Bismuth Isotopes Research Articles

Cyclotron production of no-carrier-added 206Bi (6.24 d) and 205Bi (15.31 d) as tracers for biological studies and for the development of alpha-emitting radiotherapeutic agents

The production and radiochemical purification of no-carrier-added (NCA) bismuth isotopes (i.e. 6.24 d 206Bi and 15.31 d 205Bi) was studied. The Bi isotopes are intended for use as tracers in biodistribution studies and in the design and testing of α-emitting radiotherapeutic agents. The total cross sections and yields for the production of 206Bi and 205Bi from the proton bombardment of natural Pb targets were measured using the stacked-foils technique. A radiochemical method for the separation and purification of NCA Bi radioactivities from a multi-gram Pb target was also tested, modified, and improved to provide aqueous solutions of chemically and biologically useful amounts of NCA 206,205Bi for measuring tissue and subcellular-distributions, and for studies covering several chemical aspects of the development of Pb/Bi-radiotherapeutic agents.

Excited states in neutron-deficientBi195

Excited states in /sup 195/Bi were populated by the /sup 182/W(/sup 19/F,6n) and /sup 169/Tm(/sup 30/Si,4n) reactions. The subsequent ..gamma..-ray emission was studied using in-beam spectroscopic methods including excitation functions, ..gamma..-ray angular distributions, ..gamma..-..gamma..-t coincidence, conversion electron, and pulsed-beam-..gamma.. timing measurements. Three isomeric states were located in /sup 195/Bi(J/sup ..pi../,t/sub 1/2/,E): (((13/2)/sup +/), 32 +- 2 ns, 888 keV); (((25/2)/sup +/), 80 +- 10 ns, 2196 keV); and (((29/2)/sup -/), 750 +- 50 ns, 2311+..delta.. keV). The structure of the observed states is interpreted within the shell-model framework. Systematic features of excited state energies and transition rates in the odd-A bismuth isotopes are discussed. A comparison of intruder states analogous to those in odd-A antimony nuclei of the Z = 50 transition region is made.

In-beam studies of203, 205Bi and shell-model features of odd-a bismuth isotopes

States in203, 205Bi are populated using the reaction203, 205Tl(3He,3n). Theπi13/2 single-proton states and all the members of thev(2 1 + )⊗π h9/2 quintuplet are identified in both nuclei. The half-lives of the isomericJπ=21/2+ states in both isotopes are measured and found to be 90±7 ns and 100±6 ns, and from these values suggestions for the half-lives of the previously reportedJπ=25/2+ isomers are made. The structures of the multiplets of the formv(Pb)⊗π h9/2 are calculated in the framework of the shell model and it is shown that the main features can be derived from theπ−v−1 effective interaction. The wave functions of the 4 1 + and 4 0 + states in202, 204pb are deduced indirectly from the calculation in203, 205Bi.

Alpha decay of neutron deficient polonium and bismuth isotopes

Neutron deficient isotopes of polonium and bismuth have been produced in the reactions $^{56}\mathrm{Fe}$ + $^{\mathrm{nat}}\mathrm{Ce}$ and $^{56}\mathrm{Fe}$ + $^{141}\mathrm{Pr}$, separated from the primary beam by our gas-filled on-line mass separator. The half-lives have been determined by measuring the lifetimes of individual nuclei. The new isotope $^{192}\mathrm{Po}$ (${T}_{\frac{1}{2}}=34\ifmmode\pm\else\textpm\fi{}3$ ms, ${E}_{\ensuremath{\alpha}}=7.17$ MeV) and a short-lived isomeric state in $^{191}\mathrm{Bi}$ (${T}_{\frac{1}{2}}=150\ifmmode\pm\else\textpm\fi{}15$ ms, ${E}_{\ensuremath{\alpha}}=6.86$ MeV) have been identified.

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.

Experiments on the production of fermium neutron-deficient isotopes and new possibilities of synthesizing elements with Z > 100

Experimental and theoretical data on the production of the neutron-deficient isotopes 244Fm and 246Fm in the bombardment of lead and bismuth isotopes with 40Ar and 37C1 ions are presented. By using different lead isotopes, the cross sections for the ( 40Ar, xn) reactions with x = 1, 2, 3 and 4 have been measured. It is shown that when a target of the “magic” 208Pb nucleus or its neighbours is bombarded with ions of mass $ ̆ = 40 , the compound nuclei formed appear to be weakly excited and to de-excite by emitting only 2 or 3 neutrons. New possibilities of synthesizing elements with atomic number Z > 100 are being discussed in the framework of the experimental data obtained.

