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Adaptation of a cubic smoothing spline algortihm for multi-channel data stitching at the National Ignition Facility

Description: Some diagnostics at the National Ignition Facility (NIF), including the Gamma Reaction History (GRH) diagnostic, require multiple channels of data to achieve the required dynamic range. These channels need to be stitched together into a single time series, and they may have non-uniform and redundant time samples. We chose to apply the popular cubic smoothing spline technique to our stitching problem because we needed a general non-parametric method. We adapted one of the algorithms in the literature, by Hutchinson and deHoog, to our needs. The modified algorithm and the resulting code perform a cubic smoothing spline fit to multiple data channels with redundant time samples and missing data points. The data channels can have different, time-varying, zero-mean white noise characteristics. The method we employ automatically determines an optimal smoothing level by minimizing the Generalized Cross Validation (GCV) score. In order to automatically validate the smoothing level selection, the Weighted Sum-Squared Residual (WSSR) and zero-mean tests are performed on the residuals. Further, confidence intervals, both analytical and Monte Carlo, are also calculated. In this paper, we describe the derivation of our cubic smoothing spline algorithm. We outline the algorithm and test it with simulated and experimental data.
Date: December 28, 2010
Creator: Brown, C; Adcock, A; Azevedo, S; Liebman, J & Bond, E
Partner: UNT Libraries Government Documents Department

National Ignition Facility main laser stray light analysis and control

Description: Stray light analysis has been carried out for the main laser section of the National Ignition Facility main laser section using a comprehensive non-sequential ray trace model supplemented with additional ray trace and diffraction propagation modeling. This paper describes the analysis and control methodology, gives examples of ghost paths and required tilted lenses, baffles, absorbers, and beam dumps, and discusses analysis of stray light �pencil beams� in the system.
Date: June 26, 1998
Creator: English, R E; Miller, J L; Peterson, G & Schweyen, J
Partner: UNT Libraries Government Documents Department

Ghost reflection analysis for the main laser of the National Ignition Facility

Description: Ghost reflections are a major consideration in the optical design of the National Ignition Facility (ME). The frost-order layout (e.g., spacing between components), the lens shape, and the dimensions of the building are strongly affected. In this paper we will describe the principal ghost reflections that drive the system configuration. Several specific examples will be shown to illustrate how dangerous ghost reflections are avoided and stray light concerns are managed.
Date: June 26, 1998
Creator: English, R E; Miller, J L & Schweyen, J
Partner: UNT Libraries Government Documents Department

Strongly-driven laser plasma coupling

Description: An improved understanding of strongly-driven laser plasma coupling is important for optimal use of the National Ignition Facility (NIF) for both inertial fusion and for a variety of advanced applications. Such applications range from high energy x- ray sources and high temperature hohlraums to fast ignition and laser radiography. We discuss a novel model for the scaling of strongly-driven stimulated Brillouin and Raman scattering. This model postulates an intensity dependent correlation length associated with spatial incoherence due to filamentation and stimulated forward scattering. We first motivate the model and then relate it to a variety of experiments. Particular attention is paid to high temperature hohlraum experiments, which exhibited low to modest stimulated Brillouin scattering even though this instability was strongly driven. We also briefly discuss the strongly nonlinear interaction physics for efficient generation of high energy electrons either _ by irradiating a large plasma with near quarter-critical density or by irradiating overdense targets with ultra intense laser
Date: June 25, 1998
Creator: Suter, L; Afeyan, B; Campbell, E M; Decker, C D; Kruer, W L; Moody, J et al.
Partner: UNT Libraries Government Documents Department

Role of the NIF in the development of ICF applications

Description: The National Ignition Facility (NIF) is a 1.8 MJ (at 351 nm), 192 beam laser facility being built at the Lawrence Livermore National Laboratory (LLNL) to achieve inertial fusion ignition in the laboratory. The NIF Project is being designed and built by a team from LLNL, Los Alamos National Laboratory, Sandia National Laboratory, and the University of Rochester. When completed in 2003, it will be a multipurpose facility that will be used for many applications in national security, energy, and the basic sciences. In addition to the National Security Mission, these applications include, for example, electric power generation, space propulsion, and study of basic astrophysical phenomena in the laboratory. Such applications receive benefit both through the state- of-the-art technology developments necessary to build NIF and through specific experiments that will be performed on NIF.
Date: April 23, 1998
Creator: Hogan, W.
Partner: UNT Libraries Government Documents Department

