Stable Lead Isotopes Research Articles

Differences of the mean square charge radii of the stable lead isotopes observed through electronicK X-ray shifts

Differences of the mean square charge radii of the stable lead isotopes observed through electronicK X-ray shifts

Effect of airborne lead on blood lead

The relation between uptake of lead and the level in blood (PbB) is curvilinear, but it is not certain whether this is true for all levels of intake, or only when PbB exceeds some value. Volunteers have been exposed to enhanced air lead (PbA) and epidemiological studies of the relation between PbB and PbA have been made. From these, the slope of the curve of PbB vs PbA can be estimated. Tracer experiments using radioactive or stable isotopes of lead can be used to derive the contribution of PbA to PbB. Because the response is curvilinear, the fractional contribution of PbA to PbB is greater than the slope of the curve.

Effect of airborne lead on blood lead

Abstract The relation between uptake of lead and the level in blood (PbB) is curvilinear, but it is not certain whether this is true for all levels of intake, or only when PbB exceeds some value. Volunteers have been exposed to enhanced air lead (PbA) and epidemiological studies of the relation between PbB and PbA have been made. From these, the slope of the curve of PbB vs PbA can be estimated. Tracer experiments using radioactive or stable isotopes of lead can be used to derive the contribution of PbA to PbB. Because the response is curvilinear, the fractional contribution of PbA to PbB is greater than the slope of the curve.

Use of 206Pb/ 204Pb isotope ratio in lichen, air filter, incinerator ash and gasoline samples as pollution source indicator

The stable lead isotope abundances of environmental samples collected from Helsinki area were determined. The separation of lead from samples were carried out using wet ashing and anion exchange. For the determination of the lead isotope ratios a thermal ionization mass spectrometer type MI-1309 was used. The average ratio of Pb-206/Pb-204 in air filter, lichen and incinerator ash samples were 17.5+−0,3, 17.7+−0.3 and 18.4+−0.4, respectively. The mean value of the ratio Pb-206/Pb-204 in gasoline was 16.42+−0.24. This value being significantly lower than in other samples analyzed gives an opportunity to evaluate the contribution of motor traffic to lead content of environmental samples.

High resolution measurements of isotope shifts in lead

We report laser spectroscopic measurements of isotope shifts and hyperfine structure in ten stable and unstable lead isotopes, including two not previously measured.

Stable Lead Isotopes as a Tracer in Coastal Waters

The natural abundances of the stable isotopes of lead are used to identify natural and industrial sources of lead in the coastal waters of British Columbia, Canada. The (206)Pb/(207)Pb ratios, used to characterize the lead source, had values of approximately 1.24 for coastal oceanic water, approximately 1.22 for fjord waters receiving lead from mine tailings, and approximately 1.163 for waters near urban centers. The lead concentration data are in agreement with presently accepted seawater values.

High resolution two-photon spectroscopy of the 6p 23 P o-7p 3 P o transition in stable lead isotopes

Dopplerfree two-photon speatroscopy was used to investigate isotope shifts in the 6p23Po — 6p7p3Po transition of the stable lead isotopes Pb 204, 206, 207, and 208. Two-photon transitions were induced by the 450,4 nm cw radiation of a frequency stabilized ring laser.

Neutron-Capture Cross Sections of the Stable Lead Isotopes

Neutron-capture yields for several samples of separated lead isotopes were obtained at the Oak Ridge electron linear accelerator, in the neutron energy range above 2.5 keV. These were analyzed for resonance-capture areas and parameters. The data are included in a new evaluation of lead cross-section data.[NUCLEAR REACTIONS $^{204,206,207,208}\mathrm{Pb}(n,\ensuremath{\gamma})$, ${E}_{n}>2.5$ keV, measured ${\ensuremath{\sigma}}_{n,\ensuremath{\gamma}}$; deduced levels, ${E}_{\ensuremath{\gamma}}$, $\ensuremath{\Gamma}$, ${\ensuremath{\Gamma}}_{\ensuremath{\gamma}}$, averages, R.I., enriched targets, resolution \ensuremath{\sim}0.2%.]

Lead and oxygen isotopes in ancient objects

During the past few years most archaeologists and museum curators have become familiar with the term isotope . Isotopes are atoms of the same chemical element which differ slightly from one another in mass. For instance, there are four stable isotopes of lead, 204 Pb, 206 Pb, 207 Pb and 208 Pb, having, respectively, approximate masses of 204, 206, 207 and 208 atomic mass units; and there are three isotopes of oxygen, 16 O, 17 O and 18 O, having masses of 16, 17 and 18. The isotopic composition of most elements is uniform throughout nature. That is to say, occurrences of a particular element in different places or in different chemical forms usually contain the same relative proportions of that element’s isotopes. There are, however, a few notable exceptions, and wherever they occur they are invariably of interest to the scientist. The example most familiar to the archaeologist is the variation in the proportion of 14 C in the carbon present in archaeological objects. This variation constitutes the basis of radiocarbon dating, the discovery and remarkable advances of which are being commemorated at this Symposium. In this paper we shall deal with two other elements, lead and oxygen, whose isotopic compositions vary in natural occurrences due to rather well defined mechanisms. Unlike the 12 C— 14 C relationship, which involves the decay of a radioactive species and leads directly to a dating method, the research reported here with lead and oxygen does not involve radioactive decay in the same way, and neither investigation at this stage is aimed towards developing a direct dating method for archaeological finds. With lead, the isotopic variations observed are associated with differences in the geological ages and geochemical origins of lead deposits. (The differences arise because three of the four lead isotopes are continually produced within the earth by radioactive decay of uranium and thorium.) In the case of oxygen, physical and chemical fractionation processes are responsible for the isotopic variations.

Bestimmung des Isotopenmischungsverhältnisses von Bleiproben mit der Atomabsorptionsmethode

An optical method is described for the determination of the stable isotopes of lead in small samples by using the absorption of the hyperfine components of the 4058 Å and the 2833 Å resonance lines. Hollow cathode lamps containing different mixtures (different standards and the probe) of lead are used as sources of the hyperfine components. By determining the absorption of the Pb-208 (Pb-206) component by lead vapor consisting only of Pb-208 (Pb-206) the quantity of Pb-208 (Pb-206) present in the probe can be determined. The absorbing vapor is produced by cathodic sputtering in the absorption hollow cathode lamp. The analyses of geological samples containing various percentages of Pb-208 and Pb-206 agree with values obtained by mass spectrometric method within 2 %, which is the accurancy of the method used.

Atomic Masses of the Stable Isotopes of Lead and Mercury and the Mass DifferenceD2-He4

Mass doublets have been measured from which atomic masses for the stable isotopes of mercury and lead are found. The doublet ${\mathrm{D}}_{2}$-${\mathrm{He}}^{4}$ has also been measured and found to have a value 25.6074\ifmmode\pm\else\textpm\fi{}3 mMU.