Correcting raw diagnostic data for oscilloscope recording system distortions at the National Ignition Facility

Dynamic high energy density plasma environments at the National Ignition Facility for nuclear science research

“…In simulations, realistic high mode surface imperfections were imposed upon the exterior of the ablation shell that were large enough to introduce some material mixing into the fuel but did not prevent robust burn. For example, 10 16 atoms of 124 Xe and 136 Xe could be loaded at separate radial locations in the ablator. The relative activation of the (n, 2n) products may then be directly related to the amount of ablator material mixed into the DT fuel layer.…”

“…Two xenon isotopes were successfully implanted at unique radii in a plastic capsule to test the change in activation due to mix. 124 Xe was placed at 45 mm from the inner surface and 136 Xe at 132 mm in the symmetry capsules. The capsule growth and ion implantation of the stable xenon isotopes, required several iterations.…”

“…For example, if 127 I were loaded in the capsule ablator, the 127 I(d, 2n) 127 Xe reaction produces a noble gas that can be collected and quantified using RAGS. If 124 Xe was coloaded with the 127 I, the ratio of the (d, 2n) reactions on the iodine to the 124 Xe(n, 2n) 123 Xe reaction would provide a symmetry and mix diagnostic where the xenon provides both yield normalization and a measure of collection efficiency. The ratio is integrated over the peak burn (width) while uncertainties in energy and space are eliminated.…”

“…The data analysis and evaluation environment at NIF is outlined in a series of articles [120][121][122][123][124][125]. Figure 28 shows the data analysis system block diagram.…”

“…A cell can hold up to 42 cc STP gas, and each DIM can hold four cells. The cells were commissioned in late 2015 using three different xenon isotope mixes: atmospheric xenon; pure 134 Xe; and a 4:1 mix of 124 Xe: 136 Xe. Figure 49 shows a gamma spectrum from the third mix.…”