The separation of proton and deuteron spin-dependent effects in the 116Sn(d,p)117Sn reaction

The cross section, vector analyzing power, and proton polarization have been measured for the l_n = 0 reaction ¹¹⁶Sn(d, p)¹¹⁷Sn(g.s.) at 8.22 MeV. In addition, cross section and analyzing power data have been obtained at 8.22 MeV for ${}^{116}\text{Sn}\text{(}\text{d}\text{,}\text{d}\text{)}{}^{116}\text{Sn}$ and for ¹¹⁶Sn(d, p)¹¹⁷Sn leading to excited states of ¹¹⁷Sn at 0.159, 0.317, 1.020, 1.179, 1.308 and 1.497 MeV. The cross section and analyzing power for ${}^{117}\text{Sn}\text{(}\text{p}\text{,}\text{p}\text{)}\text{Sn}$ and for ${}^{117}\text{Sn}\text{(}\text{p}\text{,}\text{d}\text{)}{}^{116}\text{Sn}$ leading to the 1.294 MeV state of ¹¹⁶Sn have also been measured at 12.91 MeV. The data for ¹¹⁶Sn(d, p)¹¹⁷Sn(g.s.) have been used to separate the contributions to the analyzing power arising from spin-dependent forces in the proton and deuteron channels. A similar analysis is presented for an $\text{l}{}_{\mathrm{n}}\text{= 0}{}^{90}\text{Zr}\text{(}\text{d, p}\text{)}{}^{91}\text{Zr}$ transition at 11 MeV. Optical-model analyses have been performed for the elastic scattering data. The reaction data have been compared with distorted-wave calculations in order to investigate the validity of various deuteron potentials, as well as to extract spectroscopic information.     

Spin of deep-hole states in 111Sn via the 112Sn(d, t) reaction

Analyzing powers measured in the study of ${}^{112}\text{Sn}\text{(}\text{d}\text{,}\text{t}\text{)}\text{at}\text{40}\text{MeV}$ bombarding energy show strong J-dependence and have been used to clearly assign the spin of a number of low-lying states in the residual nucleus. At high excitation energy (3.5–6 MeV). the inner-hole strength is shared between clearly isolated peaks on one hand and a fragmented structure on the other. This work reports on the determination of the spin of the inner-hole states and consequently on a more precise measurement of the overlapping regions between $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ Subshell components. The analyzing power data shows that the group of peaks located between 3.4 and 4.5 MeV consist of spins $\text{J =}\text{9}\text{2}\text{+}\text{1}\text{2}$, in agreement with the excitation of the $\text{1}\text{g}\text{1}\text{2}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ inner- hole strengths in ¹¹¹Sn. In addition a substantial amount of the $\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ component is observed between 4.5 and 6.0 MeV.The results of the data analysis allow us to clearly eastablish the spreading of the $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ innerhole strength and to a lesser extent the strong fragmentation of the $\text{2}\text{p}\text{1}\text{2}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ inner-hole subshells.     

The γ-decay of the 1g92 and 2p inner-hole states in 111Sn via the 112Sn(3He, αγ) reaction at 32 MeV

The γ-decay of the deeply-bound hole states in ¹¹¹Sn has been investigated at 32 MeV incident energy by means of the ¹¹²Sn(³He, αγ) reaction. The α-particles emitted near 0° were detected in a Si counter located at the image plan of the superconducting solenoidal spectrometer SOLENO. The γ-rays in coincidence with the α-particles were detected by two Ge(Li) detectors located at 90° and 142° with respect to the beam direction, respectively. Energies, spins and decay schemes have been established for the low-lying states up to 2.5 MeV excitation energy in ¹¹¹Sn. The γ-decay of the broad bump, located around 4.2 MeV and previously attributed to neutron pick-up from the inner $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{,}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ neutron. Subshells, reveals the importance of quasiparticle-phonon m the spreading mechanism of the inner-hole strengths. The $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ and 2p strength functions have been deduced from the α-decay of the enhanced structures (3 ≦ E_x≦ 8 MeV). They are compared to the ones measured in previous inclusive neutron pick-up experiments and to those calculated in the framework of the quasiparticle-phonon nuclear model.     

The quadrupole moments of the 5− states in 116Sn, 118Sn and 120Sn

The quadrupole interaction frequencies $\text{ω}{}_0\text{=}\text{3eQ}{}_1\text{V}{}_{\mathrm{zz}}\text{41(21-1)}\text{h}\text{?}$ in the 5^? state of ¹¹⁸Sn have been measured by time differential perturbed angular correlation technique in Sn, Sb and (95% Sn+5% Sb) environments. The ω₀ for ¹¹⁶Sn was determined in Sn environment only. With the help of the known electric field gradient ¹) of Sn in a Sn lattice the quadrupole moments have been deduced as $\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{118}\text{Sn}\text{) = ±0.10(4) b}\text{and}\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{116}\text{Sn}\text{) = ±0.165(60)}\text{b}$. These values together with the known²) quadrupole moment of the analogous 5^? state in ¹²⁰Sn are interpreted in terms of the pure single-particle model. The data exhibit the expected strong systematic variation of Q_I with the number of particles in the h_{$\text{11}\text{2}$}. subshell which is being filled with 1, 3 and 5 neutrons in ¹¹⁶Sn, ¹¹⁸Sn, and ¹²⁰Sn, respectively.     

Nuclear reactions of 118Sn, 121Sb,and 127I with argon ions

Excitation functions have been measured for a number of (⁴⁰Ar, xn), (⁴⁰Ar, pxn), (⁴⁰Ar, 2pxn), and (⁴⁰Ar, 3pxn) reactions induced in ¹¹⁸Sn, ¹²¹Sb and ¹²⁷I over the lab. energy interval 150–280 MeV. Values of the total fusion cross section are obtained and J_crit is deduced. The value of J_crit increases with energy and becomes as large as 110–140?, in reasonable agreement with the yrast limit deduced from the ellipsoidal liquid drop model. The competition between proton and neutron emission from the compound nucleus is examined and $\text{Γ}{}_{\mathrm{<mtext>p</mtext>}}\text{Γ}{}_{\mathrm{<mtext>n</mtext>}}$ is found to increase rapidly with the number of emitted nucleons, thereby imposing severe limits on the production of very neutron deficient miclides via compound nuclear reactions. The effect of very high angular momentum on the excitation functions is examined.     

Study of 11B at high excitations with the 9Be(3He,p)11B and 9Be(α, d)11B reactions

The nucleus ¹¹B has been studied over the excitation energy range from 8.5 MeV to 21.5 MeV with the ⁹Be(³He, p)¹¹B / reaction at / E_{³He = 38 MeV}. The analogs of the parent states in ¹¹Be have been located at 12.56, 12.92, 14.40, 16.44, 17.69, 18.0, 19.15 and 21.27 MeV. A complementary measurement with the ⁹Be(α, d)¹¹B reaction at E_α = 48 MeV demonstrates that the 16.44, 17.69, 18.0 and 19.15 MeV resonances have rather pure isospin $\text{T}{}_{\mathrm{f}}\text{=}\text{3}\text{2}$. The 14.40 MeV state is a strongly isospin-mixed analog of the $\text{5}\text{2}{}^{\mathrm{+}}\text{1.78}\text{MeV}$ state in ¹¹Be. It is argued that spin S = 1 transfer is involved in the excitation of the 16.44 MeV state and its 3.887 MeV parent in ¹¹Be in a two-step stripping process. The $\text{T}{}_{\mathrm{f}}\text{=}\text{1}\text{2}$ states and the lowest three $\text{T}{}_{\mathrm{f}}\text{=}\text{3}\text{2}$ states are compared with the predictions of DWBA utilizing shell-model form factors. It is concluded that the $\text{T}{}_{\mathrm{f}}\text{=}\text{1}\text{2}$ strength is more strongly fragmented than is implied by the calculations of Teeters and Kurath.     

E0 transitions in 114,116,118Sn

Low-lying 0⁺ states have been excited in the (p, p′) reaction via the$\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ isobaric analog resonance in ^114,116Sn and in radioactive decay in ¹¹⁸Sn. From conversion electron measurements, values of $\text{X =}\text{B(}\text{EO}\text{;0}{}^{\mathrm{+}}\text{→ 0}{}_1{}^{\mathrm{+}}\text{)}\text{B(}\text{E}\text{2; 0}{}^{\mathrm{+}}\text{→2}{}_1{}^{\mathrm{+}}\text{)}$ are obtained from the 1953 keV state in ¹¹⁴Sn, 1757 and 2027 keV states in ¹¹⁶Sn and 1758 and 2056 keV states in ¹¹⁸Sn.     

