Initial Radiation Research Articles

The Optimization of Radiation Synthesis Modes for YAG:Ce Ceramics.

Synthesis in the radiation field is a promising direction for the development of materials transformation processes, especially those differing in melting temperature. It has been established that the synthesis of yttrium-aluminum ceramics from yttrium oxides and aluminum metals in the region of a powerful high-energy electron flux is realized in 1 s, without any manifestations that facilitate synthesis, with high productivity. It is assumed that the high rate and efficiency of synthesis are due to processes that are realized with the formation of radicals, short-lived defects formed during the decay of electronic excitations. This article presents descriptions of the energy-transferring processes of an electron stream with energies of 1.4, 2.0, and 2.5 MeV to the initial radiation (mixture) for the production of YAG:Ce ceramics. YAG:Ce (Y3Al5O12:Ce) ceramics samples in the field of electron flux of different energies and power densities were synthesized. The results of a study of the dependence of the morphology, crystal structure, and luminescence properties of the resulting ceramics on the synthesis modes, electron energy, and electron flux power are presented.

The biogeography of extant lungfishes traces the breakup of Gondwana

AbstractAimLungfishes are one of the two surviving clades from the once diverse grade of lobe‐finned fishes leading to tetrapods. This classic living fossil lineage, which is the living sister to four‐limbed terrestrial vertebrates, appeared approximately 425 million years ago and rapidly diversified. However, the evolution of lungfishes after their initial radiation is poorly understood, and whether their present distribution tracks ancient geographical change is a classic problem in biogeography.LocationGlobal.TaxonLungfishes (Dipnoi).MethodsHere, we combine mitogenomic, nuclear gene and fossil data to reconstruct the timing of lungfish diversification a Bayesian tip‐dating approach to quantitatively test hypotheses of lungfish historical biogeography and divergence times. We sample all major living and extinct lungfish lineages, including three of the four species of African lungfishes (Protopterusspp.), the Australian lungfishNeoceratodus forsteri, the South American lungfishLepidosiren paradoxaand 13 fossils representing extinct lineages from across the globe.ResultsOur results demonstrate that the divergences of the three major living lungfish clades closely recapitulate the stepwise fragmentation of the Gondwana during the Mesozoic. All of our model‐based biogeographical reconstructions support a Gondwanan vicariance model for the origins of the present distribution of lungfish lineages.ConclusionsIn turn, lungfishes provide an excellent example of how the integration of fossil data may drastically change support for historical biogeographical hypotheses previously discounted by molecular data and are one of the few living animal lineages that record incredibly ancient geographical changes in their phylogeny.

Chemical abrasion: the mechanics of zircon dissolution

Abstract. Chemical abrasion is a technique that combines thermal annealing and partial dissolution in hydrofluoric acid (HF) to selectively remove radiation-damaged portions of zircon crystals prior to U–Pb isotopic analysis, and it is applied ubiquitously to zircon prior to U–Pb isotope dilution thermal ionization mass spectrometry (ID-TIMS). The mechanics of zircon dissolution in HF and the impact of different leaching conditions on the zircon structure, however, are poorly resolved. We present a microstructural investigation that integrates microscale X-ray computed tomography (µCT), scanning electron microscopy, and Raman spectroscopy to evaluate zircon dissolution in HF. We show that µCT is an effective tool for imaging metamictization and complex dissolution networks in three dimensions. Acid frequently reaches crystal interiors via fractures spatially associated with radiation damage zoning and inclusions to dissolve soluble high-U zones, some inclusions, and material around fractures, leaving behind a more crystalline zircon residue. Other acid paths to crystal cores include the dissolution of surface-reaching inclusions and the percolation of acid across zones with high defect densities. In highly crystalline samples dissolution is crystallographically controlled with dissolution proceeding almost exclusively along the c axis. Increasing the leaching temperature from 180 to 210 ∘C results in deeper etching textures, wider acid paths, more complex internal dissolution networks, and greater volume losses. How a grain dissolves strongly depends on its initial radiation damage content and defect distribution as well as the size and position of inclusions. As such, the effectiveness of any chemical abrasion protocol for ID-TIMS U–Pb geochronology is likely sample-dependent. We also briefly discuss the implications of our findings for deep-time (U-Th)/He thermochronology.

