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Recently, errors in dosimetry have become of renewed interest together with their effect on the accuracy of estimating on-orbit upset rates . In those studies, the focus was on zero mean errors in the dosimetry-the dosimetry for runs with different ions was assumed to be measured with error, but that these errors were zero mean. There is anecdotal evidence, however, that the errors in dosimetry may not be zero mean. From a single set of tests it is impossible to estimate the magnitude of this non zero-mean effect. From multiple tests of the same part, it is possible if it is assumed that the true cross-section of the part does not change, and that the fluctuations around the common non zero mean are independent. We show non zero-mean errors in dosimetry of between 10 and 30% in data sets that were not collected specifically for this study. The presence of non zero-mean errors can have a large effect on the uncertainty in the experimental determination of a part's cross-section. When estimating upset rates for a device, users of experimental test data must use their best judgement as to the magnitude of the non zero-mean error that may be present.

For precise measurements of nuclear-reaction spectra using a beam from an accelerator, a high-resolution magnetic spectrometer is a powerful tool. The full capability of a magnetic spectrometer, however, can be achieved only if the characteristics of the beam coming from the accelerator are matched to those required by the spectrometer by properly adjusting the beam line conditions. The matching methods, lateral dispersion matching, focus matching and also the kinematic correction compensate the spectrum line-broadening effects caused by the beam momentum spread and reaction kinematics. In addition, angular dispersion matching should be performed if good resolution of the scattering angle is important. Diagnostic methods developed to realize these matching conditions for the spectrometers K600 at IUCF and Grand Raiden at RCNP are presented.

Assuming isospin T is a good quantum number, the analog states of the low-lying states in T z = ′ (T 0 +1) nuclei can be found as excited T 0 +1 states in T z = ′T 0 nuclei. Therefore, if To + 1 states are identified in theexcited region of T z = ′T 0 nuclei, the structure of unstable nuclei with T z = ′(T 0 + 1) can be deduced. We measured and compared the transition strengths to pairs of excited analog states in inelastic and charge-exchange reactions on the same target nucleus. The T values of these analog states were identified by using the fact that the transition strengths to them are different depending on T. The identification of T = ½ and 3/2 nature of analog M1 and GT states in the mirror nuclei pair 2 7 Al and 2 7 Si is reported by comparing the transition strengths in high-resolution 2 7 Al(p,p') and 2 7 Al( 3 He, t) 2 7 Si reactions at 0°. The identified T = 3/2 states are analogous to the low-lying states of 2 7 Mg, which plays an important role in rp-process of nucleosynthesis.

Demand for near-zero-degree measurements using a magnetic spectrometer is increasing with the growing interest in the study of L ¼ 0 nuclear excitation modes. For the precise determination of scattering angles near 08, both horizontal and vertical scattering angle components have to be measured with good accuracy. It is, however, not easy to realize a good vertical angle resolution using modern high-resolution magnetic spectrometers with small vertical angle magnifications, like ‘‘Grand Raiden’’ at RCNP or ‘‘K600’’ at IUCF. A new ion-optical mode which enables the precise determination of vertical components of scattering angles from vertical position measurements in the focal plane has been developed for these spectrometers. For the wide range of spatial as well as momentum acceptances, vertical angle resolution better than 8 mrad is realized for Grand Raiden at RCNP. # 2001 Elsevier Science B.V. All rights reserved.

The ( α , 8 He) reaction is used to measure level energies in very proton rich nuclei. The results allow a more reliable calculation of the reaction flow in the rp and αp processes in Novae, X-ray pulsars and X-ray bursts.

