2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2017
Quantification of nuclear material such as uranium and plutonium isotopes, as well as other actin... more Quantification of nuclear material such as uranium and plutonium isotopes, as well as other actinides such as 241Am is required for nuclear material accountancy for nuclear T safeguards. Besides quantitative results, regulatory bodies such as the International Atomic Energy Agency (IAEA) need the isotopic attributes of nuclear material, e.g., $^{\mathbf {235}}\textbf{U}$ enrichment. Prominent gamma ray signatures from nuclear materials are predominantly at low energies. Besides actinides, samples may contain high activities of fission product nuclides, many of which emit higher energy gamma rays ($\ge $ 600 keV). High Purity Germanium (HPGe) detectors are commonly employed in safeguards applications that require the best possible energy resolution. The analysis of low energy gamma rays is rendered difficult because of the high Compton continuum (partial energy deposition in the HPGe) due to high energy gamma rays originating in the sample. This results in the degradation of the sens...
2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2014
This work presents the design of a read-out channel suitable for application to silicon pixel det... more This work presents the design of a read-out channel suitable for application to silicon pixel detectors for the next generation Free Electron Laser (FEL) experiments. The readout architecture, which has been carried out in a 65 nm CMOS technology, consists of a low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time-variant shaping stage and a low-power analog-to-digital converter (ADC), hosted in a 100 μm-pitch pixel. The blocks will be operated in such a way to cope with the high frame rates (exceeding 1 MHz) foreseen for future X-ray FEL machines. The paper describes in detail the architecture and the performance of the CSA and provides an overview about the analog readout channel.
This work is concerned with the design of a readout chip for application to experiments at the ne... more This work is concerned with the design of a readout chip for application to experiments at the next generation X-ray Free Electron Lasers (FEL). The ASIC, named PixFEL Matrix (PFM2), has been designed in a 65 nm CMOS technology and consists of 32 × 32 pixels. Each cell covers an area of 110 × 110 μm2 and includes a low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time-variant shaper used to process the preamplifier output signal, a 10-bit successive approximation register (SAR) analog-to-digital converter (ADC) and digital circuitry for channel control and data readout. Two different solutions for the readout channel, based on different versions of the time-variant filter, have been integrated in the chip. Both solutions can be operated in such a way to cope with the high frame rate (exceeding 1 MHz) foreseen for future X-ray FEL machines. The ASIC will be bump bonded to a slim/active edge pixel sensor to form the first demonstrator for the PixFEL X-ray imager. This work has been carried out in the frame of the PixFEL project funded by Istituto Nazionale di Fisica Nucleare (INFN), Italy.
The advancements in integrated silicon technology over the last decades have enabled significant ... more The advancements in integrated silicon technology over the last decades have enabled significant progress in all fields of engineering and science, and radiation detection is no exception. Several large-scale experiments have been made possible by the development of new ways of making circuits ever smaller, with good resistance to damaging radiation. Detectors, especially those for high-energy physics experiments, have also seen benefits from the ability of processing large silicon substrates into viable particle trackers. On the other hand, devices such as photomultiplier tubes (PMT) have been used for three quarters of a century and are still the workhorse of radiation detection in many applications. Only in the last four to five years, a new device has become attractive in overcoming some undesired shortcomings of PMTs, thanks to these advancements in silicon integrated technology. The new devices, called silicon-photomultipliers, or SiPM in short, seem to have all of the feature...
We present results of several measurements of CsI[Na] scintillation response to 3-60 keV energy n... more We present results of several measurements of CsI[Na] scintillation response to 3-60 keV energy nuclear recoils performed by the COHERENT collaboration using tagged neutron elastic scattering experiments and an endpoint technique. Earlier results, used to estimate the coherent elastic neutrino-nucleus scattering (CEvNS) event rate for the first observation of this process achieved by COHERENT at the Spallation Neutron Source (SNS), have been reassessed. We discuss corrections for the identified systematic effects and update the respective uncertainty values. The impact of updated results on future precision tests of CEvNS is estimated. We scrutinize potential systematic effects that could affect each measurement. In particular we confirm the response of the H11934-200 Hamamatsu photomultiplier tube (PMT) used for the measurements presented in this study to be linear in the relevant signal scale region.
The origin of dark matter is a driving question of modern physics. Low-energy antideuterons provi... more The origin of dark matter is a driving question of modern physics. Low-energy antideuterons provide a "smoking gun" signature of dark matter annihilation or decay, essentially free of astrophysical background. Low-energy antiprotons are a vital partner for this analysis, and low-energy antihelium could provide further discovery space for new physics. In the coming decade, AMS-02 will continue accumulating the large statistics and systematic understanding necessary for it to probe rare antinuclei signatures, and GAPS, which is the first experiment optimized specifically for low-energy cosmic antinuclei, will begin several Antarctic balloon campaigns. The connection of cosmic-ray antinuclei and dark matter is reviewed and the outlook in light of experimental progress is presented.