Study of the projected sensitivity on the anomalous quartic gauge couplings via Zγγ production at the CLIC

Gauge boson self-couplings are completely defined by the non-Abelian gauge symmetry of the Standard Model (SM). For this reason, a direct search for these couplings is extremely significant in understanding the gauge structure of the SM. The possible deviation from the SM predictions of gauge boson self-couplings would be a sign of the presence of new physics beyond the SM. In this work, we study the sensitivities on the anomalous couplings defined by dimension-8 operators related to the $ZZ\gamma\gamma$ and $Z\gamma\gamma\gamma$ quartic vertices through the process $e^+e^- \to Z\gamma\gamma$ with Z-boson decaying to charged leptons at the Compact Linear Collider (CLIC). We analyze the center-of-mass energy of 3 TeV, integrated luminosities of ${\cal L}=1, 4, 5$ $\rm ab^{-1}$, systematic uncertainties of $\delta_{sys}=0\%, 3\%, 5\%$, unpolarized and polarized electron beams and considering the Initial State Radiation and Beamstrahlung effects for extraction of expected sensitivity on the anomalous $f_ {T,j}/\Lambda^4$ couplings at $95\%$ confidence level, which are especially sensitive to the $Z\gamma\gamma$ channel. It is clear from the results that we expect better limits on the couplings if the systematic error is improved. The best limits obtained on the anomalous quartic couplings for the process $e^+e^- \to Z\gamma\gamma$ with $\sqrt{s}= 3$ TeV, ${\cal L}=5$ $\rm ab^{-1}$, and $\delta_{sys}=0\%$ can be approximately improved up to about 1.1 times better than the limits obtained with $\delta_{sys}=5\%$. Our sensitivities on the anomalous quartic couplings can set more stringent sensitivity by two orders of magnitude concerning the best sensitivity derived from the current experimental limits. Finally, with initial electron beam polarization, the sensitivity of the anomalous quartic couplings improves by almost a factor of 1.2.

Modern Concepts on the Origin and Distribution of Acipenserids (Acipenseridae)

The current data on the place and time of origin of Acipenseriformes and the family Acipenseridae, as well as on their distribution in connection with the history of the development of sea and river basins, are summarized. The supposed areas of the initial radiation of Acipenseriformes and their long-term habitation were in eastern Laurasia on a part of the modern Chita Region, Eastern and Central Mongolia, and northern and northeastern China. The eastern part of Asia should also be considered the place of origin of the family Acipenseridae. The widespread distribution of Acipenseriformes was facilitated mainly by the formation of diadromous forms from primarily freshwater species, the origin of which is associated with multiple transgressions and regressions of the ocean. Modern potamodromous acipenserids were probably formed as a result of the return of anadromous forms to living in fresh water; i.e., they are secondarily freshwater species.

Broad snouted cladoselachian with sensory specialization at the base of modern chondrichthyans

Throughout the Silurian and Devonian, cartilaginous fish successively evolved their specialized skeletal and dental characteristics, and increasingly refined their sensory systems. The Late Devonian shark taxon Maghriboselache mohamezanei gen. et sp. n. from the eastern Anti-Atlas of Morocco is known from multiple specimens preserving most of its skeletal features, which in some instances are preserved in three dimensions. Key details of the dentition, jaws, and pectoral skeleton are shared with the iconic genus Cladoselache. Phylogenetic analyses place the family Cladoselachidae as the sister group of symmoriiforms and these groups as sister group of the holocephalans. Further phylogenetic results corroborate that the initial evolutionary radiation of crown chondrichthyans occurred within or before the Late Devonian. Remarkably, this new stem holocephalan is equipped with a wide snout and large laterally separated nasal capsules: the earliest known example of this condition in the chondrichthyan and (perhaps) gnathostome record. This suggests sensory specialization approaching that of extant broad-rostrum elasmobranchs and represents a significant addition to increasingly apparent ecomorphological diversity among early chondrichthyans.

Medium-induced radiation with vacuum propagation in the pre-hydrodynamics phase

The recent discovery of the potential of jet quenching observables to constrain the initial stages after a heavy-ion collision makes imperative to have a better understanding of the process of medium-induced radiation before the formation of the quark-gluon plasma (QGP) and its impact on observables at high-pT. In this work, we generalize the BDMPS-Z framework for medium-induced radiation to account for additional emissions occurring before the creation of the QGP. For simplicity, we assume that during the pre-hydrodynamics phase the hard parton propagates as in vacuum. This set-up, allows us to isolate the contribution from the additional initial radiation by comparing with the usual scenarios in which the emitter is created inside the medium but with different starting points. Using both a numerical implementation of the fully resummed emission spectrum and the usual analytical approximations, we find that replacing an initial slab of the medium by vacuum yields to a significant reduction of the emission spectrum for low radiated gluon energies, while the high-energy tails remain largely unmodified. Finally, we assess the effect of replacing the initial medium by vacuum propagation on the single-inclusive particle suppression RAA and high-pT azimuthal asymmetry v2. Our findings indicate that considering vacuum propagation prior to hydrodynamization leads to an increase in the v2, thus corroborating the importance of the treatment of jet quenching in the initial stages for the correct description of both observables.

