Bismuth Isotopes Research Articles

Formula omitted]Pb(p,x)194Hg and 209Bi(p,x)194Hg excitation functions in the energy range 0.04–2.6 GeV

The article presents the excitation functions of 194Hg, which is formed in Pb–Bi eutectic, on lead and bismuth isotopes in deep spallation reactions. The 194Hg production cross sections were measured by direct gamma spectrometry in lead targets enriched in 208Pb, 207Pb, and 206Pb, respectively, as well as in natural lead and bismuth, irradiated with protons of 11 energies from 0.04 to 2.6 GeV. Where possible, the experimental data are compared with the data of other authors, as well as with the simulated excitation functions of this nuclide, obtained using various high-energy transport codes - MCNP6.1 (CEM03.03), PHITS (INCL4.6/GEM), Geant4 (INCL++/ABLA) and the TENDL-2019 data library evaluation.

Impact of Technologically Enhanced Naturally Occurring Radioactive Materials (TE-NORM) In oil and gas industry On Environment

Naturally-occurring radioactive material (NORM) is the term used to describe materials containing radionuclides that exist in the natural environment. The radionuclides of interest include long-lived radionuclides such as uranium-238 (238U), uranium-235 (235U) and thorium-232 (232Th) and their radioactive decay products (such as isotopes of radium, radon, polonium, bismuth and lead), and individual long-lived radionuclides such aspotassium-40 (40K), rubidium-87 (87Rb) and indium-115 (115In). The parent radionuclides have decay times (half-lives) which are comparable with or larger than the age of the earth, so they have always been present in the earth’s crust and within the tissues of all living species. Where materials contain radionuclides from the naturally occurring decay chains (238U, 235U, 232Th), the large number of radionuclides in each chain, and the resulting large range of physical and chemical properties of the individual radionuclides, means that there can be a highly variable degree of secular equilibrium between the individual members of the chains

Spontaneous and forced decay of atomic nuclei realized in two stages

The main purpose of the work is to determine the possibility of cluster decays of superheavy atomic nuclei. The universality of the principle of similarity allows you to apply it to the analysis of not studied physical processes. Analogies are observed in forced and spontaneous decays of atomic nuclei. It is shown that in two stages, processes initiated by external influence are realized: fragmentation reactions, forced fission of stable nuclei, and impact radioactivity. Nuclear reactions of fragmentation and forced fission of stable isotopes of lead and bismuth are realized under the action of particles (hadrons) and light atomic nuclei with a kinetic energy of more than 108 eV. Shock radioactivity is observed in the collision of macroobjects having a crystalline structure at speeds of at least ∼1 km/s. Also, in two stages, some radioactive decays of atomic nuclei are realized, including extremely rare cluster decays. Based on the analogies of the processes considered, some cautious predictions are made about the possibility of cluster decays of atomic nuclei in a wide range of atomic masses.

Experimental analyses of bismuth sample reactivity worth at Kyoto University Critical Assembly

ABSTRACT Sample reactivity worth experiments are carried out by substituting aluminum (Al) plates for bismuth (Bi) ones at the Kyoto University Critical Assembly. At the beginning, uncertainty quantification of bismuth isotope is conducted by deterministic calculations with nuclear data library JENDL-4.0, with the use of experimental results of sample reactivity worth. Then, with the combined use of current (Bi) and previous (Pb) experimental results that demonstrate the comparative difference in the sensitivity and uncertainty of Bi and Pb isotopes, experimental results of cross-section uncertainties of Bi isotope are available for examination of neutron characteristics of Pb–Bi coolant material in the accelerator-driven system. From the experimental analyses, further uncertainty analyses by neutron transport calculations are needed for several reactions of Bi isotope, especially with the use of the covariance data of capture, elastic scattering and inelastic scattering reactions in another nuclear data library.

Measurements and FLUKA Simulations of Bismuth, Aluminium and Indium Activation at the upgraded CERN Shielding Benchmark Facility (CSBF)

