Recent Articles

Proton Spectra from 54.8-MeV Alpha-Particle Reactions: Precompound Emission

A. Chevarier, N. Chevarier, A. Demeyer, G. Hollinger, P. Pertosa, and Tran Minh Duc

Phys. Rev. C 8, 2155 (1973) - Published 1 December, 1973

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An experimental survey of 54.8-MeV ( $α, p$ ) proton spectra is undertaken for studying pre-equilibrium emission; such deexcitation yields on the average cross sections about 250 mb, the average value measured for all the investigated reactions. Different quantitative formulations are discussed in terms of exciton state mean lifetimes; the exciton and hybrid models are found to give a good interpretation of the proton emission cross sections. A geometrical distinction between the equilibrium and nonequilibrium processes may be attempted. Odd-even effects appear in ( $α, p$ ) reactions by means of partial state density: Odd- $Z$ targets require an initial exciton number $n_{I}$ equal to five ( $3 p - 2 n - 0 h$ ) and even- $Z$ targets equal to four ( $2 p - 2 n - 0 h$ ). This result may be attributed to a pairing effect according to the odd-even character of residual nuclei.

Rotational Band Structure of ${}^{22}{Na}$ . I. Electromagnetic Transitions for Levels of $E_{ex} < 4.0$ MeV

F. Haas, R. M. Freeman, J. Fernandez Castillo, and A. Gallmann

Phys. Rev. C 8, 2169 (1973) - Published 1 December, 1973

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Electromagnetic transitions from levels of ${}^{22}{Na}$ which belong to the rotational bands $K^{π} = 3^{+}, 0^{+}$ ( $T = 0$ ) and $1^{-}$ have been studied by the ${}^{19}F (α, n γ) {}^{22}{Na}$ reaction. Lifetimes have been measured by the recoil distance method (RDM) and by the Doppler-shift attenuation method (DSAM). From a comparison of the results obtained by the two methods, the stopping powers for ${}^{22}{Na}$ in the stopping materials used have been deduced. The adopted lifetimes $τ$ (ps) for the levels studied [ $E_{ex}$ (MeV), $J^{π}$ ] are the following: 14.7 ± 0.7 [0.891, $J^{π} = 4^{+}$ ], 4.8 ± 0.3 [1.528, $J^{π} = 5^{+}$ ], 0.077 ± 0.020 [3.708, ( $J^{π} = 6^{+}$ )], 2.40 ± 0.35 [1.984, $J^{π} = 3^{+}$ ], 21.2 ± 1.0 [2.211, $J^{π} = 1^{-}$ ], 8.8 ± 0.9 [2.572, $J^{π} = 2^{-}$ ], and 0.64 ± 0.16 [3.521, $J^{π} = 3^{-}$ ]. New branches for the $γ$ -ray decay of the 1.984- and 2.572-MeV levels have been observed. The negative parity of the levels at 2.572 and 3.521 MeV has been definitively established. The electro-magnetic properties, of some of these levels, have been compared with the isobaric spin selection rules for $N = Z$ nuclei, with the predictions of the unified model of Nilsson and with recent shell-model calculations.

Rotational Band Structure of ${}^{22}{Na}$ . II. Neutron-Gamma Coincidence Measurements

R. M. Freeman, F. Haas, B. Heusch, J. Fernandez Castillo, J. W. Olness, and A. Gallmann

Phys. Rev. C 8, 2182 (1973) - Published 1 December, 1973

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Neutron- $γ$ coincidence measurements, on the reaction ${}^{19}F (α, n γ) {}^{22}{Na}$ , have been undertaken to identify transitions from some states in ${}^{22}{Na}$ below 5 MeV excitation energy, and to measure their angular correlations and the lifetimes of the levels. The 4.466-MeV level was found to decay to the 2.572-MeV level, and the 4.522-MeV level to the 1.528-MeV level. These decays, together with the angular correlation and lifetime data, are consistent with assigning the 4.466-MeV level as the $4^{-}$ member of the negative-parity rotational band, based on the $1^{-}$ level at 2.211 MeV, and the 4.522-MeV level as the $7^{+}$ state of the ground-state rotational band. The data also support assigning the 3.708-MeV level as the $6^{+}$ member of the ground-state rotational band and the 4.708-MeV level as the $5^{+}$ member of the $T = 0$ , $K = 0$ band, based on the $1^{+}$ state at 0.583 MeV. The electromagnetic properties of the ${}^{22}{Na}$ . levels are compared with the rotational model predictions and recent shell-model calculations.

