Using HT and DT gamma rays to diagnose mix in Omega capsule implosions

Schmitt, M. J.; Herrmann, H. W.; Kim, Y. H.; McEvoy, A. M.; Zylstra, A.; Hammel, B. A.; Sepke, S. M.; Leatherland, A.; Gales, S.

doi:10.1088/1742-6596/717/1/012048

Title: Using HT and DT gamma rays to diagnose mix in Omega capsule implosions

Full Record
Other Related Research

Abstract

Experimental evidence [1] indicates that shell material can be driven into the core of Omega capsule implosions on the same time scale as the initial convergent shock. It has been hypothesized that shock-generated temperatures at the fuel/shell interface in thin exploding pusher capsules diffusively drives shell material into the gas core between the time of shock passage and bang time. Here, we propose a method to temporally resolve and observe the evolution of shell material into the capsule core as a function of fuel/shell interface temperature (which can be varied by varying the capsule shell thickness). Our proposed method uses a CD plastic capsule filled with 50/50 HT gas and diagnosed using gas Cherenkov detection (GCD) to temporally resolve both the HT "clean" and DT "mix" gamma ray burn histories. Simulations using Hydra [2] for an Omega CD-lined capsule with a sub-micron layer of the inside surface of the shell pre-mixed into a fraction of the gas region produce gamma reaction history profiles that are sensitive to the depth to which this material is mixed. Furthermore, we observe these differences as a function of capsule shell thickness is proposed to determine if interface mixing is consistent with thermal diffusion λ_ii~T²/Z²ρmore »« less

Authors:: Schmitt, M. J.; Herrmann, H. W.; Kim, Y. H.; McEvoy, A. M.; Zylstra, A.; Hammel, B. A.; Sepke, S. M.; Leatherland, A.; Gales, S.

Publication Date:: Thu May 26 00:00:00 EDT 2016

Research Org.:: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1335611

Report Number(s):: LA-UR-15-28239
Journal ID: ISSN 1742-6588

Grant/Contract Number:: AC52-06NA25396

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Physics. Conference Series

Additional Journal Information:: Journal Volume: 717; Journal ID: ISSN 1742-6588

Publisher:: IOP Publishing

Country of Publication:: United States

Language:: English

Subject:: 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; gamma rays; mix; implosions

Citation Formats


                    Schmitt, M. J., Herrmann, H. W., Kim, Y. H., McEvoy, A. M., Zylstra, A., Hammel, B. A., Sepke, S. M., Leatherland, A., and Gales, S. Using HT and DT gamma rays to diagnose mix in Omega capsule implosions.  United States: N. p., 2016. 
Web.  doi:10.1088/1742-6596/717/1/012048.

Copy to clipboard


                    Schmitt, M. J., Herrmann, H. W., Kim, Y. H., McEvoy, A. M., Zylstra, A., Hammel, B. A., Sepke, S. M., Leatherland, A., & Gales, S. Using HT and DT gamma rays to diagnose mix in Omega capsule implosions.  United States.  https://doi.org/10.1088/1742-6596/717/1/012048

Copy to clipboard


                    Schmitt, M. J., Herrmann, H. W., Kim, Y. H., McEvoy, A. M., Zylstra, A., Hammel, B. A., Sepke, S. M., Leatherland, A., and Gales, S. Thu .  
"Using HT and DT gamma rays to diagnose mix in Omega capsule implosions".  United States.  https://doi.org/10.1088/1742-6596/717/1/012048.  https://www.osti.gov/servlets/purl/1335611.

Copy to clipboard


                    
@article{osti_1335611,

  title        = {Using HT and DT gamma rays to diagnose mix in Omega capsule implosions},

  author       = {Schmitt, M. J. and Herrmann, H. W. and Kim, Y. H. and McEvoy, A. M. and Zylstra, A. and Hammel, B. A. and Sepke, S. M. and Leatherland, A. and Gales, S.},

  abstractNote = {Experimental evidence [1] indicates that shell material can be driven into the core of Omega capsule implosions on the same time scale as the initial convergent shock. It has been hypothesized that shock-generated temperatures at the fuel/shell interface in thin exploding pusher capsules diffusively drives shell material into the gas core between the time of shock passage and bang time. Here, we propose a method to temporally resolve and observe the evolution of shell material into the capsule core as a function of fuel/shell interface temperature (which can be varied by varying the capsule shell thickness). Our proposed method uses a CD plastic capsule filled with 50/50 HT gas and diagnosed using gas Cherenkov detection (GCD) to temporally resolve both the HT "clean" and DT "mix" gamma ray burn histories. Simulations using Hydra [2] for an Omega CD-lined capsule with a sub-micron layer of the inside surface of the shell pre-mixed into a fraction of the gas region produce gamma reaction history profiles that are sensitive to the depth to which this material is mixed. Furthermore, we observe these differences as a function of capsule shell thickness is proposed to determine if interface mixing is consistent with thermal diffusion λii~T2/Z2ρ at the gas/shell interface. Finally, since hydrodynamic mixing from shell perturbations, such as the mounting stalk and glue, could complicate these types of capsule-averaged temporal measurements, simulations including their effects also have been performed showing minimal perturbation of the hot spot geometry.},

