13 results on '"F. Gicquel"'
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2. Initial Evaluation of a Pulsed White Spectrum Neutron Generator for Explosive Detection
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T. Kalvas, M. King, Jani Reijonen, Qing Ji, Ka-Ngo Leung, N. Andresen, G.T. Miller, Joe W. Kwan, and F. Gicquel
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Nuclear and High Energy Physics ,Materials science ,Ion beam ,Neutron emission ,business.industry ,Neutron temperature ,Ion source ,Optics ,Nuclear Energy and Engineering ,Neutron generator ,Physics::Plasma Physics ,Physics::Accelerator Physics ,Neutron source ,Neutron detection ,Neutron ,Electrical and Electronic Engineering ,business - Abstract
Successful explosive material detection in luggage and similar sized containers is a critical issue in securing the safety of all airline passengers. Tensor Technology Inc. has recently developed a methodology that will detect explosive compounds with pulsed fast neutron transmission spectroscopy. In this scheme, tritium beams will be used to generate neutrons with a broad energy spectrum as governed by the T(t,2n)4He fission reaction that produces 0-9 MeV neutrons. Lawrence Berkeley National Laboratory, in collaboration with Tensor Technology Inc., has designed and fabricated a pulsed white-spectrum neutron source for this application. The specifications of the neutron source are demanding and stringent due to the requirements of high yield and fast pulsing neutron emission, and sealed tube, tritium operation. In a unique co-axial geometry, the ion source uses ten parallel rf induction antennas to externally couple power into a toroidal discharge chamber. There are 20 ion beam extraction slits and three concentric electrode rings to shape and accelerate the ion beam into a titanium cone target. Fast neutron pulses are created by using a set of parallel-plate deflectors switching between plusmn750 V and deflecting the ion beams across a narrow slit. The generator is expected to achieve 5 ns neutron pulses at tritium ion beam energies between 80-120 kV. First experiments demonstrated ion source operation and successful beam pulsing.
- Published
- 2009
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3. Commissioning of the Low-$\beta$ Triplets of the Large Hadron Collider
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R. Ostojic, H. Thiesen, A. Perin, F. Gicquel, T. Page, K.-i. Sasaki, Sandor Feher, J. C. Perez, T.J. Peterson, Reiner Denz, C. Darve, Cedric Garion, P.J. Limon, J. Kerby, Thomas H. Nicol, Roger Rabehl, H. Prin, and S. Mathot
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Physics ,Particle physics ,Luminosity (scattering theory) ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Aperture ,Superconducting magnet ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Nuclear physics ,Dipole ,Beta (plasma physics) ,Quadrupole ,Physics::Accelerator Physics ,Electrical and Electronic Engineering ,Beam (structure) - Abstract
The low-beta triplets of the Large Hadron Collider were designed and constructed by a world-wide collaboration officially formed in 1998. Over the course of the following years the collaboration worked to produce the triplet components, including four 215 T/m, 70 mm aperture quadrupoles, a DFBX distribution feedbox, and at the low luminosity interaction points a cold D1 beam separation dipole. In 2005 the first triplet was installed in the LHC tunnel, and at the end of 2007 hardware commissioning of the first triplets started. As of August 2008 five triplets have been successfully powered. This paper documents the processes and experience gained during the commissioning phase of the LHC.
