PANDORA Project for the study of photonuclear reactions below

Tamii, Atsushi*; Pellegri, L.*; Sderstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.

European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09

https://doi.org/10.1140/epja/s10050-023-01081-w

no abstracts in English

Structural and compositional characteristics of Fukushima release particulate material from Units 1 and 3 elucidates release mechanisms, accident chronology and future decommissioning strategy

Martin, P. G.*; Jones, C. P.*; Bartlett, S.*; Ignatyev, K.*; Megson-Smith, D.*; Satou, Yukihiko; Cipiccia, S.*; Batey, D. J.*; Rau, C.*; Sueki, Keisuke*; et al.

Scientific Reports (Internet), 10, p.22056_1 - 22056_17, 2020/12

https://doi.org/10.1038/s41598-020-79169-2

Provenance of uranium particulate contained within Fukushima Daiichi Nuclear Power Plant Unit 1 ejecta material

Martin, P. G.*; Louvel, M.*; Cipiccia, S.*; Jones, C. P.*; Batey, D. J.*; Hallam, K. R.*; Yang, I. A. X.*; Satou, Yukihiko; Rau, C.*; Mosselmans, J. F. W.*; et al.

Nature Communications (Internet), 10, p.2801_1 - 2801_7, 2019/06

https://doi.org/10.1038/s41467-019-10937-z

Synchrotron radiation (SR) analysis techniques alongside secondary ion mass spectrometry (SIMS) measurements have been made on sub-mm particulate material derived from reactor Unit 1 of the Fukushima Daiichi Nuclear Power Plant (FDNPP). Using these methods, it has been possible to investigate the distribution, state and isotopic composition of micron-scale U particulate contained within the larger Si-based ejecta material. Through combined SR micro-focused X-ray fluorescence (SR-micro-XRF) and absorption contrast SR micro-focused X-ray tomography (SR-micro-XRT), the U particulate was found to be located around the exterior circumference of the highly-porous particle. Synchrotron radiation micro-focused X-ray absorption near edge structure (SR-micro-XANES) analysis of a number of these entrapped particles revealed them to exist within the U(IV) oxidation state, as UO, and identical in structure to reactor fuel. Confirmation that this U was of nuclear origin (U-enriched) was provided through secondary ion mass spectrometry (SIMS) analysis with an isotopic enrichment ratio characteristic of a provenance from reactor Unit 1 at the FDNPP. These results provide clear evidence of the event scenario (that a degree of core fragmentation and release occurred from reactor Unit 1), with such spent fuel ejecta existing; (i) within the stable U(IV) oxidation state; and (ii) contained within a bulk Si-based particle. While this U is unlikely to represent an environmental or health hazard, such assertions would likely change, however, should break-up of the Si-containing bulk particle occur. However, more important to the long-term decommissioning of the reactors (and clean-up) on the FDNPP, is the knowledge that core integrity of reactor Unit 1 was compromised with nuclear material existing outside of the reactors primary containment.

Instrumentation for diagnostics and control of laser-accelerated proton (ion) beams

Bolton, P.; Borghesi, M.*; Brenner, C.*; Carroll, D. C.*; De Martinis, C.*; Fiorini, F.*; Flacco, A.*; Floquet, V.*; Fuchs, J.*; Gallegos, P.*; et al.

Physica Medica; European Journal of Medical Physics, 30(3), p.255 - 270, 2014/05

https://doi.org/10.1016/j.ejmp.2013.09.002

First prompt in-beam -ray spectroscopy of a superheavy element; The Rf

Rubert, J.*; Dorvaux, O.*; Gall, B. J. P.*; Greenlees, P. T.*; Asfari, Z.*; Piot, J.*; Andersson, L. L.*; Asai, Masato; Cox, D. M.*; Dechery, F.*; et al.

Journal of Physics; Conference Series, 420, p.012010_1 - 012010_10, 2013/03

https://doi.org/10.1088/1742-6596/420/1/012010

The first prompt in-beam -ray spectroscopy of a superheavy element, Rf, has been performed successfully. A development of an intense isotopically enriched Ti beam using the MIVOC method enabled us to perform this experiment. A rotational band up to a spin of 20 has been discovered in Rf, and its moment of inertia has been extracted. These data suggest that there is no evidence of a significant deformed shell gap at = 104.

Bacterial production of organic acids enhances HO-dependent iodide oxidation

Li, H.-P.*; Yeager, C. M.*; Brinkmeyer, R.*; Zhang, S.*; Ho, Y.-F.*; Xu, C.*; Jones, W. L.*; Schwehr, K. A.*; Otosaka, Shigeyoshi; Roberts, K. A.*; et al.

