Thallium Isotopes Research Articles

Laser spectroscopy of radioactive lead and thallium isotopes

By collincar fast beam laser spectroscopy hyperfine structure and isotope shift have been measured of neutron deficient radioactive isotopes of lead (190Pb,191Pb,192Pb,193Pb,194Pb,195Pb,196Pb,197Pb) and thallium (188Tl190Tl,191Tl,192Tl,194Tl,196Tl). Therefrom nuclear magnetic dipole moments, electric quadrupole moments, changes of the mean square charge radii and deformation parameters are deduced and compared with predictions from theory.

205Tl NMR spin echo investigations in multiphase Tl-Ba-Ca-Cu oxide superconductors

Multiphase oxide superconductors of nominal compositions Tl2BaCa2Cu3Ox have been synthesized and characterized by resistivity and magnetic susceptibility measurements. NMR spin echoes of both thallium isotopes (203Tl and 205Tl) have been detected and the line shifts, the spin-lattice and spin-spin relaxation times have been measured at room temperature for the more abundant 205Tl nuclei. The temperature dependence of the spin-lattice relaxation rate is also reported. The results suggest that, similarly to the behavior of Y in YBa2Cu3O7 oxides, Tl has a small electronic density of states at the Fermi level in the Tl-Ba-Ca-Cu oxide superconductors.

Nuclear structure of light thallium isotopes as deduced from laser spectroscopy on a fast atom beam.

The neutron-deficient isotopes /sup 189-194/Tl have been studied using collinear fast atom beam laser spectroscopy with mass-separated beams of 7 x 10/sup 4/ to 4 x 10/sup 5/ atoms per second. By laser excitation of the 535 nm atomic transitions of atoms in the beam, the 6s/sup 2/7s /sup 2/S/sub 1/2/ and 6s/sup 2/6p /sup 2/P/sub 3/2/ hyperfine structures were measured, as were the isotope shifts of the 535 nm transitions. From these, the magnetic dipole moments, spectroscopic quadrupole moments, and isotopic changes in mean-square charge radii were deduced. A large isomer shift in /sup 193/Tl was observed, implying a larger deformation in the (9/2/sup -/ isomer than in the (1/2/sup +/ ground state. The /sup 189,191,193/Tl/sup m/ isotopes have deformations that increase as the mass decreases. A deformed shell model calculation indicates that this increase in deformation can account for the drop in energy of the (9/2/sup -/ bandhead in these isotopes. An increase in neutron pairing correlations, having opposite and compensating effects on the rotational moment of inertia, maintains the spacing of the levels in the (9/2/sup -/ strong-coupled band. Results for /sup 194/Tl/sup m/ differ from previously published values, but are consistent with the /sup 190,192/Tl/sup m/more » data.« less

Nuclear Spins of Some Indium and Thallium Isotopes

The nuclear spins of some indium and thallium isotopes have been measured at the ISOLDE facility, CERN, using on-line atomic-beam magnetic resonance techniques. The results are: 118mIn (4.5 min) I = 5, 118mIn (8.5 s) I = 8, 119In (2.3 min) I = 9/2, 119mIn (18 min) I = 1/2, 121In (25 s) I = 9/2, 121mIn (3.8 min) I = 1/2 and 191(m)T1 (5.2 min) I = 9/2. The spin values are discussed briefly in terms of current nuclear models. A slight revision of the previous magnetic moment data in 194-202T1, based on an improved value of the electronic g-factor in thallium, is included.

Effective gyromagnetic ratios in odd Thallium isotopes

Effective gyromagnetic ratios in theM1 operator have been determined in odd Thallium isotopes. The analysis has been performed within the framework of the intermediate coupling model, taking into account penetration electron matrix elements in addition to static and dynamic magnetic dipole moments.

