Three-dimensional heat transfer analysis of the Doublet III beamline calorimeter

A general three-dimensional analysis has been formulated to study the flow of heat in a neutral beam calorimeter. The boundary value problem with an arbitrary incident heat flux has been solved using Fourier analysis and Laplace transform techniques. A general solution has been obtained and subsequently studied using numerical techniques as applied to the particular geometry and incident heat flux conditions of the Doublet III injection system. Negligible errors result in unfolding the incident heat flux through the use of thermocouples located near the rear surface, if data taking is initiated at the proper time and proceeds at a sufficiently rapid rate

Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility

NIF target diagnostics are being developed to observe and measure the extreme physics of targets irradiated by the 192-beam laser. The response time of target materials can be on the order of 100ps--the time it takes light to travel 3 cm--temperatures more than 100 times hotter than the surface of the sun, and pressures that exceed 109 atmospheres. Optical and x-ray diagnostics were developed and fielded to observe and record the results of the first 4-beam experiments at NIF. Hard and soft x-ray spectra were measured, and time-integrated and gated x-ray images of hydrodynamics experiments were recorded. Optical diagnostics recorded backscatter from the target, and VISAR laser velocimetry measurements were taken of laser-shocked target surfaces. Additional diagnostics are being developed and commissioned to observe and diagnose ignition implosions, including various neutron and activation diagnostics. NIF's diagnostics are being developed at LLNL and with collaborators at other sites. To accommodate the growing number of target diagnostics, an Instrument-Based Controls hardware-software framework has been developed to facilitate development and ease integration into the NIF Integrated Computer Control System (ICCS). Individual WindowsXP PC controllers for each digitizer, power supply and camera (i.e., instruments) execute controls software unique to each instrument model. Each hardware-software controller manages a single instrument, in contrast to the complexity of combining all the controls software needed for a diagnostic into a single controller. Because of this simplification, controllers can be more easily tested on the actual hardware, evaluating all normal and off-normal conditions. Each target diagnostic is then supported by a number of instruments, each with its own hardware-software instrument-based controller. Advantages of the instrument-based control architecture and framework include reusability, testability, and improved reliability of the deployed hardware and software. Since the same instruments are commonly used on many different diagnostics, the controllers are reusable by replicating the hardware and software as a unit and reconfiguring the controller using configuration files for the specific diagnostic. Diagnostics are fully integrated and interoperable with ICCS supervisory and shot controls using these configuration files to drive the diagnostics' instrument-based controllers

Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility (NIF)

The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics including optical backscatter, time-integrated and gated X-ray sensors, and laser velocity interferometry. Diagnostics to diagnose fusion ignition implosion and neutron emissions are being planned. Many diagnostics will be developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. An instrument-based controls (I-BC) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the I-BC architecture each instrument is interfaced to a low-cost Windows XP processor and Java application. Each instrument is aggregated with others as needed in the supervisory system to form an integrated diagnostic. The Java framework provides data management, control services and operator GUI generation. I-BCs are reusable by replication and reconfiguration for specific diagnostics in XML. Advantages include minimal application code, easy testing, and better reliability. Collaborators save costs by assembling diagnostics with existing I-BCs. This paper discusses target diagnostic instrumentation used on NIF and presents the I-BC architecture and framework

Doppler-Shift Proton Fraction Measurement on a CW Proton Injector

A spectrometer/Optical Multi-channel Analyzer has been used to measure the proton fraction of the cw proton injector developed for the Accelerator Production of Tritium (APT) and the Low Energy Demonstration Accelerator (LEDA) at Los Alamos. This technique, pioneered by the Lawrence Berkeley National Laboratory (LBNL), was subsequently adopted by the international fusion community as the standard for determining the extracted ion fractions of neutral beam injectors. Proton fractions up to 95 {+-} 3% have been measured on the LEDA injector. These values are in good agreement with results obtained by magnetically sweeping the ion beam, collimated by a slit, across a Faraday cup. Since the velocity distribution of each beam species is measured, it also can be used to determine beam divergence. While divergence has not yet been ascertained due to the wide slit widths in use, non-Gaussian distributions have been observed during operation above the design-matched perveance. An additional feature is that the presence of extracted water ions can be observed. During ion source conditioning at 75 kV, an extracted water fraction > 30% was briefly observed

A tritium vessel cleanup experiment in TFTR

A simple tritium cleanup experiment was carried out in TFTR following the initial high power deuterium-tritium discharges in December 1993. A series of 34 ohmic and deuterium neutral beam fueled shots was used to study the removal of tritium implanted into the wall and limiters. A very large plasma was created in each discharge to ``scrub`` an area as large as possible. Beam-fueled shots at 2.5 to 7.5 MW of injected power were used to monitor tritium concentration levels in the plasma by detection of DT-neutrons. The neutron signal decreased by a factor of 4 during the experiment, remaining well above the expected T-burnup level. The amount of tritium recovered at the end of the cleanup was about 8% of the amount previously injected with high power DT discharges. The experience gained suggests that measurements of tritium inventory in the torus are very difficult to execute and require dedicated systems with overall accuracy of 1%

BEAM-PROFILE INSTRUMENTATION FOR BEAM-HALO MEASUREMENT : OVERALL DESCRIPTION, OPERATION, AND BEAM DATA.