D. Akimov, P. An, 3 C. Awe, 3 P.S. Barbeau, 3 B. Becker, V. Belov, 1 I. Bernardi, M.A. Blackston,... more D. Akimov, P. An, 3 C. Awe, 3 P.S. Barbeau, 3 B. Becker, V. Belov, 1 I. Bernardi, M.A. Blackston, C. Bock, A. Bolozdynya, J. Browning, B. Cabrera-Palmer, D. Chernyak, ∗ E. Conley, J. Daughhetee, J. Detwiler, K. Ding, M.R. Durand, Y. Efremenko, 6 S.R. Elliott, L. Fabris, M. Febbraro, J. Galambos, A. Gallo Rosso, A. Galindo-Uribarri, 4 M.P. Green, 6, 8 M.R. Heath, S. Hedges, 3 D. Hoang, M. Hughes, E. Iverson, T. Johnson, 3 A. Khromov, A. Konovalov, 5 E. Kozlova, 5 A. Kumpan, L. Li, 3 J.M. Link, J. Liu, K. Mann, D.M. Markoff, 3 J. Mastroberti, M. McIntyre, P.E. Mueller, J. Newby, D.S. Parno, S.I. Penttila, D. Pershey, R. Rapp, † H. Ray, J. Raybern, O. Razuvaeva, 5 D. Reyna, G.C. Rich, D. Rimal, J. Ross, 3 D. Rudik, J. Runge, 3 D.J. Salvat, A.M. Salyapongse, K. Scholberg, A. Shakirov, G. Simakov, 5 G. Sinev, ‡ W.M. Snow, V. Sosnovstsev, B. Suh, R. Tayloe, K. Tellez-Giron-Flores, I. Tolstukhin, § S. Trotter, E. Ujah, 3 J. Vanderwerp, R.L. Varner, C.J. Virtue, G. Visser, T. Wongjirad, Y.-...
We recently developed a fieldable large-area, coded-aperture, gamma imager (the Large Area Imager... more We recently developed a fieldable large-area, coded-aperture, gamma imager (the Large Area Imager - LAI). The instrument was developed to detect weak radiation sources in a fluctuating natural background. Ideally, the efficacy of the instrument is determined using receiver-operator statistics generated from measurement data in terms of probability of detection versus probability of false alarm. However, due to the impracticality of hiding many sources in public areas, it is difficult to measure the data required to generate receiver-operator characteristic (ROC) curves. Instead, we develop a high statistics "model source" from measurements of a real point source and then inject the model source into data collected from the world at large where, presumably, no source exists. In this paper we have applied this "source injection" technique to evaluate the performance of the LAI. We plotted ROC curves obtained for different source locations from the imager and for di...
2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2017
Quantification of nuclear material such as uranium and plutonium isotopes, as well as other actin... more Quantification of nuclear material such as uranium and plutonium isotopes, as well as other actinides such as 241Am is required for nuclear material accountancy for nuclear T safeguards. Besides quantitative results, regulatory bodies such as the International Atomic Energy Agency (IAEA) need the isotopic attributes of nuclear material, e.g., $^{\mathbf {235}}\textbf{U}$ enrichment. Prominent gamma ray signatures from nuclear materials are predominantly at low energies. Besides actinides, samples may contain high activities of fission product nuclides, many of which emit higher energy gamma rays ($\ge $ 600 keV). High Purity Germanium (HPGe) detectors are commonly employed in safeguards applications that require the best possible energy resolution. The analysis of low energy gamma rays is rendered difficult because of the high Compton continuum (partial energy deposition in the HPGe) due to high energy gamma rays originating in the sample. This results in the degradation of the sens...
2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2014
This work presents the design of a read-out channel suitable for application to silicon pixel det... more This work presents the design of a read-out channel suitable for application to silicon pixel detectors for the next generation Free Electron Laser (FEL) experiments. The readout architecture, which has been carried out in a 65 nm CMOS technology, consists of a low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time-variant shaping stage and a low-power analog-to-digital converter (ADC), hosted in a 100 μm-pitch pixel. The blocks will be operated in such a way to cope with the high frame rates (exceeding 1 MHz) foreseen for future X-ray FEL machines. The paper describes in detail the architecture and the performance of the CSA and provides an overview about the analog readout channel.
This work is concerned with the design of a readout chip for application to experiments at the ne... more This work is concerned with the design of a readout chip for application to experiments at the next generation X-ray Free Electron Lasers (FEL). The ASIC, named PixFEL Matrix (PFM2), has been designed in a 65 nm CMOS technology and consists of 32 × 32 pixels. Each cell covers an area of 110 × 110 μm2 and includes a low-noise charge sensitive amplifier (CSA) with dynamic signal compression, a time-variant shaper used to process the preamplifier output signal, a 10-bit successive approximation register (SAR) analog-to-digital converter (ADC) and digital circuitry for channel control and data readout. Two different solutions for the readout channel, based on different versions of the time-variant filter, have been integrated in the chip. Both solutions can be operated in such a way to cope with the high frame rate (exceeding 1 MHz) foreseen for future X-ray FEL machines. The ASIC will be bump bonded to a slim/active edge pixel sensor to form the first demonstrator for the PixFEL X-ray imager. This work has been carried out in the frame of the PixFEL project funded by Istituto Nazionale di Fisica Nucleare (INFN), Italy.