Mobility of Tl + ions in a defect pyrochlore structure TlNb 2O 5F

NMR measurements on the two naturally abundant isotopes of thallium and on fluor have been made in the defect pyrochlore TlNb 2O 5F. An Arrhenius activation energy of 0.08 eV was obtained from the temperature dependence of the 205Tl absorption linewidth. CW data indicated the presence of the electron-nuclear magnetic interactions. The spin-lattice relaxation times showed two motions of Tl + ions with the activation energies of 0.25 eV and 0.14 eV. These relaxation times were interpreted with the exchange and chemical shift interactions.

Thallium determinations in fetal tissues and maternal brain and kidney

The transfer of Tl + cations through the placental barrier of pregnant mice and rats was studied by comparing the thallium concentrations in the maternal brain and kidney and those in fetal tissue at times of 10 min to 50 h after dosage of the animals with 10 mg/kg body wt. Tl 2SO 4. The quantitative determinations were performed with field desorption mass spectrometry after dilution of the homogenised tissue samples with enriched stable isotopes of thallium. The total sample quantity required for one complete assay is 1–3 μg, the analysis time for one determination about 30 min.

Anodic oxidation — an improved technique in the chemical recovery and refinement of isotopic thallium

The Electromagnetic Isotope Separations Program of the Oak Ridge National Laboratory has been involved in the seperation, chemical recovery and refinement of the stable isotopes of thallium since 1947. The initial interest was in obtaining chemically pure, isotopically enriched samples of each of the stable isotopes of thallium for basic physical research. Recently, the major emphasis has shifted to 203Tl which is used to produce the radiopharmaceutical isotope 201Tl. Two persistent problems in the chemistry of isotopic thallium have been the production of unoxidized, homogeneous ingots of thallium metal and the elimination of sulfur contamination in thallic oxide. The application of anodic oxidation in the chemistry has resulted in a significant reduction of the problems previously encountered as well as considerable improvement in the chemical purity of the product. The details of this procedure and a general description of all of the appropriate thallium chemistry will be presented. In addition, the generalization of the technique to the refinement of other elements will be discussed.

PhotoneutronQ- value determinations using monochromatic photons

Neutron separation energies for the (γ, n) reaction have been determined for isotopes of niobium, cadmium, indium, antimony, tantalum, gold, thallium, lead and bismuth. A source of discrete energy photons which exceed the reactionQ-values was obtained from neutron capture on nickel and chromium placed in the core of the McMaster Nuclear Reactor. The photons illuminated the target and the photoneutrons produced were detected using a high resolution3He spectrometer. TheQ-values obtained possess greater precision, in most cases, than in any previous measurements.

Nuclear spin-lattice relaxation in thallium-containing chalcogenide glasses

NMR spin-lattice relaxation time (${T}_{1}$) measurements for the two naturally abundant isotopes of thallium have been performed in two thallium-containing chalcogenide glasses as a function of temperature and frequency. The results for ${T}_{1}$ indicate that there are three regions of temperature dependence from 77 K to the glass-transition temperature. The relaxation in the high-temperature region is due to thallium-electron-thallium exchange. In the middle-temperature region, the relaxation is due to localized states, most likely the localized electronic states in the forbidden gap of amorphous semiconductors. The process responsible for the relaxation at low temperatures is probably the interaction of the thallium nuclei with disorder modes characteristic of amorphous materials.

Core excitations to the low-lying states of thallium isotopes

The admixture of core excitations to the low-lying states ofA=203 andA=205 thallium isotopes has been calculated. The wave functions obtained reproduce the electromagnetic properties as well as the hyperfine splittings and the isomer shifts of both thallium isotopes.