Real Potential in Alpha-Nucleus Scattering

P. Mailandt, J. S. Lilley, and G. W. Greenlees

Phys. Rev. C 8, 2189 (1973) - Published 1 December, 1973

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Measurements of $α$ -nucleus elastic differential-cross-section data at 27 MeV from ${}^{45}{Sc}$ , ${}^{65}{Cu}$ , ${}^{90}{Zr}$ , and ${}^{122}{Sn}$ , over the angular range 15 (×2.5) to 175° are reported. The data are analyzed using both a standard six-parameter optical model and a folding model. The latter uses an effective nucleon- $α$ interaction obtained from a global analysis of free nucleon- $α$ scattering data below 12 MeV incident nucleon energy which is folded with a nuclear matter distribution to obtain the real part of the $α$ -nucleus potential. The fits with the folding model are improved appreciably over those obtained using the standard optical model and are sensitive to the choice of matter parameters. The matter mean-square radii deduced are in good agreement with other estimates.

3.62-MeV Doublet in ${}^{41}{Ca}$

S. L. Tabor, R. W. Zurmühle, and D. P. Balamuth

Phys. Rev. C 8, 2200 (1973) - Published 1 December, 1973

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$γ$ spectra were measured in coincidence with particles detected near 0° from the ${}^{40}{Ca} (d, p γ) {}^{41}{Ca}$ and ${}^{42}{Ca} ({}^{3}{He}, α γ) {}^{41}{Ca}$ reactions corresponding to an excitation energy of 3.62 MeV in ${}^{41}{Ca}$ . The absence of ground-state decays from the 3.62-MeV state when populated by the ( $d, p γ$ ) reaction under the experimental conditions of a previous deuteron vector-analyzing power measurement removes the conflict between the spin assignment of $j^{π} = {\frac{1}{2}}^{-}$ to this state from the analyzing power experiment and previous $γ$ -ray branching-ratio measurements.

[NUCLEAR REACTIONS ${}^{40}{Ca} (d, p γ)$ , $E = 11$ MeV; ${}^{42}{Ca} ({}^{3}{He}, α γ)$ , $E = 18$ MeV; measured coin $γ$ spectrum 3.62-MeV level. Enriched target.]

High-Spin States in the Continuum. I. ${}^{20}{Ne}$

L. K. Fifield, R. W. Zurmühle, D. P. Balamuth, and J. W. Noé

Phys. Rev. C 8, 2203 (1973) - Published 1 December, 1973

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We describe a new angular-correlation method for assigning spins to states that are selectively populated in reactions of the type ${}^{12}C ({}^{12}C, α) {}^{20}{Ne}$ and which decay by the emission of an $α$ particle to a state of nonzero spin, which decays in turn to a spin-zero state by the emission of a $γ$ ray. Such states are not accessible to conventional particle-particle angular-correlation techniques. The new method consists of measuring the triple-angular correlation of the two $α$ particles and the $γ$ ray from the reaction ${}^{12}C ({}^{12}C, α_{1} α_{2} γ) {}^{16}O$ with the first emitted $α$ particle observed at zero degrees, the $γ$ ray observed at a fixed angle, and the second emitted $α$ particle observed over a range of angles. Applications of this method to the determination of the spins of two states in ${}^{20}{Ne}$ , at 15.18 ± 0.02 MeV ( $6^{+}$ ) and 17.40 ± 0.02 MeV ( $9^{-}$ ), are discussed. The 17.40-MeV state has been identified as the $9^{-}$ member of the lowest negative-parity band in ${}^{20}{Ne}$ ; the $6^{+}$ assignment to the level at 15.18 MeV is in disagreement with an earlier assignment of spin and parity $9^{-}$ to this level.

