Determination of gaseous fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility

Cassata, William S.; Stoeffl, W.; Jedlovec, D.; Golod, A. B.; Shaughnessy, D. A.; Yeamans, C. B.; Edwards, Ellen R.; Schneider, Dieter

doi:10.1007/s10967-015-4662-8

Cited by 7 publications

(9 citation statements)

References 11 publications

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“…It is assumed that >95% of the target chamber gas was pumped through the RAGS system during the 15-min collection interval, consistent with experiments conducted during the commissioning of RAGS and recent assessments of its pumping rate. 6 The detector efficiency determined from this calibration is 0.065 6 0.009% at 1294 keV (the main 41 Ar photopeak) and 0.0177 6 0.0003% at 249 keV (a 135 Xe photopeak). For comparison, a known quantity of fission gas obtained from a 252 Cf source was directly injected into the RAGS collection reservoir equipped with a different HPGe detector of the same make and model (the detector used on the beryllium shot failed shortly after the shot), and a comparable efficiency of 0.0171 6 0.0004% was obtained for the 249 keV Ar (the gamma intensity is 99.16%).…”

Section: IImentioning

confidence: 91%

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

et al. 2017

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For the first time, 41Ar produced by the (n,ϒ) reaction from 40Ar in the beryllium shell of a DT filled Inertial Confinement Fusion capsule has been measured. Ar is co-deposited with beryllium in the sputter deposition of the capsule shell. Combined with a measurement of the neutron yield, the radioactive 41Ar then quantifies the areal density of beryllium during the DT neutron production. The measured 1.15 ± 0.17 × 10+8 atoms of 41Ar are 2.5 times that from the best post-shot calculation, suggesting that the Ar and Be areal densities are correspondingly higher than those calculated. Possible explanations are that (1) the beryllium shell is compressed more than calculated, (2) beryllium has mixed into the cold DT ice, or more likely (3) less beryllium is ablated than calculated. Since only one DT filled beryllium capsule has been fielded at NIF, these results can be confirmed and expanded in the future.

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Section: IImentioning

confidence: 91%

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

et al. 2017

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“…The initial studies involve measurements of the isotope distributions of fission fragments identified from the observation of characteristic -rays. In the nuclear fission process, a heavy nucleus typically separates into energetic fission fragments with different masses sharing a total kinetic energy gain of approximately 22 , 23 . Details of the induced fission process over a wide range of projectile species and energies are still not well understood for many fissionable nuclei.…”

Section: Scientific Motivation and Relevancementioning

confidence: 99%

“…Neutron-induced fission experiments at the National Ignition Facility (NIF) have demonstrated the capability to rapidly collect and detect short-lived gaseous fission fragment isotopes for the first time, following an approximately 80 ps-long pulse of nearly neutrons into from a burning deuterium-tritium fusion plasma 23 . The neutron-induced fission at NIF, and the present experiment at PHELIX, demonstrate fission studies in a new time-domain amid plasma environments.…”

Section: Scientific Motivation and Relevancementioning

confidence: 99%

First on-line detection of radioactive fission isotopes produced by laser-accelerated protons

Boller

Zylstra

Neumayer

et al. 2020

Sci Rep

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The on-going developments in laser acceleration of protons and light ions, as well as the production of strong bursts of neutrons and multi-$$\hbox {MeV}$$ MeV photons by secondary processes now provide a basis for novel high-flux nuclear physics experiments. While the maximum energy of protons resulting from Target Normal Sheath Acceleration is presently still limited to around $$100 \, \hbox {MeV}$$ 100 MeV , the generated proton peak flux within the short laser-accelerated bunches can already today exceed the values achievable at the most advanced conventional accelerators by orders of magnitude. This paper consists of two parts covering the scientific motivation and relevance of such experiments and a first proof-of-principle demonstration. In the presented experiment pulses of $$200 \, \hbox {J}$$ 200 J at $$\approx \, 500 \, \hbox {fs}$$ ≈ 500 fs duration from the PHELIX laser produced more than $$10^{12}$$ 10 12 protons with energies above $$15 \, \hbox {MeV}$$ 15 MeV in a bunch of sub-nanosecond duration. They were used to induce fission in foil targets made of natural uranium. To make use of the nonpareil flux, these targets have to be very close to the laser acceleration source, since the particle density within the bunch is strongly affected by Coulomb explosion and the velocity differences between ions of different energy. The main challenge for nuclear detection with high-purity germanium detectors is given by the strong electromagnetic pulse caused by the laser-matter interaction close to the laser acceleration source. This was mitigated by utilizing fast transport of the fission products by a gas flow to a carbon filter, where the $$\upgamma$$ γ -rays were registered. The identified nuclides include those that have half-lives down to $$39 \, \hbox {s}$$ 39 s . These results demonstrate the capability to produce, extract, and detect short-lived reaction products under the demanding experimental condition imposed by the high-power laser interaction. The approach promotes research towards relevant nuclear astrophysical studies at conditions currently only accessible at nuclear high energy density laser facilities.

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“…DU in the hohlraum generates fission products from high energy neutron interactions. RAGS collected the gaseous products and independent fission yields for several xenon radio-isotopes have been determined (see Cassata et al below) [185]. Foils implanted with noble gases, or small rectangular pieces of rigid materials, called postage stamps, may be glued to the outside of the target holder at a fixed and well-known distance with respect to the target center.…”

Section: Grh Diagnostic For Determination Of Ablator Areal Density Inmentioning

confidence: 99%

“…It has demonstrated the collection of fission noble gases with half-lives ranging from 9 s to 2.8 h, as well as 19 O (27 s), 18 F (110 min), and 23 Ne (34 s) at detector locations next to system getters, traps, and chambers. The 18 F radioactivity is used to characterize the pumping speed for gases from the TC to the RAGS system; the time to pump half of the remaining gas is found to be 180 s. Recently 13 N, believed to be from (D, n) reactions on the carbon capsule shell, has been collected on the hot getters, and observed with RAGS system detectors [185].…”

Section: Compton Gamma Spectrometermentioning

confidence: 99%

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

Cerjan

Bernstein

Hopkins

et al. 2018

J. Phys. G: Nucl. Part. Phys.

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The generation of dynamic high energy density plasmas in the pico-to nanosecond time domain at high-energy laser facilities affords unprecedented nuclear science research possibilities. At the National Ignition Facility (NIF), the primary goal of inertial confinement fusion research has led to the synergistic development of a unique high brightness neutron source, sophisticated nuclear diagnostic instrumentation, and versatile experimental platforms. These novel experimental capabilities provide a new path to investigate nuclear processes and structural effects in the time, mass and energy density domains relevant to astrophysical phenomena in a unique terrestrial environment. Some immediate applications include neutron capture cross-section evaluation, fission fragment production, and ion energy loss measurement in

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Determination of gaseous fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility

Cited by 7 publications

References 11 publications

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

First on-line detection of radioactive fission isotopes produced by laser-accelerated protons

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

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