The CERN High energy AcceleRator Mixed field (CHARM) facility is situated in the CERN Proton Synchrotron (PS) East Experimental Area. The facility receives a pulsed proton beam from the CERN PS with a beam momentum of 24 GeV/c with 5·1011 protons per pulse with a pulse length of 350 ms and with a maximum average beam intensity of 6.7·1010 protons per second. The extracted proton beam impacts on a cylindrical copper target. The shielding of the CHARM facility includes the CERN Shielding Benchmark Facility (CSBF) situated laterally above the target that allows deep shielding penetration benchmark studies of various shielding materials. This facility has been significantly upgraded during the extended technical stop at the beginning of 2016. It consists now of 40 cm of cast iron shielding, a 200 cm long removable sample holder concrete block with 3 inserts for activation samples, a material test location that is used for the measurement of the attenuation length for different shielding materials as well as for sample activation at different thicknesses of the shielding materials. Activation samples of bismuth, aluminium and indium were placed in the CSBF in September 2016 to characterize the upgraded version of the CSBF. Monte Carlo simulations with the FLUKA code have been performed to estimate the specific production yields of bismuth isotopes (206Bi, 205Bi, 204Bi, 203Bi, 202Bi, 201Bi) from 209Bi, 24Na from 27Al and 115mI from 115I for these samples. The production yields estimated by FLUKA Monte Carlo simulations are compared to the production yields obtained from γ-spectroscopy measurements of the samples taking the beam intensity profile into account. The agreement between FLUKA predictions and γ-spectroscopy measurements for the production yields is at a level of a factor of 2.

The Collective Radioactive Decay of Atomic Nuclei Initiated by an External Mechanical Impact: Science Fiction or a New Class of Physical Processes

Abnormally high pressure or temperature can significantly reduce the lifetime of atomic nuclei including stable. A hypothesis on stable nuclei decays caused by mechanical collision of macro-objects containing these nuclei is put forward. Mechanisms of such decays are presented. At the same time the distance between interacting nuclei can be significantly higher than the range of nuclear interaction (as manifestations of strong interaction). In decays initiated by external impact, the mean lifetime with respect to particular decay can change depending on these factors. The hypothesis is verified experimentally. When a bismuth bullet collides with a steel flat target, we see different types of stable bismuth isotope decay including cluster one, which is not found in nature (if there is no external impacts). This new class of physical processes can be related to the collective radioactive decay of atomic nuclei initiated by an external mechanical impact.

Theoretical approaches on the α-decay of spherical Bismuth isotopes

In this paper, the alpha decay process is investigated through the theoretical approaches for spherical Bismuth (Bi) isotopes in the range 187 [Formula: see text] A [Formula: see text] 214. The results are compared with the experimental data for isotopes of Bi with the modified Coulomb and proximity potential model (MCPPM). We analyze the systematics of alpha decay half-life (HL) of Bi isotopes versus the decay energy and the total [Formula: see text]-kinetic energy. The results and their systematics are compared with the available experimental data and with those data obtained from empirical models as the Viola-Seaborg (VS) formula, Royer (R) and the two versions of modified Brown (mB) empirical formulas. The computed half-lives (HLs) are compared with the experimental data and also with the existing empirical estimates and are found in good agreement.

Shape evolution for neutron-deficient bismuth isotopes studied by resonance laser ionization spectroscopy

In-source laser spectroscopy experiments for bismuth isotopes at the 306.77 nm atomic transition has been carried out at the IRIS (Investigation of Radioactive Isotopes at Synchrocyclotron) facility of Petersburg Nuclear Physics Institute. New data on isotope shifts for 189–198,211Bi isotopes and isomers have been obtained. The changes in the mean-square charge radii were deduced. The large isomer shift has been observed for the intruder isomer states of Bi with spin I = 1/2 (A = 193, 195, 197). This testifies to the shape coexistence in these nuclei with the intruder isomer states more deformed than the ground states. Marked deviation from the nearly spherical behavior for ground states of the even-neutron Bi isotopes at N < 109 is demonstrated, in contrast to the Pb and Tl isotopic chains.

Detailed spectroscopy of Bi195

An experiment focused on the study of shape coexistence and new high-spin structures in $^{195}\mathrm{Bi}$ has been performed. The nucleus is in a transitional region of the bismuth isotope chain. A large number of new states have been found, resulting in a significant extension of the previously known level scheme. Several new collective structures have been identified. A strongly coupled rotational band built upon the $13/{2}^{+}$ isomeric state was extended up to ${I}^{\ensuremath{\pi}}=(49/{2}^{+})$ and an energy of 5706 keV. The ${I}^{\ensuremath{\pi}}=31/{2}^{+}$ member of the $\ensuremath{\pi}{i}_{13/2}$ band was also found to feed a new long-lived isomeric state with an excitation energy of 2616 keV and a spin and parity of ${I}^{\ensuremath{\pi}}=29/{2}^{+}$. The half-life of the $29/{2}^{+}$ isomeric state was determined to be $1.49(1)\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{s}$. It decays via the emission of 457-keV $E2$ and 236-keV $E1$ transitions, respectively. A low-energy 46-keV $E2$ transition has been identified to depopulate the ($29/{2}^{\ensuremath{-}}$) isomeric state, with a measured half-life of ${T}_{1/2}=614(5)\phantom{\rule{0.28em}{0ex}}\mathrm{ns}$. This transition allows the excitation energy of the isomeric state to be determined as 2381 keV. The feeding patterns of both $29/{2}^{+}$ and ($29/{2}^{\ensuremath{-}}$) isomeric states have also been described. This is the first time collective structures have also been observed up to high spins and excitation energies in the neutron-deficient $^{195}\mathrm{Bi}$ nucleus. Evidence for the manifestation of shape coexistence in $^{195}\mathrm{Bi}$ is also discussed.