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- 2009
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4. D–D neutron generator development at LBNL
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Ka-Ngo Leung, M. King, F. Gicquel, T.-P. Lou, Jani Reijonen, and S.K. Hahto
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Radiation ,Chemistry ,Point source ,Astrophysics::High Energy Astrophysical Phenomena ,Nuclear engineering ,Ion source ,Generator (circuit theory) ,Nuclear physics ,Neutron generator ,Physics::Plasma Physics ,Nuclear fusion ,Neutron detection ,Neutron source ,Neutron ,Nuclear Experiment - Abstract
The plasma and ion source technology group in Lawrence Berkeley National Laboratory is developing advanced, next generation D-D neutron generators. There are three distinctive developments, which are discussed in this presentation, namely, multi-stage, accelerator-based axial neutron generator, high-output co-axial neutron generator and point source neutron generator. These generators employ RF-induction discharge to produce deuterium ions. The distinctive feature of RF-discharge is its capability to generate high atomic hydrogen species, high current densities and stable and long-life operation. The axial neutron generator is designed for applications that require fast pulsing together with medium to high D-D neutron output. The co-axial neutron generator is aimed for high neutron output with cw or pulsed operation, using either the D-D or D-T fusion reaction. The point source neutron generator is a new concept, utilizing a toroidal-shaped plasma generator. The beam is extracted from multiple apertures and focus to the target tube, which is located at the middle of the generator. This will generate a point source of D-D, T-T or D-T neutrons with high output flux. The latest development together with measured data will be discussed in this article.
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- 2005
- Full Text
- View/download PDF
5. Analysis of fissile materials by high-energy neutron-induced fission decay gamma-rays
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G. Garabedian, Richard B. Firestone, Zs. Révay, Jani Reijonen, G. A. English, Ka-Ngo Leung, György Molnár, Dale L. Perry, Bryan B. Bandong, and F. Gicquel
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Physics ,Fission products ,Neutron emission ,Health, Toxicology and Mutagenesis ,Radiochemistry ,Public Health, Environmental and Occupational Health ,Fission product yield ,Pollution ,Fast fission ,Analytical Chemistry ,Nuclear physics ,Uranium-238 ,Nuclear Energy and Engineering ,Prompt neutron ,Radiology, Nuclear Medicine and imaging ,Long-lived fission product ,Delayed neutron ,Spectroscopy - Abstract
Author(s): Firestone, R.B.; English, G.A.; Reijonen, J.; Gicquel, F.; Leung, K.-N.; Perry, D.L.; Garabedian, G.; Bandong, B.; Revay, Zs.; Molnar, G.L. | Abstract: Thermal neutrons from the Budapest Research Reactor and fast neutrons from the Berkeley Neutron Generator Facility have been used to analyze uranium. It has been shown that both prompt and delayed gamma rays from neutron capture and fission product decay can be used to analyze uranium concentrations and 235U enrichment. Detection of neutrons from the spontaneous fission of 238U has also been demonstrated for uranium analysis. The observation of high-energy gamma rays following the decay of short-lived fission products is a sensitive indication of fissile material, and the ratio of fission product gamma ray intensities can uniquely determine the concentrations of fission isotopes.
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- 2005
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6. First PGAA and NAA experimental results from a compact high intensity D–D neutron generator
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Richard B. Firestone, F. Gicquel, Alan R. Smith, H. Koivunoro, László Szentmiklósi, Jani Reijonen, G. Garabedian, J.A. English, György Molnár, Ka-Ngo Leung, Dale L. Perry, Mingshan Sun, B. Bandong, Zs. Révay, and T.-P. Lou
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Physics ,Nuclear and High Energy Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Nuclear Theory ,Plasma ,Ion source ,Nuclear physics ,Neutron generator ,Deuterium ,Electromagnetic shielding ,Neutron source ,Neutron ,Neutron activation analysis ,Nuclear Experiment ,Instrumentation - Abstract
High neutron output D–D neutron generators have been developed in the Plasma and Ion Source Technology Group in LBNL. A new facility has been build to enable testing and running these powerful generators. The co-axial neutron generator and the shielding/moderator structure are described in this presentation. Also presented are the first PGAA (Prompt Gamma Activation Analysis) and NAA (Neutron Activation Analysis) results measured in this neutron facility.
