Neutron Radiation Shielding For The NIF Streaked X-Ray Detector (SXD) Diagnostic

Conference · Thu Nov 02 00:00:00 EST 2006

DOI:https://doi.org/10.13182/FST07-A1631· OSTI ID:896618

Song, P; Holder, J; Young, B; Kalantar, D; Eder, D; Kimbrough, J

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is preparing for the National Ignition Campaign (NIC) scheduled in 2010. The NIC is comprised of several ''tuning'' physics subcampaigns leading up to a demonstration of Inertial Confinement Fusion (ICF) ignition. In some of these experiments, time-resolved x-ray imaging of the imploding capsule may be required to measure capsule trajectory (shock timing) or x-ray ''bang-time''. A capsule fueled with pure tritium (T) instead of a deutriun-tritium (DT) mixture is thought to offer useful physics surrogacy, with reduced yields of up to 5e14 neutrons. These measurements will require the use of the NIF streak x-ray detector (SXD). The resulting prompt neutron fluence at the planned SXD location ({approx}1.7 m from the target) would be {approx}1.4e9/cm{sup 2}. Previous measurements suggest the onset of significant background at a neutron fluence of {approx} 1e8/cm{sup 2}. The radiation damage and operational upsets which starts at {approx}1e8 rad-Si/sec must be factored into an integrated experimental campaign plan. Monte Carlo analyses were performed to predict the neutron and gamma/x-ray fluences and radiation doses for the proposed diagnostic configuration. A possible shielding configuration is proposed to mitigate radiation effects. The primary component of this shielding is an 80 cm thickness of Polyethylene (PE) between target chamber center (TCC) and the SXD diagnostic. Additionally, 6-8 cm of PE around the detector provide from the large number of neutrons that scatter off the inside of the target chamber. This proposed shielding configuration reduces the high-energy neutron fluence at the SXD by approximately a factor {approx}50.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 896618
• Report Number(s): UCRL-CONF-225998; TRN: US0700808
• Resource Relation: Journal Volume: 52; Journal Issue: 4; Conference: Presented at: American Nuclear Society, Albuquerque, NM, United States, Nov 12 - Nov 16, 2006
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
22 GENERAL STUDIES OF NUCLEAR REACTORS
CONFIGURATION
IGNITION
INERTIAL CONFINEMENT
MIXTURES
NEUTRON FLUENCE
NEUTRONS
PHYSICS
POLYETHYLENES
PROMPT NEUTRONS
RADIATION DOSES
RADIATION EFFECTS
RADIATIONS
SHIELDING
TARGET CHAMBERS
THICKNESS
TRITIUM
TUNING
US NATIONAL IGNITION FACILITY