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Title: A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

Abstract

CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [1];  [1];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [2];  [2];  [2];  [2];  [2]; ORCiD logo [2];  [2]; ORCiD logo [3];  [4];  [4]
  1. Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
  2. Lawrence Livermore National Laboratory, Livermore, California 94550, USA
  3. Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
  4. Laboratory for Laser Energetics, Rochester, New York 14623, USA
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1366923
Report Number(s):
LLNL-JRNL-731776
Journal ID: ISSN 0034-6748; RSINAK
DOE Contract Number:
AC52-07NA27344
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 11
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 70 PLASMA PHYSICS AND FUSION; 42 ENGINEERING

Citation Formats

Sutcliffe, G. D., Milanese, L. M., Orozco, D., Lahmann, B., Gatu Johnson, M., Séguin, F. H., Sio, H., Frenje, J. A., Li, C. K., Petrasso, R. D., Park, H. -S., Rygg, J. R., Casey, D. T., Bionta, R., Turnbull, D. P., Huntington, C. M., Ross, J. S., Zylstra, A. B., Rosenberg, M. J., and Glebov, V. Yu. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility. United States: N. p., 2016. Web. doi:10.1063/1.4960072.
Sutcliffe, G. D., Milanese, L. M., Orozco, D., Lahmann, B., Gatu Johnson, M., Séguin, F. H., Sio, H., Frenje, J. A., Li, C. K., Petrasso, R. D., Park, H. -S., Rygg, J. R., Casey, D. T., Bionta, R., Turnbull, D. P., Huntington, C. M., Ross, J. S., Zylstra, A. B., Rosenberg, M. J., & Glebov, V. Yu. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility. United States. doi:10.1063/1.4960072.
Sutcliffe, G. D., Milanese, L. M., Orozco, D., Lahmann, B., Gatu Johnson, M., Séguin, F. H., Sio, H., Frenje, J. A., Li, C. K., Petrasso, R. D., Park, H. -S., Rygg, J. R., Casey, D. T., Bionta, R., Turnbull, D. P., Huntington, C. M., Ross, J. S., Zylstra, A. B., Rosenberg, M. J., and Glebov, V. Yu. Fri . "A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility". United States. doi:10.1063/1.4960072. https://www.osti.gov/servlets/purl/1366923.
@article{osti_1366923,
title = {A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility},
author = {Sutcliffe, G. D. and Milanese, L. M. and Orozco, D. and Lahmann, B. and Gatu Johnson, M. and Séguin, F. H. and Sio, H. and Frenje, J. A. and Li, C. K. and Petrasso, R. D. and Park, H. -S. and Rygg, J. R. and Casey, D. T. and Bionta, R. and Turnbull, D. P. and Huntington, C. M. and Ross, J. S. and Zylstra, A. B. and Rosenberg, M. J. and Glebov, V. Yu.},
abstractNote = {CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.},
doi = {10.1063/1.4960072},
journal = {Review of Scientific Instruments},
number = 11,
volume = 87,
place = {United States},
year = {Fri Aug 05 00:00:00 EDT 2016},
month = {Fri Aug 05 00:00:00 EDT 2016}
}
  • CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint ofmore » the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.« less
  • CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint ofmore » the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.« less
  • When used at facilities like OMEGA and the NIF, CR-39 is exposed to high vacuum environments before and after irradiation by charged particles and neutrons. Using an electrostatic linear accelerator at MIT, studies have been conducted to investigate the effects of high vacuum exposure on the sensitivity of CR-39 to fusion protons in the {approx}1-9 MeV energy range. High vacuum conditions, of order 10{sup -5} Torr, experienced by CR-39 samples at these facilities were emulated. It is shown that vacuum exposure times longer than {approx}16 h before proton irradiation result in a decrease in proton sensitivity, whereas no effect wasmore » observed for up to 67 h of vacuum exposure after proton irradiation. CR-39 sensitivity curves are presented for samples with prolonged exposure to high vacuum before and after proton irradiation.« less
  • Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition,more » comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.« less
  • Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition,more » comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.« less