[NUCLEAR REACTIONS ${}^{12}C ({}^{12}C, α_{1}) {}^{20}{Ne}^{*} (α_{2}) {}^{16}O^{*} (γ) {}^{16}O$ (g.s.), $E = 36.3, 37.2$ MeV; measured $σ (E_{α_{1}}, E_{α_{2}}, E_{γ}, θ_{α_{1}}, θ_{α_{2}}, θ_{γ}, ϕ_{γ})$ . ${}^{20}{Ne}$ deduced levels $J$ , $π$ , branching ratios.]

High-Spin States in the Continuum. II. ${}^{24}{Mg}$

L. K. Fifield, R. W. Zurmühle, and D. P. Balamuth

Phys. Rev. C 8, 2217 (1973) - Published 1 December, 1973

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The spins and parities of several states in ${}^{24}{Mg}$ have been determined with a triple angular-correlation technique. These states were selectively populated in the ${}^{16}O ({}^{12}C, α) {}^{24}{Mg}$ reaction, and decayed by $α$ -particle emission to the 1.63-MeV ( $2^{+}$ ) state in ${}^{20}{Ne}$ . The results are: 13.42 MeV, $6^{+}$ ; 13.84 MeV, $6^{+}$ ; 14.14 MeV, $8^{+}$ ; 15.15 MeV, $7^{-}$ ; 16.30 MeV, $8^{+}$ ; 16.55 MeV, $8^{+}$ + $9^{-}$ ; 16.84 MeV, $8^{+}$ . In addition, the spins of the following states were determined from the angular correlations of the $α$ particles leading to the ${}^{20}{Ne}$ ground state: 12.83 MeV, $6^{+}$ ; 13.75 MeV, $5^{-}$ ; 16.46 MeV, $7^{-}$ . A search was made for particle decays of the 11.86-MeV ( $6^{+}$ , $8^{+}$ ) and 13.20-MeV ( $8^{+}$ ) states in ${}^{24}{Mg}$ ; no particle decay branch was found for either state. Statistical-model calculations have been performed to investigate the usefulness of such calculations in assigning spins to states selectively populated in the ${}^{16}O ({}^{12}C, α) {}^{24}{Mg}$ reaction.

[NUCLEAR REACTIONS ${}^{16}O ({}^{12}C, α_{1}) {}^{24}{Mg}^{*} (α_{2}) {}^{20}{Ne}^{*} (γ) {}^{20}{Ne}$ (g.s.), ${}^{16}O ({}^{12}C, α_{1}) {}^{24}{Mg}^{*} (α_{2}) {}^{20}{Ne}$ (g.s.), $E = 35 - 38$ MeV; measured $σ (E_{α_{1}}, E_{α_{2}}, E_{γ}, θ_{α_{1}}, θ_{α_{2}}, θ_{γ}, ϕ_{γ})$ , $σ (E_{α_{1}}, E_{α_{2}}, θ_{α_{1}}, θ_{α_{2}})$ . ${}^{24}{Mg}$ deduced levels $J$ , $π$ , branching ratios. Hauser-Feshbach calculations.]

Study of $1^{+}$ States in ${}^{48}V$

J. W. Smith, L. Meyer-Schützmeister, Gerald Hardie, and P. P. Singh

Phys. Rev. C 8, 2232 (1973) - Published 1 December, 1973

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15 states in ${}^{48}V$ have been studied by means of the ${}^{46}{Ti} ({}^{3}{He}, p) {}^{48}V$ reaction induced by a 17-MeV ${}^{3}{He}^{+ +}$ beam from the Argonne tandem Van de Graaff. The proton angular distributions led to the identification of one $0^{+}$ state (the isobaric analog of the ${}^{48}{Ti}$ ground state) and 7 $1^{+}$ states. The excitation energies of the $1^{+}$ states are compared with those predicted by a shell-model calculation which assumed a ${(π f_{\frac{7}{2}})}^{3} {(ν f_{\frac{7}{2}})}^{- 3}$ configuration. The differential cross sections for populating states in ${}^{48}V$ by transferring an $n - p$ pair with 0 or 0 + 2 units of angular momenta are compared with similar cross sections in neighboring nuclei to investigate possible regularities in this mass region. The $γ$ decay of the $0^{+}$ and $1^{+}$ states was determined by studying $p - γ$ coincidences associated with the ${}^{48}{Ti} ({}^{3}{He}, p γ) {}^{48}V$ reaction. The $γ$ decay of the $1^{+}$ states shows a definite pattern which is compared with one based on a selection rule involving the signatures of the wave functions describing the $1^{+}$ states.

