The SPIDER fission fragment spectrometer for fission product yield measurements

Meierbachtol, K.; Tôvesson, F.; Shields, D.; Arnold, C. W.; Blakeley, R.E.; Bredeweg, T. A.; Devlin, M.; Hecht, Adam; Heffern, L. E.; Jorgenson, Justin; Laptev, A.; Mader, D.; O’Donnell, J. M.; Sierk, Arnold J.; White, Morgan Curtis

doi:10.1016/j.nima.2015.02.032

Cited by 36 publications

(28 citation statements)

References 24 publications

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“…This quantity has often been measured and tabulated. As pioneered by the Cosi fan Tutti spectrometer measurements at ILL, Grenoble [107], recently, experiments which measure both the energies and velocities of fission fragments are beginning to produce data sets with much improved mass resolution [108]. Yields with mass resolutions approaching 1 u will provide a much more stringent test of models than do the historical lower-resolution distributions.…”

Section: Mass Resolutionmentioning

confidence: 99%

Langevin model of low-energy fission

Sierk

2017

Phys. Rev. C

109

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Background: Since the earliest days of fission, stochastic models have been used to describe and model the process. For a quarter century, numerical solutions of Langevin equations have been used to model fission of highly excited nuclei, where microscopic potential-energy effects have been neglected. Purpose: In this paper I present a Langevin model for the fission of nuclei with low to medium excitation energies, for which microscopic effects in the potential energy cannot be ignored. Method: I solve Langevin equations in a five-dimensional space of nuclear deformations. The macroscopicmicroscopic potential energy from a global nuclear structure model well benchmarked to nuclear masses is tabulated on a mesh of approximately 10 7 points in this deformation space. The potential is defined continuously inside the mesh boundaries by use of a moving five-dimensional cubic spline approximation. Because of reflection symmetry, the effective mesh is nearly twice this size. For the inertia, I use a (possibly scaled) approximation to the inertia tensor defined by irrotational flow. A phenomenological dissipation tensor related to one-body dissipation is used. A normal-mode analysis of the dynamical system at the saddle point, and the assumption of quasi-equilibrium, provide distributions of initial conditions appropriate to low excitation energies, and is extended to model spontaneous fission. A dynamical model of post-scission fragment motion including dynamical deformations and separation allows the calculation of final mass and kinetic-energy distributions, along with other interesting quantities. Results: The model makes quantitative predictions for fragment mass and kinetic-energy yields, some of which are very close to measured ones. Varying the energy of the incident neutron for induced fission allows the prediction of energy dependences of fragment yields and average kinetic energies. With a simple approximation for spontaneous fission starting conditions, quantitative predictions are made for some observables which are close to measurements. Conclusions: This model is able to reproduce several mass and energy yield observables with a small number of physical parameters, some of which do not need to be varied after benchmarking to 235 U(n,f) to predict results for other fissioning isotopes.

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Section: Mass Resolutionmentioning

confidence: 99%

Langevin model of low-energy fission

Sierk

2017

Phys. Rev. C

109

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“…However, this advantage is counterbalanced by the limited time-of-flight resolution. Nowadays, new detection systems such as SPIDER [5], VERDI [6], and FALSTAFF [7] are being developed, pushing further the detection technology, based on the combination of the energy and time-of-flight measurements, as previously used in the Cosi Fan Tutte experiment [8]. With the advent of electromagnetic spectrometers, such as Lohengrin [9] or Hiawatha [10], high-resolution data on isobaric yields can be measured with an uncertainty below 5%, while isotopic identification is still limited to the light fission fragment group; see for example Ref.…”

Section: Introductionmentioning

confidence: 99%

Accurate isotopic fission yields of electromagnetically induced fission of U238 measured in inverse kinematics at relativistic energies

Pellereau¹,

Taïeb²,

Chatillon³

et al. 2017

Phys. Rev. C

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SOFIA (Studies On Fission with Aladin) is a novel experimental program, dedicated to accurate measurements of fission-fragment isotopic yields. The setup allows us to fully identify, in nuclear charge and mass, both fission fragments in coincidence for the whole fission-fragment range. It was installed at the GSI facility (Darmstadt), to benefit from the relativistic heavy-ion beams available there, and thus to use inverse kinematics. This paper reports on fission yields obtained in electromagnetically induced fission of 238 U.

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“…The design goal is to achieve a mass resolution of A/∆A ∼ 130. Other recently developed 2v-2E spectrometers are the STEFF (SpecTrometer for Exotic Fission Fragments), built by the University of Manchester [178], and the SPIDER (SPectrometer for Ion DEtermination in fission Research) [179] at LANSCE (Los Alamos), which are exploited in neutron-induced-fission experiments, see Section 3.2.3 for further details.…”

Section: 12mentioning

confidence: 99%

“…[124],182 Hg[229] and179,189 Au[160], recently measured by fusion-fission reactions are also marked in blue. The border of the lightest known isotopes is shown by the thick solid line, β-stable nuclei are shown on a gray background.Figure is modified from [17].…”

mentioning

confidence: 99%

Nuclear fission: a review of experimental advances and phenomenology

2017

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In the last two decades, through technological, experimental and theoretical advances, the situation in experimental fission studies has changed dramatically. With the use of advanced production and detection techniques both much more detailed and precise information can now be obtained for the traditional regions of fission research and, crucially, new regions of nuclei have become routinely accessible for fission studies. This work first of all reviews the recent developments in experimental fission techniques, in particular the resurgence of transfer-induced fission reactions with light and heavy ions, the emerging use of inverse-kinematic approaches, both at Coulomb and relativistic energies, and of fission studies with radioactive beams. The emphasis on the fission-fragment mass and charge distributions will be made in this work, though some of the other fission observables, such as prompt neutron and γ-ray emission will also be reviewed. A particular attention will be given to the low-energy fission in the so far scarcely explored nuclei in the very neutron-deficient lead region. They recently became the focus for several complementary experimental studies, such as β-delayed fission with radioactive beams at ISOLDE(CERN), Coulex-induced fission of relativistic secondary beams at FRS(GSI), and several prompt fusion-fission studies. The synergy of these approaches allows a unique insight in the new region of asymmetric fission around [Formula: see text]Hg, recently discovered at ISOLDE. Recent extensive theoretical efforts in this region will also be outlined. The unprecedented high-quality data for fission fragments, completely identified in Z and A, by means of reactions in inverse kinematics at FRS(GSI) and VAMOS(GANIL) will be also reviewed. These experiments explored an extended range of mercury-to-californium elements, spanning from the neutron-deficient to neutron-rich nuclides, and covering both asymmetric, symmetric and transitional fission regions. Some aspects of heavy-ion induced fusion-fission and quasifission reactions will be also discussed, which reveal their dynamical features, such as the fission time scale. The crucial role of the multi-chance fission, probed by means of multinucleon-transfer induced fission reactions, will be highlighted. The review will conclude with the discussion of the new experimental fission facilities which are presently being brought into operation, along with promising 'next-generation' fission approaches, which might become available within the next decade.

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The SPIDER fission fragment spectrometer for fission product yield measurements

Cited by 36 publications

References 24 publications

Langevin model of low-energy fission

Langevin model of low-energy fission

Accurate isotopic fission yields of electromagnetically induced fission of U238 measured in inverse kinematics at relativistic energies

Nuclear fission: a review of experimental advances and phenomenology

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