Download or read book Interpretation of Neutron Time of flight Signals from Current mode Detectors written by and published by . This book was released on 1996 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron time-of-flight (nToF) signals from current-mode neutron detectors are often used to determine burn-averaged ion temperature from ICF targets because the spread of the neutron energy distribution is a function of the temperature of the reacting ions. The measured signal will, however, be a convolution of the actual neutron signal, the detector response, and the response of the recording system. In addition, scattered neutrons will arrive at the detector later than unscattered neutrons, further broadening the signal. The ion temperature derived from nToF data depends strongly on the functions used to fit the data or the methods utilized to unfold the neutron energy spectrum. A functional form based on known and measured properties of the detectors is used to fit the integral of the time-of-flight signal, allowing ion temperature derivations from targets with lower neutron yield than previously possible.
Download or read book A Novel Method for Modeling the Neutron Time of Flight nTOF Detector Response in Current Mode to Inertial Confinement Fusion Experiments written by and published by . This book was released on 2013 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are several machines in this country that produce short bursts of neutrons for various applications. A few examples are the ZU+2010machine, operated by Sandia National Laboratories in Albuquerque, NMU+2020; the OMEGA Laser Facility at the University of Rochester in Rochester, NYU+00A7; and the National Ignition Facility (NIF) operated by the Department of Energy at Lawrence Livermore National Laboratory in Livermore, CaliforniaU+2021. They all incorporate neutron time of flight (nTOF) detectors which measure neutron yield, and the shapes of the waveforms from these detectors contain germane information about the plasma conditions that produce the neutrons. However, the signals can also be %E2%80%9Cclouded%E2%80%9D by a certain fraction of neutrons that scatter off structural components and also arrive at the detectors, thereby making analysis of the plasma conditions more difficult. These detectors operate in current mode - i.e., they have no discrimination, and all the photomultiplier anode charges are integrated rather than counted individually as they are in single event counting. Up to now, there has not been a method for modeling an nTOF detector operating in current mode. MCNPU+2010PoliMiU+F0D1was developed in 2002 to simulate neutron and gammaU+2010ray detection in a plastic scintillator, which produces a collision data output table about each neutron and photon interaction occurring within the scintillator; however, the postU+2010processing code which accompanies MCNPU+2010PoliMi assumes a detector operating in singleU+2010event counting mode and not current mode. Therefore, the idea for this work had been born: could a new postU+2010processing code be written to simulate an nTOF detector operating in current mode? And if so, could this process be used to address such issues as the impact of neutron scattering on the primary signal? Also, could it possibly even identify sources of scattering (i.e., structural materials) that could be removed or modified to produce %E2%80%9Ccleaner%E2%80%9D neutron signals? This process was first developed and then applied to the axial neutron time of flight detectors at the ZU+2010Facility mentioned above. First, MCNPU+2010PoliMi was used to model relevant portions of the facility between the source and the detector locations. To obtain useful statistics, variance reduction was utilized. Then, the resulting collision output table produced by MCNPU+2010PoliMi was further analyzed by a MATLAB postprocessing code. This converted the energy deposited by neutron and photon interactions in the plastic scintillator (i.e., nTOF detector) into light output, in units of MeVee%D1%84 (electron equivalent) vs time. The time response of the detector was then folded into the signal via another MATLAB code. The simulated response was then compared with experimental data and shown to be in good agreement. To address the issue of neutron scattering, an %E2%80%9CIdeal Case, %E2%80%9D (i.e., a plastic scintillator was placed at the same distance from the source for each detector location) with no structural components in the problem. This was done to produce as %E2%80%9Cpure%E2%80%9D a neutron signal as possible. The simulated waveform from this %E2%80%9CIdeal Case%E2%80%9D was then compared with the simulated data from the %E2%80%9CFull Scale%E2%80%9D geometry (i.e., the detector at the same location, but with all the structural materials now included). The %E2%80%9CIdeal Case%E2%80%9D was subtracted from the %E2%80%9CFull Scale%E2%80%9D geometry case, and this was determined to be the contribution due to scattering. The time response was deconvolved out of the empirical data, and the contribution due to scattering was then subtracted out of it. A transformation was then made from dN/dt to dN/dE to obtain neutron spectra at two different detector locations.
Download or read book Signal Predictions for a Proposed Fast Neutron Interrogation Method written by and published by . This book was released on 1992 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have applied the Monte Carlo radiation transport code COG) to assess the utility of a proposed explosives detection scheme based on neutron emission. In this scheme a pulsed neutron beam is generated by an approximately seven MeV deuteron beam incident on a thick Be target. A scintillation detector operating in the current mode measures the neutrons transmitted through the object as a function of time. The flight time of unscattered neutrons from the source to the detector is simply related to the neutron energy. This information along with neutron cross section excitation functions is used to infer the densities of H, C, N and O in the volume sampled. The code we have chosen to use enables us to create very detailed and realistic models of the geometrical configuration of the system, the neutron source and of the detector response. By calculating the signals that will be observed for several configurations and compositions of interrogated object we can investigate and begin to understand how a system that could actually be fielded will perform. Using this modeling capability many early on with substantial savings in time and cost and with improvements in performance. We will present our signal predictions for simple single element test cases and for explosive compositions. From these studies it is dear that the interpretation of the signals from such an explosives identification system will pose a substantial challenge.