γ-decay of the deeply-bound hole states in 101Pd, 105Pd, 107Pd, 111Sn, 117Sn observed in the (3He, αγ) reaction at 70 MeV

The γ-decay of deep-hole states in ^{101, 105, 107}Pd was studied via the (³He, αγ) reaction at E_³he = 70 MeV and supplemented by data from ^{112, 118}Sn targets to investigate the deep-hole spreading mechanism. The γ-decay pattern for the $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ deep-hole state shows a strong dependence on the spreading width: if the deep-hole state is observed as a sharp peak, it mainly decays to the low-lying $\text{7}\text{2}{}^{\mathrm{+}}$ state by a spin-flip M1 transition with a large M1-E2 mixing ratio; if the deep-hole state is observed as a broad bump, it decays statistically indicating the complete spreading of the hole strength over the underlying states; if the deep-hole state is observed with a structure intermediate between a sharp peak and broad bump, its γ-decay shows both decay patterns.A sharp peak at E_x = 2.396 MeV in ¹⁰¹Pd which carries a large fraction of the $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ hole strength (C²S = 2.0) was found to be a single state having a width of less than 2.5 keV.For the spin-flip M1 transition the destructive interference between the $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ component and the coupled components of the deep-hole state was found in heavily spread states.A quasiparticle-plus-rotor (QPR) model was applied to calculate the fragmentation in the doorway stage for the $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ neutron deep-hole state in the Pd isotopes. A reasonable agreement between the calculation and the experimental results was obtained for the strength fragmentation, for the nucleus ¹⁰¹Pd. However, the large M1-E2 mixing ratio experimentally observed was not reproduced.     

Direct transfer and two-step processes in the 42Ca(α, 3He)43Ca reaction

The ⁴²Ca(α, ³He)⁴³Ca reaction has been studied at 36 MeV incident energy. Angular distributions have been measured from 4° to 42° using a split-pole spectrometer and position sensitive Si detectors, for about 40 levels located up to 6 MeV excitation energy. A local zero-range DWBA analysis has been carried out; l = 3 and 4 assignments are tentatively proposed for levels located above 4 MeV excitation energy, indicating a strong fragmentation of the $\text{1}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ strength between 4 and 6 MeV and the location of the main component of the $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ strength above 6 MeV. A number of weakly excited levels cannot be reproduced by DWBA analysis. Their angular distributions have been compared with the results of coupled-reaction-channel calculations assuming two-step excitation of weak coupling states with a [⁴²Ca¹ ? $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ structure. A reasonable agreement has been obtained, confirming that the two-step process cannot be neglected in the analysis of the (α, ³he) reaction.     

The reaction 55Mn(d, t)54Mn

Neutron pick-up cross sections and vector analyzing powers have been measured for the reaction ⁵⁵Mn($\text{d}$, t)⁵⁴Mn at 17 MeV. The mixture of $\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ to $\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ transfer to the low-lying l_n = 1 states has been found. Evidence of the $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ hole nature of several strong l_n = 3 states above 1 MeV has been obtained.     

The 52Cr(t,p)54 reaction at Et = 15 MeV

Using the ⁵²Cr(t, p)⁵⁴Cr reaction at a bombarding energy of 15 MeV, excitation energies have been measured for 30 levels up to E_x = 5.583 MeV in ⁵⁴Cr. Angular distributions were obtained for all but one of these levels; these have been compared with distorted-wave Born approximation (DWBA) calculations to determine the L-transfer (and hence J^π). The measured cross sections have been compared to the predictions of DWBA calculations that use two-neutron transfer amplitudes from a shell-model calculation with the active neutrons restricted to the $\text{(2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{,}\text{If}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}$ orbitals.     

Study of low-lying states in 92Tc with the 92Mo(3He,t) reaction

States in ⁹²Tc have been studied by means of the ⁹²Mo(³He, t) reaction at 27.5 MeV. The Q-value for this reaction and the excitation energy of the isobaric ground state analogue of ⁹²Mo were determined to be ?7.882 ± 0.030 MeV and 3.813 ± 0.030 MeV respectively. Strongly populated levels in ⁹²Tc appear to belong to configurations arising from the $\text{(1g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{\pi }}\text{(1g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}_{\mathrm{\nu }}{}^{\mathrm{?1}}$ multiplet.     

The distribution of 3p12 strength in 209Bi

An optimized Woods-Saxon potential, which gives excellent fits to the observed proton states in ²⁰⁹Bi and ²⁰⁷Tl, is used to calculate the excitation energy of the unbound $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ proton state in ²⁰⁹Bi. Using the wave functions given by the above potential, the strength of the core-particle interaction is calculated. The effect of the vibration of the core on the fragmentation of the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state is estimated. It is found that the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state at 5.123 MeV loses more than 80% of its strength to five $\text{1}\text{2}{}^{\mathrm{?}}$ collective states in ²⁰⁹Bi and the observed $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state at 3.64 MeV is actually an almost equal mixture of the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ single-proton state and the ($\text{4}{}^{\mathrm{+}}\text{, 1}\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$) collective state.     