Diversity-Dependent Diversification in the History of Marine Animals.

AbstractBy comparing detrended estimates of diversity (taxonomic richness) and rates of origination, extinction, and net diversification, I show that at the global scale over the course of the Phanerozoic eon, rates of diversification and origination are negatively correlated with diversity. By contrast, extinction rates are only weakly correlated with diversity for the most part. These results hold for both genus- and species-level data and for many alternative analytical protocols. The asymmetry between extinction on the one hand and origination and net diversification on the other hand supports a model whereby extinction is largely driven by abiotic perturbations, with subsequent origination filling the void left by depleted diversity. Diversity dependence is somewhat weaker, but still evident, if the initial Ordovician radiation or rebounds from major mass extinctions are omitted from analysis; thus, diversity dependence is influenced, but not dominated, by these special intervals of Earth history. In the transition from Paleozoic to post-Paleozoic time, diversity dependence of origination weakens while that of extinction strengthens; however, diversity dependence of net diversification barely changes in strength. Despite nuances, individual clades largely yield results consistent with those for the aggregate data on all animals. On the whole, diversity-dependent diversification appears to be a pervasive factor in the macroevolution of marine animal life.

Weak radiative decay Lambda _{c}^{+}rightarrow Sigma ^{+}gamma using light-cone sum rules

We calculate the decay width of the Lambda _{c}^{+}rightarrow Sigma ^{+}gamma using light-cone sum rules. For the initial quark radiation an effective Hamiltonian is constructed, where the internal quark line shrinks to a point. The final quark radiation is studied within the full theory. The leading twist light-cone distribution amplitudes of the Sigma ^+ serve as the non-perturbative input for the sum rules calculation, and the perturbative kernel is calculated at leading order. The branching fraction we obtain is mathcal{B}(Lambda _{c}^{+}rightarrow Sigma ^{+}gamma )=1.03pm 0.36 times 10^{-4}, which is below the recent upper limits <2.6 times 10^{-4} and <4.4 times 10^{-4} given by the Belle collaboration and the BESIII collaboration, respectively.

Contrasting patterns of disparity suggest differing constraints on the evolution of trilobite cephalic structures during the Cambrian ‘explosion’

AbstractTrilobites are an abundant group of Palaeozoic marine euarthropods that appear abruptly in the fossil recordc. 521 million years ago. Quantifying the development of morphological variation (or ‘disparity’) through time in fossil groups like trilobites is critical in understanding evolutionary radiations such as the Cambrian ‘explosion’. Here, I use geometric morphometrics to quantify ‘cumulative disparity’ in functionally‐important structures within the trilobite cephalon across their initial radiation during Cambrian Series 2. Overall cephalic disparity increased rapidly and attained a maximum within several million years. This pattern is dominated by the cephalic outline (in particular the genal spines), reflecting rapid, convergent expansion to the extremes of morphospace in a few early families. In contrast, removing the outline and focusing on structures such as the glabella and eye ridges (associated with feeding and vision, respectively) showed a more gradual increase in disparity, closer in line with taxonomic diversity and supporting the hypothesis of a relatively accurate trilobite fossil record. These contrasting patterns suggest that disparity in different structures was constrained in different ways, with extrinsic (ecological) factors probably having the major impact on overall disparity. It also implies that patterns of disparity in isolated substructures cannot necessarily be taken individually as representative of overall morphologies.

Singlet vector-like T quark production in association with Wb at the CLIC

In a simplified model including an SU(2) singlet vector-like top quark T (VLT) with charge 2/3, we investigate the associated production of Wb with VLT at a Compact Linear Collider (CLIC). Focusing on the T → Wb decay channel, we discuss two decay models: and . In this paper, we consider recent experimental limits including the electroweak precision observables, the width of the top quark, and the direct LHC searches. Through a detailed detector simulation, we show the exclusion and discovery capability on the T at 3 TeV CLIC, where the initial state radiation effect has also been considered. The results show that it is promising to detect the VLT at future high-energy e + e − colliders.