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Preliminary Calibration of Radial Neutron Time Of Flight Detectors on a Dense Plasma Focus written by Jacquelynne Vaughan and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron time-of-flight (nTOF) detectors are commonly used for fast neutron detection on nuclear fusion plasma experiments in high energy density physics. The 4.6-kJ dense plasma focus (DPF) at UC San Diego can generate neutron yields of up to ~108. Two nTOF detectors radially situated at 1.3 m from the DPF are each composed of an EJ-204 plastic scintillator and an Hamamatsu R7724 photomultiplier tube. Several hundred experimental shots have been taken over the course of four different anode types. Of those, 203 shots with neutron data were selected to calibrate both nTOF detectors. A Be-activation detector generates absolute neutron yield data and has a lower detection limit of 1.1·106 neutrons. The latter is used to calibrate the signal areas in the nTOF data, and directly correlate those signal areas with the number of neutrons incident on the detector at its radius from the DPF. This preliminary analysis finds that the two nTOF detectors have approximate efficiencies of 8100 and 1700 photons per DD neutron, respectively. Further analysis can improve the correlation as well as investigate the cross-calibration between the two nTOF detectors more thoroughly.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interpretation of neutron detector signals during the pbf severe fuel damage scoping test written by R. D. Crowe and published by . This book was released on 1983 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975-02 with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutron Time of flight Signals from Expanding Or Contracting Spherical Sources written by and published by . This book was released on 1996 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The width of the energy distribution of fusion-produced neutrons is often used as an indication of the temperature of the reacting ions. The Doppler broadening of the neutron energy is due to the center-of-mass velocity of reacting ion pairs and is characterized by the ion temperature for a Maxwellian distribution of ions with zero collective velocity. If there is bulk fluid motion or turbulence characterized by a velocity on the order of the ion thermal speed, a significant additional broadening may introduced. Suggestions of this phenomenon have been observed for two classes of laser targets. The first is a g̀̀as bag ̀̀target, in which a deuterated hydrocarbon gas is contained in a thin spherical membrane and illuminated uniformly. The second target is an ICF capsule with a deuterated plastic inner layer. In both cases, measured neutron energy distributions were wider than expected from theoretical ion temperatures alone would predict, and if interpreted as indicative of the ion temperature, are inconsistent with the neutron yields observed.
Download or read book Particle Detectors written by Hermann Kolanoski and published by Oxford University Press. This book was released on 2020-06-30 with total page 949 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the fundamentals of particle detectors as well as their applications. Detector development is an important part of nuclear, particle and astroparticle physics, and through its applications in radiation imaging, it paves the way for advancements in the biomedical and materials sciences. Knowledge in detector physics is one of the required skills of an experimental physicist in these fields. The breadth of knowledge required for detector development comprises many areas of physics and technology, starting from interactions of particles with matter, gas- and solid-state physics, over charge transport and signal development, to elements of microelectronics. The book's aim is to describe the fundamentals of detectors and their different variants and implementations as clearly as possible and as deeply as needed for a thorough understanding. While this comprehensive opus contains all the materials taught in experimental particle physics lectures or modules addressing detector physics at the Master's level, it also goes well beyond these basic requirements. This is an essential text for students who want to deepen their knowledge in this field. It is also a highly useful guide for lecturers and scientists looking for a starting point for detector development work.
Download or read book Laser Program Annual Report written by and published by . This book was released on 1986 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Detector Neutron Energy Response Using Time of flight Techniques written by and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Research of the National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1975 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Theory and Practice of Scintillation Counting written by J. B. Birks and published by Elsevier. This book was released on 2013-10-22 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Theory and Practice of Scintillation Counting is a comprehensive account of the theory and practice of scintillation counting. This text covers the study of the scintillation process, which is concerned with the interactions of radiation and matter; the design of the scintillation counter; and the wide range of applications of scintillation counters in pure and applied science. The book is easy to read despite the complex nature of the subject it attempts to discuss. It is organized such that the first five chapters illustrate the fundamental concepts of scintillation counting. Chapters 6 to 10 detail the properties and applications of organic scintillators, while the next four chapters discuss inorganic scintillators. The last two chapters provide a review of some outstanding problems and a postscript. Nuclear physicists, radiation technologists, and postgraduate students of nuclear physics will find the book a good reference material.
Download or read book Associated Particle Detector for the Neutron Time of Flight Spectrometer written by Richard C. Lamb and published by . This book was released on 1960 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Abstracts written by and published by . This book was released on with total page 2664 pages. Available in PDF, EPUB and Kindle. Book excerpt:
