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This paper is devoted to the calculations of alpha decay half-lives of 186−218Po (Z=84) isotopes and actinide nuclei between the atomic numbers Z = 90 and Z = 102, using an energy-dependent potential model. The α-nucleus effective potential employed in this study includes a Coulomb potential, a centrifugal barrier potential, and a nuclear potential. The nuclear potential is chosen to be the energy-dependent singularized harmonic potential, typical of nuclear interactions. The role of the energy-dependent potential is very significant in this study. Indeed, when compared to the experimental data, our results are found to be improved when energy-dependent interaction potential is employed compared to when energy-independent interactions are used, especially for small values of the parameter γ as evidenced by the values of the root mean square deviation. [ABSTRACT FROM AUTHOR]

This paper analyzes the design of an alpha-decay sail. While previous studies have been conducted on the feasibility of alpha-decay sails, none have investigated the effects of different backing materials and backing material thicknesses on propulsion. This paper conducts simulations using the particle simulation toolkit Geant4 to determine the thrust produced from alpha-decay sails constructed of 238Pu and a backing layer made of aluminum, beryllium, lithium, or polyethylene. The results demonstrate that alpha-decay sails can be a very useful form of in-space propulsion, having the potential to dramatically decrease travel time beyond distances of 100 AU. [ABSTRACT FROM AUTHOR]

Using the Coulomb and Proximity Potential Model (CPPM) and a Q-value dependent surface diffuseness parameter in the proximity potential, the alpha decay half-lives of 75 experimentally synthesized superheavy nuclei were determined. Comparisons are made between the obtained results and experimentally determined alpha decay half-lives, as well as the predictions of Yang et al.'s recent study [Nucl. Phys. A 1014 (2021) 122250], which is based on the Unified Fission Model (UFM) with a new preformation parameter. The lowest standard deviation of 0.621 is obtained for CPPM calculations with Q-value-dependent surface diffuseness parameter. The calculation is extended further to estimate the alpha decay half-lives of 2 8 4 − 3 1 5 119 and 2 8 7 − 3 1 6 120 superheavy isotopes and compared with the predictions of UFM. Finally, the results of the calculations are compared to the predictions of the UDL formula [Phys. Rev. Lett. 103 (2009) 072501] and the modified Hutsukawa formula [Nucl. Part. Phys. Proc. 339 (2023) 92]. [ABSTRACT FROM AUTHOR]

Well-developed α clusters are known to exist in light N=Z nuclei, and their properties are reasonably well described with modern nuclear structure theories. However, 'modestly' developed clusters in medium to heavy nuclei remain little understood, both theoretically and experimentally. Extension of the focus to include modestly developed clusters leads us to a concept of 'generalized clusters' and 'cluster ubiquitousness'. The former includes clusters more weakly bound than an α cluster, such as deuteron, triton and He3 , and even clusters partially broken owing to nuclear medium effects. The latter means the existence of clusters in any nuclei, where cluster development was not previously discussed. Effects of the tensor and the spin–orbit interactions on the coexistence of clusters with independent nucleons are discussed using recent nuclear theoretical models. A mixture of the clusters with shell-like components plays an essential role in the synthesis of elements in the universe and the origin of life, together with an α decay. It is also pointed out that clustering in heavy nuclei may accelerate fission and fusion processes. Future experimental plans using cluster knockout reactions, which have the potential to extract information of 'generalized clusters' in a variety of nuclei including stable and unstable nuclei, are also discussed. This article is part of the theme issue 'The liminal position of Nuclear Physics: from hadrons to neutron stars'. [ABSTRACT FROM AUTHOR]

By using a superconducting transition edge sensor (TES) to measure the thermal energy of individual decay events with high energy resolution, decay energy spectrometry provides a unique fingerprint to identify each radionuclide in a sample. The proposed measurement requires optimizing the thermal parameters of the detector for use with 5 MeV scale energy deposited by alpha decay of the sample radionuclides. The thermal performance of deep-etched silicon TES chips is examined with the use of an onboard resistive heater. With known heater power and bath temperature, the thermal conductance, heat capacity, and frame temperature are calculated and compared to theory. [ABSTRACT FROM AUTHOR]

In this section of Resonance, we invite readers to pose questions likely to be raised in a classroom situation. We may suggest strategies for dealing with them, or invite responses, or both. "Classroom" is equally a forum for raising broader issues and sharing personal experiences and viewpoints on matters related to teaching and learning science. G Gamow's alpha-decay theory (1928) is somewhat ad hoc for the reason that an alpha-particle inside a radioactive nucleus is supposed to move back and forth, through the dense mass of nucleons (retaining its identity), a number of times before it comes out. This short paper attempts to address this shortcoming via nuclear disintegration. [ABSTRACT FROM AUTHOR]

Experimental results on the α decay and fission of high-K isomers are reviewed. Despite the sparse available information, it seems that there is hindrance to the α decay and fission processes from isomeric states relative to the same processes in the ground states. This may have profound consequences, especially for the creation and observation of super-heavy nuclei. To understand the hindrances to α decay and fission that arise when high-K isomers are involved, theoretical descriptions must reflect the pair-broken character of the states, which alters both the potential and inertial terms used in describing these fundamental processes. [ABSTRACT FROM AUTHOR]

A systematic study of the ground-state properties of even–even Po, Rn, Ra and Th isotopes is conducted using the self-consistent Skyrme-Hartree–Fock–Bogoliubov (HFB) theory. Different Skyrme interactions are employed in the study. The bulk properties such as binding energy, two-neutron separation energies, two-proton separation energies and neutron skin thickness are investigated. The obtained results from the Skyrme-HFB formalism are compared with the calculated results from the Finite Range Droplet Model (FRDM) and the available experimental data. Our theoretical values were found to be consistent with their counterparts. In addition, the density-dependent cluster model is utilized to estimate α -decay half-lives. A good agreement is achieved between the calculated results and the recent experimental data. [ABSTRACT FROM AUTHOR]

The importance of alpha decay to understanding nuclear structure has been well established. To calculate alpha decay half-lives, the choice of the nuclear potential is important. The Michigan-3-Yukawa (M3Y) nucleon-nucleon (NN ) effective interactions and NN effective interactions derived from relativistic mean field theory Lagrangian (R3Y) have been successfully used in alpha decay study within the double-folding model. In this study, we investigate the use of the microscopically deduced B3Y-Fetal effective interactions that stem from the lowest order constrained variational approach (LOCV) in studying alpha decay half-lives. Secondly, we study the effect of using various density-dependent parametrizations on alpha decay half-lives. We found that the density-dependent parametrization BDB3Y0-Fetal gives the best description of the alpha decay half-lives. Moreover, in order to predict the alpha decay half-lives of unmeasured superheavy nuclei with Z = 120 , an empirical preformation probability formula was obtained using the BDB3Y0-Fetal results and experimental data. The preformation formula obtained together with the Q α values derived from the Weizsäcker-Skyrme-type nuclear mass model with radial basis corrections (WS-type+RBF) and the BDB3Y0-Fetal NN interaction was used to predict the alpha decay half-lives of unmeasured superheavy nuclei with Z = 120 . [ABSTRACT FROM AUTHOR]

Background: A significant challenge in cancer therapy lies in eradicating hidden disseminated tumor cells. Within Nuclear Medicine, Targeted Alpha Therapy is a promising approach for cancer treatment tackling disseminated cancer. As tumor size decreases, alpha-particles gain prominence due to their high Linear Energy Transfer (LET) and short path length. Among alpha-particle emitters, 211At stands out with its 7.2 hour half-life and 100% alpha emission decay. However, optimizing the pharmacokinetics of radiopharmaceuticals with short lived radionuclides such as 211At is pivotal, and in this regard, pretargeting is a valuable tool. This method involves priming the tumor with a modified monoclonal antibody capable of binding both the tumor antigen and the radiolabeled carrier, termed the "effector molecule. This smaller, faster-clearing molecule improves efficacy. Utilizing the Diels Alder click reaction between Tetrazine (Tz) and Trans-cyclooctene (TCO), the Tz-substituted effector molecule combines seamlessly with the TCO-modified antibody. This study aims to evaluate the in vivo biodistribution of two Poly-L-Lysine-based effector molecule sizes (10 and 21 kDa), labelled with 211At, and the in vitro binding of the most favorable polymer size, in order to optimize the pretargeted radioimmunotherapy with 211At. Results: In vivo results favor the smaller polymer's biodistribution pattern over the larger one, which accumulates in organs like the liver and spleen. This is especially evident when comparing the biodistribution of the smaller polymer to a directly labelled monoclonal antibody. The smaller variant also shows rapid and efficient binding to SKOV-3 cells preloaded with TCO-modified Trastuzumab in vitro, emphasizing its potential. Both polymer sizes showed equal or better in vivo stability of the astatine-carbon bond compared to a monoclonal antibody labelled with the same prosthetic group. Conclusions: Overall, the small Poly-L-Lysine-based effector molecule (10 kDa) holds the most promise for future research, exhibiting significantly lower uptake in the kidneys and spleen compared to the larger effector (21 kDa) while maintaining an in vivo stability of the astatine-carbon bond comparable to or better than intact antibodies. A proof of concept in vitro cell study demonstrates rapid reaction between the small astatinated effector and a TCO-labelled antibody, indicating the potential of this novel Poly-L-Lysine-based pretargeting system for further investigation in an in vivo tumor model. [ABSTRACT FROM AUTHOR]

Within the framework of the Coulomb and Proximity Potential Model, the alpha decay half-lives of isotones of Z = 104 − 132 superheavy nuclei with neutron number N = 148, 150, 152, 160, 162, 164, 172, 176, 178, 180, 182, 184, 198, and 200 are investigated systematically by including a Q-value and Isospin dependent preformation factor in the model. The predictive power of the model after including the preformation parameter is verified by calculating the alpha decay half-lives of 65 superheavy nuclei whose experimental alpha decay half-lives are known. For the study of alpha decay of the isotones, the Q-values are calculated using the KTUY and WS4 mass tables. The results are compared with the predictions of empirical models like the Universal Decay Law, Royer Formula, and Akrawy–Poenaru Formula (Modified Royer Formula). From the study, we conclude that after 126, the neutron shell closure occurs are N = 184, for both Z = 114 and 126 superheavy nuclei. Also, Possible neutron magic numbers N = 178, 180, and 182 corresponding to Z = 114 were identified. The island of stability next to Z = 114, N = 184 is located at Z = 126, and N = 184. [ABSTRACT FROM AUTHOR]

The phenomenon of laser-assisted alpha decay is studied within the framework of non-Hermitian quantum theory integrated with the (t, t ′)-formalism. The width and the lifetime of the alpha cluster of a specific isotope is extracted from the spectrum of the complex-scaled Hamiltonian operator of the nuclear system and estimated numerically. The laser-field-induced correction to the lifetime is computed by first-order (t, t ′)-perturbation calculation with regard to different polarization states and control parameters of the external laser field, adjusting appropriate intensity and photon energy pairs by examining the limit of the non-relativistic approximation of the problem. [ABSTRACT FROM AUTHOR]

Alpha decay half-lives of heavy and superheavy nuclei are studied by using eight different nuclear potentials such as Denisov potential (DP00), Christensen and Winther potential (CW), Broglia and Winther potential 1991 (BW91), Aage Winther potential (AW95), Bass 1973 (Bass73), Bass 1977 (Bass77), Bass 1980 (Bass80) and nuclear proximity 2000 (Prox00). Alpha decay half-lives produced by these potentials are compared with that of experiments. Alpha decay half-lives resulting from Prox00 show good agreement with the experimental data. The deviations produced by these potentials are predicted using statistical parameters such as root mean square deviation σ , mean deviation ( δ ¯ ), index f ¯ and root mean square error. The Prox00 nuclear potential exhibits minimal deviations when predicting experimental half-lives in heavy and superheavy nuclei, outperforming seven other potential models. Hence, Prox00 may be used to predict alpha decay half-lives of heavy and superheavy nuclei. [ABSTRACT FROM AUTHOR]

