Publications

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Investigating Volumetric Inclusions of Semiconductor Materials to Improve Flashover Resistance in Dielectrics

Steiner, Adam M.; Siefert, Christopher S.; Shipley, Gabriel A.; Redline, Erica M.; Dickens, Sara D.; Jaramillo, Rex J.; Chavez, Tom C.; Hutsel, Brian T.; Frye-Mason, Gregory C.; Peterson, Kyle J.; Bell, Kate S.; Balogun, Shuaib A.; Losego, Mark D.; Sammeth, Torin M.; Kern, Ian J.; Harjes, Cameron D.; Gilmore, Mark A.; Lehr, Jane M.

Abstract not provided.

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TYPE Conference Poster YEAR 2021
OSTIDOI

An X-ray Intensity Operations Monitor (AXIOM) (Final LDRD Project Report)

Ulmen, Benjamin A.; Webb, Timothy J.; Radtke, Gregg A.; Olson, Aaron J.; Depriest, Kendall D.; Coffey, Sean K.; Looker, Quinn M.; Gao, Xujiao G.; Nicholas, Ryder N.; Edwards, Jarrod D.; McCourt, Andrew L.; Bell, Kate S.

The Saturn accelerator has historically lacked the capability to measure time-resolved spectra for its 3-ring bremsstrahlung x-ray source. This project aimed to create a spectrometer called AXIOM to provide this capability. The project had three major development pillars: hardware, simulation, and unfold code. The hardware consists of a ring of 24 detectors around an existing x-ray pinhole camera. The diagnostic was fielded on two shots at Saturn and over 100 shots at the TriMeV accelerator at Idaho Accelerator Center. A new Saturn x-ray environment simulation was created using measured data to validate. This simulation allows for timeresolved spectra computation to compare the experimental results. The AXIOM-Unfold code is a new parametric unfold code using modern global optimizers and uncertainty quantification. The code was written in Python, uses Gitlab version control and issue tracking, and has been developed with long term code support and maintenance in mind.

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TYPE SAND Report YEAR 2021
OSTIDOI

The Differential Absorption Hard X-Ray Spectrometer at the Z Facility

IEEE Transactions on Plasma Science

Bell, Kate S.; Coverdale, Christine A.; Ampleford, David A.; Bailey, James E.; Loisel, Guillaume P.; Harper-Slaboszewicz, V.H.; Schwarz, Jens S.; Moy, Kenneth

The differential absorption hard X-ray (DAHX) spectrometer is a diagnostic developed to measure time-resolved radiation between 60 keV and 2 MeV at the Z Facility. It consists of an array of seven Si PIN diodes in a tungsten housing that provides collimation and coarse spectral resolution through differential filters. DAHX is a revitalization of the hard X-ray spectrometer that was fielded on Z prior to refurbishment in 2006. DAHX has been tailored to the present radiation environment in Z to provide information on the power, spectral shape, and time profile of the hard emission by plasma radiation sources driven by the Z machine.

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TYPE Journal Article YEAR 2017
ScopusOSTIDOI

Coarse spectral characterization of warm x-rays at the Z facility using a filtered thermoluminescent dosimeter array

Review of Scientific Instruments

Harper-Slaboszewicz, V.H.; Ulmen, Benjamin A.; Parzyck, Christopher T.; Ampleford, David A.; McCourt, Andrew L.; Bell, Kate S.; Coverdale, Christine A.

A new collimated filtered thermoluminescent dosimeter (TLD) array has been developed at the Z facility to characterize warm x-rays (hν > 10 keV) produced by Z pinch radiation sources. This array includes a Kapton debris shield assembly to protect the TLDs from the source debris, a collimator array to limit the field of view of the TLDs to the source region, a filter wheel containing filters of aluminum, copper and tungsten up to 3 mm thick to independently filter each TLD, and a hermetically sealed cassette containing the TLDs as well as tungsten shielding on the sides and back of the array to minimize scattered radiation reaching the TLDs. Here experimental results from a krypton gas puff and silver wire array shot are analyzed using two different functional forms of the energy spectrum to demonstrate the ability of this diagnostic to consistently extend the upper end of the x-ray spectrum characterization from ~50 keV to >1 MeV.

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TYPE Journal Article YEAR 2017
OSTIDOI

Analyzing non-LTE Kr plasmas produced in high energy density experiments: From the Z machine to the National Ignition Facility

Ampleford, David A.; Dasgupta, A.D.; Clark, R.E.; Giuliani, J.G.; Ouart, N.D.; Velikovich, A.L.; Hansen, Stephanie B.; Jennings, Christopher A.; Flanagan, Timothy M.; Bell, Kate S.; Harvey-Thompson, Adam J.; Jones, Brent M.; May, M.M.; Barrios, M.B.; Scott, H.S.; Fournier, K.F.; Colvin, J.C.; Kemp, G.K.

Abstract not provided.

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TYPE Conference Poster YEAR 2016
OSTI

Non-thermal x-ray emission from wire array z-pinches

Ampleford, David A.; Hansen, Stephanie B.; Jennings, Christopher A.; Webb, Timothy J.; Harper-Slaboszewicz, V.H.; Loisel, Guillaume P.; Flanagan, Timothy M.; Bell, Kate S.; Jones, Brent M.; Rochau, G.A.; Chittenden, Jeremy P.; Sherlock, Mark S.; Appelbe, Brian A.; Giuliani, John G.; Ouart, Nicholas O.; Seely, John S.; McPherson, Leroy A.

We report on experiments demonstrating the transition from thermally-dominated K-shell line emission to non-thermal, hot-electron-driven inner-shell emission for z pinch plasmas on the Z machine. While x-ray yields from thermal K-shell emission decrease rapidly with increasing atomic number Z, we find that non-thermal emission persists with favorable Z scaling, dominating over thermal emission for Z=42 and higher (hn ≥ 17keV). Initial experiments with Mo (Z=42) and Ag (Z=47) have produced kJ-level emission in the 17-keV and 22-keV Kα lines respectively. We will discuss the electron beam properties that could excite these non - thermal lines. We also report on experiments that have attempted to control non - thermal K - shell line emission by modifying the wire array or load hardware setup.

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TYPE SAND Report YEAR 2015
OSTIDOI
36 Results
36 Results