Download or read book Neutron and Gamma Time of flight Measurements in Inertial Confinement Fusion Experiments written by Zaarah L. Mohamed and published by . This book was released on 2021 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This work includes the study of various nuclear processes relevant to inertial confinement fusion (ICF) plasmas and big bang nucleosynthesis via experiments performed at the OMEGA laser facility. Neutron and gamma time-of-flight detectors were used to determine various quantities of interest in cryogenic and room temperature implosions. In particular, xylene neutron time-of-flight (nTOF) detectors were used to determine areal densities from backscattered neutrons for OMEGA cryogenic experiments using a forward fit analysis. This analysis was extended to a recently deployed second nTOF line of sight (LOS) on OMEGA. The presence of two nTOF LOS enables a comparison of two measurements to study implosion symmetry, however, these two measurements still leave a lack of coverage around the target chamber which makes it difficult to infer the 3D shape of the areal density. This analysis can easily be extended to additional nTOF lines of sight in the future. The original xylene nTOF detector was also used to infer properties of the 5He ground state and first excited state via a simple wave-function amplitude analysis of neutron spectra from warm TT implosions. These quantities are particularly interesting because of their relationship to the gamma spectrum produced by DT fusion and additionally because the TT neutron spectrum is a background observed in the neutron spectra produced on cryogenic implosions. The ground state mass inferred via forward fit agrees with the accepted value [Audi et al., Nucl. Phys. A 729 (2003)], but the lifetime inferred here is about 70% longer than the accepted value [Wong, Anderson, & McClure, Nucl. Phys. 71 (1965)]. The mass and width of the first excited state were also inferred and compared to previously reported values, though there is a wide spread in the previously reported values. Cherenkov detectors were used to study gamma rays from the reactions D(T,5He)[gamma], H(D,3He)[gamma], and H(T,4He)[gamma] at low energies. The measurements detailed in this work result in a DT gamma-to-neutron branching ratio of (8.42 ł 2.84) × 10-5 measured at a center-of-mass (CM) energy of 19 ł 2 keV. This branching ratio is a factor of 2 larger than the branching ratio previously inferred on an ICF platform [Kim et al., Phys. Rev. C 85 (2012)], however, the error bars on the two measurements overlap. Considering a recent measurement of the DT gamma spectrum [Horsfield et al., Phys. Rev. C. 104 (2021)], the branching ratio measurement detailed in this work also appears to be in agreement with accelerator measurements [Cecil & Wilkinson, Phys. Rev. Lett. 53 (1984); Morgan et al., Phys. Rev. C. 33 (1986)] that isolated the ground state DT gamma. S factors for H(D,3He)[gamma] and H(T,4He)[gamma] were determined at low energies (ECM=16-37 keV). The inferred H(D,3He)[gamma] S factor appears to agree with accelerator data. The H(T,4He)[gamma] S factor inferred from one detector with a relatively high gamma energy threshold appears to be 25-70% larger than an evaluated S factor determined by including accelerator data at higher CM energies [Canon et al., Phys. Rev. C 65 (2002)], however, only two accelerator data points currently exist for comparison at these low energies and these two accelerator data points are in reasonable agreement with the S factors inferred using the high threshold detector as detailed in this work. Another detector with a very low minimum gamma energy threshold was also used to study the H(T,4He)[gamma] S factor. This detector inferred significantly higher values for the H(T,4He)[gamma] S factor, but this particular measurement is thought to be contaminated by detection of neutron-induced gammas from remaining shell material. These time-of-flight gamma measurements require some assumptions concerning the gamma spectrum from each reaction in order to infer branching ratios or S factors. This is not ideal, however, traditional pulse height gamma detection cannot be used for detection of fusion gammas in ICF experiments due to the short time scales involved. Two potential designs are discussed for a true gamma spectrometer intended for operation at ICF facilities"--Pages ix-x.
