[en] The performance of a sodium laser guide star adaptive optics system depends crucially on the characteristics of the laser guide star in the sodium layer. System performance is quite sensitive to sodium layer spot radiance, that is, return per unit sterradian on the sky, hence we have been working to improve projected beam quality via improvements to the laser and changes to the launched beam format. The laser amplifier was reconfigured to a ''bounce-beam'' geometry, which considerably improves wavefront quality and allows a larger round instead of square launch beam aperture. The smaller beacon makes it easier to block the unwanted Rayleigh light and improves the accuracy of Hartmann sensor wavefront measurements in the A0 system. We present measurements of the beam quality and of the resulting sodium beacon and compare to similar measurements from last year

[en] This paper reports that since the initiation of state and federal regulations for underground storage tanks (USTs) in the mid-1980s, there has been a sharp increase in the number of reported sites with soil or groundwater contamination from motor fuels. Recent Environmental Protection Agency (EPA) statistics show that there are currently over 85,000 UST sites where contamination has been confirmed, and most of these are motor fuel storage sites. The goal of remediation activities at these sites should be to provide rapid and effective control and/or treatment of the contaminated are. There is also a desire to perform corrective actions in the manner that efficiently allocates both human and economic resources. Perhaps that is to be expected, given the complexity of the problem, the relative newness of these issues, and the diversity of participants. There are many entities affected, both large and small, within and outside the petroleum industry

[en] The American Petroleum Institute (API) is a trade association for the domestic petroleum industry in the USA, with over 2000 corporate and 5000 individual members. Subsurface research activities are managed by the API soil/groundwater technical task force, a committee made up of over 25 member company engineers, hydrologists, soil scientists, and chemists representing both the research and operations sectors of the petroleum industry. The research areas of the group have been divided into five principle areas: biodegradation processes, fate and transport, remediation, decision making tools for remediation, and detection/analytical methods. A summary of each of the current projects in these subject areas is presented

[en] Any adaptive optics system must be calibrated with respect to internal aberrations in order for it to properly correct the starlight before it enters the science camera. Typical internal calibration consists of using a point source stimulus at the input to the AO system and recording the wavefront at the output. Two methods for such calibration have been implemented on the adaptive optics system at Lick Observatory. The first technique, Phase Diversity, consists of taking out of focus images with the science camera and using an iterative algorithm to estimate the system wavefront. A second technique uses a newly installed instrument, the Phase-Shifting Diffraction Interferometer, which has the promise of providing very high accuracy wavefront measurements. During observing campaigns in 1998, both of these methods were used for initial calibrations. In this paper we present results and compare the two methods in regard to accuracy and their practical aspects

[en] Deformable mirrors (DMs) have been successfully used in astronomical adaptive optics at near-infrared wavelengths, greatly reducing atmospheric-induced aberrations [1]. Extending this capability to the soft and hard x-ray regime is now required in order to take full advantage of the beam quality characteristic of new generation synchrotron facilities and X-ray Free Electron Lasers (XFELs). Achieving this goal challenges both current mirror manufacturing techniques and physical optics modeling. The Lawrence Livermore National Laboratory (LLNL) is currently developing an x-ray DM to correct wavefront aberrations introduced along the beam path of a typical x-ray beam-line [2]. To model the expected performance of such a mirror, we have also developed simulation code based on the wavefront propagation library of functions PROPER [3]. Here we present the current status of the project, including metrology done on the mirror substrate. Additionally we report on results from our wavefront simulation code, which have proven very useful in predicting technical aspects of mirror deployment at a typical x-ray facility.

[en] The direct detection of photons emitted or reflected by extrasolar planets, spatially resolved from their parent star, is a major frontier in the study of other solar systems. Direct detection will provide statistical information on planets in 5-50 AU orbits, inaccessible to current Doppler searches, and allow spectral characterization of radius, temperature, surface gravity, and perhaps composition. Achieving this will require new dedicated high-contrast instruments. One such system under construction is the Gemini Planet Imager (GPI.) This combines a high-order/high-speed adaptive optics system to control wavefront errors from the Earth's atmosphere, an advanced coronagraph to block diffraction, ultrasmooth optics, a precision infrared interferometer to measure and correct systematic errors, and a integral field spectrograph/polarimeter to image and characterize target planetary systems. We predict that GPI will be able to detect planets with brightness less than 10^-7 of their parent star, sufficient to observe warm self-luminous planets around a large population of targets

[en] The Gemini Planet Imager (GPI) is an extreme AO coronagraphic integral field unit YJHK spectrograph destined for first light on the 8m Gemini South telescope in 2011. GPI fields a 1500 channel AO system feeding an apodized pupil Lyot coronagraph, and a nIR non-common-path slow wavefront sensor. It targets detection and characterizion of relatively young (<2GYr), self luminous planets up to 10 million times as faint as their primary star. We present the coronagraph subsystem's in-lab performance, and describe the studies required to specify and fabricate the coronagraph. Coronagraphic pupil apodization is implemented with metallic half-tone screens on glass, and the focal plane occulters are deep reactive ion etched holes in optically polished silicon mirrors. Our JH testbed achieves H-band contrast below a million at separations above 5 resolution elements, without using an AO system. We present an overview of the coronagraphic masks and our testbed coronagraphic data. We also demonstrate the performance of an astrometric and photometric grid that enables coronagraphic astrometry relative to the primary star in every exposure, a proven technique that has yielded on-sky precision of the order of a milliarsecond.

[en] Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2(micro)m were corrected to over 40% of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to(approx)10% of the theoretical peak intensity limit. After a campaign to improve the beam quality of the laser system, and to improve calibration accuracy and stability of the adaptive optics system using new techniques for phase retrieval and phase-shifting diffraction interferometry, the system performance has been substantially increased. The next step will be to use the Lick system for astronomical science observations, and to demonstrate this level of performance with the new system being installed on the 10-meter Keck II telescope