Stellar neutron capture in the thallium isotopes

view Abstract Citations (15) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Stellar neutron capture in the thallium isotopes. Macklin, R. L. ; Winters, R. R. Abstract High-resolution neutron-capture cross-section data for isotopically enriched samples of Tl-203 and Tl-205 were obtained at the Oak Ridge Electron Linear Accelerator time-of-flight facility. The resonance-parameter data were used to calculate neutron capture probabilities over a range of stellar interior temperatures. A semiempirical estimate is also interpolated for the radioactive Tl-204 and Pb-205, and the results are employed to recalculate the time scale of s-process nucleosynthesis. Publication: The Astrophysical Journal Pub Date: September 1976 DOI: 10.1086/154667 Bibcode: 1976ApJ...208..812M Keywords: Absorption Cross Sections; Capture Effect; Neutron Cross Sections; Nuclear Fusion; Stellar Models; Thallium Isotopes; Linear Accelerators; Neutron Flux Density; Radioactive Isotopes; Stellar Interiors; Stellar Temperature; Astrophysics full text sources ADS |

αdecay ofTl186

..cap alpha.. decay for thallium isotopes has never been clearly established. In this study thallium and mercury nuclides were produced by (/sup 14/N, xn and pxn) reactions induced by 168-MeV /sup 14/N bombardments of /sup 182/W and investigated using an on-line mass-separator facility. ..cap alpha..-particle and ..gamma..- and x-ray spectral measurements were made simultaneously. At A=186 a new ..cap alpha.. peak was observed with E/sub alpha/=5.641 +- 0.010 MeV; we assign it to 28-sec /sup 186/Tl. By assuming the 405.3-keV (2/sup +/..-->..0/sup +/) transition to encompass the EC/..beta../sup +/ decay of 28-sec /sup 186/Tl its ..cap alpha..-decay branch was determined to be (6 +- 2) x 10/sup -4/. Measurements at A=184 and A=185 revealed no ..cap alpha.. groups that could be assigned with any certainty to /sup 184/,/sup 185/Tl. The measurements did, however, corroborate the ..cap alpha..-decay energies and total half-lives for /sup 183 -185/Hg as reported by P. G. Hansen et al. (AIP)

Excitation of light Hg nuclei in the decay of Tl

Recent YASNAPP (Dubna) experimental results on the decay of light thallium isotopes ( 188, 189, 190, 191, 192, 193, 194, 195, 197Tl) are briefly reviewed. From the systematics of available experimental data on the excited states of light even and odd Hg nuclei general conclusions are drawn. New calculations have been performed for the energy levels and electromagnetic properties of light even Hg nuclei by coupling two valence-shell proton holes (cluster) to the quadrupole core vibration. The properties of light odd Hg nuclei have been calculated on the basis of the pairing-plus-quadrupole residual interaction model by coupling one neutron quasiparticle to the anharmonic quadrupole core vibration. These nuclei have also been considered by coupling a three-neutron-hole cluster to vibrations. The theoretical results are qualitatively similar in both representations and explain many experimental data.

Hyperfine structure and nuclear magnetic moments of some neutron-deficient thallium isotopes

Using the atomic-beam magnetic resonance method, hyperfine structure (h.f.s.) measurements have been performed in the2P1/2 electronic ground state of the neutron-deficient thallium isotopes193–202Tl. In the doubly odd isotopes, the magnetic dipole hyperfine interaction constantsa were determined, while in the odd-A isotopes, direct measurements of the nuclearg-factors,g I , were made. The electronicg-factor was measured in198Tl. The magnetic dipole moments of the doubly odd isotopes have been evaluated by a direct comparison with known values in the stable isotope203Tl. The moments of the odd-A isotopes are in agreement with pervious measurements by optical spectroscopy. A discussion of the magnetic dipole moments in terms of different nuclear models is included. The moments of the 2− nuclear ground states of the doubly odd isotopes may be interpreted as arising from a combination of the configurations 2− (πs1/2 vf5/2) and 2− (πs1/2 vp3/2).