Background: Diffusing alpha‐emitters Radiation Therapy ("Alpha DaRT") is a new technique that enables the use of alpha particles for the treatment of solid tumors. Alpha DaRT employs interstitial sources carrying a few μ$\mu$Ci of 224$^{224}$Ra below their surface, designed to release a chain of short‐lived atoms (progeny of 224$^{224}$Ra) which emit alpha particles, along with beta, Auger, and conversion electrons, x‐ and gamma rays. These atoms diffuse around the source and create—primarily through their alpha decays—a lethal high‐dose region measuring a few millimeters in diameter. Purpose: While previous studies focused on the dose from the alpha emissions alone, this work addresses the electron and photon dose contributed by the diffusing atoms and by the atoms remaining on the source surface, for both a single Alpha DaRT source and multi‐source lattices. This allows to evaluate the low‐LET contribution to the tumor dose and tumor cell survival, and demonstrate the sparing of surrounding healthy tissue. Methods: The low‐LET dose is calculated using the EGSnrc and FLUKA Monte Carlo (MC) codes. We compare the results of a simple line‐source approximation with no diffusion to those of a full simulation, which implements a realistic source geometry and the spread of diffusing atoms. We consider two opposite scenarios: one with low diffusion and high 212$^{212}$Pb leakage, and the other with high diffusion and low leakage. The low‐LET dose in source lattices is calculated by superposition of single‐source contributions. Its effect on cell survival is estimated with the linear quadratic model in the limit of low dose rate. Results: For sources carrying 3 μ$\umu$Ci/cm 224$^{224}$Ra arranged in a hexagonal lattice with 4 mm spacing, the minimal low‐LET dose between sources is ∼18−30$\sim 18-30$ Gy for the two test cases and is dominated by the beta contribution. The low‐LET dose drops below 5 Gy ∼3$\sim 3$ mm away from the outermost source in the lattice with an effective maximal dose rate of <0.04$<0.04$ Gy/h. The accuracy of the line‐source/no‐diffusion approximation is ∼15%$\sim 15\%$ for the total low‐LET dose over clinically relevant distances (2–4 mm). The low‐LET dose reduces tumor cell survival by a factor of ∼2−200$\sim 2-200$. Conclusions: The low‐LET dose in Alpha DaRT can be modeled by conventional MC techniques with appropriate leakage corrections to the source activity. For 3 μ$\umu$Ci/cm 224$^{224}$Ra sources, the contribution of the low‐LET dose can reduce cell survival inside the tumor by up to two orders of magnitude. The low‐LET dose to surrounding healthy tissue is negligible. Increasing source activities by a factor of 5 can bring the low‐LET dose itself to therapeutic levels, in addition to the high‐LET dose contributed by alpha particles, leading to a "self‐boosted" Alpha DaRT configuration, and potentially allowing to increase the lattice spacing. [ABSTRACT FROM AUTHOR]

Identifying and characterizing the decay chains forms a crucial part of nuclide identification in the synthesis of super-heavy elements (SHEs), which is achieved via cold or hot fusion reactions. A systematic theoretical calculation of alpha-decay half-lives in this region of the periodic system may be useful in the identification of new nuclei in both types of reactions. Here, we obtain the alpha-decay half-lives in the framework of the dynamical cluster-decay model (DCM) based on quantum mechanical fragmentation theory (QMFT), built using pre-formation probability and penetration probability. We calculate the α-decay half-life using the DCM (ℓ = 0 case), which considers the compound nucleus hot due to its recoil energy after neutron emission, providing a more accurate description than other models. Decay half-lives are compared with experimental results. [ABSTRACT FROM AUTHOR]

From 7 naturally occurring Nd isotopes, 5 are unstable in relation to α decay. If an excited level of the daughter nucleus is populated, or the daughter nucleus is unstable, γ quanta can be emitted. We used an ultra-low background spectrometry system with 4 high purity germanium (HPGe) detectors (about 225 cm3 volume each) to search for such decays using a highly purified Nd-containing sample with mass of 2.381 kg. Measurements were performed at the INFN Gran Sasso underground laboratory (with an overburden of about 3600 m w.e.) during 51,237 h. Half-life limits for α decays of 143Nd and 145Nd were determined to be T1/2(143Nd) > 1.1 × 1020 year and T1/2(145Nd) > 2.7 × 1019 year at 90% C.L. This is an increase of three and two orders of magnitude, respectively, compared with the most restrictive values currently given in literature. A limit for α decay of 144Nd to the excited level of 140Ce with Eexc = 1596.2 keV was determined for the first time as T1/2(144Nd → 140Ce*) > 9.3 × 1020 year. Restriction for the α decay of 146Nd to the excited level of 142Ce with Eexc = 641.3 keV was increased by 3 orders of magnitude to T1/2(146Nd → 142Ce*) > 1.4 × 1021 year. For α and 2α decays of 148Nd, first T1/2 limits were set as 4.2 × 1018 year and 2.1 × 1020 year, respectively. [ABSTRACT FROM AUTHOR]

We propose to investigate the time modulation of radioisotope decays deep underground as a method to explore axion dark matter. In this work, we focus on the α-decay of heavy isotopes and develop a theoretical description for the θ-dependence of α-decay half-lives, which enables us to predict the time variation of α-radioactivity in response to an oscillating axion dark matter background. To probe this scenario, we have recently constructed and installed a setup deep underground at the Gran Sasso Laboratory, based on the α-decay of Americium-241. This prototype experiment, named RadioAxion-α, will allow us to explore a broad range of oscillation's periods, from a micro-second up to one year, thus providing competitive limits on the axion decay constant across 13 orders of magnitude in the axion mass, ranging from 10−9 eV to 10−20 eV after one month of data collection, and down to 10−22 eV after three years.