We present zero-degree differential cross sections and transverse spin-transfer coefficients D{sub NN}(0{degree}) for the {sup 17,18}O({rvec p},{rvec n}){sup 17,18}F reactions at E{sub p}=118 MeV. For the transition to the {sup 17}F(g.s.) to which several multipoles contribute, the measured D{sub NN}(0{degree})={minus}0.13{plus_minus}0.05 is used to separate the Fermi and Gamow-Teller contributions at 0{degree}. The empirical Gamow-Teller strengths and the Fermi strengths are employed to estimate the solar neutrino absorption cross section in {sup 17}O and {sup 18}O. {copyright} {ital 1999} {ital The American Physical Society}

The position of the K 17 2 shell orbital plays a significant role in determining the shell correction energy and hence the stability of the superheavy elements. A deformed component of this orbital, 1 2 + [880] , comes down in energy with increasing prolate deformation, and is expected to have an excitation energy of less than 2 MeV in nuclei with N = 153. We have performed the reaction 248Cm(4He,3He) using 98.5-MeV alpha particles from the IUCF cyclotron to populate high-l states in 249Cm. this reaction preferentially excites high-l states because of the angular momentum mismatch. The emerging 3He ions were momentum analyzed with the K600 magnetic spectrometer. Spectra were measured at θcm = 4.1°, 6.1°, 10.2°, 12.2°, and 16.2° The spectrometer was calibrated with the 208Pb(4He,3He) and 232Th(4He,3He) reactions at the same incident energy. Three strong peaks were identified in the 248Cm(4He,3He) spectrum and these have been given tentative assignments: 593 keV, 15 2 11 2 − [725] ; 1560 keV and 1898 keV, 17 2 1 2 + [880] , 15 2 13 2 − [716] . Our data do not distinguish between the 17 2 + and 15 2 − assignments.

Analyzing powers for {rvec p}p{r_arrow}pn{pi}{sup +} were measured for the first time close to threshold at beam energies that yield maximum pion momentum fractions ({eta}{equivalent_to}p{sub c.m.}{sup max}/m{sub {pi}}c) of {eta}=0.22, 0.42, and 0.50, and enable a decomposition of the low order partial waves. Cross sections were measured at seven different beam energies with {eta}=0.07, 0.17, 0.22, 0.28, 0.34, 0.42, and 0.50. The analysis shows that pion s-wave channels dominate the reaction. The p-wave channel containing the {Delta} resonance contributes, at {eta}=0.22, less than one-tenth of the total cross section and less than one-third of the total cross section at {eta}=0.42 and 0.50. The nonresonant p-wave channel contributes less than 1{percent} of the cross section at these three energies. {copyright} {ital 1998} {ital The American Physical Society}

Analyzing powers were measured and used to quantify the observation that s-wave processes dominate near threshold. Values of Ay(θπ,φπ=0°) are presented for η values of 0.22, 0.42 and 0.50. Maximum analyzing powers AN0 are equal to −0.13, −0.24, and −0.28, respectively. A partial wave analysis, made possible by the new analyzing powers and available cross sections, indicates that the s-wave contribution to the cross section constitutes about 91% of the total cross section at η=0.22, or 300 MeV. It decreases to about 75% for η=0.5.

A complete set of spin observables was measured for the 2 H(p,n)2p reaction at 200 MeV at the Indiana University Cyclotron Facility (IUCF) with the high intensity polarized ion source (HIPIOS) and the Indiana Neutron Polarization Facility (INPOL). The incident proton beam was delivered successively in each of the three spin states, normal ( N ), sideways ( S ), and longitudinal ( L ). Two large-volume neutron polarimeters placed along the 0° and 24° beam lines measured the polarizations of the emitted neutrons in each of the three spin states. The measured cross sections and spin observables are compared with three-body Faddeev calculations, which generally agree with the data. The ratio of the longitudinal to transverse response is suppressed rather than enhanced, as predicted by some models.

We measured the analyzing power and the efficiency of a new neutron polarimeter that was designed to measure G/sub E//sup n/, the neutron electric form factor. The polarimeter calibration was performed as experiment E377 at the Indiana University Cyclotron Facility (IUCF) with the /sup 14/C(p/spl I.oarr/,n/spl I.oarr/)/sup 14/N reaction at proton beam energies of 124.0, 164.6, and 199.7 MeV without any shielding material ahead of the polarimeter; in addition, at 164.6 MeV we measured the analyzing power with 10 cm of lead, sandwiched between 3.5-cm iron plates, ahead of the polarimeter.