Lifetime Measurements of Excited States in ${}^{38}K$

H. Hasper and P. B. Smith

Phys. Rev. C 8, 2240 (1973) - Published 1 December, 1973

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Excitation energies and mean lives of levels in ${}^{38}K$ up to 3.85 MeV, excited in the ${}^{40}{Ca} (d, α γ) {}^{38}K$ reaction at $E_{d} = 4.421$ MeV, have been measured using the Doppler-shift attenuation method. The $γ$ rays were detected at 31.7 and 121.7° in coincidence with $α$ particles detected in an annular detector with an average angle of 169°. The following mean lifetimes were found (excitation energy in keV, lifetimes in fsec): 459, > 4000; 1698, 65 ± 17; 2401, 90 ± 25; 2613, $9000_{- 2000}^{+ 7000}$ ; 2646, > 12000; 2829, 280 ± 70; 2870, 4500 ± 1200; 2993, 220 ± 50; 3315, 2450 ± 420; 3342, < 55; 3668, < 150; 3725, < 120; 3849, < 55. Several spin-parity restrictions made in earlier work have been made stricter on the basis of these results.

[NUCLEAR REACTION ${}^{40}{Ca} (d, α γ) {}^{38}K$ , $E_{d} = 4.42$ MeV; measured $α γ$ coin., $E_{γ}$ , Doppler-shift attenuation. ${}^{38}K$ deduced levels $E$ , $T_{\frac{1}{2}}$ , $B (Λ)$ .]

Systematic Study of the ${}^{88}{Sr}$ ( ${}^{16}O$ , ${}^{15}N$ ) Reaction

N. Anantaraman

Phys. Rev. C 8, 2245 (1973) - Published 1 December, 1973

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The systematics of the ${}^{88}{Sr}$ ( ${}^{16}O$ , ${}^{15}N$ ) one-proton transfer reaction is investigated for six incident energies between 44.0 and 59.0 MeV. Angular distributions for the prominent transitions are presented. Finite-range no-recoil calculations with optical-model parameters determined from the elastic scattering of ${}^{16}O$ on ${}^{88}{Sr}$ and of ${}^{15}N$ on ${}^{89}Y$ fit the transfer angular distributions well, except for transitions involving large $Q$ mismatch. The energy-dependent normalization obtained for the transition to the $2 p_{\frac{1}{2}}$ state indicates the increasing importance of recoil contributions at higher incident energies. A semiclassical treatment of the transfer reaction seems to be adequate at incident energies below the Coulomb barrier.

[NUCLEAR REACTIONS ${}^{88}{Sr}$ ( ${}^{16}O$ , ${}^{15}N$ ), ${}^{88}{Sr}$ ( ${}^{16}O$ , C), ${}^{88}{Sr}$ ( ${}^{16}O$ , ${}^{16}O$ ) $E = 44 - 59$ MeV measured $σ (E, θ)$ ; deduced optical-model parameters. Enriched target, DWBA analysis, resolution 400 keV, $θ = 60^{\circ} - 160^{\circ}$ .]