National Ignition Facility Site Management Plan

Description: The purpose of the NIF Site Management Plan is to describe the roles, responsibilities, and interfaces for the major NIF Project organizations involved in construction of the facility, installation and acceptance testing of special equipment, and the NIF activation. The plan also describes the resolution of priorities and conflicts. The period covered is from Critical Decision 3 (CD3) through the completion of the Project. The plan is to be applied in a stepped manner. The steps are dependent on different elements of the project being passed from the Conventional Facilities (CF) Construction Manager (CM), to the Special Equipment (SE) CMs, and finally to the Activation/ Start-Up (AS) CM. These steps are defined as follows: The site will be coordinated by CF through Project Milestone 310, end of conventional construction. The site is defined as the fenced area surrounding the facility and the CF laydown and storage areas. The building utilities that are installed by CF will be coordinated by CF through the completion of Project Milestone 310, end of conventional construction. The building utilities are defined as electricity, compressed air, de-ionized water, etc. Upon completion of the CF work, the Optics Assembly Building/Laser and Target Area Building (OAB/LTAB) will be fully operational. At that time, an Inertial Confinement Fusion (ICF) Program building coordinator will become responsible for utilities and site activities. * Step 1. Mid-commissioning (temperature stable, +1{degree}C) of an area (e.g., Laser Bay 2, OAB) will precipitate the turnover of that area (within the four walls) from CF to SE. * Step 2. Interior to the turned-over space, SE will manage all interactions, including those necessary by CF. * Step 3. As the SE acceptance testing procedures (ATPS) are completed, AS will take over the management of the area and coordinate all interactions necessary by CF and SE. For ...
Date: September 1, 1997
Creator: Roberts, V.
Partner: UNT Libraries Government Documents Department

NIF optics phase gradient specfication

Description: A root-mean-square (rms) phase gradient specification seems to allow a good connection between the NIP optics quality and focal spot requirements. Measurements on Beamlet optics individually, and as a chain, indicate they meet the assumptions necessary to use this specification, and that they have a typical rms phase gradient of {approximately}80 {angstrom}/cm. This may be sufficient for NIP to meet the proposed Stockpile Stewardship Management Program (SSMP) requirements of 80% of a high- power beam within a 200-250 micron diameter spot. Uncertainties include, especially, the scale length of the optics phase noise, the ability of the adaptive optic to correct against pump-induced distortions and optics noise, and the possibility of finding mitigation techniques against whole-beam self-focusing (e.g. a pre- correction optic). Further work is needed in these areas to better determine the NIF specifications. This memo is a written summary of a presentation on this topic given by W. Williams 24 April 1997 to NIP and LS&T personnel.
Date: May 2, 1997
Creator: Williams, W.; Auerbach, J.; Hunt, J.; Lawson, L.; Manes, K.; Orth, C. et al.
Partner: UNT Libraries Government Documents Department

Lawrence Livermore National Laboratory's activities to achieve ignition by x-ray drive on the National Ignition Facility

Description: The National Ignition Facility (NIF) is a MJ-class glass laser-based facility funded by the Department of Energy which has achieving thermonuclear ignition and moderate gain as one of its main objectives. In the summer of 1998, the project is about 40% complete, and design and construction is on schedule and on cost. The NIF will start firing onto targets in 2001, and will achieve full energy in 2004. The Lawrence Livermore National Laboratory (LLNL), together with the Los Alamos National Laboratory (LANL) have the main responsibility for achieving x-ray driven ignition on the NIF. In the 1990�s, a comprehensive series of experiments on Nova at LLNL, followed by recent experiments on the Omega laser at the University of Rochester, demonstrated confidence in understanding the physics of x-ray drive implosions. The same physics at equivalent scales is used in calculations to predict target performance on the NIF, giving credence to calculations of ignition on the NIF. An integrated program of work in preparing the NIF for x-ray driven ignition in about 2007, and the key issues being addressed on the current ICF facilities [(Nova, Omega, Z at Sandia National Laboratory (SNL), and NIKE at the Naval Research Laboratory (NRL)] are described.
Date: July 20, 1998
Creator: Bernat, T. P.; Hammel, B. A.; Kauffman, R. L.; Kilkenny, J. D.; Landen, O. L.; Lindl, J. D. et al.
Partner: UNT Libraries Government Documents Department