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 $A=182\ensuremath{-}187$.

Levels inBi203,Bi205, andBi207

The decay of the odd-mass isotopes of polonium to levels in ${\mathrm{Bi}}^{203}$, ${\mathrm{Bi}}^{205}$, and ${\mathrm{Bi}}^{207}$ have been studied. Isotopically separated sources have been produced in the Princeton-Pennsylvania accelerator and mass-dispersed by means of the Princeton electromagnetic isotope separator. $\ensuremath{\gamma}$-ray and conversion-electron spectra have been observed. With the aid of $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences, level schemes have been constructed for these three bismuth isotopes.

Positive-parity states in some odd-mass bismuth isotopes

The electron capture decays of 207,205,203,201Po have been investigated. Several excited levels have been established in the bismuth daughters. Special attention is paid to a group of positive-parity levels at 1902 ( 1 2 + ), 2060 ( case3 2 + ) and 2405 ( 5 2 + ) in 207Bi; at 1497 ( 1 2 + ), 1709 ( 3 2 + ) and 1969 keV ( 5 2 + ) in 205Bi; at 1098 ( 1 2 + ), 1313 ( 3 2 + ) and 1488 keV ( 5 2 + ) in 203Bi and at 846 keV ( 1 2 + ) in 205Bi. It is proposed that these states are due to holes in the Z = 82 proton shell, and some arguments supporting this interpretation are given.

Hyperfine Structure of ^209Bismuth in the 6p^2(P3_0)7s P4_12 State*

The hyperfine-structure separation of the 6p2(P30)7s P412 state of 209Bi was measured in the 4722-Å transition with a grating spectrograph. The measurement was carried out because a precise value was required in our studies of the spectra of radioactive bismuth isotopes. Our result is Δν(P412)=819.5±3.1 mK. It differs from the previously quoted value of 830 mK, and agrees with a recent result of Dickie and Kelly.

Alpha decay of neutron deficient astatine isotopes

Isotopes of astatine lighter than mass 205 were studied at the Heavy Ion Linear Accelerator by bombardment of 185Re and 187Re with 20Ne, using Si (Au) surface barrier detectors in on-line measurements. Mass number assignments of astatine 201 through 196 are based on excitation functions and on genetic relationships with polonium isotopes. Accurate alpha energies are reported for 204At through 196At, for 202Po through 194Po and for four light bismuth isotopes. Half-lives are given for 202At through 196At, and for the bismuth isotopes. Isomerism was detected in 202At, 200At and 198At.

The use of bismuth radionuclides in analysis. Part II. The determination of radon in waters

A rapid radiochemical method is described for determining radon in water, based on the equliibrium of bismuth214 with its parent radon. This bismuth isotope is precipitated from solution by n-propyl gallate with inactive bismuth as a carrier. The precipitate of bismuth propyl gallate is collected on a ftlter, dried, mounted and BETA counted on a conventional instrument. The lower limit of sensitivity is about 20 picocuries per liter when a simple Geiger assembly is used. The storage in polythene containers of water samples taken for analysis is not recommended, as this polymeric material can absorb radon gas from aqueous solutions. (auth)

Spallation of Bismuth by 380-Mev Protons

Bismuth was bombarded by the 380-Mev proton beam of the Nevis Cyclotron to determine production cross sections of various spallation products. Products isolated and assayed were radioactive isotopes of polonium, bismuth, lead, thallium, mercury, gold, and platinum. Each of these elements was separated from the bismuth targets, carefully purified, and counted using a NaI(TlI) crystal scintillation counter having $4\ensuremath{\pi}$ geometry and ${99}_{\ensuremath{-}4}^{+1}$% efficiency for photons between 20 and 100 kev.A mass-yield curve was constructed from these results and compared to the mass-yield curve constructed from available Monte Carlo calculations. The calculated data fit the experimental data quite well for products within about 20 mass number units of the target. A lower limit to the total spallation cross section of 1.14\ifmmode\pm\else\textpm\fi{}0.05 barns was obtained.