A neutron facility for the study of (n,p) reactions was set up at the Indiana University Cyclotron Facility. The neutrons were produced by the reaction 7 Li(p,n) 7 Be. The energy spread of the neutron beam is dominated by the thickness of the 7 Li production target. At the (n,p) target the collimated neutron-beam intensity is about 10 5 n/s/cm 2 for a 1 μA proton beam at 120 MeV on a 7 Li target 100 mg/cm 2 thick. The distance between the neutron production target and the (n,p) target, 3.14 m, makes it possible by time-of-flight to eliminate neutrons degraded below the maximum energy by scattering. Protons from the (n,p) reaction are detected simultaneously at three laboratory angles (7.5°, 12.5°, and 17.5°), in three particle telescopes each consisting typically of three hyperpure Ge elements. All three telescopes are mounted in a common cryostat. Spectra are obtained at other angles including zero by magnetically deflecting the (n,p) protons. Spectra recorded at E n = 118 MeV for (n,p) reactions on several light nuclei are presented.

The ${}^{28}\mathrm{Si}(\ensuremath{\alpha}{,}^{8}\mathrm{He}{)}^{24}\mathrm{Si}$ reaction has been used to measure the energies of the first two excited states in ${}^{24}$Si. The excitation energies were found to be $1.879\ifmmode\pm\else\textpm\fi{}0.011$ and $3.441\ifmmode\pm\else\textpm\fi{}0.010\mathrm{MeV}$. These data allow for the first time the calculation of the stellar reaction rate of ${}^{23}\mathrm{Al}(p,\ensuremath{\gamma}{)}^{24}\mathrm{Si}$ on the basis of experimental information. This reaction is of considerable interest, since it might lead to a decrease of the ${}^{22}$Na production in nova explosions, and solve the discrepancy between the ${}^{22}$Na yield predictions of nova models and recent COMPTEL observations. We show, however, that the temperatures and densities required for a significantly reduced ${}^{22}$Na yield are not reached in current nova models.

The isoscalar giant dipole resonance (ISGDR) in ${}^{208}\mathrm{Pb}$ has been investigated using inelastic scattering of 200 MeV $\ensuremath{\alpha}$ particles at and near 0\ifmmode^\circ\else\textdegree\fi{} where the angular distribution of the ISGDR can be clearly differentiated from those of other modes. The ``difference of spectra'' technique was employed to separate the ISGDR from the high-energy octupole resonance (HEOR). These data provide the clearest evidence yet for the ISGDR adjacent to the HEOR. With these results, all expected isoscalar $\ensuremath{\lambda}\ensuremath{\le}3$ resonances in ${}^{208}\mathrm{Pb}$ have been identified.

We measured the spin observables ${A}_{y},$ $P$, and ${S}_{{\mathrm{NN}}^{\ensuremath{'}}}$ for the ${}^{208}$Pb${(p,n)}^{208}$Bi reaction at 135 MeV at laboratory angles of 0$\ifmmode^\circ\else\textdegree\fi{}$, 3$\ifmmode^\circ\else\textdegree\fi{}$, 6$\ifmmode^\circ\else\textdegree\fi{}$, and 9$\ifmmode^\circ\else\textdegree\fi{}$. The overall energy resolution was about 1 MeV. Data for ${S}_{{\mathrm{NN}}^{\ensuremath{'}}}$ are compared with distorted-wave impulse-approximation calculations that use random-phase approximation wave functions. Comparisons are also made for the ${}^{48}$Ca${(p,n)}^{48}$Sc reaction. The agreement between these calculations and the data is generally good, after adjustment of the nucleon-nucleon interaction in the random-phase approximation calculations to place the 0${}^{+}$ isobaric-analog states at the correct excitation energies. A single adjustment of the nucleon-nucleon force works for both target nuclei.

