[en] A revolutionary new laser called the Petawatt, developed by Lawrence Livermore researchers after an intensive three-year development effort, has produced more than 1,000 trillion (open-quotes petaclose quotes) watts of power, a world record. By crossing the petawatt threshold, the extraordinarily powerful laser heralds a new age in laser research. Lasers that provide a petawatt of power or more in a picosecond may make it possible to achieve fusion using significantly less energy than currently envisioned, through a novel Livermore concept called open-quotes fast ignition.close quotes The petawatt laser will also enable researchers to study the fundamental properties of matter, thereby aiding the Department of Energy's Stockpile Stewardship efforts and opening entirely new physical regimes to study. The technology developed for the Petawatt has also provided several spinoff technologies, including a new approach to laser material processing

[en] The purpose of this project was to develop a high peak power laser system (100 TW) and begin initial high intensity experiments that exploit its short pulse width (30 fs) and high repetition rate (1 - 10 Hz). Such a laser system presents unique capabilities such as permitting ultrafast time-resolved plasma physics experiments by probing the plasma with the 30 fs laser pulse. The high repetition rate also allows detailed, systematic studies of phenomena, not possible with large, single shot laser systems. During the previous year we have made good progress on the development of the laser. We have demonstrated the production of pulses up to the 5 TW level at 10 Hz and have installed an additional amplifier to take the system to 20 TW. We have pulse compressed the pulses to 30 fs and have developed a number of diagnostics to characterize the laser prepulse. During this year we have also activated a target chamber to begin plasma physics experiments in gas jet targets

[en] We have fabricated large aperture (40-cm) kinoform phase plates for producing super-Gaussian focal plane intensity profiles. The continuous phase screen, designed using a new iterative procedure, was fabricated in fused silica as a 16-level, one-wave deep rewrapped phase profile using a lithographic process and wet etching in buffered hydrofluoric acid. The observed far-field contains 94% of the incident energy inside the desired spot

[en] A Fast Optical Multichannel Analyzer (FOMA) was built for spectroscopic measurements with fast time resolution on the DIII-D tokamak. The FOMA utilizes a linear photodiode array (RETICON RL 1024 SA) as the detector sensor. An external recharge switch and ultrafast operational amplifiers permit a readout time per pixel of 300 ns. In conjunction with standard CAMAC digitizer and timing modules, a readout time of 500 μs is achieved for the full 1024-element array. Data acquired in bench tests and in actual spectroscopic measurements on the DIII-D tokamak is presented to illustrate the camera's capability. 4 refs., 3 figs

[en] It has long been understood that the transposition of data from printouts to data collection sheets, and the subsequent manipulation of this data with measurement values, is an obvious error source in optical tooling projects. Ideas for computerized data collection have been under consideration for some time, yet they lacked the versatility needed for even the most typical optical tooling jobs. Surveyors experienced with optical tooling were used to designing the measurement strategy that worked best for each job. There was no canned formula that worked with every case. After extensive field testing a program was developed that worked in as many cases as possible. The program contains ideal files for components and monumentation, format sheets for set-up and measurement of components, and a summary sheet of work accomplished so far. This allows for the step by step movement through the measurement process

[en] We have resolved the expansion of intensely irradiated atomic clusters on a femtosecond time scale. These data show evidence for resonant heating, similar to resonance absorption, in spherical cluster plasmas