  doi          = {10.1088/1742-6596/717/1/012048},

  journal      = {Journal of Physics. Conference Series},

  number       = ,

  volume       = 717,

  place        = {United States},

  year         = {Thu May 26 00:00:00 EDT 2016},

  month        = {Thu May 26 00:00:00 EDT 2016}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1088/1742-6596/717/1/012048

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 2 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

Three-dimensional simulations of ablative hydrodynamic instabilities in indirectly driven targets

Technical Report Marinak, M. M. ; Tipton, R. E. ; Remington, B. A.

To model ignition in a National Ignition Facility (NIF) capsule implosion, the authors must understand the behavior of instabilities that can cause breakup of the pellet shell. During a capsule implosion, shocks that transit the shell cause growth of perturbations at the surface or at an interface because of a Richtmyer-Meshkov type of instability. Following shock breakout, or earlier for a shaped pulse, the low-density ablated plasma accelerates the pusher, and the ablation front is Rayleigh-Taylor (RT) unstable. Ablation and finite density gradients have the effect of stabilizing the short wavelength modes. Unstable modes present on the outer surface growmore »« less
https://doi.org/10.2172/376952

Full Text Available
Anomalous yield reduction in direct-drive DT implosions due to 3He addition

Journal Article Herrmann, Hans W ; Langenbrunner, James R ; Mack, Joseph M ; ... - Physics of Plasmas

Glass capsules were imploded in direct drive on the OMEGA laser [T. R. Boehly et aI., Opt. Commun. 133, 495, 1997] to look for anomalous degradation in deuterium/tritium (DT) yield (i.e., beyond what is predicted) and changes in reaction history with {sup 3}He addition. Such anomalies have previously been reported for D/{sup 3}He plasmas, but had not yet been investigated for DT/{sup 3}He. Anomalies such as these provide fertile ground for furthering our physics understanding of ICF implosions and capsule performance. A relatively short laser pulse (600 ps) was used to provide some degree of temporal separation between shock andmore »« less
https://doi.org/10.1063/1.3141062

Full Text Available
Diagnosing ignition with DT reaction history

Journal Article Wilson, D C ; Bradley, P A ; Herrmann, H W ; ... - Review of Scientific Instruments

A full range DT reaction history of an ignition capsule, from 10{sup 9} to 10{sup 20} neutrons/ns, offers the opportunity to diagnose fuel conditions hundreds of picoseconds before and during burn. The burn history begins with a sharp rise when the first shock reaches the center of the capsule. The level of this jump reflects the combined shock strength and the adiabat of DT fuel. Changes to the four laser pulses driving the capsule implosion which are large enough to degrade the yield make measurable changes to the reaction history. Low mode asymmetries grow during convergence but change the reactionmore »« less
https://doi.org/10.1063/1.2969420
Diagnosing ICF gamma-ray physics

Conference Herrmann, Hans W ; Kim, Y H ; Mc Evoy, A ; ...

Gamma rays produced in an ICF environment open up a host of physics opportunities we are just beginning to explore. A branch of the DT fusion reaction, with a branching ratio on the order of 2e-5 {gamma}/n, produces 16.7 MeV {gamma}-rays. These {gamma}-rays provide a direct measure of fusion reaction rate (unlike x-rays) without being compromised by Doppler spreading (unlike neutrons). Reaction-rate history measurements, such as nuclear bang time and burn width, are fundamental quantities that will be used to optimize ignition on the National Ignition Facility (NIF). Gas Cherenkov Detectors (GCD) that convert fusion {gamma}-rays to UV/visible Cherenkov photonsmore »« less
Full Text Available
Report of visit to LLNL 26 June to 10 July 2010

Technical Report Haines, M. G.

On this visit my principal activity was focused on the capsule and in particular to ascertain whether the heat-flow-driven electrothermal (ET) instability would occur in NIF indirect-drive experiments. Filamentary structures, assumed to be associated with the ET instability, have been observed years ago in the coronal plasma of direct-drive and more recently by proton probing of targets irradiated directly with an intense short-pulse (~1ps.) laser. A different proton probing diagnostic based on a subsidiary exploding pusher source has also shown filamentary structures in direct drive experiments at 10¹³ – 10¹⁵ W cm^-2 intensity, but with only 47μm resolution. Recently measurementsmore »« less
https://doi.org/10.2172/1124810

Full Text Available

Similar Records