Gamma-Ray-Multiplicity Measurements for ( $α, p$ ), ( $α, α^{'}$ ), ( $d, α$ ), ( $p, α$ ), ( $d, p$ ), and ( $p, p^{'}$ ) Reactions

J. H. Degnan, B. L. Cohen, G. R. Rao, K. C. Chan, and L. Shabason

Phys. Rev. C 8, 2255 (1973) - Published 1 December, 1973

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Using a method introduced previously measurements were made of the $γ$ -ray multiplicity $N_{γ}$ (the average number of $γ$ rays emitted in the decay of residual nuclei left by nuclear reactions) as a function of excitation energy $E^{*}$ for ( $p, α$ ) and ( $d, α$ ) reactions on ${}^{51}V$ , ${}^{56}{Fe}$ , and ${}^{57}{Fe}$ targets; ( $α, p$ ) reactions on ${}^{51}V$ , ${}^{56}{Fe}$ , ${}^{57}{Fe}$ , ${}^{58}{Ni}$ , ${}^{64}{Ni}$ , ${}^{93}{Nb}$ , and Ag; ( $α, α^{'}$ ) reactions on ${}^{51}V$ , ${}^{55}{Mn}$ , ${}^{56}{Fe}$ , ${}^{57}{Fe}$ , ${}^{59}{Co}$ , and ${}^{64}{Ni}$ ; ( $d, p$ ) reactions on ${}^{51}V$ , ${}^{55}{Mn}$ , ${}^{56}{Fe}$ , Ag, and ${}^{119}{Sn}$ ; and ( $p, p^{'}$ ) reactions on ${}^{56}{Fe}$ , ${}^{112}{Sn}$ , and ${}^{122}{Sn}$ . Bombarding energies ranged from 12 to 19 MeV. $N_{γ}$ was observed to be generally between 1 and 5 for $E^{*}$ between 3 and 10 MeV for the ( $p, p^{'}$ ), ( $d, p$ ), ( $d, α$ ), ( $p, α$ ), and ( $α, α^{'}$ ) reactions investigated, and somewhat higher for the ( $α, p$ ) reactions. $N_{γ}$ increases with $E^{*}$ , and is larger for higher angular momentum transfer reactions although it is not as much larger as angular momentum transfer considerations alone would suggest. (This can be explained as a level-density effect for compound-nucleus reactions—the average angular momentum of the states excited by the reactions is severely limited by the level-density spin-cutoff parameter.) The dependence of $N_{γ}$ on the average excess angular momentum of the residual nuclei was investigated using calculated spin distributions for the residual nuclei. This dependence is similar to that for neutron capture $N_{γ}' s - N_{γ}$ increases with excess angular momenta for excess angular momenta of more than 2 or 3 units.

Isobaric Analogs of ${}^{51}{Ti}$ Levels Observed Through the ${}^{50}{Ti} (p, p^{'} γ) {}^{50}{Ti}$ Reaction

Franklin D. Snyder and B. D. Kern

Phys. Rev. C 8, 2267 (1973) - Published 1 December, 1973

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Five isobaric-analog resonances in the ${}^{50}{Ti} (p, p^{'} γ)$ reaction at incident proton energies of 3.598, 3.614, 4.30, 4.38, and 4.58 MeV have been investigated through $p^{'}$ and $γ$ -ray angular distributions and $p^{'} - γ$ coincidence angular correlations. Particle-spin amplitude mixing ratios for the 2.598-, 3.614-, 4.38-, and 4.58-MeV resonances have been determined as $δ (\frac{p_{\frac{3}{2}}}{p_{\frac{1}{2}}})$ equal to 0.40 ± 0.15, ${- 3.6}_{- 1.6}^{+ 1.0}$ , -0.1 ± 0.6, and 0.18 ± 0.16, respectively. The weak-coupling-model calculations of Divadeenam and Beres for ${}^{51}{Ti}$ are in good agreement with the mixing ratios determined for the 2 ${}^{+}{excited}$ ${}^{50}{Ti}$ core plus $p$ -wave neutron. The spin-parities of the 4.30- and 4.38-MeV resonances have been established as ${\frac{5}{2}}^{-}$ and ${\frac{3}{2}}^{-}$ .

[NUCLEAR REACTIONS ${}^{50}{Ti} (p, p^{'} γ)$ , $E = 3.5 - 4.8$ MeV, IAR; measured $σ_{p^{'} 1.55} (E, θ)$ , $σ_{γ (1.55 \to 0)} (E, θ)$ , $σ_{p^{'} - γ} (E, θ_{γ})$ ; deduced $J$ , $l_{p}$ , $l_{p^{'}}$ , $δ_{p^{'}}$ .]