Onset of deformation in neutron-deficient Bi isotopes studied by laser spectroscopy

In-source laser spectroscopy experiments for bismuth isotopes at the 306.77-nm atomic transition has been carried out at the Investigation of Radioactive Isotopes on Synchrocyclotron facility of Petersburg Nuclear Physics Institute. New data on isotope shifts and hyperfine structure for Bi ground states and isomers $(^{189,190\mathrm{m}1,190\mathrm{m}2,191,192,192\mathrm{m},194,194\mathrm{m},198\mathrm{m}}\mathrm{Bi})$ have been obtained. The changes in the mean-square charge radii $\ensuremath{\delta}\ensuremath{\langle}{r}^{2}\ensuremath{\rangle}$ and magnetic-moment values have been deduced. For Bi nuclei a marked deviation from the isotopic trend of $\ensuremath{\delta}\ensuremath{\langle}{r}^{2}\ensuremath{\rangle}$ in lead and thallium isotopic chains has been demonstrated at $N\phantom{\rule{0.16em}{0ex}}l\phantom{\rule{0.16em}{0ex}}111$. This has been interpreted as an indication of the onset of quadrupole deformation. Analysis of the magnetic moments for odd-odd Bi isotopes also points to the possible increase in deformation at $N\phantom{\rule{0.16em}{0ex}}l\phantom{\rule{0.16em}{0ex}}111$.

Impact of intermediate and high energy nuclear data on the neutronic safety parameters of MYRRHA accelerator driven system

Perturbation of external neutron source can cause significant local power changes transformed into undesired safety-related events in an accelerator driven system. Therefore for the accurate design of MYRRHA sub-critical core it is important to evaluate the uncertainty of power responses caused by the uncertainties in nuclear reaction models describing the particle transport from primary proton energy down to the evaluated nuclear data table range. The calculations with a set of models resulted in quite low uncertainty on the local power caused by significant perturbation of primary neutron yield from proton interactions with lead and bismuth isotopes. The considered accidental event of prescribed proton beam shape loss causes drastic increase in local power but does not practically change the total core thermal power making this effect difficult to detect. In the same time the results demonstrate a correlation between perturbed local power responses in normal operation and misaligned beam conditions indicating that generation of covariance data for proton and neutron induced neutron multiplicities for lead and bismuth isotopes is needed to obtain reliable uncertainties for local power responses.

Laser spectroscopy studies of intruder states inBi193,195,197

In-source laser spectroscopy experiments on bismuth isotopes using the 306.77-nm atomic transition have been carried out at the Investigation of Radioactive Isotopes on Synchrocyclotron facility of the Petersburg Nuclear Physics Institute. New data for the isotope shifts and hyperfine structures of $^{193,195,197}\mathrm{Bi}^{\mathrm{g},\mathrm{m}}$ isotopes and isomers have been obtained. A large isomer shift between $I=1/{2}^{+}$ (intruder) and $I=9/{2}^{\ensuremath{-}}$ (normal) states has been found. The charge radii of the $^{193,195,197}\mathrm{Bi}$ ground states follow the trend found previously for isotonic (spherical) lead nuclei. The larger radii for the $1/{2}^{+}$ isomers suggest a larger deformation of these isomers compared to the ground state and support the shape coexistence interpretation of the previously obtained experimental data. Magnetic moments of Bi intruder isomers depart from the trend of the magnetic moments of the $1/{2}^{+}$ thallium ground states at $Nl114$.

Isomeric decay spectroscopy of theBi217isotope

The structure of the neutron-rich bismuth isotope 217Bi has been studied for the first time. The fragmentation of a primary 238U beam at the FRS-RISING setup at GSI was exploited to perform γ-decay spectroscopy, since μs isomeric states were expected in this nucleus. Gamma rays following the decay of a t1/2=3 μs isomer were observed, allowing one to establish the low-lying structure of 217Bi. The level energies and the reduced electric quadrupole transition probability B(E2) from the isomeric state are compared to large-scale shell-model calculations.