Cross-section excitation-energy spectra and angular distributions were measured for the $^{2}\mathrm{H}$(p,n)2p reaction at 135 MeV in 6\ifmmode^\circ\else\textdegree\fi{} steps from 0\ifmmode^\circ\else\textdegree\fi{} to 30\ifmmode^\circ\else\textdegree\fi{} (laboratory), using the beam swinger facility at the Indiana University Cyclotron Facility. The target was a 12.8 mg/${\mathrm{cm}}^{2}$ foil of ${\mathrm{CD}}_{2}$. Neutron energies were measured by the time-of-flight method using large-volume plastic scintillator arrays at flight paths of 91 m. The overall energy resolution was 260 keV. The 0\ifmmode^\circ\else\textdegree\fi{} spectrum is dominated by a large peak near 0 MeV of relative energy in the final 2p system; this peak corresponds to the two protons in the $^{1}$${\mathit{S}}_{0}$ state. The wider-angle spectra are dominated by a broad peak centered at 10 to 20 MeV of excitation which is the quasifree scattering peak. The spectra are compared with impulse approximation and three-body Faddeev calculations. \textcopyright{} 1996 The American Physical Society.

Gamow-Teller (1{sup +}) strength was studied in {sup 38}K with the analog reactions {sup 38}Ar({ital p},{ital n}){sup 38}K and {sup 38}Ca({beta}{sup +}){sup 38}K. The ({ital p},{ital n}) reaction was performed at 135 MeV using the beam swinger facility at the Indiana University Cyclotron Facility. Excitation-energy spectra were measured at 15 angles between 0{degree} and 63{degree}. Neutron energies were measured by the time-of-flight method using a large-volume plastic scintillator array at a flight path of 131.0 m. The overall energy resolution was 280 keV. Gamow-Teller (GT) strength was extracted from the measured angular distributions to discrete 1{sup +} final states. The {beta}-decay experiment was performed with the ISOLDE on-line mass separator facility at CERN. The {beta}-decay branching ratios were determined by observing the delayed {gamma} decays of {sup 38}K. These decay measurements provide an increased sensitivity over earlier measurements and are able to extract transitions down to {approximately} 10{sup {minus}4} of the strongest branches. The {ital B}(GT) values obtained from the two experiments are generally in good agreement, except for the transition to the first 1{sup +} state at 0.46 MeV, which is observed to be much weaker in the ({ital p},{ital n}) measurements. The {beta}-decay measurements provide good resolution andmore » high sensitivity while the ({ital p},{ital n}) measurements extend the {beta}-decay measurements to higher excitation energies. The summed {ital B}(GT) strength is {approximately}50{percent} of the simple Ikeda sum rule. The distribution of GT strength is in reasonable agreement with that predicted from a shell-model calculation using {open_quote}{open_quote}effective{close_quote}{close_quote} GT operators. {copyright} {ital 1996 The American Physical Society.}« less

We describe how polarization-transfer data can be used to identify J π = 0 − , 1 − and 2 − components of the Δ T = 1, Δ L = 1, Δ S = 1 isovector “spin-dipole” resonance seen in charge-exchange reactions at medium energies. Data for 40 Ca(p,n) are compared with distorted-wave impulse approximation (DWIA) calculations with theory of finite Fermi systems (TFFS) wave functions.

The isoscalar giant dipole resonance (ISGDR) in 208 Pb has been investigated using inelastic scattering of 200 MeV α particles at and near 0° where the angular distribution of the ISGDR can be clearly differentiated from other modes. The “difference of spectra” technique was employed to separate the contribution from the high-energy octupole resonance (HEOR). Preliminary angular distribution data provide clear evidence for the ISGDR adjacent to the HEOR.

The {sup 20}Ne({ital p},{ital n}){sup 20}Na reaction at 135 MeV was studied experimentally using the beam-swinger neutron time-of-flight facility at the Indiana University Cyclotron Facility. Backgrounds {similar_to}10{times} lower than an earlier experiment were obtained using the ``stripper loop`` storage ring to achieve {similar_to}2 {mu}s between beam bursts. We were able to see a weakly excited state at 2.65 MeV in {sup 20}Na with a {Delta}{ital l}=2 angular distribution. The angular distribution is consistent with a DWIA calculation assuming a 3{sup +} final state. The characteristics of this state are important to know for considerations of possible breakout in the hot CNO cycle in supernovae explosions.