Construction safety program for the National Ignition Facility Appendix A: Safety Requirements

Description: These rules apply to all LLNL employees, non-LLNL employees (including contract labor, supplemental labor, vendors, personnel matrixed/assigned from other National Laboratories, participating guests, visitors and students) and construction contractors/subcontractors. The General Safety and Health rules shall be used by management to promote accident prevention through indoctrination, safety and health training and on-the-job application. As a condition for contracts award, all contractors and subcontractors and their employees must certify on Form S & H A-1 that they have read and understand, or have been briefed and understand, the National Ignition Facility OCIP Project General Safety Rules.
Date: January 14, 1997
Creator: Cerruti, S. J.
Partner: UNT Libraries Government Documents Department

Development system performance issues of the NIF master oscillator and pulse forming networking

Description: A crucial step in the development of a complex laser system is initial testing of an integrated system. Issues arise at the system level which are not easily observed in component level testing. The NIF master oscillator room (MOR) contains a network of fiber and integrated optic components which can interact, potentially reducing system performance. Here we present some of the system problems we have seen in integrated tests and our solutions. Issues include ASE in the fiber amplifiers, filtering effects in the PM fiber, and regulation of average optical power.
Date: October 29, 1998
Creator: Browning, D; Dreifuerst, G; Penko, F; Rothenberg, J & Wilcox, R
Partner: UNT Libraries Government Documents Department

Construction safety program for the National Ignition Facility, Appendix A

Description: Topics covered in this appendix include: General Rules-Code of Safe Practices; 2. Personal Protective Equipment; Hazardous Material Control; Traffic Control; Fire Prevention; Sanitation and First Aid; Confined Space Safety Requirements; Ladders and Stairways; Scaffolding and Lift Safety; Machinery, Vehicles, and Heavy Equipment; Welding and Cutting-General; Arc Welding; Oxygen/Acetylene Welding and Cutting; Excavation, Trenching, and Shoring; Fall Protection; Steel Erection; Working With Asbestos; Radiation Safety; Hand Tools; Electrical Safety; Nonelectrical Work Performed Near Exposed High-Voltage Power-Distribution Equipment; Lockout/Tagout Requirements; Rigging; A-Cranes; Housekeeping; Material Handling and Storage; Lead; Concrete and Masonry Construction.
Date: June 26, 1997
Creator: Cerruti, S. J.
Partner: UNT Libraries Government Documents Department

National Ignition Facility system design requirements conventional facilities SDR001

Description: This System Design Requirements (SDR) document specifies the functions to be performed and the minimum design requirements for the National Ignition Facility (NIF) site infrastructure and conventional facilities. These consist of the physical site and buildings necessary to house the laser, target chamber, target preparation areas, optics support and ancillary functions.
Date: April 9, 1996
Creator: Hands, J.
Partner: UNT Libraries Government Documents Department

Capsule design for the National Ignition Facility

Description: Several choices exist in the design and production of capsules intended to ignite and propagate fusion burn of the DT fuel when imploded by indirect drive at the National Ignition Facility. These choices include ablator material, ablator dopant concentration and distribution, capsule dimensions, and x-ray drive profile (shock timings and strengths). The choice of ablator material must also include fabrication and material characteristics, such as attainable surface finishes, permeability, strength, transparency to radio frequency and infrared radiation, thermal conductivity, and material homogeneity. Understanding the advantages and/or limitations of these choices is an ongoing effort for LLNL and LANL designers. At this time, simulations in one- two- and three- dimensions show that capsules with either a copper doped beryllium or a polyimide (C<sup>22</sup>H<sup>10</sup>N<sup>2</sup>O<sup>4</sup>) ablator material have both the least sensitivity to initial surface roughnesses and favorable fabrication qualities. Simulations also indicate the existence of capsule designs based on these ablator materials which ignite and burn when imploded by less than nominal laser performance (900 kJ energy, 250 TW power, producing 250 eV peak radiation temperature). We will describe and compare these reduced scale capsules, in addition to several designs which use the expected 300 eV peak x-ray drive obtained from the nominal NIF laser (1.3 MJ, 500 TW).
Date: August 1, 1998
Creator: Bradley, P. A.; Cook, R. C.; Dittrich, T. R.; Haan, S. W.; Hinkel, D. E.; Marinak, M. M. et al.
Partner: UNT Libraries Government Documents Department