The halo experiment presently being conducted at the Low Energy Demonstration Accelerator (LEDA) at Los Alamos National Laboratory (LANL) has specific instruments that acquire horizontally and vertically projected particle-density beam distributions out to greater than 10{sup 5}:1 dynamic range. They measure the core of the distributions using traditional wire scanners, and the tails of the distribution using water-cooled graphite scraping devices. The wire scanner and halo scrapers are mounted on the same moving frame whose location is controlled with stepper motors. A sequence within the Experimental Physics and Industrial Control System (EPICS) software communicates with a National Instrument LabVIEW virtual instrument to control the motion and location of the scanner/scraper assembly. Secondary electrons from the wire scanner 0.03-mm carbon wire and protons impinging on the scraper are both detected with a lossy-integrator electronic circuit. Algorithms implemented within EPICS and in Research Systems Interactive Data Langugage (IDL) subroutines analyse and plot the acquired distributions. This paper describes this beam profile instrument, describes their experience with its operation, compares acquired profile data with simulations, and discusses various beam profile phenomena specific to the halo experiment

Matrix Metalloprotease 9 Mediates Neutrophil Migration into the Airways in Response to Influenza Virus-Induced Toll-Like Receptor Signaling

The early inflammatory response to influenza virus infection contributes to severe lung disease and continues to pose a serious threat to human health. The mechanisms by which neutrophils gain entry to the respiratory tract and their role during pathogenesis remain unclear. Here, we report that neutrophils significantly contributed to morbidity in a pathological mouse model of influenza virus infection. Using extensive immunohistochemistry, bone marrow transfers, and depletion studies, we identified neutrophils as the predominant pulmonary cellular source of the gelatinase matrix metalloprotease (MMP) 9, which is capable of digesting the extracellular matrix. Furthermore, infection of MMP9-deficient mice showed that MMP9 was functionally required for neutrophil migration and control of viral replication in the respiratory tract. Although MMP9 release was toll-like receptor (TLR) signaling-dependent, MyD88-mediated signals in non-hematopoietic cells, rather than neutrophil TLRs themselves, were important for neutrophil migration. These results were extended using multiplex analyses of inflammatory mediators to show that neutrophil chemotactic factor, CCL3, and TNFα were reduced in the Myd88−/− airways. Furthermore, TNFα induced MMP9 secretion by neutrophils and blocking TNFα in vivo reduced neutrophil recruitment after infection. Innate recognition of influenza virus therefore provides the mechanisms to induce recruitment of neutrophils through chemokines and to enable their motility within the tissue via MMP9-mediated cleavage of the basement membrane. Our results demonstrate a previously unknown contribution of MMP9 to influenza virus pathogenesis by mediating excessive neutrophil migration into the respiratory tract in response to viral replication that could be exploited for therapeutic purposes

Evasion of influenza A viruses from innate and adaptive immune responses

The influenza A virus is one of the leading causes of respiratory tract infections in humans. Upon infection with an influenza A virus, both innate and adaptive immune responses are induced. Here we discuss various strategies used by influenza A viruses to evade innate immune responses and recognition by components of the humoral and cellular immune response, which consequently may result in reduced clearing of the virus and virus-infected cells. Finally, we discuss how the current knowledge about immune evasion can be used to improve influenza A vaccination strategies

Follicular Helper T Cells are Essential for the Elimination of Plasmodium Infection

CD4+ follicular helper T (Tfh) cells have been shown to be critical for the activation of germinal center (GC) B-cell responses. Similar to other infections, Plasmodium infection activates both GC as well as non-GC B cell responses. Here, we sought to explore whether Tfh cells and GC B cells are required to eliminate a Plasmodium infection. A CD4 T cell-targeted deletion of the gene that encodes Bcl6, the master transcription factor for the Tfh program, resulted in complete disruption of the Tfh response to Plasmodium chabaudi in C57BL/6 mice and consequent disruption of GC responses and IgG responses and the inability to eliminate the otherwise self-resolving chronic P. chabaudi infection. On the other hand, and contrary to previous observations in immunization and viral infection models, Signaling Lymphocyte Activation Molecule (SLAM)-Associated Protein (SAP)-deficient mice were able to activate Tfh cells, GC B cells, and IgG responses to the parasite. This study demonstrates the critical role for Tfh cells in controlling this systemic infection, and highlights differences in the signals required to activate GC B cell responses to this complex parasite compared with those of protein immunizations and viral infections. Therefore, these data are highly pertinent for designing malaria vaccines able to activate broadly protective B-cell responses