[en] The utilization of high-power short pulse laser employing chirped-pulse amplification (CPA) for material processing and inertial confinement research is widely increasing. The performance of these high-power CPA laser system continues to be limited by the ability of the pulse compression gratings to hold up to the high-average-power or high-peak-power of the laser. Pulse compression gratings used in transmission and fabricated out of bulk fused silica have intrinsically the highest laser damage threshold when compared with metal or multilayer dielectric gratings that work in reflection. LLNL has developed processing capability to produce high efficiency fused silica transmission gratings at sizes useful to future Petawatt-class systems, and has demonstrated high efficiency at smaller aperture. This report shows that fused silica diffraction exhibiting >95% efficiency into the -1 diffraction order in transmission (90^o deflection of the incident light, at an incidence angle of 45^o to the grating face). The microstructure of this grating consisted of grooves ion-beam etched to a depth of 1.6 microns with a pitch of 0.75 microns, using a holographically produced photoresist mask that was subsequently stripped away in significance to the fabrication of the small scale high efficiency grating was the development of the processing technology and infrastructure for production of such gratings at up to 65 cm diameter. LLNL is the currently the only location in the world with the ability to coat, interferometrically expose, and ion etch diffractive optics at this aperture. Below, we describe the design, fabrication, performance and, the scaleup process for a producing a high-efficiency transmission grating on a 65 cm fused silica substrate

[en] This paper discusses construction of an EUV (60-350 angstrom) space and time resolving, grazing incidence spectrograph (STRS). The simultaneous spectral coverage of the instrument ranges from 20 to 60 angstrom, depending on the wavelength region. The spectral resolution is about 1 angstrom. The spectral resolution, accomplished by using the pinhole camera effect and the inherent astigmatism of a concave grating in grazing incidence, is about 2 m, with a total field of view of 60 cm at a distance of 2 cm from the plasma. The detector consists of a 75 mm MCP image intensifier optically coupled to three CCD area array detectors. Time resolution of up to 2 ms is achieved with high speed read-out electronics. A PDP 11.73 minicomputer controls the spectrograph and collects and reduces 3.0 MB of data per shot. The complete design of the STRS and the results of initial tests of the detector system, spectrograph, and data handling software are presented

[en] Entry of herpes simplex virus-1 (HSV-1) into cells requires a concerted action of four viral glycoproteins gB, gD, and gH-gL. Previously, cell surface expression of gD had been shown to confer resistance to HSV-1 entry. To investigate any similar effects caused by other entry glycoproteins, gB and gH-gL were coexpressed with Nectin-1 in Chinese hamster ovary (CHO) cells. Interestingly, cellular expression of gB had no effect on HSV-1(KOS) entry. In contrast, entry was significantly reduced in cells expressing gH-gL. This effect was further analyzed by expressing gH and gL separately. Cells expressing gL were normally susceptible, whereas gH-expressing cells were significantly resistant. Further experiments suggested that the gH-mediated interference phenomenon was not specific to any particular gD receptor and was also observed in gH-expressing HeLa cells. Moreover, contrary to a previous report, gL-independent cell surface expression of gH was detected in stably transfected CHO cells, possibly implicating cell surface gH in the interference phenomenon. Thus, taken together these findings indicate that cellular expression of gH interferes with HSV-1 entry

[en] Background: Previous studies of patients with surgically resected non-small cell lung cancer and chest wall invasion have shown conflicting results with respect to prognosis. Whether high-risk subsets of the T3 N0 M0 population exist with respect to patterns of failure and overall survival has been difficult to ascertain, owing to small numbers of patients in most series. Methods and Materials: A retrospective review was performed to determine patterns of failure and overall survival for patients with completely resected T3 N0 M0 non-small cell lung cancer. From 1979 to 1993, 92 evaluable patients underwent complete resection for T3 N0 M0 non-small cell lung cancer. The following potential prognostic factors were recorded from the history: tumor size, location, grade, histology, patient age, use of adjuvant radiation therapy (18 of 92 patients), and type of surgical procedure (chest wall or extrapleural resection). Results: The actuarial 2- and 4-year overall survival rates for the entire cohort were 48% and 35%, respectively. The actuarial local control at 4 years was 94%. Neither the type of surgical procedure performed nor the addition of thoracic radiation therapy impacted local control or overall survival. Conclusion: Patients with completely resected T3 N0 M0 non-small cell lung cancer have similar local control and overall survival irrespective of primary location, type of surgery performed, or use of adjuvant radiation therapy. Additionally, the tumor recurrence rate and overall survival found in this study support the placement of this group of patients in Stage IIB of the 1997 AJCC lung staging classification