Overview of recent KDP damage experiments and implications for NIF tripler performance

Description: Considerable attention has been paid over the years to the problem of growing high purity KDP and KD*P to meet damage threshold requirements of ICF lasers at LLNL. The maximum fluence requirement for KD*P triplers on the National Ignition Facility (NIF) is 14.3 J/cm<sup>2</sup> at 351 nm in a 3 ns pulse. Currently KD*P (conventional or rapid grown) cannot meet this requirement without laser (pre)conditioning. In this overview, recent experiments to understand laser conditioning and damage phenomena in KDP and KD*P will be discussed. These experiments have lead to a fundamental revision of damage test methods and test result interpretation. In particular, the concept of a damage threshold has given way to measuring performance by damage distributions using millimeter sixed beams. Automated R/l (conditioned) damage tests have shown that the best rapidly grown KDP crystals exhibit the same damage distributions at the best conventionally grown KD*P. Continuous filtration of the growth solution and post growth thermal sealing are shown to increase the damage performance as well. In addition, centimeter size beams from multijoule lasers have been used to study stepwise laser conditioning in KDP. These tests have shown that an increase in the damage threshold of ~1.5X is attainable with 8-12 shots of increasing fluence. The experiments show that the damage density (pinpoints/mm<sup>3</sup>) evolves exponentially and once formed, the micron sized bulk pinpoints remain stable against increases in local fluence. The information obtained from damage distributions and conditioning studies has been used with model NIF spatial profiles to determine the probability of damage and the local pinpoint density generated in a tripler. Calculations based on test data have shown that .for well conditioned, high quality rapid growth KDP or conventional growth KD*P the damage probability is less than 3%. Furthermore, the fluence profiles expected on NIF lead to only small ...
Date: July 14, 1998
Creator: Carmen, L.; De Yoreo, J.; Jennings, R.; Milam, D.; Runkel, M.; Sell, W. et al.
Partner: UNT Libraries Government Documents Department

Construction safety program for the National Ignition Facility

Description: The Construction Safety Program (CSP) for NIF sets forth the responsibilities, guidelines, rules, policies and regulations for all workers involved in the construction, special equipment installation, acceptance testing, and initial activation and operation of NIF at LLNL during the construction period of NIF.
Date: June 26, 1997
Creator: Cerruti, S.J.
Partner: UNT Libraries Government Documents Department

NIF Title III engineering plan

Description: The purpose of this document is to define the work that must be accomplished by the NIF Project during Title III Engineering. This definition is intended to be sufficiently detailed to provide a framework for yearly planning, to clearly identify the specific deliverables so that the Project teams can focus on them, and to provide a common set of objectives and processes across the Project. This plan has been preceded by similar documents for Title I and Title II design and complements the Site Management Plan, the Project Control Manual, the Quality Assurance Program Plan, the RM Parsons NIF Title III Configuration Control Plan, the Integrated Project Schedule, the Preliminary Safety Analysis Report, the Configuration Management Plan, and the Transition Plan.
Date: June 1, 1998
Creator: Deis, G
Partner: UNT Libraries Government Documents Department

Images of the Laser Entrance Hole from the Static X-ray Imager at NIF

Description: The Static X-ray Imager (SXI) at the National Ignition Facility (NIF) is a pinhole camera using a CCD detector to obtain images of hohlraum wall x-ray drive illumination patterns seen through the laser entrance hole (LEH). Carefully chosen filters combined with the CCD response allows recording images in the x-ray range of 3 to 5 keV with 60 {micro}m spatial resolution. The routines used to obtain the apparent size of the backlit LEH, and the location and intensity of beam spots are discussed and compared to predictions. A new soft x-ray channel centered at 870 eV (near the x-ray peak of a 300 eV temperature ignition hohlraum) is discussed.
Date: May 4, 2010
Creator: Schneider, M; Jones, O; Meezan, N; Milovich, J; Town, R; Alvarez, S et al.
Partner: UNT Libraries Government Documents Department

3D Surface Mapping of Capsule Fill-Tube Assemblies used in Laser-Driven Fusion Targets