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- 2004
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7. VALIDATION AND PERFORMANCE OF THE LHC CRYOGENIC SYSTEM THROUGH COMMISSIONING OF THE FIRST SECTOR
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L. Serio, A. Bouillot, J. Casas-Cubillos, A. Chakravarty, S. Claudet, F. Gicquel, P. Gomes, M. Kumar, P. K. Kush, F. Millet, A. Perin, R. Rabehl, M. R. Singh, M. Soubiran, L. Tavian, J. G. Weisend, John Barclay, Susan Breon, Jonathan Demko, Michael DiPirro, J. Patrick Kelley, Peter Kittel, Arkadiy Klebaner, Al Zeller, Mark Zagarola, Steven Van Sciver, Andrew Rowe, John Pfotenhauer, Tom Peterson, and Jennifer Lock
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Physics ,Interconnection ,Large Hadron Collider ,Physics::Instrumentation and Detectors ,Project commissioning ,Nuclear engineering ,Astrophysics::Instrumentation and Methods for Astrophysics ,Mechanical engineering ,Refrigeration ,Particle accelerator ,Cryogenics ,Cooling capacity ,Accelerators and Storage Rings ,Line (electrical engineering) ,law.invention ,law ,Physics::Accelerator Physics - Abstract
The cryogenic system [1] for the Large Hadron Collider accelerator is presently in its final phase of commissioning at nominal operating conditions. The refrigeration capacity for the LHC is produced using eight large cryogenic plants and eight 1.8 K refrigeration units installed on five cryogenic islands. Machine cryogenic equipment is installed in a 26.7-km circumference ring deep underground tunnel and are maintained at their nominal operating conditions via a distribution system consisting of transfer lines, cold interconnection boxes at each cryogenic island and a cryogenic distribution line. The functional analysis of the whole system during all operating conditions was established and validated during the first sector commissioning in order to maximize the system availability. Analysis, operating modes, main failure scenarios, results and performance of the cryogenic system are presented.
- Published
- 2008
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8. Development of advanced neutron/gamma generators for imaging and active interrogation applications
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D.H. Morse, Arlyn J. Antolak, Jani Reijonen, Ka-Ngo Leung, T.-P. Lou, T. Kalvas, H. Vainionpaa, M. Piestrup, R. Gough, G.T. Miller, M. King, Barney Lee Doyle, N. Andresen, and F. Gicquel
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Nuclear physics ,Nuclear reaction ,Generator (circuit theory) ,Photon ,Neutron generator ,Physics::Plasma Physics ,Chemistry ,Nuclear engineering ,Nuclear fusion ,Neutron ,Plasma ,Ion source - Abstract
We report here on the development of neutron and photon sources for use in imaging and active interrogation applications, where there is a growing urgency for more advanced interrogation tools. These devices include high yield D-D, D-T and T-T fusion reaction based neutron generators and also low energy nuclear reaction based high-energy gamma generators. One common feature in these various devices is the use of a high-efficiency, RF-induction discharge ion source. This discharge method provides high plasma density for high output current, high atomic species from molecular gases for high efficiency neutron or gamma generation and long lifetime. Predictable discharge characteristics of these plasma generators allow accurate modeling for both the beam dynamics and for the heat loads at the target spot. Current status of the neutron and gamma generator development with experimental data will be presented.
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- 2007
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- View/download PDF
9. Single ion implantation with scanning probe alignment
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Tzv. Ivanov, Ivo W. Rangelow, Arun Persaud, Frances I. Allen, Jeffrey Bokor, K. Ivanova, Thomas Schenkel, James Alexander Liddle, F. Gicquel, and S. J. Park
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Ion beam ,business.industry ,Chemistry ,Physics ,General Engineering ,Scanning confocal electron microscopy ,Scanning capacitance microscopy ,Focused ion beam ,Scanning probe microscopy ,Ion implantation ,Ion beam deposition ,Engineering ,Physics::Plasma Physics ,Optoelectronics ,Electron beam-induced deposition ,Atomic physics ,business ,Ion Implantation Scanning probe microscopy - Abstract
We present results from our development of a single ion implantation technique integrated with a scanning force microscope. Accurate alignment at the 5nm level is a crucial requirement for reliable single ion placement. We address this through integration of the ion beam with a scanning probe tip containing an aperture. Single ion registration is based on detection of secondary electron bursts from single, high charge state ions. We describe formation of scanning probe tips with holes and sensing poles by focused ion and electron beam processing (drilling and thin film deposition). Ion transport studies through apertures show stable transmission for >10h with 1nA scale beam intensities on precollimators.