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 Neutron Time of Flight Measurements of Charged Particle Energy Loss in Inertial Confinement Fusion Plasmas written by and published by . This book was released on 2015 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of the Neutron Time of Flight Spectra from Inertial Confinement Fusion Experiments written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron time-of-flight diagnostics have long been used to characterize the neutron spectrum produced by inertial confinement fusion experiments. The primary diagnostic goals are to extract the d+t → n+[alpha] (DT) and d+d→ n+3He (DD) neutron yields and peak widths, and the amount DT scattering relative to its unscattered yield, also known as the down-scatter ratio (DSR). These quantities are used to infer yield weighted plasma conditions, such as ion temperature (Tion) and cold fuel areal density. We report on novel methodologies used to determine neutron yield, apparent Tion, and DSR. These methods invoke a single temperature, static fluid model to describe the neutron peaks from DD and DT reactions and a spline description of the DT spectrum to determine the DSR. Both measurements are performed using a forward modeling technique that includes corrections for line-of-sight attenuation and impulse response of the detection system. Lastly, these methods produce typical uncertainties for DT Tion of 250 eV, 7% for DSR, and 9% for the DT neutron yield. For the DD values, the uncertainties are 290 eV for Tion and 10% for the neutron yield.
Download or read book Advanced Diagnostics for Magnetic and Inertial Fusion written by Peter E. Stott and published by Springer Science & Business Media. This book was released on 2011-06-28 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the International Conference on Advanced Diagnostics for Magnetic and Inertial Fusion, held September 3-7, 2001 at Villa Monastero, Varenna, Italy. This volume focuses on future diagnostic requirements for fusion energy research emphasizing advanced diagnostics, new techniques and areas where further progress is required.
Download or read book Using high energy density plasmas for nuclear experiments relevant to nuclear astrophysics written by Maria Gatu Johnson and published by Frontiers Media SA. This book was released on 2023-04-14 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Time of flight Measurements Made with Neutrons from Nuclear Explosions in Space written by and published by . This book was released on 1963 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During the 1962 high altitude test series, measurements of the energy spectra of the neutrons from three devices were made by the space physics group of the Los Alamos Scientific Laboratory. The explosions occurred at high altitudes, above the atmosphere, and near Johnston Island. The measurements were made with detectors flown from Kauai, Hawaii to above the atmosphere, on two-stage Nike-Apache rockets. The range between the explosion and the detector packages was about 1300 km. For each of the tests, two moderated fission detectors and two plastic fluor detectors were flown, except that on the third test, an extra fluor detector which had been recovered from the ocean, was also flown. Useful records were obtained for every rocket flown, which makes thirteen neutron spectrum measurements recovered out of thirteen attempts. Although the prime objective of the experiments was to measure the neutron energy spectra, a secondary objective was accomplished in the field of time-of-flight measurements on the resonance structure of various nuclides. Since the experiments were not designed specifically to make cross section measurements, the results are not as detailed as they could be, but some useful results were obtained.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 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 1994-11 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Physics of Inertial Fusion written by Stefano Atzeni and published by OUP Oxford. This book was released on 2004-06-03 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is on inertial confinement fusion, an alternative way to produce electrical power from hydrogen fuel by using powerful lasers or particle beams. It involves the compression of tiny amounts (micrograms) of fuel to thousand times solid density and pressures otherwise existing only in the centre of stars. Thanks to advances in laser technology, it is now possible to produce such extreme states of matter in the laboratory. Recent developments have boosted laser intensities again with new possibilities for laser particle accelerators, laser nuclear physics, and fast ignition of fusion targets. This is a reference book for those working on beam plasma physics, be it in the context of fundamental research or applications to fusion energy or novel ultra-bright laser sources. The book combines quite different areas of physics: beam target interaction, dense plasmas, hydrodynamic implosion and instabilities, radiative energy transfer as well as fusion reactions. Particular attention is given to simple and useful modelling, including dimensional analysis and similarity solutions. Both authors have worked in this field for more than 20 years. They want to address in particular those teaching this topic to students and all those interested in understanding the technical basis.
Download or read book Inertial Confinement Fusion written by and published by . This book was released on 1997 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy and Water Development Appropriations for 2011 Dept of Energy fiscal year 2011 justifications written by United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development and published by . This book was released on 2010 with total page 1732 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Time of Flight Measurements on the Inelastic Scattering of 14 8 Mev Neutrons written by Gerard K. O'Neill and published by . This book was released on 1954 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Time of Flight Measurements of Neutron Spectra in a Graphite Uranium Lattice at Different Temperatures written by Atomic Energy Research Establishment (Harwell, England). Nuclear Physics Division and published by . This book was released on 1961 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of Fusion Neutron Energy Spectra at JET by Meansof Time of flight Techniques written by P. van Belle and published by . This book was released on 1994 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Prompt Fission Neutron Spectrum Using a Gamma Tag Double Time of flight Setup written by Ezekiel Blain and published by . This book was released on 2014 with total page 310 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 1976 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:
