Evolution of fission-fragment mass distributions in the neutron-deficient lead region

Ghys, L.; Andreyev, A. N.; Huyse, M.; Duppen, P. Van; Sels, S.; Andel, B.; Antalic, S.; Barzakh, A. E.; Capponi, L.; Cocolios, T. E.; Derkx, X.; Witte, H. De; Elseviers, J.; Fedorov, D. V.; Fedosseev, V. N.; Heßberger, F. P.; Kalaninová, Z.; Köster, U.; Lane, John F.; Liberati, V.; Lynch, K. M.; Marsh, B. A.; Mitsuoka, S.; Möller, P.; Nagame, Y.; Nishio, K.; Ota, S.; Pauwels, D.; Page, R. D.; Popescu, L.; Radulov, D.; Rajabali, M. M.; Randrup, J.; Rapisarda, E.; Rothe, S.; Sandhu, Kirandeep; Seliverstov, M. D.; Sjödin, A. M.; Truesdale, V. L.; Beveren, C. Van; Bergh, P. Van den; Wakabayashi, Y.; Warda, M.

doi:10.1103/physrevc.90.041301

Cited by 40 publications

(62 citation statements)

References 46 publications

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“…[10] with respect to 70 charge yields measured at GSI [12], and in Ref. [13] with respect to new and older data in the neutron-deficient Pb region.…”

Section: Introductionmentioning

confidence: 99%

Calculated fission-fragment yield systematics in the region74≤Z≤94and90≤N≤150

Möller

Randrup

2015

Phys. Rev. C

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Background: In the seminal experiment by Schmidt et al. [Nucl. Phys. A 665, 221 (2000)] in which fissionfragment charge distributions were obtained for 70 nuclides, asymmetric distributions were seen above nucleon number A ≈ 226 and symmetric below. Because asymmetric fission had often loosely been explained as a preference for the nucleus to always exploit the extra binding of fragments near 132 Sn it was assumed that all systems below A ≈ 226 would fission symmetrically because available isotopes do not have a proton-to-neutron Z/N ratio that allows division into fragments near 132 Sn. But the finding by Andreyev et al. [Phys. Rev. Lett. 105, 252502 (2010)] did not conform to this expectation because the compound system 180 Hg was shown to fission asymmetrically. It was suggested that this was a new type of asymmetric fission, because no strong shell effects occur for any possible fragment division.Purpose: We calculate a reference data base for fission-fragment mass yields for a large region of the nuclear chart comprising 987 nuclides. A particular aim is to establish whether 180 Hg is part of a contiguous region of asymmetric fission and if so its extent, or if, in contrast to the actinides there are scattered smaller groups of nuclei that fission asymmetrically in this area of the nuclear chart. Methods:We use the by now well benchmarked Brownian shape-motion method and perform random walks on the previously calculated five-dimensional potential-energy surfaces. The calculated shell corrections are damped out with energy according to a prescription developed earlier. Results:We have obtained a theoretical reference data base of fission-fragment mass yields for 987 nuclides. These results show an extended region of asymmetric fission with approximate extension 74 ≤ Z ≤ 85 and 100 ≤ N ≤ 120. The calculated yields are highly variable. We show 20 representative plots of these variable features and summarize the main aspects of our results in terms of "nuclear-chart" plots showing calculated degrees of asymmetry versus N and Z.Conclusions: Experimental data in this region are rare: only ten or so yield distributions have been measured, some with very limited statistics. We agree with several measurements with higher statistics. Regions where there might be differences between our calculated results and measurements lie near the calculated transition line between symmetric and asymmetric fission. To draw more definite conclusions about the accuracy of the present implementation of the Brownian shape-motion approach in this region experimental data, with reliable statistics, for a fair number of suitably located additional nuclides are clearly needed. Because the nuclear potential-energy structure is so different in this region compared to the actinide region additional experimental data together with fission theory studies that incorporate additional, dynamical aspects should provide much new insight.

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“…[10] with respect to 70 charge yields measured at GSI [12], and in Ref. [13] with respect to new and older data in the neutron-deficient Pb region.…”

Section: Introductionmentioning

confidence: 99%

Calculated fission-fragment yield systematics in the region74≤Z≤94and90≤N≤150

Möller

Randrup

2015

Phys. Rev. C

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“…The use of two silicon detectors in a compact geometry allowed both singles α/fission decays and double-fold fission-fragment coincidences to be efficiently measured. The same method was later used for βDF studies of 178 Tl [120], 194,196 At [131,116] and of 200,202 Fr [131]. A detailed discussion of the results will be given in Section 3.5.3.…”

Section: Recent βDf Results At Recoil Separatorsmentioning

confidence: 99%

“…The recent novel experiments at the ISOLDE mass separator at CERN (Geneva) [48] used the same method to identify βDF of 178,180 Tl [129,120,130], 194,196 At [119] and 200,202 Fr [131], they will be discussed in details below.…”

Section: Production Of βDf Nuclei and Determination Of Their Propertiesmentioning

confidence: 99%

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Alpha Decay and Beta-Delayed Fission: Tools for Nuclear Physics Studies

Duppen

Andreyev

2018

The Euroschool on Exotic Beams - Vol. 5

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“…The introduction of the resonance laser-ionization technique has increased the element selectivity of the ionization process [8], which has enabled a large research program to be undertaken, among others, in the lead region; see, e.g., Refs. [9][10][11][12][13][14][15][16][17]. Alternative production routes are found in the combination of in-flight fusion-evaporation or fragmentation facilities with a gas catcher [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

In-Source Laser Spectroscopy with the Laser Ion Source and Trap: First Direct Study of the Ground-State Properties ofPo217,219

Fink¹,

Cocolios²,

Andreyev³

et al. 2015

Phys. Rev. X

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A Laser Ion Source and Trap (LIST) for a thick-target, isotope-separation on-line facility has been implemented at CERN ISOLDE for the production of pure, laser-ionized, radioactive ion beams. It offers two modes of operation, either as an ion guide, which performs similarly to the standard ISOLDE resonance ionization laser ion source (RILIS), or as a more selective ion source, where surface-ionized ions from the hot ion-source cavity are repelled by an electrode, while laser ionization is done within a radiofrequency quadrupole ion guide. The first physics application of the LIST enables the suppression of francium contamination in ion beams of neutron-rich polonium isotopes at ISOLDE by more than 1000 with a reduction in laser-ionization efficiency of only 20. Resonance ionization spectroscopy is performed directly inside the LIST device, allowing the study of the hyperfine structure and isotope shift of 217 Po for the first time. Nuclear decay spectroscopy of 219 Po is performed for the first time, revealing its half-life, α-to-β-decay branching ratio, and α-particle energy. This experiment demonstrates the applicability of the LIST at radioactive ion-beam facilities for the production and study of pure beams of exotic isotopes.

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Evolution of fission-fragment mass distributions in the neutron-deficient lead region

Cited by 40 publications

References 46 publications

Calculated fission-fragment yield systematics in the region74≤Z≤94and90≤N≤150

Calculated fission-fragment yield systematics in the region74≤Z≤94and90≤N≤150

Alpha Decay and Beta-Delayed Fission: Tools for Nuclear Physics Studies

In-Source Laser Spectroscopy with the Laser Ion Source and Trap: First Direct Study of the Ground-State Properties ofPo217,219

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