Dynamic shear-modulus data are presented for two silicone oils DC704 and DC705 for frequencies between 1 mHz and 10 kHz at temperatures covering more than five decades of relaxation-time variation. Data are fitted to the alpha part of a phenomenological model previously shown to describe well the dynamic shear modulus of squalane, which has a large beta process [Hecksher et al., J. Chem. Phys. 146, 154504 (2017)]. That model is characterized by additivity of the alpha and beta shear compliance and by a high-frequency decay of the alpha process in proportion to ω−1/2, where ω is the angular frequency. The fits of the alpha part of this model to the DC704 and DC705 data are compared to fits by a Havriliak–Negami type model, a Barlow–Erginsav–Lamb model, and a Cole–Davidson type model. At all temperatures, the best fit is obtained by the alpha part of the squalane model. This strengthens the conjecture that so-called t -relaxation, leading to high-frequency loss decays proportional to ω−1/2, is generic to the alpha relaxation of supercooled liquids [J. C. Dyre, Phys. Rev. E 74, 021502 (2006); Nielsen et al., J. Chem. Phys. 130, 154508 (2009); and Pabst et al., J. Phys. Chem. Lett. 12, 3685–3690 (2021)]. [ABSTRACT FROM AUTHOR]

We studied the alpha decay half-life of Americium isotopes (Z = 9 5) with mass numbers ranging from 223 to 243. Our investigation employed the Coulomb and proximity potential model (CPPM), in addition to alternative analytical and semiempirical formulas. The calculations took into account both experimental and theoretical Q-values, as well as the total alpha kinetic energy. We analyzed the behavior of the hindrance factor concerning changes in the mass numbers of parent nuclei within the range of 223–243, and also examined the impact of magic numbers associated with closed shells. To evaluate the accuracy of our findings, we utilized the SemFIS, UNIV, and Royer formulas to make predictions, which were then compared to the existing experimental data. [ABSTRACT FROM AUTHOR]

The alpha decay half-lives of heavy and superheavy nuclei with Z = 80 - 116 are calculated by a deformed double folding model. To obtain the potential between alpha cluster and daughter nucleus, the R3Y-L1, R3Y-W, R3Y-Z, R3Y-HS, R3Y-NL2 and R3Y-NLSH nucleon-nucleon (NN ) interactions from the relativistic mean field approach are used. Here, the deformation of the daughter nucleus is taken into consideration, while the alpha cluster is assumed to be spherical. The alpha cluster penetration probability has been determined using the Wentzel-Kramers-Brillouin (WKB) semiclassical approximation. By comparison between the calculated half-lives and the experimental ones, it is found that the R3Y-NLSH interaction has the highest accuracy. After establishing the best R3Y parametrizations for the deformed nuclei, they are then used to predict the alpha decay half-lives of unmeasured superheavy nuclei with Z = 120 and 122 . In this case, the Weizsäcker-Skyrme-type nuclear mass model with radial basis corrections (WS-type+RBF) was used to determine the Q α values and preformation factors. The calculations suggest that N = 184 could be a magic number, a deduction that is consistent with previous theoretical calculations. [ABSTRACT FROM AUTHOR]

The isotopic yield and half-lives of the spontaneous fission of superheavy nuclei Z = 1 1 9 and Z = 1 2 0 are studied. First, the theoretical formalism is validated by applying it to known isotopes of superheavy nuclei which can undergo spontaneous fission. Half-lives obtained from this work indicate that all the half-lives are approximately twice when compared to experimental measurements. Thereafter, we explored the isotopic yield and half-lives of spontaneous fission for the superheavy nuclei Z = 1 1 9 and Z = 1 2 0 by studying the driving potential, yield and penetration probability. The superheavy nuclei Z = 1 1 9 can undergo alpha decay up to A = 3 0 6. Thereafter they undergo spontaneous fission. Similarly, the superheavy nuclei Z = 1 2 0 undergo spontaneous fission beyond A=309. It is observed that the superheavy nuclei Z = 1 1 9 undergo spontaneous fission through the fission fragment combination of Sn+Tm, however, the superheavy nuclei Z = 1 2 0 undergo spontaneous fission with the fragments Sn+Yb. The larger spontaneous half-life is of the order of ns from the superheavy nuclei 3 0 7 119 and 3 1 0 120. Further investigations were required in the evaluation of the anticipated fission fragment combinations and half-lives of 3 0 7 − 3 1 0 119 and 3 1 0 − 3 1 3 120. [ABSTRACT FROM AUTHOR]

The Cubic plus Yukawa plus Exponential (CYE) model has been used to study the different decay properties of Superheavy nuclei 298,310114, 306,318122, 308,310124, 310,322126 and compared them with the available theoretical and experimental values. Here, the half-lives of several clusters have been computed that have not yet been detected experimentally. Hopefully, this will assist future research in this area. As a result of comparing the three different decay modes (α-decay, cluster radioactivity and spontaneous fission), it was possible to predict the predominant decay modes of Superheavy nuclei. [ABSTRACT FROM AUTHOR]

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In this paper, we systematically studied half-lives of the different decay modes using various theoretical models such as the unified fission model (UFM) and the effective liquid drop model. Beta-decay half-lives were evaluated using semi-empirical formulae available in the literature. We compared half-lives of all the studied decay modes and identified shorter half-lives among the same in 2 0 5 − 2 3 3 Ac nuclei. We investigated the actinium series which is similar to the thorium series. Among these decay series, alpha-emitting isotopes show great promise for cancer treatment because of their short path length and high-energy transfer of radiation. Furthermore, we predicted the decay chains of the actinium isotopes. All the decay series of actinium ends with the formation of stable nuclei or with longer half-lives. The predicted decay series and new isotopes during the decay process are helpful in the field of medicine and radiotherapy. [ABSTRACT FROM AUTHOR]