Machine learning confirms new records of maniraptoran theropods in Middle JurassicUKmicrovertebrate faunas

AbstractCurrent research suggests that the initial radiation of maniraptoran theropods occurred in the Middle Jurassic, although their fossil record is known almost exclusively from the Cretaceous. However, fossils of Jurassic maniraptorans are scarce, usually consisting solely of isolated teeth, and their identifications are often disputed. Here, we apply different machine learning models, in conjunction with morphological comparisons, to a suite of isolated theropod teeth from Bathonian microvertebrate sites in the UK to determine whether any of these can be confidently assigned to Maniraptora. We generated three independent models developed on a training dataset with a wide range of theropod taxa and broad geographical and temporal coverage. Classification of the Middle Jurassic teeth in our sample against these models and comparison of the morphology indicates the presence of at least three distinct dromaeosaur morphotypes, plus a therizinosaur and troodontid in these assemblages. These new referrals significantly extend the ranges of Therizinosauroidea and Troodontidae by some 27 myr. These results indicate that not only were maniraptorans present in the Middle Jurassic, as predicted by previous phylogenetic analyses, but they had already radiated into a diverse fauna that pre‐dated the break‐up of Pangaea. This study also demonstrates the power of machine learning to provide quantitative assessments of isolated teeth in providing a robust, testable framework for taxonomic identifications, and highlights the importance of assessing and including evidence from microvertebrate sites in faunal and evolutionary analyses.

Modern Concepts on the Origin and Distribution of Acipenserids (Acipenseridae)

The current data on the place and time of origin of Acipenseriformes and the family Acipenseridae, as well as on their distribution in connection with the history of the development of sea and river basins, are summarized. The supposed areas of the initial radiation of Acipenseriformes and their long-term habitation were in eastern Laurasia on a part of the modern Chita Region, Eastern and Central Mongolia, and northern and northeastern China. The eastern part of Asia should also be considered the place of origin of the family Acipenseridae. The widespread distribution of Acipenseriformes was facilitated mainly by the formation of diadromous forms from primarily freshwater species, the origin of which is associated with multiple transgressions and regressions of the ocean. Modern potamodromous acipenserids were probably formed as a result of the return of anadromous forms to living in fresh water; i.e., they are secondarily freshwater species

Mechanisms of Nanoscale Radiation Enhancement by Metal Nanoparticles: Role of Low Energy Electrons.

Metal nanoparticles are considered as highly promising radiosensitizers in cancer radiotherapy. Understanding their radiosensitization mechanisms is critical for future clinical applications. This review is focused on the initial energy deposition by short-range Auger electrons; when high energy radiation is absorbed by gold nanoparticles (GNPs) located near vital biomolecules; such as DNA. Auger electrons and the subsequent production of secondary low energy electrons (LEEs) are responsible for most the ensuing chemical damage near such molecules. We highlight recent progress on DNA damage induced by the LEEs produced abundantly within about 100 nanometers from irradiated GNPs; and by those emitted by high energy electrons and X-rays incident on metal surfaces under differing atmospheric environments. LEEs strongly react within cells; mainly via bound breaking processes due to transient anion formation and dissociative electron attachment. The enhancement of damages induced in plasmid DNA by LEEs; with or without the binding of chemotherapeutic drugs; are explained by the fundamental mechanisms of LEE interactions with simple molecules and specific sites on nucleotides. We address the major challenge of metal nanoparticle and GNP radiosensitization; i.e., to deliver the maximum local dose of radiation to the most sensitive target of cancer cells (i.e., DNA). To achieve this goal the emitted electrons from the absorbed high energy radiation must be short range, and produce a large local density of LEEs, and the initial radiation must have the highest possible absorption coefficient compared to that of soft tissue (e.g., 20-80 keV X-rays).

