WFM will be to detect transient sources to be observed by the LAD. However, with its wide field of view and good energy resolution of <300 eV, the WFM will be an excellent monitoring instrument to study long term variability of many classes of X-ray sources. The sensitivity of the WFM will be 2.1 mCrab in a one day observation, and 270 mCrab in 3s in observations of in the crowded field of the Galactic Center. The high duty cycle of the instrument will make it an ideal detector of fast transient phenomena, like X-ray bursters, soft gamma repeaters, terrestrial gamma flashes, and not least provide unique capabilities in the study of gamma ray bursts. A dedicated burst alert system will enable the distribution to the community of ~100 gamma ray burst positions per year with a ~1 arcmin location accuracy within 30 s of the burst. This paper provides an overview of the design, configuration, and capabilities of the LOFT WFM instrument.
The Astrophysical Journal, 2011
The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been con... more The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60-750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the subcutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.
Lettere al Nuovo Cimento, 1977
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1985
A description is given of a bent-crystal spectrometer for pionic X-rays. The instrument is of the... more A description is given of a bent-crystal spectrometer for pionic X-rays. The instrument is of the modified DuMond type and makes use of a combined pi-production-X-ray target. It is situated in a 20 muA, 590 MeV proton beam at SIN. Combination of high mechanical precision and a laser interferometer system makes it possible to measure wavelength ratios with a precision
Czechoslovak Journal of Physics, 2005
The PHENIX detector at RHIC has been designed to study hadronic and leptonic signatures of the Qu... more The PHENIX detector at RHIC has been designed to study hadronic and leptonic signatures of the Quark Gluon Plasma in heavy ion collisions and spin dependent structure functions in polarized proton collisions. The baseline detector measures muons in two muon spectrometers located forward and backward of mid-rapidity, and measures hadrons, electrons, and photons in two central spectrometer arms, each of which covers 90 in azimuth and 0.35 units of rapidity. Further progress requires extending rapidity coverage for hadronic and electromagnetic signatures by upgrading the functionality of the PHENIX muon spectrometers to include photon and jet measurement capabilities. Tungsten calorimeters with silicon pixel readout and fine transverse and longitudinal segmentation are proposed to attain this goal. The use of such a design provides the highest density and finest granularity possible in a calorimeter.
The Electron Observatory (ELO) is a Silicon Tungsten (Si-W) imaging calorimeter concept that has ... more The Electron Observatory (ELO) is a Silicon Tungsten (Si-W) imaging calorimeter concept that has its origin in the Si-W detectors built by the WiZard collaboration for cosmic ray observations from space. It is specifically designed to measure the cosmic ray electron spectrum up to energy of 10 TeV and search for flux anisotropies at these energies. e present an in-depth analysis of this project of its simulated performance and plans for future implementations
Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications, 2012
... S. BORISOV, N. DE SIMONE, V. DI FELICE, NN NIKONOV, F. PALMA, P. PICOZZA and R. SPARVOLI INFN... more ... S. BORISOV, N. DE SIMONE, V. DI FELICE, NN NIKONOV, F. PALMA, P. PICOZZA and R. SPARVOLI INFN, Sezione di Roma Tor Vergata, Via della ... R. BELLOTTI, A. BRUNO, and A. MONACO INFN, Sezione di Bari, Via Amendola 173, I70126 Bari, Italy and University of Bari ...
Bulletin of the Russian Academy of Sciences: Physics, 2015
The results of measuring albedo deuteron fluxes in the vicinity of the Earth are presented. The d... more The results of measuring albedo deuteron fluxes in the vicinity of the Earth are presented. The data were obtained in the PAMELA experiment conducted aboard the Resurs DK 1 artificial Earth satellite. High precision detectors of the instrument setup allow us to identify albedo deuterons and measure their spectra in the energy interval from 70 to 600 MeV/nucleon at altitudes of 350-600 km for different geomag netic latitudes.
Hyperfine Interactions, 1999
The DEAR (DAΦNE Exotic Atom Research) experiment at the new φ-factory DAΦNE of Laboratori Naziona... more The DEAR (DAΦNE Exotic Atom Research) experiment at the new φ-factory DAΦNE of Laboratori Nazionali di Frascati aims for a 1% measurement of the line shift of the K-complex due to strong interaction in kaonic hydrogen. This presentation is meant to prove that the high statistics and good resolution obtainable with DEAR will be able to disentangle the kaonic hydrogen K-complex lines (a cascade unconstrained fit), obtaining in this way constraints for what concerns the cascade parameters and, consequently, information regarding the physical processes involved in the kaonic hydrogen atomic cascade.
Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray, 2010
The use of large-area, fine-pitch Silicon detectors has demonstrated the feasibility of wide fiel... more The use of large-area, fine-pitch Silicon detectors has demonstrated the feasibility of wide field imaging experiments requesting very low resources in terms of weight, volume, power and costs. The flying SuperAGILE instrument is the first such experiment, adopting large-area Silicon microstrip detectors coupled to one-dimensional coded masks. With less than 10 kg, 12 watt and 0.04 m3 it provides 6-arcmin
Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray, 2012
The Large Observatory for X-ray Timing (LOFT) is one of the four candidate ESA M3 missions consid... more The Large Observatory for X-ray Timing (LOFT) is one of the four candidate ESA M3 missions considered for launch in the 2022 timeframe. It is specifically designed to perform fast X-ray timing and probe the status of the matter near black holes and neutron stars. The LOFT scientific payload is composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a 10 m 2-class pointed instrument with 20 times the collecting area of the best past timing missions (such as RXTE) over the 2-30 keV range, which holds the capability to revolutionize studies of X-ray variability down to the millisecond time scales. Its groundbreaking characteristic is a low mass per unit surface, enabling an effective area of ~10 m 2 (@10 keV) at a reasonable weight. The development of such large but light experiment, with low mass and power per unit area, is now made possible by the recent advancements in the field of large-area silicon detectors-able to time tag an X-ray photon with an accuracy <10 μs and an energy resolution of ~260 eV at 6 keV-and capillary-plate X-ray collimators. In this paper, we will summarize the characteristics of the LAD instrument and give an overview of its capabilities.
La Rivista del Nuovo Cimento, 1999
Review of Scientific Instruments, 1995
Physics Letters B, 1993
Inclusive direct photon invariant cross sections have been measured in both pp and pp collisions ... more Inclusive direct photon invariant cross sections have been measured in both pp and pp collisions at &amp;amp;amp;amp;surd;s = 24.3 GeV at the CERN SPS, permitting the first measurement of the difference of the pp and pp cross sections. The direct photon cross section in pp collisions has been found to be systematically larger than that in pp collisions, which indicates
Physics Letters B, 2010
The inclusive charged particle transverse momentum distribution is measured in proton-proton coll... more The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at √ s = 900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (|η| < 0.8) over the transverse momentum range 0.15 < p T < 10 GeV/c. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for |η| < 0.8 is p T INEL = 0.483 ± 0.001 (stat.) ± 0.007 (syst.) GeV/c and p T NSD = 0.489 ± 0.001 (stat.) ± 0.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger p T than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET.
Nuclear Physics B - Proceedings Supplements, 1999
A 3-layer edge-on silicon microstrip detector for the SYRMEP/FRONTRAD project has been designed a... more A 3-layer edge-on silicon microstrip detector for the SYRMEP/FRONTRAD project has been designed and realised. The image matrix is made by 764 pixels with dimensions 300 (thickness of the single detectors) x 200 (strip pitch) ~tm 2. The system has a sensitive area of 50 x 1 mm 2, an inter-layer distance of = 100 ~tm and an efficiency of = 80% for 20 keV photons. The image is acquired by scanning the object across the beam crosssection and the overall statistics on the single pixel is obtained by summing up the information of corresponding pixels in the three layers, thereby reducing the effect of possible noisy or not functioning pixels. Experimental results obtained at the SYRMEP/FRONTRAD beam line of the ELETTRA synchrotron radiation machine with this innovative detector are presented.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1993
This report was prepared as an account of work sponsored by an agency of the United States Govern... more This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996
The SYRMEP (SYnchrotron Radiation for MEdical Physics) collaboration is now developing a microstr... more The SYRMEP (SYnchrotron Radiation for MEdical Physics) collaboration is now developing a microstrip silicon detector with high granularity and high efficiency for research in digital mammography. The project is planning to use a monochromatic X-ray beam, from a bending magnet, of ELETTRA, the synchrotron facility installed in Trieste. The detector is a matrix of pixels, formed by the stacking of
Optical Engineering, 1997
The concept of a new bidimensional photon-counting, MCPbased detector is presented together with ... more The concept of a new bidimensional photon-counting, MCPbased detector is presented together with estimates of imaging and dynamic range performances. The first results of tests on the position readout system, a silicon drift chamber, are also presented.
Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray, 2012
LOFT (Large Observatory For x-ray Timing) is one of the four missions selected in 2011 for assess... more LOFT (Large Observatory For x-ray Timing) is one of the four missions selected in 2011 for assessment study for the ESA M3 mission in the Cosmic Vision program, expected to be launched in 2024. The LOFT mission will carry two instruments with their prime sensitivity in the 2-30 keV range: a 10 m 2 class large area detector (LAD) with a <1° collimated field of view and a wide field monitor (WFM) instrument based on the coded mask principle, providing coverage of more than 1/3 of the sky. The LAD will provide an effective area ~20 times larger than any previous mission and will by timing studies be able to address fundamental questions about strong gravity in the vicinity of black holes and the equation of state of nuclear matter in neutron stars. The prime goal of the WFM will be to detect transient sources to be observed by the LAD. However, with its wide field of view and good energy resolution of <300 eV, the WFM will be an excellent monitoring instrument to study long term variability of many classes of X-ray sources. The sensitivity of the WFM will be 2.1 mCrab in a one day observation, and 270 mCrab in 3s in observations of in the crowded field of the Galactic Center. The high duty cycle of the instrument will make it an ideal detector of fast transient phenomena, like X-ray bursters, soft gamma repeaters, terrestrial gamma flashes, and not least provide unique capabilities in the study of gamma ray bursts. A dedicated burst alert system will enable the distribution to the community of ~100 gamma ray burst positions per year with a ~1 arcmin location accuracy within 30 s of the burst. This paper provides an overview of the design, configuration, and capabilities of the LOFT WFM instrument.
The Astrophysical Journal, 2011
The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been con... more The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60-750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the subcutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.
Lettere al Nuovo Cimento, 1977
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1985
A description is given of a bent-crystal spectrometer for pionic X-rays. The instrument is of the... more A description is given of a bent-crystal spectrometer for pionic X-rays. The instrument is of the modified DuMond type and makes use of a combined pi-production-X-ray target. It is situated in a 20 muA, 590 MeV proton beam at SIN. Combination of high mechanical precision and a laser interferometer system makes it possible to measure wavelength ratios with a precision
Czechoslovak Journal of Physics, 2005
The PHENIX detector at RHIC has been designed to study hadronic and leptonic signatures of the Qu... more The PHENIX detector at RHIC has been designed to study hadronic and leptonic signatures of the Quark Gluon Plasma in heavy ion collisions and spin dependent structure functions in polarized proton collisions. The baseline detector measures muons in two muon spectrometers located forward and backward of mid-rapidity, and measures hadrons, electrons, and photons in two central spectrometer arms, each of which covers 90 in azimuth and 0.35 units of rapidity. Further progress requires extending rapidity coverage for hadronic and electromagnetic signatures by upgrading the functionality of the PHENIX muon spectrometers to include photon and jet measurement capabilities. Tungsten calorimeters with silicon pixel readout and fine transverse and longitudinal segmentation are proposed to attain this goal. The use of such a design provides the highest density and finest granularity possible in a calorimeter.
The Electron Observatory (ELO) is a Silicon Tungsten (Si-W) imaging calorimeter concept that has ... more The Electron Observatory (ELO) is a Silicon Tungsten (Si-W) imaging calorimeter concept that has its origin in the Si-W detectors built by the WiZard collaboration for cosmic ray observations from space. It is specifically designed to measure the cosmic ray electron spectrum up to energy of 10 TeV and search for flux anisotropies at these energies. e present an in-depth analysis of this project of its simulated performance and plans for future implementations
Astroparticle, Particle, Space Physics, Radiation Interaction, Detectors and Medical Physics Applications, 2012
... S. BORISOV, N. DE SIMONE, V. DI FELICE, NN NIKONOV, F. PALMA, P. PICOZZA and R. SPARVOLI INFN... more ... S. BORISOV, N. DE SIMONE, V. DI FELICE, NN NIKONOV, F. PALMA, P. PICOZZA and R. SPARVOLI INFN, Sezione di Roma Tor Vergata, Via della ... R. BELLOTTI, A. BRUNO, and A. MONACO INFN, Sezione di Bari, Via Amendola 173, I70126 Bari, Italy and University of Bari ...
Bulletin of the Russian Academy of Sciences: Physics, 2015
The results of measuring albedo deuteron fluxes in the vicinity of the Earth are presented. The d... more The results of measuring albedo deuteron fluxes in the vicinity of the Earth are presented. The data were obtained in the PAMELA experiment conducted aboard the Resurs DK 1 artificial Earth satellite. High precision detectors of the instrument setup allow us to identify albedo deuterons and measure their spectra in the energy interval from 70 to 600 MeV/nucleon at altitudes of 350-600 km for different geomag netic latitudes.
