Tests are ongoing to conduct ~20 MA z-pinch implosions on the Z accelerator at Sandia National Laboratory using Ar, Kr, and D2 gas puffs as the imploding loads. The relatively high cost of operations on a machine of this scale imposes stringent requirements on the functionality, reliability, and safety of gas puff hardware. Here we describe the development of a prototype gas puff system including the multiple-shell nozzles, electromagnetic drivers for each nozzle's valve, a UV pre-ionizer, and an inductive isolator to isolate the ~2.4 MV machine voltage pulse present at the gas load from the necessary electrical and fluid connections made to the puff system from outside the Z vacuum chamber. This paper shows how the assembly couples to the overall Z system and presents data taken to validate the functionality of the overall system.
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http://dx.doi.org/10.1063/1.4809511 | DOI Listing |
Rev Sci Instrum
August 2024
Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
Bayesian inference applied to x-ray spectroscopy data analysis enables uncertainty quantification necessary to rigorously test theoretical models. However, when comparing to data, detailed atomic physics and radiation transfer calculations of x-ray emission from non-uniform plasma conditions are typically too slow to be performed in line with statistical sampling methods, such as Markov Chain Monte Carlo sampling. Furthermore, differences in transition energies and x-ray opacities often make direct comparisons between simulated and measured spectra unreliable.
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February 2024
Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808, USA.
Contemp Clin Trials
March 2024
VA HSR&D Houston Center of Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey VA Medical Center, (MEDVAMC 152), 2002 Holcombe Blvd., Houston, TX 77030, USA; Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; VA South Central Mental Illness Research, Education and Clinical Center, Houston, TX (a virtual center), USA. Electronic address:
Background: Obsessive compulsive disorder (OCD) is effectively treated with exposure and response prevention (ERP), yet very few veterans receive ERP for OCD within the Veterans Health Administration (VHA). Veterans are a clinically complex population, and no prior research has evaluated the effectiveness of ERP in veterans with OCD or comorbid OCD and posttraumatic stress disorder (PTSD). Given the limited accessibility of ERP-trained providers within VHA, assessment of video telehealth (VTH) delivery of ERP is warranted.
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View Article and Find Full Text PDFIn inertial confinement fusion (ICF) implosions, the interface between the cryogenic DT fuel and the ablator is unstable to shock acceleration (the Richtmyer-Meshkov instability, RM) and constant acceleration (Rayleigh-Taylor instability, RT). Instability growth at this interface can reduce the final compression, limiting fusion burnup. If the constant acceleration is in the direction of the lighter material (negative Atwood number), the RT instability produces oscillatory motion that can stabilize against RM growth.
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