Atomic beam resonance apparatus with six-pole magnets for radioactive isotopes

The construction of an atomic beam resonance apparatus with focusing six-pole magnets for measurements of spins and magnetic moments of radioactive nuclei is reported. The main features are similar to those of the apparatus of Hamilton, Lemonick, and Pipkin † † The author is much indebted to Professor D. R. Hamilton and Dr. A. Lemonick for having submitted some data of their apparatus prior to publication. . The principles of the design and of maximizing the intensity are discussed. The effective solid angle, averaged over the velocity distribution of the beam, has been calculated to be about 3 × 10 −4 steradians in a typical case, which is one order of magnitude larger than can be obtained by the conventional method. The apparatus has been used for measurements on four radioactive bismuth isotopes, which will be reported elsewhere.

Radiations from decay of bismuth-203, bismuth-204, lead-204 m, and bismuth-205

A study has been made of the radiations from the neutron-deficient isotopes 203Bi, 204Bi, 205Bi and 204 m Pb, principally by conversion electron spectroscopy with four 180° electron spectrographs of the permanent-magnet type. The decay schemes of the bismuth isotopes are found to be very complex, and in spite of high-resolution studies and some coincidence work, unique level schemes cannot be given in any case. A new transition in the decay of the 1hr 204Pb isomer has been identified at 289·5 keV, and this is interpretated as arising from a 4 + state of 204Pb at 1563 keV. A comparison is given of the results of the present study of 205Bi decay with those of other recent spectroscopic studies of the 205Pb levels.

Spins of bismuth isotopes of masses 203, 204, 205 and 206

The six-pole focusing atomic beam apparatus in Uppsala 1) has been used for the measurement of the ground state spins of four neutron deficient bismuth isotopes. The experimental results are: for 12 h Bi 203, I = 9 2 ; for 13 h Bi 204, I = 6 ; for 14.5 d i 205, I = 9 2 ; for 6.3 d Bi 206, I = 6.

XVII.—The Sargent Diagram for the Electron-capture Process, and the Disintegration Energies of Heavy β-emitters

SynopsisA Sargent diagram is presented containing 12 plotted points relative to capture-active species in the range of atomic number (Z) from 89 to 98 inclusive. Arguments are adduced to show that the “allowed” line of the diagram is located as theory predicts, and the capture transformations of other heavy capture-active species are discussed with the aid of the diagram. In particular, values are deduced for the energies of capture transformation of 17 species for which 79 ≤ Z ≤ 85, and, taking count of these values, the energies of β-disintegration of 150 species having 76 ≤ Z ≤ 98 are assumed known, and are suitably plotted against neutron number N. Discontinuities are found, for certain values of isotopie number, in the region of N = 126 (and Z = 82). Values of α-disintegration energy are also deduced for certain isotopes of bismuth and lead.

Isotopic Assignments of Bismuth Isotopes Produced with High Energy Particles

Abstract : A number of isotopes of bismuth have been identified from the bombardment of lead with high energy deuterons and protons. Evidence for these assignments is based chiefly on the daughter lead and thallium activities resulting from electron-capture decay.

Systematics of Alpha-Radioactivity

Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region of relatively low alpha-energy and long half-life at low mass numbers for such elements as astatine, emanation, francium, and possibly higher elements as had been noted already for bismuth and polonium. Methods and examples of using alpha-decay data to define the energy surface in the heavy element region are discussed. The regularities in alpha-decay are used for predictions of nuclear properties including predictions of the beta-stable nuclides among the heavy elements.The half-life vs. energy correlations show that the even-even nuclides conform well with existing alpha-decay theory, but all nuclear types with odd nucleons show prohibited decay. The reason for this prohibition is not found in spin changes in the alpha-emission but in the assembly of the components of the alpha-particle, and this theory is discussed further in terms of observations made on nuclides having two or more alpha-groups. Using most of the even-even nuclei to define "normal nuclear radius" calculations are now able to show the shrinkage in the regions of lead and of 126 neutrons to amount to about 10 percent. The much greater change in "effective radius" for bismuth isotopes can be dissociated into the effects of odd nucleons superimposed on the actual decrease in nuclear radius. The simple expression $r=1.48{A}^{\frac{1}{3}}\ifmmode\cdot\else\textperiodcentered\fi{}{10}^{\ensuremath{-}13}$ cm seems to fit the data for the even-even nuclei outside of the region of 126 neutrons better than more complex functions.

Artificial Radioactive Isotopes of Bismuth and Lead

Artificial Radioactive Isotopes of Bismuth and Lead