We investigated different decay modes such as heavy particle radioactivity (HPR), spontaneous fission (SF), alpha decay and beta-decay in superheavy (SH) region 104  ≤ Z ≤  126. In HPR, different emissions from Zmin  = 28 to maximum heavy particle (HP) emission up to Zmax  =  Z −  82 were considered. In the evaluation of Q -values, mass excess Weizsäcker-Skyrme 4+radial basis function (WS4+RBF) values were taken into account. The half-lives of cluster decay determined using modified generalised liquid drop model (MGLDM) and Coulomb and proximity potential model (CPPM) were in close agreement with the experimental results. The MGLDM produce less deviation compared with CPPM. The role of asymmetry effect, relative neutron excess, pairing effect and Coulomb effect on half-lives were studied. A band of neutron numbers from 193 to 200 shows extra stability against HPR. The HPR of 86Kr, 94Zr, 91Y and 96Mo is observed in the superheavy elements Z  = 118, 122 − 124 and 126. The dominant decay mode identified is compared with SF, alpha and beta ± decay, the majority of decay chains end with the lead nuclei, which is also evident in supernova and galaxy spectrum. This study could be useful in nuclear astrophysics. [ABSTRACT FROM AUTHOR]

In the present work, we use the complex-energy shell model formalism to describe the alpha decay of the212Po nucleus. Single-particle bases constructed from Woods-Saxon potentials are used to build many-body basis. Spin-isospinGaussian effective interaction between all pairs of nucleons is considered. Four-body spectroscopic factor and single-particle width are calculated. The stability of the spectroscopic factor renormalization protocol is demonstrated, thus ensuring its physical significance, and its influence on the calculated alpha decay is presented. It is observed that the renormalization modifies the calculated half-life by∼40 %, which is a value three times larger than the experimental. Still, without appealing to any cluster structure from the beginning, i.e., all calculations were carried out using single nucleon degree of freedom.

The barrier penetrability, decay constant and decay half-life of 1-n halo nuclei 11Be, 15,17,19C, 22N, 23O, 24,26F, 29,31Ne, 34,37Na, 35,37Mg, and 55Ca; and 2-n halo nuclei 22C, 27,29F, 34Ne, 36Na, and 46P from Z = 127 – 132 parents were calculated within the framework of the Coulomb and proximity potential model by calculating the Q-values using the finite-range droplet model. A comparison between the decay half-lives is made by considering the halo candidates as a normal cluster and as a deformed structure with a rms radius. Neutron shell closure at 190, 196, 198, 200, 204, and 208 are identified from the plot of decay half-lives versus the neutron number of daughter nuclei (NP). The calculation of alpha decay half-life and spontaneous decay half-life showed that the majority of the parent nuclei survive spontaneous fission and decay through alpha emission. The Geiger - Nuttall plots of log10 T1/2 versus Q−1/2 and universal plots of log10 T1/2 versus − ln P for the emission of all 1-n and 2-n halo nuclei from the parents considered here are linear and show the validity of Geiger - Nuttall law in the case of decay of halo nuclei from superheavy elements. [ABSTRACT FROM AUTHOR]

The luminescence and scintillation properties of Ce3+ doped alkali phosphate glasses 56P 2 O 5 :8Gd 2 O 3 :5Al 2 O 3 :1CeBr 3 :30XCl (PGAC:X, X = Li/Na/K/Rb/Cs) were studied for their potential applications in gamma and alpha detection. In the Fourier Transform Infrared Spectroscopy (FTIR), X-ray Luminescence (XRL), Photoluminescence (PL), and transmittance spectra, the red shift was found and explained by the concept of optical basicity. Broad Ce3+ emission and energy transfer from Gd3+ to Ce3+ were observed in XRL and PL measurements. Scintillation performance was studied by irradiating the samples under 137Cs gamma and 241Am alpha sources. The fast, intermediate, and slow decay components under gamma and alpha excitation were found around 30, 200 and 3000 ns, respectively. The decay time increased slightly from PGAC:Li to PGAC:Cs, indicating the less effective transition from Gd3+ to Ce3+. The alpha decay time was longer than the gamma decay time, revealing the Pulse Shape Discrimination (PSD) capability of the glasses for particle identification. The XRL intensity reduced significantly from PGAC:Li to PGAC:Cs samples did not reflect the scintillation tendency. By successfully detecting gamma and alpha scintillation signals, the scintillation performance of all samples was found to be similar. In general, all samples can be used for gamma and alpha detection. Using Rb+ or Cs+ ions is favorable in terms of high density and light yield, while Li+ ions enhance the transmittance and homogeneity. Furthermore, a correlation between P–O–H groups within the glass matrix and scintillation performance was also observed. [ABSTRACT FROM AUTHOR]

Within the macroscopic approach, investigation of different decay modes such as alpha-decay, cluster-decay (12C to 40Ca), heavy particle radioactivity (HPR) (58Ni to 85Rb), and spontaneous fission (SF) half-lives are investigated in detail in the superheavy element (SHE), Z = 119. The decay energies, penetration probability, and different decay half-lives in the isotopes of synthesized superheavy nuclei (SHN) 290–303119 are evaluated. Both 12C and 40Ar cluster emissions reveal shorter half-lives when compared to other cluster emissions. Furthermore, 85Rb heavy particle emission from the SHN 290–303119 discloses shorter half-lives compared to other heavy particle emissions. From the comparison of different decay half-lives, it is observed that 85Rb HPR is dominant in the region 290–299119, alpha-decay is dominant for the 300–302119, and SF half-lives are predominant in 303119 nuclei. Hence, the prediction of decay modes and decay path in the SHE, Z = 119 are helpful in the identification of experimentally synthesized SHE. [ABSTRACT FROM AUTHOR]