Decay of ${}^{59}{Fe}$ to Levels of ${}^{59}{Co}$

S. C. Pancholi, J. J. Pinajian, Noah R. Johnson, Ashok Kumar, S. K. Soni, M. M. Bajaj, S. L. Gupta, and N. K. Saha

Phys. Rev. C 8, 2277 (1973) - Published 1 December, 1973

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The decay of 45.1-day ${}^{59}{Fe}$ has been studied with a 40- ${cm}^{3}$ Ge(Li) detector, a Ge(Li) low-energy photon detector, and a Ge(Li)-NaI(T1) coincidence system. The measured $γ$ -ray energies in keV (intensities in parentheses) are as follows: 142.648 (1.02 ± 0.04)%, 192.344 (3.08 ± 0.10)%, 334.8 ± 0.2 (0.27 ± 0.01)%, 382.0 ± 0.4 (0.018 ± 0.003)%, 1099.224 (56.5 ± 1.5)%, 1291.564 (43.2 ± 1.1)%, 1481.7 ± 0.2 (0.059 ± 0.006)%. $γ - γ$ coincidence measurements show that the 382.0-keV $γ$ ray is in coincidence with the 1099.22-keV $γ$ ray and that the 1481.7-keV $γ$ ray is a ground-state transition, thereby establishing a ${}^{59}{Co}$ level at 1481.7 ± 0.2 keV. $γ - γ$ directional correlations were measured for the following cascades, and the expansion coefficients obtained are: 142.65-1291.56 keV, $A_{2} = - 0.070 \pm 0.005$ ; 334.8-1099.22 keV, $A_{2} = - 0.099 \pm 0.012$ ; and 192.34-1099.22 keV, $A_{2} = + 0.008 \pm 0.004$ . The mixing parameters $δ$ for the 142.65-, 192.34-, and 334.8-keV $γ$ rays and the $B (M 1) ↓$ and $B (E 2) ↓$ values for the transitions from the 1099.22-, 1291.56-, and the 1434.21-keV levels in ${}^{59}{Co}$ are deduced. The low-lying levels in ${}^{59}{Co}$ are discussed in terms of core coupling model calculations.

[RADIOACTIVITY ${}^{59}{Fe}$ [from ${}^{59}{Co} (n, p)$ ]; measured $E_{γ}$ , $I_{γ}$ , $γ - γ$ coin, $γ γ (θ)$ ; deduced ${}^{59}{Co}$ Levels, $J^{π}$ , $γ$ mixing ratios, $B (M 1)$ and $B (E 2)$ values.]

States of ${}^{94}{Mo}$ from the ${}^{95}{Mo} (d, t) {}^{94}{Mo}$ Reaction

J. E. Holden and W. W. Daehnick

Phys. Rev. C 8, 2286 (1973) - Published 1 December, 1973

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The ${}^{95}{Mo} (d, t) {}^{94}{Mo}$ reaction has been studied at 17-MeV incident energy. Energy spectra were measured at 12 angles from 9 to 50° laboratory angle in an Enge split-pole spectrograph. The energy resolution was 8 keV. 77% of the expected extracore pickup strength is accounted for by the six strongest $l = 2$ transitions. The spectroscopic sums for final $J^{π} = 0^{+}$ , $2^{+}$ , and $4^{+}$ among these six levels are fully consistent with those predicted by the assumption of pure ${(d_{\frac{5}{2}})}^{3} \to {(d_{\frac{5}{2}})}^{2}$ transitions. Angular distributions were measured for an additional 16 levels up to 3.7 MeV excitation. Seven of these levels have not been previously reported. The existence of a ${}^{94}{Mo}$ level at 1.746 MeV is confirmed in this experiment.

[NUCLEAR REACTIONS ${}^{95}{Mo} (d, t)$ , $E_{d} = 17.0$ MeV; measured $σ (E_{t}, θ)$ , 8-keV resolution. ${}^{94}{Mo}$ deduced levels, $l_{n}$ , $S$ ; DWBA analysis. Enriched target.]