Scintillating bolometers: A promising tool for rare decays search

The idea of using a scintillating bolometer was first suggested for solar neutrino experiments in 1989. After many years of developments, now we are able to exploit this experimental technique, based on the calorimetric approach with cryogenic particle detectors, to investigate rare events such as Neutrinoless Double Beta Decay and interaction of Dark Matter candidates. The possibility to have high resolution detectors in which a very large part of the natural background can be discriminated with respect to the weak expected signal is very appealing. The goal to distinguish the different types of interactions in the detector can be achieved by means of scintillating bolometer. The simultaneous read-out of the heat and scintillation signals made with two independent bolometers enable this precious feature leading to possible background free experiment. In the frame of the LUCIFER project we report on how exploiting this technique to investigate Double Beta Decay for different isotope candidates. Moreover we demonstrate how scintillating bolometers are suited for investigating other rare events such as α decays of long living isotopes of lead and bismuth.

Alpha-Decay Study of Unfavored Transitions in Bismuth Isotopes

The unfavored α transitions of bismuth isotopes, including the newly observed α-decay fine structure in 209Bi [Beeman et al., Phys. Rev. Lett. 108 (2012) 062501] are investigated by the generalized density-dependent cluster model (GDDCM). Instead of the Wentzel—Kramers—Brillouin barrier penetration probability, the exact solution of the Schrödinger equation under outgoing Coulomb wave boundary conditions is presented. The calculated α-decay half-lives are found to be in good agreement with the experimental data for both odd-A and odd-odd nuclei. This indicates that the GDDCM has good applicability for unfavored α transitions in addition to favored ones. Some predictions on α-decay half-lives are also made for reference in future experiments.

Rapid method for determination of 228Ra in water samples

A new rapid method for the determination of 228Ra in natural water samples has been developed at the SRNL/EBL (Savannah River National Lab/Environmental Bioassay Laboratory) that can be used for emergency response or routine samples. While gamma spectrometry can be employed with sufficient detection limits to determine 228Ra in solid samples (via 228Ac), radiochemical methods that employ gas flow proportional counting techniques typically provide lower minimal detectable activity levels for the determination of 228Ra in water samples. Most radiochemical methods for 228Ra collect and purify 228Ra and allow for 228Ac daughter ingrowth for ~36 h. In this new SRNL/EBL approach, 228Ac is collected and purified from the water sample without waiting to eliminate this delay. The sample preparation requires only about 4 h so that 228Ra assay results on water samples can be achieved in 90 %), followed by rapid cation exchange removal of calcium. Lead, bismuth, uranium, thorium and protactinium isotopes are also removed by the cation exchange separation. 228Ac is eluted from the cation resin directly onto a DGA Resin cartridge attached to the bottom of the cation column to purify 228Ac. DGA Resin also removes lead and bismuth isotopes, along with Sr isotopes and 90Y. La is used to determine 228Ac chemical yield via ICP-MS, but 133Ba can also be used instead if ICP-MS assay is not available. Unlike some older methods, no lead or strontium holdback carriers or continual readjustment of sample pH is required.

Half-life of bismuth isotopes predicted by the Coulomb and proximity potential model; a proposition for the spherical nuclei

We know that the ground state energy, half-life, spin and parity of the heavy nuclei can be determined via the study of alpha decay. Bearing this in mind, we have calculated the penetration probability in the barrier, the decay constant and thereby the half-lives of 21 isotopes of Bi by using the proximity potential model. The comparison with the existing data is motivating.

Onset of deformation atN=112in Bi nuclei

The high spin states in ${}^{195}$Bi were studied by $\ensuremath{\gamma}$-ray spectroscopic method using the ${}^{181}$Ta(${}^{20}$Ne, 6$n$) fusion-evaporation reaction at 130 MeV. The $\ensuremath{\gamma}\ensuremath{\gamma}$ coincidence data were taken using an array of eight clover high-purity germanium detectors. The spin and parity assignments of the excited states were made from the measured directional correlation from oriented states ratios and integrated polarization asymmetry ratios. The results show, for the first time, the evidence of a rotational-like band based on a 13/2${}^{+}$ bandhead in this nucleus, indicating the onset of deformation at the neutron number $N=112$ for the bismuth isotopes. The results obtained were found to be consistent with the prediction of the total Routhian surface calculations using the Woods-Saxon potential. The same calculations also predicted a change in shape from oblate to triaxial in ${}^{195}$Bi at high rotational frequency.

HALF-LIVES OF BISMUTH DEFORMED ISOTOPES IN MULTIPLE APPROXIMATION BASIS

We intend to study the half-lives of Bismuth isotopes via the alpha decay process. To go through the problem, we consider a potential model in which an angle-dependence is considered. Our results reveal that taking into account the multipole approximations for both parent and daughter nuclei will improve the results.

Cross Sections of Bismuth and Polonium Isotopes in the Reaction of 209Bi with Protons

Cross Sections of Bismuth and Polonium Isotopes in the Reaction of 209Bi with Protons