The Modified Generalized Liquid Drop Model (MGLDM) has been used for calculating the ground-to-ground states of α -decay half-lives for various Ac, Th, Pa, U and Np isotopes in the mass number range of 2 0 5 ≤ A ≤ 2 4 5. To account for the nuclear proximity energy, the potential of Blocki et al.74 [J. Blocki, J. Randrup, W. J. Swiatecki and C. F. Tsang, Ann. Phys. NY 105 (1977) 427] is used. The experimental Q α values are used to evaluate the α -decay half-lives. It can be observed that the logarithm of α -decay half-life increases with increasing neutron number (N), with evident minimum at the magic number 126, where the neutron shell is closed. The calculated results are compared with available experimental data and with the predictions of different empirical formulae such as, ARF, MARF, Royer, AKRE, Akrawy, NRB, VS, MVS, YQZR and MYQZR. It is found that the MGLDM is able to predict the experimental half-lives with a standard deviation of 0.6892 (the lowest one among all the other applied empirical formulae), and is therefore suitable for predicting the α -decay half-lives for unknown and new heavy nuclei. [ABSTRACT FROM AUTHOR]

A physical model that can quantitatively describe the spontaneous alpha-particle emission mechanism from atomic nuclei in the spherical nucleus approximation has been applied to the evaluation of the half-life of the 1 4 6 Sm nuclide. The one-parameter, semi-empirical model used in this study has been developed in the frame of a quantum mechanical mechanism of alpha tunnelling through a potential barrier, taking into account centrifugal and overlapping effects. The calculation procedure yielded a value of 1 4 5. 1 ± 0. 3 Myr for the half-life of the extinct 1 4 6 Sm isotope. This value, even if in disagreement with the few old measurements performed on the artificially obtained 1 4 6 Sm, is thought to represent the most reliable indication of the α -decay rate for such challenging nuclide. [ABSTRACT FROM AUTHOR]

Nuclear radiation detectors are indispensable for research in the field of nuclear radiation, X-ray spectroscopy and other areas. Interest in silicon p–i–n detectors of nuclear radiation is increasing today due to the possibility of their operation under normal conditions. In this paper, an equivalent circuit of a silicon–lithium p–i–n nuclear radiation detector is proposed. The proposed circuit is obtained using the classical Shockley equation for silicon semiconductors and the telegraph equations. The parameters of the equivalent circuit were determined using the multiple regression method. As a result of simulation of the model in the MATLAB Simulink graphical development environment, the amplitude-frequency and phase-frequency characteristics of the proposed model were obtained. Using the Monte Carlo method, the alpha-decay of the uranium isotope 92 233 U , thorium isotope 90 227 Th and americium isotope 95 241 Am the alpha-decay spectrum was obtained. Obtained alpha-decay spectra coincides with the experimental data, presented in previous works of other authors. [ABSTRACT FROM AUTHOR]

Based on the Unified Fission Model with a Woods–Saxon potential (UFMWS), we have investigated alpha decay and cluster radioactivity of actinide nuclei. To ensure accuracy, we determined the most precise Q -values by comparing the results of four nuclear mass models: the liquid drop model (LDM), the DZ28 model, the WS4 model, and the finite range droplet model (FRDM), which were recently improved using a machine learning algorithm. Among these models, it is found that the improved WS4 (IWS4) provides the most accurate Q -values, enabling the UFMWS model to effectively reproduce experimental alpha and cluster decay half-lives. Consequently, the UFMWS model using IWS4 Q -values was employed to explore various combinations of parent nuclei and alpha particle as well as even–even emitted clusters ranging from Be to Si. The obtained results are consistent with previous study that identified minima in half-lives near corresponding to the doubly magic 2 0 8 Pb daughter nucleus or its neighboring nuclei. It is found that neutron-deficient parent nuclei generally displayed the shortest half-lives, most of which are within the experimental range. Considering the experimental limitations, cluster decays favorable for measurement in the actinide region were identified. Interestingly, these decays did not involve the most neutron-deficient nuclei. [ABSTRACT FROM AUTHOR]

Background: Recent developments in alpha and beta emitting radionuclide therapy highlight the importance of developing efficient methods for patient‐specific dosimetry. Traditional tabulated methods such as Medical Internal Radiation Dose (MIRD) estimate the dose at the organ level while more recent numerical methods based on Monte Carlo (MC) simulations are able to calculate dose at the voxel level. A precalculated MC (PMC) approach was developed in this work as an alternative to time‐consuming fully simulated MC. Once the spatial distribution of alpha and beta emitters is determined using imaging and/or numerical methods, the PMC code can be used to achieve an accurate voxelized 3D distribution of the deposited energy without relying on full MC calculations. Purpose: To implement the PMC method to calculate energy deposited by alpha and beta particles emitted from the Ra‐224 decay chain. Methods: The GEANT4 (version 10.7) MC toolkit was used to generate databases of precalculated tracks to be integrated in the PMC code as well as to benchmark its output. In this regard, energy spectra of alpha and beta particles emitted by the Ra‐224 decay chain were generated using GAMOS (version 6.2.0) and imported into GEANT4 macro files. Either alpha or beta emitting sources were defined at the center of a homogeneous phantom filled with various materials such as soft tissue, bone, and lung where particles were emitted either mono‐directionally (for database generation) or isotropically (for benchmarking). Two heterogeneous phantoms were used to demonstrate PMC code compatibility with boundary crossing events. Each precalculated database was generated step‐by‐step by storing particle track information from GEANT4 simulations followed by its integration in a PMC code developed in MATLAB. For a user‐defined number of histories, one of the tracks in a given database was selected randomly and rotated randomly to reflect an isotropic emission. Afterward, deposited energy was divided between voxels based on step length in each voxel using a ray‐tracing approach. The radial distribution of deposited energy was benchmarked against fully simulated MC calculations using GEANT4. The effect of the GEANT4 parameter StepMax on the accuracy and speed of the code was also investigated. Results: In the case of alpha decay, primary alpha particles show the highest contribution (>99%) in deposited energy compared to their secondary particles. In most cases, protons act as the main secondary particles in the deposition of energy. However, for a lung phantom, using a range cutoff parameter of 10 µm on primary alpha particles yields a higher contribution of secondary electrons than protons. Differences between deposited energy calculated by PMC and fully simulated MC are within 2% for all alpha and beta emitters in homogeneous and heterogeneous phantoms. Additionally, statistical uncertainties are less than 1% for voxels with doses higher than 5% of the maximum dose. Moreover, optimization of the parameter StepMax is necessary to achieve the best tradeoff between code accuracy and speed. Conclusions: The PMC code shows good performance for dose calculations deposited by alpha and beta emitters. As a stand‐alone algorithm, it is suitable to be integrated into clinical treatment planning systems. [ABSTRACT FROM AUTHOR]