Jet fragmentation via azimuthal angular correlations of electrons from heavy flavor decay in pp, p -Pb, and Pb-Pb collisions using PYTHIA8+Angantyr calculations

Measurements in heavy flavor azimuthal angular correlation provide insight into the production, propagation, and hadronization of heavy flavor jets in ultrarelativistic hadronic and heavy-ion collisions. These measurements across different colliding systems, such as $p\text{\ensuremath{-}}A$ and $A\text{\ensuremath{-}}A$, help us isolate the possible modification in particle production due to cold nuclear matter (CNM) effects and the formation of quark-gluon plasma (QGP), respectively. Jet correlation studies give direct access to the initial parton dynamics produced in these collisions. This article studies the azimuthal angular correlations of electrons from heavy flavor hadron decays in $pp, p$-Pb, and Pb-Pb collisions at $\sqrt{{s}_{NN}}=5.02$ TeV using $\text{PYTHIA8}+\text{Angantyr}$. We study the production of heavy flavor jets with different parton level processes, including multiparton interactions, different color reconnection prescriptions, and initial and final state radiation processes. In addition, we add the hadron-level processes, i.e., Bose-Einstein and rescattering effects, to quantify the effect due to these processes. The heavy flavor electron correlations are calculated in the different trigger and associated ${p}_{\mathrm{T}}$ intervals to characterize the impact of hard and soft scattering in the various colliding systems. The yields and the sigmas associated with the near-side (NS) and away-side (AS) correlation peaks are calculated and studied as a function of associated ${p}_{\mathrm{T}}$ for different trigger ${p}_{\mathrm{T}}$ ranges.

Postradiosurgery cystic degeneration in brain metastases causing delayed and potentially severe sequelae: systematic review and illustrative cases.

Cystic postradiation degeneration has previously been described in the literature as a rare but potentially severe complication after central nervous system (CNS) irradiation for vascular malformations. Limited cases have been reported in the setting of brain metastases. Thirty-six total cases, including three reported here, of cystic postradiation degeneration are identified. Of 35 cases with complete clinical information, 34 (97.25%) of 35 were symptomatic from cystic changes at diagnosis. The average time between initial radiation dose and cyst development was 7.61 years (range 2-31 years). Although most patients were initially treated conservatively with medication, including steroids, 32 (88.9%) of 36 ultimately required surgical intervention. The most common interventions were craniotomy for cyst fenestration or resection (25 of 36; 69.4%) and Ommaya placement (8 of 36). After intervention, clinical improvement was seen in 10 (67%) of 15 cases, with persistent or worsening deficit or death seen in 5 (33%) of 15. Cysts were decompressed or obliterated on postoperative imaging in 20 (83.3%) of 24 cases, and recurrence was seen in 4 (16.7%) of 24. Cystic degeneration is a rare and delayed sequela after radiation for brain metastases. This entity has the potential to cause significant and permanent neurological deficit if not properly recognized and addressed. Durable control can be achieved with a variety of surgical treatments, including cyst fenestration and Ommaya placement.

Measurement of $$\mathcal{B}r(H \to Z\gamma )$$ at the 250 GeV ILC

The $e^+e^- \to HZ$ process with the subsequent decay of the Higgs boson $H \to Z\gamma$ is studied, where both $Z$ bosons are reconstructed in the final states with two jets. The analysis is performed using Monte Carlo data samples obtained with detailed ILD (The International Large Detector) detector simulation assuming an integrated luminosity of 2 ab$^{-1}$, beam polarizations of ${\cal{P}}_{e^-e^+} = (-0.8, +0.3)$, and center-of-mass energy of $\sqrt{s}$ = 250 GeV. The analysis is repeated for the case of two 0.9 ab$^{-1}$ data samples with polarizations ${\cal{P}}_{e^-e^+} = (\mp0.8, \pm0.3)$. Contributions of the potential background processes are studied using all available ILD MC event samples. The largest background comes from the $e^+e^- \to W^+W^-$ process supplemented by an energetic photon produced by initial state radiation. To suppress this background we require that at least one of the $Z$ bosons decays to $b$-jets. To reduce the jet reconstruction uncertainties the $M_{\Delta} = M(jj\gamma) - M(jj) + M(Z_{\rm nom})$ variable is used, where $M(Z_{\rm nom})$ = 91.2 GeV. The $M_{\Delta}$ distributions are obtained for the studied signal and backgrounds to estimate the expected accuracy of the ${\cal B}r(H \to Z\gamma)$ measurement. The accuracy is 22$\%$ for the option of the single polarization sample described above and deteriorate to 24$\%$ in case of the sample with two polarizations. The proposed method can be applied at any future $e^+e^-$ collider.

