Indium Isotopes Research Articles

Study of heavy odd-mass indium isotopes from the (γ, p) reaction on tin

A series of bombardments using the 25-MeV bremsstrahlung on enriched isotopes Sn 120O 2, Sn 122O 2, Sn 124O 2, and natural tin have resulted in the discovery of new isotopes In 121, In 123, and their isomers. The previously reported activity of In 119 is assigned to In 1198. The results are as follows: energies of energies of half-lives β rays γ rays (MeV) (MeV) In 119g 2.3 min 1.6 0.77 In 121g 30 sec 0.94 In 123g 10 sec 1.10 In 121m 3.1 min 3.7 In 123m 36 sec 4.6 Decay schemes and level assignments are proposed. All the decay characteristics beautifully fit into shell model systematics, allowing us systematical studies on pertinent nuclear properties. Relative yields of photoreaction on tin are also derived on the basis of these decay sche mes.

Spins of Indium-109, Indium-110m, and Indium-111

The nuclear spins of three neutron-deficient radioactive isotopes of indium have been measured by the use of the atomic-beam magnetic-resonance techique. Results are I =9/2 for 4.3-hr In/sup 109/; I = 7 for 5.0-hr In/sup 110m/; and I =9/2 for 2.8-day In/sup 111/. (auth)

Hfs of the5P122State ofIn115andIn113: Hfs Anomalies in the Stable Isotopes of Indium

The hfs splittings of the $5^{2}P_{\frac{1}{2}}$ states of ${\mathrm{In}}^{115}$ and ${\mathrm{In}}^{113}$ have been measured by the atomic-beam magnetic-resonance method. We find: $\ensuremath{\Delta}\ensuremath{\nu}({\mathrm{In}}^{115})=[11409.7506\ifmmode\pm\else\textpm\fi{}(20)]\ifmmode\times\else\texttimes\fi{}{10}^{6} invsec,$ $\ensuremath{\Delta}\ensuremath{\nu}({\mathrm{In}}^{113})=[11385.4300\ifmmode\pm\else\textpm\fi{}(20)]\ifmmode\times\else\texttimes\fi{}{10}^{6} invsec.$ A comparison of the ratio of the dipole coupling constants of the two isotopes in the ${P}_{\frac{1}{2}}$ state and in the ${P}_{\frac{3}{2}}$ state with the ratio of the nuclear ${g}_{I}$ factors yields the following hfs anomalies: ${\ensuremath{\Delta}}_{\frac{1}{2}}=(7.5\ifmmode\pm\else\textpm\fi{}1.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}, {\ensuremath{\Delta}}_{\frac{3}{2}}=\ensuremath{-}(23.8\ifmmode\pm\else\textpm\fi{}1.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}.$ The fractional change in the nuclear radius between ${\mathrm{In}}^{113}$ and ${\mathrm{In}}^{115}$, $\frac{\ensuremath{\delta}R}{R}$, is found to be 3.66\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ as compared to 5.85\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ calculated on the assumption of an incompressible nucleus.

Hfs of the5P322State ofIn115andIn113: Octupole Interactions in the Stable Isotopes of Indium

The zero-field hfs intervals in the $5^{2}P_{\frac{3}{2}}$ state of ${\mathrm{In}}^{115}$ and ${\mathrm{In}}^{113}$ have been measured by the use of conventional atomic-beam techniques. The magnetic octupole interaction constants for these atomic systems are determined from the measured intervals and corrected for perturbations of the electronic states. They are ${c}^{\ensuremath{'}}({\mathrm{In}}^{115})=[0.001702\ifmmode\pm\else\textpm\fi{}(35)]\ifmmode\times\else\texttimes\fi{}{10}^{6} invsec,$ ${c}^{\ensuremath{'}}({\mathrm{In}}^{113})=[0.001728\ifmmode\pm\else\textpm\fi{}(45)]\ifmmode\times\else\texttimes\fi{}{10}^{6} invsec.$ The estimated values of the nuclear magnetic octupole moments of ${\mathrm{In}}^{115}$ and ${\mathrm{In}}^{113}$ are compared to the predictions of the single-particle and collective models of the nucleus.