Total Energy Associated with Prompt $γ$ -Ray Emission in the Spontaneous Fission of ${}^{252}{Cf}$

E. Nardi, A. Gavron, and Z. Fraenkel

Phys. Rev. C 8, 2293 (1973) - Published 1 December, 1973

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The total energy associated with the emission of prompt $γ$ rays in spontaneous fission of ${}^{252}{Cf}$ was measured as a function of the fission-fragment mass and kinetic energy. The $γ$ -ray energy shows a saw-tooth curve behavior as a function of mass, and a small decrease with increasing kinetic energy. The measurements were carried out using plastic scintillators.

Gamma-Gamma Directional Correlation of the 485-934-keV Cascade in ${}^{115}{In}$

Robert J. Koshut and Atam P. Arya

Phys. Rev. C 8, 2298 (1973) - Published 1 December, 1973

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The $γ - γ$ directional correlation of the 485-934-keV $γ$ cascade in ${}^{115}{In}$ following the decay of ${}^{115}{Cd}^{m}$ ( $t_{\frac{1}{2}} = 43$ days) was measured using a 10.6- ${cm}^{3}$ Ge(Li) detector and a 7.6 × 7.6-cm NaI(Tl) detector in conjunction with a multichannel analyzer in the standard fast-coincidence configuration. The results obtained are consistent with most probable spin assignments to the various levels as ${7 / 2}^{+}$ for the 1419-keV, ${7 / 2}^{+}$ for 934-keV, and ${9 / 2}^{+}$ for the ground state of ${}^{115}{In}$ . The possible value of the quadrupole content for the 934-keV $γ$ ray is found to be in the range 6 to 35%, while for the 485-keV $γ$ ray, the possible value of the quadrupole content is in the range 91 to 96%.

${}^{232}{Th}$ Mössbauer Effect Linewidth Measurements

A. B. Carpenter and N. Hershkowitz

Phys. Rev. C 8, 2302 (1973) - Published 1 December, 1973

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Coulomb excitation Mössbauer effect experiments have been performed on the first excited state of ${}^{232}{Th}$ using Th-metal targets and Th-metal and various Th-compound absorbers. The metal is shown to yield a Mössbauer linewidth in agreement with that predicted by electronic measurements of the half-life of the first excited state. The zero-thickness absorber linewidth (half width at half maximum), absorber recoilless fraction, and source recoilless fraction were found to be $Γ_{0} = 8.66 \pm 0.64$ mm/sec, $f_{a} = 0.45 \pm 0.12$ , and $f_{s} = 0.23 \pm 0.08$ , respectively, for Th metal. Experiments performed on noncubic absorber materials gave broadened spectra which are attributed to electric quadrupole hyperfine interactions.

[NUCLEAR REACTIONS ${}^{232}{Th} (α, α)$ , $E = 49.4$ keV; measured Mössbauer effect. ${}^{232}{Th}$ level deduced $T_{\frac{1}{2}}$ , hyperfine fields.]

Nuclear Spectroscopy of ${}^{109}{Ag}$ from the ${}^{108}{Pd} ({}^{3}{He}, d)$ Reaction

R. L. Auble, F. E. Bertrand, Y. A. Ellis, and D. J. Horen

Phys. Rev. C 8, 2308 (1973) - Published 1 December, 1973

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The energy levels of ${}^{109}{Ag}$ are studied by means of the ${}^{108}{Pd} ({}^{3}{He}, d)$ reaction at 27-MeV bombarding energy. Deuteron angular distributions are compared with distorted-wave Born-approximation predictions to extract $l$ transfers and spectroscopic strengths. Several previously unreported or poorly established levels are excited including a low-lying ${\frac{1}{2}}^{+}$ state at 706 keV. The available data are summarized and compared with previous studies of odd-mass silver and indium nuclei.