Study of e+e−→ηϕ via initial state radiation at Belle

Using 980 fb−1 of data collected on and around the ϒ(nS) (n=1, 2, 3, 4, 5) resonances with the Belle detector at the KEKB collider, we measure the cross section of e+e−→ηϕ from threshold to 3.95 GeV via initial state radiation. There are clear ϕ(1680) and J/ψ signals but no significant ϕ(2170) signal in the ηϕ final state. The branching fraction B[J/ψ→ηϕ] is measured to be (7.2±0.8±0.5)×10−4. The resonant parameters of ϕ(1680) are determined to be mϕ(1680)=(1696±8±10) MeV/c2 (statistical and systematic errors, respectively), Γϕ(1680)=(175±13±16) MeV and, depending on the possible presence of predominantly constructive or destructive interference between ϕ(1680) and continuum production, Γϕ(1680)e+e−·B[ϕ(1680)→ηϕ] and B[ϕ(1680)→ηϕ] are determined to be (75±10±11) eV and (25±12±2)% or (207±16±20) eV and (23±10±2)%, respectively. The upper limit for Γϕ(2170)e+e−·B[ϕ(2170)→ηϕ] is determined to be either 0.17 or 18.6 eV at the 90% confidence level.Received 1 September 2022Accepted 10 October 2022DOI:https://doi.org/10.1103/PhysRevD.107.012006Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasHadronic decaysQuark modelParticles & Fields

Diversity, Form, and Postembryonic Development of Paleozoic Insects.

While Mesozoic, Paleogene, and Neogene insect faunas greatly resemble the modern one, the Paleozoic fauna provides unique insights into key innovations in insect evolution, such as the origin of wings and modifications of postembryonic development including holometaboly. Deep-divergence estimates suggest that the majority of contemporary insect orders originated in the Late Paleozoic, but these estimates reflect divergences between stem groups of each lineage rather than the later appearance of the crown groups. The fossil record shows the initial radiations of the extant hyperdiverse clades during the Early Permian, as well as the specialized fauna present before the End Permian mass extinction. This review summarizes the recent discoveries related to the documented diversity of Paleozoic hexapods, as well as current knowledge about what has actually been verified from fossil evidence as it relates to postembryonic development and the morphology of different body parts.

Production of double heavy quarkonia at super Z factory

Within the color singlet model, we calculate the exclusive production of double charmonia, double bottomonia, and double B_c mesons at future super Z factory. The two heavy quarkonia or B_c’s are either two S-wave Fock states (^1S_0, ~^3S_1), or one S-wave and one P-wave states (^1P_1,~^3P_J~(J=0,1,2)). The top three Z^0 propagated channels in cross sections for double charmonia are sigma {(J/psi +h_c)}_{Z^0}=(454.0^{+39.1}_{-59.2})times 10^{-5} fb, sigma {(eta _c+chi _{c2})}_{Z^0}=(284.2^{+22.2}_{-35.3})times 10^{-5} fb, and sigma {(eta _c+chi _{c0})}_{Z^0}=(137.0^{+9.9}_{-16.4})times 10^{-5} fb. For double bottomonia, they are sigma {(eta _b+Upsilon )}_{Z^0}=(428.6^{+67.9}_{-60.9})times 10^{-4} fb, sigma {(Upsilon +chi _{b2})}_{Z^0}=(230.6^{+23.6}_{-22.2})times 10^{-4} fb, and sigma {(Upsilon +Upsilon )}_{Z^0}=(119.9^{+18.4}_{-16.6})times 10^{-4} fb. For double B_c mesons, they are sigma {(B_c^{*+}+B_c^{*-})}_{Z^0}=(1150^{+87}_{-84})times 10^{-3} fb, sigma {(B_c^{*+}+chi _{bc2}^-)}_{Z^0}=(1133^{-16}_{+22})times 10^{-3} fb, and sigma {(eta _{bc}^++B_c^{*-})}_{Z^0}=(634.6^{+47.8}_{-45.8})times 10^{-3} fb. Here the uncertainties come from the varying masses of constituent heavy quarks, which bring up to 20% corrections. The cross sections of double B_c mesons are roughly one order of magnitude larger than those of the double bottomonia, and two orders of magnitude larger than those of the double charmonia. To make it helpful for experimental study, we present the total cross sections sigma as functions of CM energy sqrt{s}, sigma as functions of the renormalization scale mu , the angle distributions dsigma /dcostheta , and the p_T distributions dsigma /dp_{t}. We also find that the initial state radiation can bring about 30–40% suppresions when 1%m_Z energy is losing, and cross sections can increase by about 2–3 times or decrease by an order of magnitude when adopting different potential models which becomes the major source of uncertainty. The numerical results show that it might be not optimistic for the experimental observation, but it is still far from excluded at the FCC-ee and also the CEPC running in the Z factory mode.