Evidence for the natural radioactivity of indium.

A CONSIDERATION of the energetics of radioactive decay shows that two isotopes of the same mass number but neighbouring atomic number cannot both be stable if the rest mass of the neutrino is zero. A number of such neighbouring isobaric pairs exists in Nature; in some cases the expected radioactivity has been found in one member of the pair, with a period of decay comparable to, or longer than, the age of the earth (for example, the well-known case of 4019K). The two naturally existing isotopes of indium—11349In and 11549In (abundances 4.5 and 94.5 per cent respectively)—are each members of such isobaric pairs, the first with 11348Cd, and the second with 11550Sn. Accordingly, it was decided to search for radioactivity among these elements, as none had hitherto been found.

The Hyperfine Structure of the Stable Isotopes of Indium

The atomic beams magnetic resonance method has been applied to the study of the h.f.s. of the metastable $^{2}P_{\frac{3}{2}}$ state of both ${\mathrm{In}}^{113}$ and ${\mathrm{In}}^{115}$. It has been found that the separations of the energy levels at zero external magnetic field are completely described by the equation $W=\frac{\mathrm{haC}}{2}+hbC(C+1)$, where $C=F(F+1)\ensuremath{-}I(I+1)\ensuremath{-}J(J+1)$, and $a$ and $b$ are the magnetic dipole and electric quadrupole interaction constants, respectively. No evidence has been found to indicate the existence of a nuclear moment of higher order than the quadrupole moment. These are the heaviest atoms in which a critical search for such moments has been made.The numerical values of the constants for ${\mathrm{In}}^{115}$ are: ${{a}^{115},=242.165\ifmmode\pm\else\textpm\fi{}0.002 \frac{\mathrm{mc}}{sec}.}{{b}^{115},=1.56098\ifmmode\pm\else\textpm\fi{}0.00006 \frac{\mathrm{mc}}{sec}.}$ The ratio $\frac{{a}^{115}}{{a}^{113}}$ has been determined by Hardy and Millman to be 1.00224\ifmmode\pm\else\textpm\fi{}0.00010. From this value, and the results of our measurements, the numerical values of the constants for ${\mathrm{In}}^{113}$ are: ${{a}^{113},=241.624\ifmmode\pm\else\textpm\fi{}0.024 \frac{\mathrm{mc}}{sec}.}{{b}^{113},=1.53855\ifmmode\pm\else\textpm\fi{}0.00015 \frac{\mathrm{mc}}{sec}.}$ where the uncertainties in ${a}^{113}$ and ${b}^{113}$ follow from the uncertainty in the ratio of the $a'\mathrm{s}$. The numerical values of the electric quadrupole moments are: ${{Q}^{115},=1.161\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}24}{\mathrm{cm}}^{2}}{{Q}^{113},=1.144\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}24}{\mathrm{cm}}^{2}.}$ It is seen from the ratios $\frac{{I}^{115}}{{I}^{113}}=1$, $\frac{{a}^{115}}{{a}^{113}}=1.00224$, $\frac{{b}^{115}}{{b}^{113}}=1.01146$, that in these measurable nuclear properties ${\mathrm{In}}^{113}$ and ${\mathrm{In}}^{115}$ exhibit the greatest degree of similarity observed for any pair of isotopes of odd mass differing in mass by two units.