Available information pertaining to the nuclear structure of ground and excited states for all known nuclei with mass numbers A=245 have been compiled and evaluated. The adopted level and decay schemes, as well as the detailed nuclear properties and configuration assignments based on experimental data, are presented for these nuclides. When there are insufficient data, expected values from systematics of nuclear properties and/or theoretical calculations are utilized. Unexpected or discrepant experimental results are also noted. Since the last evaluation, new rotational bands in 245Pu have been observed to high spin from transfer reaction 244Pu(209Bi, 208Bi γ) by 2014Ho16. While in 245Am, the 249Bk α decay measurements by 2013Ah03 added a new rotational band based on π 3/2[521] configuration. The 245Pu β − decay scheme is basically what was proposed in the late 60's and 47 γ rays have still not been placed. In 245Cm, precise alpha energies and intensities were measured by 2015Ah03 in 249Cf α decay. Their reported alpha energies of the main α group were about 2 keV lower than in the previous evaluation. The spin and parity of the g.s. of 245Es is still ambiguous as more detailed information on the decay is needed. With the production of 249No via fusion evaporation reaction by groups in Dubna and GSI, it's alpha decay was studied and some properties of the daughter 245Fm were published and included in this evalaution. Information on the other nuclides is scarce and not much has been investigated since the last evaluation. A summary and compilation of the discovery of the various nuclides in this mass region is given in: 2013Fr02 (245Pu, 245Am, 245Cm, 245Bk, 245Cf), 2011Me01 (245Es), and 2013Th02 (245Md, 245Fm). [ABSTRACT FROM AUTHOR]

Using 377 available experimental data, we have obtained an empirical formula to calculate alpha decay half-lives based on Geiger–Nuttall law for even–even, even–odd, odd–even and odd–odd nuclei. The coefficients of Geiger–Nuttall law have been modified as a function of the atomic number of the parent nucleus and the orbital angular momentum. The obtained root mean square deviations from experimental half-lives for even–even, even–odd, odd–even and odd–odd nuclei are 0.3265, 0.5412, 0.4848 and 0.4353, respectively. For most nuclei, the obtained results from this formula are in good agreement with the experimental data. We compared our results with other formulas such as universal decay law, Royer, AKRA, MYQZR and Luo. Also, using this formula, we presented predictions for superheavy nuclei with Z = 1 1 8 –124 using the Q -values based on the finite range droplet model and Weizsäcker–Skyrme. It is found that the behavior of the half-life of alpha decay is sensitive to the used Q -values. [ABSTRACT FROM AUTHOR]

An effect of intensive alpha radiation of 238Pu (content in glass up to 4.0 wt %) on the properties of borosilicate glass (BSG) of the Experimental and Demonstration Center at the Mining and Chemical Combine (EDC MCC) for SNF reprocessing was examined. The characteristics of the BSG were studied immediately after preparing the samples and upon set the dose induced by alpha decays in the sample unit volume (α/cm3). The 238Pu uniform distribution in the samples was proved by autoradiography and destructive chemical analysis with α-spectrometric ending. The density of the BSG samples was in the range of 2.71–2.72 g/cm3 depending on the plutonium content and did not change with time. The 238Pu leaching rate on the 28th day at 90°С for two parallel glass samples with a cumulative dose of 1.70 × 1018 α/cm3 was 5.0 × 10–7 g/(cm2 day), which corresponds to the values regulated by the requirements (NP-019-15: Collection, processing, storage, and conditioning of liquid radioactive waste. Safety requirements). The amorphous structure of the sample was preserved at a dose load of 3.2 × 1018 α/cm3 of glass, its density did not vary, and the surface had a vitreous shine. Defects such as crack, chip, turbidity were not found on them. [ABSTRACT FROM AUTHOR]

We have investigated the competition between -decay, spontaneous fission and cluster decay processes of the superheavy even nuclei such as , Cn, Fl, Lv, Og , , and by using modified generalized liquid drop model (MGLDM) and Coulomb and proximity potential model (CPPM). Barrier penetrability is evaluated using WKB approximation. The half-life resulting from the these models were compared with the effective liquid drop model (ELDM) and Dong et al., [Nuclear Physics A 832, 198 (2010)]. The predicted dominant decay modes are presented in chart for the superheavy elements with even atomic number of range 110 Z 126. The current research will be helpful in the synthesis of new superheavy elements and also unexplored isotopes of known superheavy elements. [ABSTRACT FROM AUTHOR]