The advancements in integrated silicon technology over the last decades have enabled significant ... more The advancements in integrated silicon technology over the last decades have enabled significant progress in all fields of engineering and science, and radiation detection is no exception. Several large-scale experiments have been made possible by the development of new ways of making circuits ever smaller, with good resistance to damaging radiation. Detectors, especially those for high-energy physics experiments, have also seen benefits from the ability of processing large silicon substrates into viable particle trackers. On the other hand, devices such as photomultiplier tubes (PMT) have been used for three quarters of a century and are still the workhorse of radiation detection in many applications. Only in the last four to five years, a new device has become attractive in overcoming some undesired shortcomings of PMTs, thanks to these advancements in silicon integrated technology. The new devices, called silicon-photomultipliers, or SiPM in short, seem to have all of the feature...
We present results of several measurements of CsI[Na] scintillation response to 3-60 keV energy n... more We present results of several measurements of CsI[Na] scintillation response to 3-60 keV energy nuclear recoils performed by the COHERENT collaboration using tagged neutron elastic scattering experiments and an endpoint technique. Earlier results, used to estimate the coherent elastic neutrino-nucleus scattering (CEvNS) event rate for the first observation of this process achieved by COHERENT at the Spallation Neutron Source (SNS), have been reassessed. We discuss corrections for the identified systematic effects and update the respective uncertainty values. The impact of updated results on future precision tests of CEvNS is estimated. We scrutinize potential systematic effects that could affect each measurement. In particular we confirm the response of the H11934-200 Hamamatsu photomultiplier tube (PMT) used for the measurements presented in this study to be linear in the relevant signal scale region.
The origin of dark matter is a driving question of modern physics. Low-energy antideuterons provi... more The origin of dark matter is a driving question of modern physics. Low-energy antideuterons provide a "smoking gun" signature of dark matter annihilation or decay, essentially free of astrophysical background. Low-energy antiprotons are a vital partner for this analysis, and low-energy antihelium could provide further discovery space for new physics. In the coming decade, AMS-02 will continue accumulating the large statistics and systematic understanding necessary for it to probe rare antinuclei signatures, and GAPS, which is the first experiment optimized specifically for low-energy cosmic antinuclei, will begin several Antarctic balloon campaigns. The connection of cosmic-ray antinuclei and dark matter is reviewed and the outlook in light of experimental progress is presented.
D. Akimov, P. An, 3 C. Awe, 3 P.S. Barbeau, 3 B. Becker, V. Belov, 1 I. Bernardi, M.A. Blackston,... more D. Akimov, P. An, 3 C. Awe, 3 P.S. Barbeau, 3 B. Becker, V. Belov, 1 I. Bernardi, M.A. Blackston, C. Bock, A. Bolozdynya, J. Browning, B. Cabrera-Palmer, D. Chernyak, ∗ E. Conley, J. Daughhetee, J. Detwiler, K. Ding, M.R. Durand, Y. Efremenko, 6 S.R. Elliott, L. Fabris, M. Febbraro, J. Galambos, A. Gallo Rosso, A. Galindo-Uribarri, 4 M.P. Green, 6, 8 M.R. Heath, S. Hedges, 3 D. Hoang, M. Hughes, E. Iverson, T. Johnson, 3 A. Khromov, A. Konovalov, 5 E. Kozlova, 5 A. Kumpan, L. Li, 3 J.M. Link, J. Liu, K. Mann, D.M. Markoff, 3 J. Mastroberti, M. McIntyre, P.E. Mueller, J. Newby, D.S. Parno, S.I. Penttila, D. Pershey, R. Rapp, † H. Ray, J. Raybern, O. Razuvaeva, 5 D. Reyna, G.C. Rich, D. Rimal, J. Ross, 3 D. Rudik, J. Runge, 3 D.J. Salvat, A.M. Salyapongse, K. Scholberg, A. Shakirov, G. Simakov, 5 G. Sinev, ‡ W.M. Snow, V. Sosnovstsev, B. Suh, R. Tayloe, K. Tellez-Giron-Flores, I. Tolstukhin, § S. Trotter, E. Ujah, 3 J. Vanderwerp, R.L. Varner, C.J. Virtue, G. Visser, T. Wongjirad, Y.-...
We recently developed a fieldable large-area, coded-aperture, gamma imager (the Large Area Imager... more We recently developed a fieldable large-area, coded-aperture, gamma imager (the Large Area Imager - LAI). The instrument was developed to detect weak radiation sources in a fluctuating natural background. Ideally, the efficacy of the instrument is determined using receiver-operator statistics generated from measurement data in terms of probability of detection versus probability of false alarm. However, due to the impracticality of hiding many sources in public areas, it is difficult to measure the data required to generate receiver-operator characteristic (ROC) curves. Instead, we develop a high statistics "model source" from measurements of a real point source and then inject the model source into data collected from the world at large where, presumably, no source exists. In this paper we have applied this "source injection" technique to evaluate the performance of the LAI. We plotted ROC curves obtained for different source locations from the imager and for di...
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Papers by Lorenzo Fabris