Spectroscopic information on 35S and 37S from the (d,p) reaction

The reactions ³⁴S(d,p)³⁵S and ³⁶S(d,p)³⁷S were studied at the incident deuteron energy of 12.3 MeV. Proton groups were analysed using a multi-angle magnetic spectrograph with the resolving power $\text{E}\text{ΔE}\text{≈ 1400}$. Precise Q-values corresponding to 13 states of ³⁵S up to the excitation energy of 7483 keV and 22 states of ³⁷S up to the excitation energy of 6406 keV are presented. The ground-state transition Q-value for the reaction ³⁶S(d,p)³⁷S was found to be 2079.12 ± 0.13 keV. Angular distributions of proton groups corresponding to 6 states in ³⁵S and to 11 states in ³⁷S were analysed using DWBA calculations. Transferred orbital angular momenta and spectroscopic factors were deduced. Summed spectroscopic strengths show that substantial parts of single-particle strengths for $\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{and}\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ in both reactions are exhausted b observed transitions.     

Study of the 91Zr(d, 3He)90Y reaction

The ⁹¹Zr(d, ³He) reaction was studied at a deuteron energy of 28 MeV. Angular distributions were measured from 13° to 47°; l_p values were extracted for the prominent lines of ⁹⁰Y. The l_p values and transition strengths were determined by DWBA analysis. The angular distributions for the $\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ doublet (g.s. and 0.20 MeV state) exhibit the characteristic l = 1 shape. States at 1.42, 1.57, 1.64 and 1.81 MeV were also populated strongly in the (d, ³He) reaction; the 1.42, 1.57 and 1.81 MeV levels contain l= 1 transition strength and are most likely members of the $\text{(π}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ multiplet. The 2.03 MeV state has a characteristic l = 3 angular distribution and is suggested to be the only member of the $\text{(π}\text{f}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}$ sextet to be unambiguously observed in this study, most probably the 5^? or 4^? member. The members of the $\text{(π}\text{g}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)(ν}\text{d}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}$ sextet were populated weakly (less than 100 μb/sr) in this reaction.     

Excitation of the deeply bound g92 neutron hole state in 117Sn by a neutron pickup reaction with 81.7 MeV 3He particles

Neutron hole states have been investigated by neutron pickup reactions on ⁹²Mo, ¹¹⁸Sn, ¹⁴⁰Ce and ²⁰⁸Pb with 81.7 MeV ³He particles. A strong effect of angular momentum mismatch has been observed to reduce the cross section for low-spin orbits. It causes the deeply bound $\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ orbit to appear in the spectrum of the α-particles from the ${}^{118}\text{Sn(τ, α)}{}^{117}$Sn reaction as a strong broad peak. It may provide a nice tool for investigating the coupling mechanism between the deeply bound holes and the core.     

The level structure of 90Mo

High-spin states of the N = 48 nucleus ⁹⁰Mo have been studied using the 33 MeV ⁹⁰Zr(³He, 3nγ) reaction. A previously unknown level structure above the 8⁺ isomer and several new lower-lying levels have been identified. The results are discussed in terms of shell-model calculations which allow four protons in the $\text{2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{and}\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ subshells and two neutron holes in the $\text{1}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{,}\text{or}\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ orbitals.     

Level structure of 48Sc from the 48Ca(p,nγ) reaction

Levels of ⁴⁸Sc up to 3.33 MeV excitation were studied by the reaction ⁴⁸Ca(p,nγ)⁴⁸Sc employing a variety of experimental techniques. A level scheme of ⁴⁸Sc comprising 29 excited states and 54 transitions were determined from the measurements of γ-γ coincidences and γ-ray excitation functions. Within the framework of the statistical compound nucleus model spins and parities of the ⁴⁸Sc levels were assigned from the angular distributions and linear polarizations of the de-excitation γ-rays as well as the excitation functions of the residual levels. From the present experimental results and other available data we tentatively identified some of the levels of the ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^9$, $\text{1}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)}$, ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^9\text{, 2}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$), ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^7\text{, 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$) and ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^7\text{, 1}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$) configurations in addition to the well-known ($\text{π}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{, v}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$) multiplet.     

High-resolution proton scattering on 46Ti

Differential cross sections were measured for ⁴⁶Ti(p, p) and ⁴⁶Ti(p, p₁) at four angles between E_p = 1.5 and 3.1 MeV, with an overall energy resolution of about 300 eV. Spins, parities, total and partial widths were extracted for 144 resonances. Six analogue states were identified. The s-wave states have expected spacing and width distributions, while the $\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ states behave anomalously. The $\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and $\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ strength functions were determined.