[NUCLEAR REACTIONS ${}^{108}{Pd} ({}^{3}{He}, d)$ , $E = 27$ ; measured $σ (E_{d}, θ)$ ; ${}^{109}{Ag}$ deduced levels, $l_{p}$ , $S$ , $J$ , $π$ .]

Shell Model in the Lead Region

Chin W. Ma and William W. True

Phys. Rev. C 8, 2313 (1973) - Published 1 December, 1973

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The structure of the low-lying states in ${}^{206}{Pb}$ , ${}^{210}{Pb}$ , ${}^{210}{Po}$ , ${}^{208}{Bi}$ , ${}^{210}{Bi}$ , ${}^{208}{Tl}$ , ${}^{206}{Tl}$ , and ${}^{206}{Hg}$ has been calculated using a conventional shell-model approach with a central Gaussian-shaped interaction plus $P_{2}$ and $P_{3}$ multipole interactions where the $P_{2}$ and $P_{3}$ strengths were varied for each nucleus. The results are compared with the experimental data and other calculations. The agreements between the experimental energies and spectroscopic factors and the calculations are in general good. The agreements between the experimental and calculated $E 2$ and $M 1$ rates in ${}^{206}{Pb}$ and ${}^{210}{Po}$ are also fairly good.

Lifetime Measurements for the First Excited States in ${}^{107}{Cd}$ and ${}^{105}{Cd}$

R. Rougny, M. Meyer-Lévy, R. Béraud, J. Rivier, and R. Moret

Phys. Rev. C 8, 2332 (1973) - Published 1 December, 1973

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We performed delayed coincidence measurements for the first excited levels of ${}^{107}{Cd}$ and ${}^{105}{Cd}$ and obtained the following results: $τ (205 keV, {}^{107}{Cd}) = (1.03 \pm 0.05)$ ns, $τ (321 keV, {}^{107}{Cd}) \leq 60$ ps, $τ (131 keV, {}^{105}{Cd}) = (2.52 \pm 0.15)$ ns. Experimental results are in agreement with the predictions of the intermediate coupling nuclei.

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Proton Spectra from 54.8-MeV Alpha-Particle Reactions: Precompound Emission

Rotational Band Structure of ${}^{22}{Na}$ . I. Electromagnetic Transitions for Levels of $E_{ex} < 4.0$ MeV

Rotational Band Structure of ${}^{22}{Na}$ . II. Neutron-Gamma Coincidence Measurements

Real Potential in Alpha-Nucleus Scattering

3.62-MeV Doublet in ${}^{41}{Ca}$

High-Spin States in the Continuum. I. ${}^{20}{Ne}$

High-Spin States in the Continuum. II. ${}^{24}{Mg}$

Study of $1^{+}$ States in ${}^{48}V$

Lifetime Measurements of Excited States in ${}^{38}K$

Systematic Study of the ${}^{88}{Sr}$ ( ${}^{16}O$ , ${}^{15}N$ ) Reaction

Gamma-Ray-Multiplicity Measurements for ( $α, p$ ), ( $α, α^{'}$ ), ( $d, α$ ), ( $p, α$ ), ( $d, p$ ), and ( $p, p^{'}$ ) Reactions

Isobaric Analogs of ${}^{51}{Ti}$ Levels Observed Through the ${}^{50}{Ti} (p, p^{'} γ) {}^{50}{Ti}$ Reaction

Decay of ${}^{59}{Fe}$ to Levels of ${}^{59}{Co}$

States of ${}^{94}{Mo}$ from the ${}^{95}{Mo} (d, t) {}^{94}{Mo}$ Reaction

Total Energy Associated with Prompt $γ$ -Ray Emission in the Spontaneous Fission of ${}^{252}{Cf}$

Gamma-Gamma Directional Correlation of the 485-934-keV Cascade in ${}^{115}{In}$

${}^{232}{Th}$ Mössbauer Effect Linewidth Measurements

Nuclear Spectroscopy of ${}^{109}{Ag}$ from the ${}^{108}{Pd} ({}^{3}{He}, d)$ Reaction

Shell Model in the Lead Region

Lifetime Measurements for the First Excited States in ${}^{107}{Cd}$ and ${}^{105}{Cd}$

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