Description: This paper presents the development of a 3D surface mapping system used to measure the surface of a fusion target Capsule Fill-Tube Assembly (CFTA). The CFTA consists of a hollow Ge-doped plastic sphere, called a capsule, ranging in outer diameter between 2.2 mm and 2.6 mm and an attached 150 {micro}m diameter glass-core fill-tube that tapers down to a 10{micro} diameter at the capsule. The mapping system is an enabling technology to facilitate a quality assurance program and to archive 3D surface information of each capsule used in fusion ignition experiments that are currently being performed at the National Ignition Facility (NIF). The 3D Surface Mapping System is designed to locate and quantify surface features with a height of 50 nm and 300 nm in width or larger. Additionally, the system will be calibrated such that the 3D measured surface can be related to the capsule surface angular coordinate system to within 0.25 degree (1{sigma}), which corresponds to approximately 5 {micro}m linear error on the capsule surface.
Date: February 18, 2011
Creator: Buice, E S; Alger, E T; Antipa, N A; Bhandarkar, S D; Biesiada, T A; Conder, A D et al.
Partner: UNT Libraries Government Documents Department

PLANNING TOOLS FOR ESTIMATING RADIATION EXPOSURE AT THE NATIONAL IGNITION FACILITY

Description: A set of computational tools was developed to help estimate and minimize potential radiation exposure to workers from material activation in the National Ignition Facility (NIF). AAMI (Automated ALARA-MCNP Interface) provides an efficient, automated mechanism to perform the series of calculations required to create dose rate maps for the entire facility with minimal manual user input. NEET (NIF Exposure Estimation Tool) is a web application that combines the information computed by AAMI with a given shot schedule to compute and display the dose rate maps as a function of time. AAMI and NEET are currently used as work planning tools to determine stay-out times for workers following a given shot or set of shots, and to help in estimating integrated doses associated with performing various maintenance activities inside the target bay. Dose rate maps of the target bay were generated following a low-yield 10{sup 16} D-T shot and will be presented in this paper.
Date: October 22, 2010
Creator: Verbeke, J; Young, M; Brereton, S; Dauffy, L; Hall, J; Hansen, L et al.
Partner: UNT Libraries Government Documents Department

Final optics damage inspection (FODI) for the National Ignition Facility

Description: The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) will routinely fire high energy shots (approaching 10 kJ per beamline) through the final optics, located on the target chamber. After a high fluence shot, exceeding 4J/cm2 at 351 nm wavelength, the final optics will be inspected for laser-induced damage. The FODI (Final Optics Damage Inspection) system has been developed for this purpose, with requirements to detect laser-induced damage initiation and to track and size it's the growth to the point at which the optic is removed and the site mitigated. The FODI system is the 'corner stone' of the NIF optic recycle strategy. We will describe the FODI system and discuss the challenges to make optics inspection a routine part of NIF operations.
Date: October 23, 2007
Creator: Conder, A; Alger, T; Azevedo, S; Chang, J; Glenn, S; Kegelmeyer, L et al.
Partner: UNT Libraries Government Documents Department

Mirror Sub-Assembly End-Effector Design

Description: The Optic Assembly Building (OAB) is a facility where large optical mirror units are assembled and installed into Line Replaceable Units (LRUs) for deployment into the National Ignition Facility (NIF) laser system. The New Optics Insertion Device (NOID) is a powered jib crane specially designed to handle large optical assemblies. The NOID arm has three degrees of freedom. it can rotate about the vertical boom, travel up and down the boom, and extend away from and retract in towards the boom. The NOID is used to assist in the assembly of five types of Laser Mirror (LM) LRUs. These five LMs have been creatively named, LM4, LM5, LM6, LM7, and LM8. The LM4 and LM5 LRUs each contain four Mirror Sub-Assemblies (MSAs). The LM6, LM7, and LM8 LRUs each contain 2 MSAs. The MSAs are assembled apart from the LRU and are then installed in the LRU at the LM4-8 workstations. An MSA NOID End-Effector is required to interface with the MSAs and install them into the LRUs. The End-Effector must attach to the robo-hand on the end of the NOID arm. At the time the MSA NOID End-Effector was being designed the NOID, the LM4-5 workstation, and the LM6-8 workstation were already installed in the OAB. The LRUs and the MSAs designs were also complete. The MSA NOID End-Effector design had to work with the assembly equipment and LRU designs that were already in place.
Date: January 8, 2007
Creator: Butlin, B
Partner: UNT Libraries Government Documents Department