- Published
- 2004
10. Fast slit-beam extraction and chopping for neutron generator
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Jaakko Hannes Vainionpaa, S. K. Hahto, Jani Reijonen, Ka-Ngo Leung, F. Gicquel, T. G. Miller, M. King, and T. Kalvas
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Physics ,Ion beam ,Physics::Instrumentation and Detectors ,business.industry ,Einzel lens ,Neutron temperature ,Neutron spectroscopy ,Chopper ,Optics ,Neutron generator ,Physics::Plasma Physics ,Physics::Accelerator Physics ,Neutron detection ,Atomic physics ,business ,Instrumentation ,Beam (structure) - Abstract
High-intensity fast white neutron pulses are needed for pulsed fast neutron transmission spectroscopy (PFNTS). A compact tritium–tritium fusion reaction neutron generator with an integrated ion beam chopping system has been designed, simulated, and tested for PFNTS. The design consists of a toroidal plasma chamber with 20 extraction slits, concentric cylindrical electrodes, chopper plates, and a central titanium-coated beam target. The total ion beam current is 1A. The beam chopping is done at 30keV energy with a parallel-plate deflector integrated with an Einzel lens. Beam pulses with 5ns width can be achieved with a 15ns rise/fall time ±1500V sweep on the chopper plates. The neutrons are produced at 120keV energy. A three-dimensional simulation code based on Vlasov iteration was developed for simulating the ion optics of this system. The results with this code were found to be consistent with other simulation codes. So far we have measured 50ns ion beam pulses from the system.
- Published
- 2006
- Full Text
- View/download PDF
11. Continuity of care during the COVID-19 pandemic: Qualitative results from a mixed-methods study
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M. Dubois, Katharina Tabea Jungo, Yael Rachamin, S. Bertato, F. Gicquel, Michael J. Deml, Julie Dubois, Sven Streit, and Oliver Senn
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medicine.medical_specialty ,education.field_of_study ,Coronavirus disease 2019 (COVID-19) ,business.industry ,media_common.quotation_subject ,Population ,Public Health, Environmental and Occupational Health ,Qualitative property ,Retrospective cohort study ,Feeling ,Family medicine ,Preparedness ,2.I. Oral presentations: The impact of COVID-19 on health services ,Pandemic ,Medicine ,Continuity of care ,AcademicSubjects/MED00860 ,AcademicSubjects/SOC01210 ,ddc:301 ,business ,education ,AcademicSubjects/SOC02610 ,Parallel Programme ,media_common - Abstract
Background Decreases in health service use were observed globally during the COVID-19 pandemic. In the quantitative part of this mixed-methods study, we documented similar trends in Switzerland, with a retrospective cohort study showing a 15-20% decrease in general practitioner (GP) consultations/chronic disease monitoring in spring 2020. These changes need to be understood, particularly for individuals at risk of COVID-19 complications, as many have conditions requiring regular monitoring. Methods With a mixed-methods design, we examine continuity of care for at-risk groups (people: ≥65-years-old, with cancer, diabetes, respiratory disease, etc.) between Mar-2020 and Apr-2021. Following quantitative analyses, we qualitatively studied changes in GP/patient practices thru semi-structured interviews with 23 GPs and 36 at-risk patients. We here focus on thematically analyzed qualitative results. Results Qualitative data helped explain observed reductions in consultations/monitoring: 1) some patients were discouraged to seek care by official recommendations and/or GPs during the first semi-shutdown; 2) some patients perceived GP offices as closed/overburdened; 3) some patients feared contracting coronavirus; 4) some patients sought alternatives to traditional primary care consultations (e.g., tele-consultations, consulting pharmacists/other professionals, self-reliance). Many patients did not feel that there was discontinuity of their cares. GPs commonly described feeling like an underutilized resource during the pandemic and explained how they could have been mobilized for population needs. Conclusions During the first wave, there was a mismatch between 1) GPs' reported availability/preparedness to adequately care for at-risk patients, and 2) some GPs discouraging at-risk patients to come for consultations, at-risk patients' perceptions that their care was not “urgent” in a pandemic setting, and patient perceptions that GPs were otherwise unavailable/overburdened. Key messages Qualitative data offer explanations for health service use reductions during the COVID-19 pandemic. Results provide potential paths forward and highlight GP views of being an underutilized resource.