Hyperfine Interactions, 1999
The DEAR (DAΦNE Exotic Atom Research) experiment at the new φ-factory DAΦNE of Laboratori Naziona... more The DEAR (DAΦNE Exotic Atom Research) experiment at the new φ-factory DAΦNE of Laboratori Nazionali di Frascati aims for a 1% measurement of the line shift of the K-complex due to strong interaction in kaonic hydrogen. This presentation is meant to prove that the high statistics and good resolution obtainable with DEAR will be able to disentangle the kaonic hydrogen K-complex lines (a cascade unconstrained fit), obtaining in this way constraints for what concerns the cascade parameters and, consequently, information regarding the physical processes involved in the kaonic hydrogen atomic cascade.
Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray, 2010
The use of large-area, fine-pitch Silicon detectors has demonstrated the feasibility of wide fiel... more The use of large-area, fine-pitch Silicon detectors has demonstrated the feasibility of wide field imaging experiments requesting very low resources in terms of weight, volume, power and costs. The flying SuperAGILE instrument is the first such experiment, adopting large-area Silicon microstrip detectors coupled to one-dimensional coded masks. With less than 10 kg, 12 watt and 0.04 m3 it provides 6-arcmin
Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray, 2012
The Large Observatory for X-ray Timing (LOFT) is one of the four candidate ESA M3 missions consid... more The Large Observatory for X-ray Timing (LOFT) is one of the four candidate ESA M3 missions considered for launch in the 2022 timeframe. It is specifically designed to perform fast X-ray timing and probe the status of the matter near black holes and neutron stars. The LOFT scientific payload is composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a 10 m 2-class pointed instrument with 20 times the collecting area of the best past timing missions (such as RXTE) over the 2-30 keV range, which holds the capability to revolutionize studies of X-ray variability down to the millisecond time scales. Its groundbreaking characteristic is a low mass per unit surface, enabling an effective area of ~10 m 2 (@10 keV) at a reasonable weight. The development of such large but light experiment, with low mass and power per unit area, is now made possible by the recent advancements in the field of large-area silicon detectors-able to time tag an X-ray photon with an accuracy <10 μs and an energy resolution of ~260 eV at 6 keV-and capillary-plate X-ray collimators. In this paper, we will summarize the characteristics of the LAD instrument and give an overview of its capabilities.
La Rivista del Nuovo Cimento, 1999
Review of Scientific Instruments, 1995
Physics Letters B, 1993
Inclusive direct photon invariant cross sections have been measured in both pp and pp collisions ... more Inclusive direct photon invariant cross sections have been measured in both pp and pp collisions at &amp;amp;amp;amp;surd;s = 24.3 GeV at the CERN SPS, permitting the first measurement of the difference of the pp and pp cross sections. The direct photon cross section in pp collisions has been found to be systematically larger than that in pp collisions, which indicates
Physics Letters B, 2010
The inclusive charged particle transverse momentum distribution is measured in proton-proton coll... more The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at √ s = 900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (|η| < 0.8) over the transverse momentum range 0.15 < p T < 10 GeV/c. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for |η| < 0.8 is p T INEL = 0.483 ± 0.001 (stat.) ± 0.007 (syst.) GeV/c and p T NSD = 0.489 ± 0.001 (stat.) ± 0.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger p T than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET.
Nuclear Physics B - Proceedings Supplements, 1999
A 3-layer edge-on silicon microstrip detector for the SYRMEP/FRONTRAD project has been designed a... more A 3-layer edge-on silicon microstrip detector for the SYRMEP/FRONTRAD project has been designed and realised. The image matrix is made by 764 pixels with dimensions 300 (thickness of the single detectors) x 200 (strip pitch) ~tm 2. The system has a sensitive area of 50 x 1 mm 2, an inter-layer distance of = 100 ~tm and an efficiency of = 80% for 20 keV photons. The image is acquired by scanning the object across the beam crosssection and the overall statistics on the single pixel is obtained by summing up the information of corresponding pixels in the three layers, thereby reducing the effect of possible noisy or not functioning pixels. Experimental results obtained at the SYRMEP/FRONTRAD beam line of the ELETTRA synchrotron radiation machine with this innovative detector are presented.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1993
This report was prepared as an account of work sponsored by an agency of the United States Govern... more This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996
The SYRMEP (SYnchrotron Radiation for MEdical Physics) collaboration is now developing a microstr... more The SYRMEP (SYnchrotron Radiation for MEdical Physics) collaboration is now developing a microstrip silicon detector with high granularity and high efficiency for research in digital mammography. The project is planning to use a monochromatic X-ray beam, from a bending magnet, of ELETTRA, the synchrotron facility installed in Trieste. The detector is a matrix of pixels, formed by the stacking of