In positron emission tomography (PET), parallax errors degrade spatial resolution. The depth of interaction (DOI) information provides the position in the depth of the scintillator interacting with the γ-rays, thus reducing parallax errors. A previous study developed a Peak-to-Charge discrimination (PQD), which can separate spontaneous alpha decay in LaBr3:Ce. Since decay constant of GSO:Ce depends on Ce concentration, the PQD is expected to discriminate GSO:Ce scintillators with different Ce concentration. In this study, the PQD-based DOI detector system was developed, which can be processed online and implemented in PET. A detector was composed of four layers of GSO:Ce crystals and a PS-PMT. The four crystals were obtained from both the top and bottom of ingots with a nominal Ce concentration of 0.5 mol% and 1.5 mol%. The PQD was implemented on the Xilinx Zynq-7000 SoC board with 8ch Flash ADC to gain real-time processing, flexibility, and expandability. The results showed that the mean Figure of Merits in 1D between four scintillators are 1.5, 0.99, 0.91 for layers between 1st–2nd, 2nd–3rd, and 3rd–4th respectively, and the mean Error Rate in 1D between four scintillators are 3.50%, 2.96%, 13.3%, and 1.88% for layers 1, 2, 3, and 4, respectively. In addition, the introduction of the 2D PQDs resulted in the mean Figure of Merits in 2D greater than 0.9 and the mean Error Rate in 2D less than 3% in all layers. [ABSTRACT FROM AUTHOR]

() and () reactions induced by the alpha decays of uranium, thorium, and their daughter nuclides generate the intrinsic neutron and gamma backgrounds in modern ultralow background neutrino and dark matter detectors. In order to minimize the background, it is essential to select materials on the basis of a detailed analysis of relative concentrations of radionuclides and calculations of neutron and gamma-radiation yields. The NeuCBOT (Neutron Calculator Based On TALYS) program makes it possible to perform such calculations. The present article gives a review of a new version of the NeuCBOT program and a comparison of the results of calculations with different software tools. [ABSTRACT FROM AUTHOR]

The alpha decay half-lives of Bismuth isotopes have been investigated systematically by using Wentzel–Kramers–Brillioun (WKB) method and the Bohr–Sommerfeld quantization condition. Three forms of the potentials; Woods–Saxon (WS), Woods–Saxon Squared (WS 2 ) and hybrid potentials have been used to describe the nuclear interaction between the alpha and daughter nuclei. Present results have been compared with the experimental data and results of previous calculations. We have obtained better agreement with the experimental data by using WS 2 potential than other potentials. [ABSTRACT FROM AUTHOR]

In this research, the alpha decay fine structure for odd–odd nuclei has been investigated considering the effects of incompressibility of nuclear matter density in the range of 8 3 ≤ Z ≤ 9 2. In our calculations, transitions from the parent nuclei's ground state to the daughter nuclei's excited states have been considered. In these calculations, the double-folding model with effective finite-range nucleon–nucleon interactions was used in the framework of BDM3Y1, CDM3Y2, CDM3Y4, CDM3Y6 and BDM3Y1 configurations to calculate alpha-daughter nucleus interaction. These different versions of nucleon–nucleon interaction apply values of 176 MeV to 270 MeV for the incompressibility term of nuclear matter in calculations. WKB approximation along with the Cluster formation model has been used to calculate partial half-lives and branching ratio. The results of these calculations regarding partial half-lives in the framework of CDM3Y6 (K = 2 5 2 MeV) interactions indicate a better agreement with the corresponding experimental data than density-dependent interactions. It has also shown that by decreasing the values of incompressibility, the partial half-lives increase compared to the experimental data. [ABSTRACT FROM AUTHOR]

The nuclear structure systematics of the superheavy nuclei lying at the extreme of mass for Z = 120 , and their α -decay half-lives have been studied using the relativistic mean-field (RMF) model. The results are obtained using four different point-coupling parameters after analysing the reliability of these parameter sets for the binding energy of experimentally observed nuclei ( Z = 100 –118) by comparing them with the available experimental and WS-4 microscopic calculations. The optimal parameter set thus obtained is further used for predicting the Z = 120 α -decay chain and decay half-lives. [ABSTRACT FROM AUTHOR]

Yukawa-plus-exponential potential, a generalisation of modified liquid drop model, incorporates the finite range of nuclear force and diffuse nuclear surface. The range of Yukawa folding function, a, accounts for both surface diffuseness and saturation condition. The present study deals with the influence of a, in experimentally identified cluster decay of heavy nuclei. Further, its dependence on neutron excess of the parent nucleus, has been studied. For the experimentally identified cluster emitters, systematic calculations for values of a between 0.54 fm and 0.8 fm have been carried out. The results suggest that as a increases, the nuclear interaction potential widens and deepens, which subsequently influences the total potential. The study shows the dependence of surface diffuseness on neutron excess of isotopes of a parent nucleus. A correlation between a, corresponding to the best-matching half-lives with experimental ones, and the neutron excess of the corresponding parent nuclei has been carried out with an appropriate fitting function. Based on the good agreement between the calculated and experimental half-lives and the branching ratio for cluster emission relative to alpha, the analysis has been extended to alpha and cluster emission of heavy and superheavy nuclei in the range 99 ≤ Z ≤ 116 with 252 ≤ A ≤ 293 . Half-lives of alpha decay of the superheavy nuclei match reasonably well with the experimental values. Predicted half-lives of the clusters, 46 Ar and 48 Ca from 253 Es and 252 Fm respectively, compare well with other predictions. [ABSTRACT FROM AUTHOR]

Several methods to detect thermal neutrons make use of the naturally occurring 6Li isotope, as it has a rather high cross-section for neutron capture followed by a decay into an alpha particle and a triton. Due to the high chemical reactivity of lithium, the use of the stable isotopic salt 6LiF is generally preferred to the pure 6Li. The typical method for depositing thin layers of 6LiF on suitable substrates, therefore creating so-called neutron converters, is evaporation under vacuum. The evaporation technique, as well as a newly developed chemical deposition process, are described along with their benefits and drawbacks, and the results of neutron detection tests performed with the two types of converters coupled to silicon diodes show convenient performances. [ABSTRACT FROM AUTHOR]