RadioactiveIn107,In108,In109, andSn108

A new indium isotope which decayed with a 33\ifmmode\pm\else\textpm\fi{}2-min. half-life has been produced by deuteron and proton bombardments of cadmium 106. Evidence for the assignment of the activity to indium 107 is given. Characteristic radiations are positrons of 2-Mev energy and gamma-rays. An indium isotope which decayed with a 4.30\ifmmode\pm\else\textpm\fi{}0.15-hr. half-life has been produced by a deuteron and proton bombardment of cadmium 108 and by an alpha-bombardment of cadmium 106. The assignment is made to indium 109. Decay is by emission of 0.75\ifmmode\pm\else\textpm\fi{}0.05-Mev positrons, by $K$-electron capture, and by emission of gamma-rays. Two genetically related isotopes in tin and indium have been assigned to mass number 108. The tin isotope, which is produced by bombarding cadmium 106 with alpha-particles, decays with a half-life of 4.5 hr. by $K$-electron capture. The indium isotope, which is produced by the decay of the tin isotope and by bombarding cadmium 108 with deuterons, decays with a half-life of about 55 min. by emitting positrons of 2-Mev energy and gamma-rays.

The Radioactive Isotopes of Indium

It is shown that radioactive isotopes of indium may be formed possessing ten distinct half-lives ranging from 13 seconds to 50 days. By producing the various isotopes with different methods of excitation and measuring the energies of the beta- and gamma-radiations emitted by each, it now becomes possible to assign with reasonable certainty each radioactivity to an isotope of a particular mass number. Energy level diagrams can be constructed for certain of the excited nuclei. Increased resolution of the magnetic beta-ray spectrometer now makes it possible to identify positively the element in which internally converted gamma-rays are emitted. This is accomplished by observing the differences in the $K\ensuremath{-}$, $L\ensuremath{-}$ and $M$-conversion electron energies and comparing with known binding energies obtained from x-ray analysis. The total conversion coefficients are observed in several cases, and the ratios of $K$- to $L$-conversion coefficients for individual gamma-rays are used to compute the probable energy level spin values on the basis of present theory. A radioactivity of 50-day half-life assigned to ${\mathrm{In}}^{114}$ is shown to consist of a gamma-ray emission followed by a beta-ray of half-life 72 seconds and energy 1.98 Mev. It thus becomes possible to observe the form of this beta-spectrum in the magnetic spectrometer, and since it is an allowed transition it is significant to compare it with the present theory of beta-decay which has been developed only for transitions of this type and until now always tested by measurements on forbidden spectra. Within the probable errors the experimental results conform with the theoretical predictions of the Fermi theory.

Radioactive Isotopes of Indium from Alpha-Bombardment of Silver

Radioactive Isotopes of Indium from Alpha-Bombardment of Silver

Induced Radioactivity in Cadmium and Indium

The artificial activation of cadmium and indium now yields at least three radioactive isotopes of cadmium and eight radioactive isotopes of indium. The probable masses of several of these isotopes have been determined. In cadmium bombarded with deuterons two chain reactions are observed in which the active cadmium decays to radioactive indium. These are Cd (56 hour) to In (4.5 hour), and Cd (3.75 hour) to In (2.1 hour). Evidence is presented for believing that a new 65-hour gamma-radiation is due to an excited state of a normally stable indium isotope of mass 113. The energies and decay constants of many of the radiations have been accurately measured by means of a magnetic spectrometer of high resolving power.

The Radioactive Isotopes of Indium

Although there are but two stable isotopes of indium whose mass numbers are 113 and 115, seven radioactive periods are shown to exist. Six of these whose half-life periods are 13 seconds, 72 seconds, 54 minutes, 2.3 hours, 4.1 hours and 50 days emit negative electrons, and one period of 20 minutes is radiopositive. By bombarding indium with slow neutrons, deuterons and very fast neutrons, and by bombarding cadmium with deuterons it is possible to assign with considerable confidence each period to a certain indium isotope. The conclusions are that the 54 minute and 13 second activities are both due to ${\mathrm{In}}^{116}$, the 4.1-hour and 50-day periods are both ${\mathrm{In}}^{114}$ and the 20-minute, 72-second and 2.3-hour periods are from isotopes of mass 111, 112, and 117, respectively. Beta-ray energy limits are approximately 2.15 Mev for the 50-day period and 1.75 Mev for the 20-minute positive period.