12. Utility of chromosomal microarray analysis for the exploration of isolated and severe fetal growth restriction diagnosed before 24 weeks' gestation.
- Author
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Dap M, Gicquel F, Lambert L, Perdriolle-Galet E, Bonnet C, and Morel O
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- Chromosome Aberrations, DNA Copy Number Variations, Female, Gestational Age, Humans, Microarray Analysis, Pregnancy, Retrospective Studies, Fetal Growth Retardation diagnosis, Fetal Growth Retardation genetics, Prenatal Diagnosis
- Abstract
Objective: This study aimed to evaluate the utility of chromosomal microarray analysis (CMA), for the genetic exploration of isolated and severe intrauterine growth restriction (IUGR) diagnosed before 24 weeks gestation (WG)., Methods: This retrospective study included singleton fetuses diagnosed with severe IUGR without structural anomalies before 24 WG referred between 2013 and 2021 who underwent prenatal genetic analysis. IUGR was defined by estimated fetal weight ≤3rd centile for gestational age. Genetic analysis, including QF-PCR and CMA, was systematically offered as part of the etiologic evaluation., Results: Of 101 referred fetuses, CMA and QF-PCR were performed in 67 fetuses. Among these 67 cases, a total of 10.5% (7/67) chromosomal abnormalities were detected. CMA detected three pathogenic copy number variants (CNV) (3/67, 4.5%) and three variants of unknown signification (VUS) (3/67, 4.5%). Karyotype detected one chromosomal abnormality. All of the QF-PCR were normal. Two fetuses with pathogenic CNV shows Doppler abnormalities., Conclusion: Our study found that in fetuses with severe, isolated, and very early-onset growth restriction, the rate of pathogenic CNV detected by CMA was 4.5%. Although this cohort is too small to draw a definitive conclusion, the presence of Doppler abnormalities couldn't exclude the possibility of genetic abnormalities., (© 2022 John Wiley & Sons Ltd.)
- Published
- 2022
- Full Text
- View/download PDF
13. D-D neutron generator development at LBNL.
- Author
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Reijonen J, Gicquel F, Hahto SK, King M, Lou TP, and Leung KN
- Abstract
The plasma and ion source technology group in Lawrence Berkeley National Laboratory is developing advanced, next generation D-D neutron generators. There are three distinctive developments, which are discussed in this presentation, namely, multi-stage, accelerator-based axial neutron generator, high-output co-axial neutron generator and point source neutron generator. These generators employ RF-induction discharge to produce deuterium ions. The distinctive feature of RF-discharge is its capability to generate high atomic hydrogen species, high current densities and stable and long-life operation. The axial neutron generator is designed for applications that require fast pulsing together with medium to high D-D neutron output. The co-axial neutron generator is aimed for high neutron output with cw or pulsed operation, using either the D-D or D-T fusion reaction. The point source neutron generator is a new concept, utilizing a toroidal-shaped plasma generator. The beam is extracted from multiple apertures and focus to the target tube, which is located at the middle of the generator. This will generate a point source of D-D, T-T or D-T neutrons with high output flux. The latest development together with measured data will be discussed in this article.
- Published
- 2005
- Full Text
- View/download PDF
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