203Tl(n, γ) reaction and level structure of204Tl

The low-lying level structure of81204Tl has been studied by means of the thermal-neutron capture reaction on203Tl. The γ-ray spectrum from this reaction was studied below 1.8 MeV with a Ge(Li) spectrometer. Owing to the great complexity of the decay scheme γ-γ coincidence measurements using two Ge(Li) detectors were made. Spin and parity assignments for some of the lowest-lying levels are proposed. The level energy values are 140.6, 300.0, 318.4, 432.3 471.6, 488.2, 535.9, 628.3, 736.7, 1013.6, 1051.9, 1250.7, 1474.3 and 1741.1 keV. The agreement of the present results with a recent calculation of the low-energy spectra of odd-odd thallium isotopes seems satisfactory, at least for what concerns the first excited levels.

224. Foils and films of thallium isotopes for nuclear investigations: T S Nazarova and A A Rozen,Prib Tekh Eksper, No 1, Jan–Feb 1972, 217 ( in Russian)

224. Foils and films of thallium isotopes for nuclear investigations: T S Nazarova and A A Rozen,Prib Tekh Eksper, No 1, Jan–Feb 1972, 217 ( in Russian)

αDecay of Neutron-Deficient Isotopes of Bismuth and Lead Produced in (Ar,xn) and (Kr,xn) Reactions

Neutron-deficient isotopes of bismuth and lead have been produced in various heavy-ion---induced reactions. Argon and krypton ions were used as projectiles on $^{159}\mathrm{Tb}$, $^{155}\mathrm{Gd}$, and $^{109}\mathrm{Ag}$. We observed $\ensuremath{\alpha}$ emission from bismuth nuclides and isomers with $A=190\ensuremath{-}197$ and from lead isotopes with $A=186\ensuremath{-}190$. We give results on mass assignments, $\ensuremath{\alpha}$-decay energies, half-lives, and $\ensuremath{\alpha}$ branching ratios. Two new lead isotopes were found: $^{187}\mathrm{Pb}$, ${E}_{\ensuremath{\alpha}}=6.08$ MeV, ${t}_{\frac{1}{2}}=17.5$ sec; and $^{186}\mathrm{Pb}$, ${E}_{\ensuremath{\alpha}}=6.32$ MeV, ${t}_{\frac{1}{2}}=7.9$ sec. No $\ensuremath{\alpha}$-emitting isotopes of thallium were found, and upper limits significantly below 1% can be set on the $\ensuremath{\alpha}$ branching ratios of T1 isotopes with $A=182\ensuremath{-}187$.

The decay of 195mPb and 197mPb

Ge(Li) γ-spectra, Si(Li) electron spectra, and Ge(Li)-Ge(Li) coincidence spectra were obtained from 195mpb and 197mpb sources. These data were used to construct partial energy level schemes for the 195T1 and 197T1 daughters. The data are consistent with a spin and parity of 9 2 − for the isomeric states in both thallium isotopes.

Hyperfine Structure of Thallium Bromide

The hyperfine structure of the J = 2 and J = 3 rotational states of TlBr has been measured with a molecular-beam electric resonance spectrometer. Hyperfine transition frequencies were measured under conditions of very weak electric and magnetic fields. The linewidth was 500 Hz. The hyperfine interaction constants have been determined for 205Tl79Br, 203Tl79Br, 205Tl81Br, and 203Tl81Br in the first five vibrational states for J = 2. In addition, the interaction constants for J = 3, υ = 0 were determined for Tl79Br and Tl81Br, but it was not possible to resolve the effect of the two thallium isotopes in the J = 3 state. The spectra measured are well described by a hyperfine Hamiltonian containing the bromine quadrupole interaction, the spin–rotation interactions of both the thallium and the bromine nuclei, and both the scalar and tensor parts of the spin–spin interaction between the nuclei. The dependence of the magnetic hfs constants on vibrational state and on isotopic composition shows good agreement with theory. The magnetic octupole interaction of the bromine nucleus in TlBr is negligibly small, and we find no evidence for nuclear polarization or pseudoquadrupole effects.