Collection of solid and gaseous samples to diagnose inertial confinement fusion implosions.
Collection of representative samples of debris following inertial confinement fusion implosions in order to diagnose implosion conditions and efficacy is a challenging endeavor because of the unique conditions within the target chamber such as unconverted laser light, intense pulse of x-rays, physical chunks of debris, and other ablative effects. We present collection of gas samples following an implosion for the first time. High collection fractions for noble gases were achieved. We also present collection of solid debris samples on flat plate collectors. Geometrical collection efficiencies for Au hohlraum material were achieved and collection of capsule debris (Be and Cu) was also observed. Asymmetric debris distributions were observed for Au and Be samples. Collection of Be capsule debris was higher for solid collectors viewing the capsule through the laser entrance hole in the hohlraum than for solid collectors viewing the capsule around the waist of the hohlraum. Collection of Au hohlraum material showed the opposite pattern: more Au debris was collected around the waist than through the laser entrance hole. The solid debris collectors were not optimized for minimal Cu backgrounds, which limited the conclusions about the symmetry of the Cu debris. The quality of the data limited conclusions on chemical fractionation effects within the burning, expanding, and then cooling plasma.
Radiochemistry measurements on Phebus laser
We have developed a silicon radiochemistry diagnostic to measure the glass pusher areal density <ρΔR≳ of D‐T filled targets and irradiated with the two beams of the Phebus laser. We describe the experimental setup (debris automated retrieval and counting systems) and its performance. This diagnostic has been used to characterize the implosions performed in direct and indirect drive schemes. DT final densities as high as 100×DT liquid have been achieved.
The honesty of thinking : reflections on critical thinking in Nietzsche's middle period and the later Heidegger
This dissertation engages with contemporary interpretations of Nietzsche and Heidegger on the issue of self-knowing with respect to the notions of honesty and authenticity. Accounting for the two philosophers' developing conceptions of these notions allows a response to interpreters who conceive the activity of self-knowing as a primarily personal problem. The alternative accounts proposed take as a point of departure transitional texts that reveal both thinkers to be engaged in processes of revision. The reading of honesty in Chapters 1 and 2 revolves around Nietzsche's groundwork on prejudice in Morgenrothe (1880-81), where he first problematizes the moral-historical forces entailed in actuating the 'will to truth'. The reading of authenticity in Chapters 3 and 4 revolves around Heidegger's lectures on what motivates one's thinking in Was heist Denken? (1951-52). The lectures call into question his previous formal suppositions on what calls forth one's 'will-to-have-a-conscience', in an interpretation of Parmenides on the issue of thought's linguistic determination, discussed further in the context of Unterwegs zur Sprache (1950-59). Chapter 5 shows how Heidegger's confrontation with Nietzsche contributed to his ongoing revisions to the notion of authenticity, and to the attending conceptions of critique and its authority. Particular attention is given to the specific purposes to which distinct Nietzschean foils are put near the confrontation's beginning--in Heidegger's lectures on Nietzsche's second Unzeitgemasse Betrachtung (1938), and in the monograph entitled Besinnung (1939) which they prepare--and near its end, in the interpretation of Also Sprach Zarathustra (1883-85) presented in the first half of Was heist Denken? Chapter 6 recapitulates the developments traced from the vantage point of the retrospective texts Die Zollikoner Seminare (1959-72) and the fifth Book of Die frohliche Wissenschaft (1887). Closing remarks are made in relation to recent empirical research on the socio-environmental structures involved in determining self-identity.