Environmental Science & Technology, 46(9), p.4837 - 4844, 2012/03

https://doi.org/10.1021/es203683v

In order to develop an understanding of the role that microorganisms play in the transport of I in soil-water systems, naturally occurring bacteria isolated from the F-area subsurface of the Savannah River Site (SRS) were assessed for iodide oxidizing activity. Spent liquid medium from a number of SRS bacterial cultures enhanced iodide oxidation 2-10 fold in the presence of hydrogen peroxide (HO). From a time-series measurements of peroxidase activities and organic acid concentrations, it was hypothesized that microbial organic acid exudate promoted iodide oxidation via following mechanisms; (1) organic acids interact with HO to form strong iodide oxidizing agents, peroxy carboxylic acids, and (2) organic acid secretion led to enhanced rates of HO-dependent iodide oxidation by lowering the pH of the culture medium.

Search for a 2-quasiparticle high- isomer in Rf

Robinson, A. P.*; Khoo, T. L.*; Seweryniak, D.*; Ahmad, I.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; Chowdhury, P.*; Davids, C. N.*; Greene, J.*; et al.

Physical Review C, 83(6), p.064311_1 - 064311_7, 2011/06

https://doi.org/10.1103/PhysRevC.83.064311

We have identified an isomer with a half-life of 17 s in Rf through a calorimetric conversion electron measurement tagged with implanted Rf nuclei using the fragment mass analyzer at Argonne National Laboratory. The low population yield for this isomer suggests that this isomer should not be a 2-quasiparticle high- isomer which is typically observed in the N = 152 isotones, but should be a 4-quasiparticle one. Possible reasons of the non-observation of a 2-quasiparticle isomer are this isomer decays by fission with a half-life similar to that of the ground state of Rf. Another possibility, that there is no 2-quasiparticle isomer at all, would imply an abrupt termination of axially symmetric deformed shape at Z=104.

Bridging the nuclear structure gap between stable and super heavy nuclei

Seweryniak, D.*; Khoo, T. L.*; Ahmad, I.*; Kondev, F. G.*; Robinson, A.*; Tandel, S. K.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; Chowdhury, P.*; et al.

Nuclear Physics A, 834(1-4), p.357c - 361c, 2010/03

https://doi.org/10.1016/j.nuclphysa.2010.01.039

Experimental data on single-particle energies in nuclei around Z=100 and N=152 play an important role to test validity of theoretical predictions for shell structure of superheavy nuclei. We found high-K two-quasiparticle isomers in No and No, and evaluated energies of proton single-particle orbitals around Z=100. We also found a new high-K three quasiparticle isomer in Rf. Energies of neutron single-particle orbitals were also evaluated from experimental data of the decay of Rf. Comparisons between the present experimental data and various theoretical calculations for the proton single-particle orbitals indicate that the calculation by using the Woods-Saxon potential gives the best agreement with the data.

isomers and octupole vibrations in shell-stabilized isotones

Robinson, A. P.*; Khoo, T. L.*; Ahmad, I.*; Tandel, S. K.*; Kondev, F. G.*; Nakatsukasa, Takashi*; Seweryniak, D.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; et al.

Physical Review C, 78(3), p.034308_1 - 034308_6, 2008/09

https://doi.org/10.1103/PhysRevC.78.034308

Isomers have been identified in Cm and No with quantum number , which decay through rotational bands built on octupole vibrational states. For isotones with atomic number 102, the and 2 states have remarkably stable energies, indicating neutron excitations. An exception is a singular minimum in the 2 energy at Cm, due to the additional role of proton configurations.

Isomeric decay studies around Pt and Tb

Podolyk, Zs.*; Steer, S. J.*; Pietri, S.*; Werner-Malento, E.*; Regan, P. H.*; Rudolph, D.*; Garnsworthy, A. B.*; Hoischen, R.*; Grska, M.*; Gerl, J.*; et al.

European Physical Journal; Special Topics, 150(1), p.165 - 168, 2007/11

https://doi.org/10.1140/epjst/e2007-00294-4

Relativistic energy projectile fragmentation of Pb has been used to produce a range of exotic nuclei. The nuclei of interest were studied by detecting delayed rays following the decay of isomeric states. Experimental information on the excited states of the neutron-rich Pt N=126 nucleus, following internal decay of two isomeric states, was obtained for the first time. In addition, decays from the previously reported isomeric and states in Tb and Gd, respectively, have been observed. These isomeric decays represent the highest discrete states observed to date following a prejectile fragmentation reaction, and opens up the possibilty of doing "high-spin physics" using this technique.