The Sn-120(He-3,t)Sb-120 charge-exchange reaction has been investigated at E(He-3) = 200 MeV and theta approximate to 0 degrees to study neutron decay from the isobaric analog state at E(x)=10.20 MeV in Sb-120. The low-energy neutrons (average energy similar to 0.85 MeV) were detected in coincidence with tritons observed in the focal plane of a high-resolution magnet spectrometer. Four small deuterated NE230 scintillation detectors were mounted at distances of 9.5 cm from the target resulting in an overall neutron detection efficiency including solid angle of >1%. This efficiency was obtained by combining the measured dependence on neutron energy with a calculated neutron evaporation spectrum. From the measured ratio of coincidence to singles events a branching ratio of >86% was deduced for neutron decay. The observation of isospin-violating neutron decay with a branching ratio close to 100% is in agreement with the expectation that the escape width (Gamma up arrow) of the isobaric analog state in Sb-120 is small compared to its spreading-width (Gamma down arrow). Triton spectra measured in coincidence with gamma rays from the deexcitation of the final nucleus display pronounced structures related to the thresholds for neutron emission, in agreement with the characteristics of calculated evaporation spectra.

Gadolinium oxysulfide doped with terbium was exposed to 45 MeV proton irradiation in the specially designed High Energy Materials Irradiation Chamber at the Indiana University Cyclotron Facility. This exposure was accomplished to determine the functional relationship between sample temperature and fluorescence intensity. Luminescent intensity dropped to half of the measured 113°C value at a temperature of 133°C. This effect was analyzed to determine the activation energy for radiationless transition. This result will provide a good understanding of the radiation hardness and spectral response for this fluor for possible use in the future development of a high energy accelerator beam positioning system.

Motivated by the need of spectroscopic data to better understand the astrophysical rp-process, we developed a new experimental method using the Grand Raiden magnet spectrometer to study protin rich nuclei with α and 3 He induced reactions. First results of the 24 Mg( 4 He, 6 He) 22 Mg reaction at 206 MeV and 0° are presented, showing states relevant for resonant reaction rate calculations of the proton capture 21 Na(p,γ) 22 Mg and the 18 Ne(α,p) 21 Na reaction which controls the break-out of the hot CNO cycles at X-ray burst conditions.

The Gamow-Teller transition strengths, $B$(GT), in $pf$-shell nuclei are of interest in nuclear physics as well as in nuclear astrophysics. A high-resolution (${}^{3}\mathrm{He},t$) charge-exchange (CE) reaction was performed on the ${T}_{z}=+1$ nucleus ${}^{54}$Fe at 0${}^{\ensuremath{\circ}}$ and at an intermediate incident energy of 140 MeV/nucleon for the study of precise GT transition strengths to the final ${T}_{z}=0$ nucleus ${}^{54}$Co. By applying dispersion matching techniques for a high-quality ${}^{3}$He beam at RCNP, an energy resolution of 21 keV and an angular resolution of 5 mr were realized. The bumplike structure of the GT resonance observed in low-resolution CE reactions at around the excitation energy (${E}_{x}$) of 10 MeV was resolved in individual $L$ $=$ 0, GT states. Excitation strengths were obtained for these GT states. If the ${R}^{2}$ value that is defined by the ratio between GT and Fermi unit cross sections is known, the $B$(GT) values can be determined from the excitation strengths. For the derivation of the ${R}^{2}$ value, the ``merged analysis'' combining the GT strength distribution from the ${}^{54}$Fe(${}^{3}\mathrm{He},t$)${}^{54}$Co study and the half-life from a ${}^{54}$Ni $\ensuremath{\beta}$ decay was used, where $T=1$ isospin symmetry for $A=54$ isobars was assumed. The GT strengths were compared with a shell-model calculation using the GXPF1 interaction. The final GT states can have the isospin values $T$ $=$ 0, 1, and 2. The isospin $T$ of each GT state observed in the $8.3\ensuremath{\le}{E}_{x}\ensuremath{\le}12.0$ MeV region of the ${}^{54}$Fe(${}^{3}\mathrm{He},t$)${}^{54}$Co spectrum was identified by comparing the excitation strength with that of corresponding $M1$ state observed in a ${}^{54}$Fe($p,{p}^{\ensuremath{'}}$)${}^{54}$Fe experiment. The $B$(GT) values of the states identified to have $T=2$, in particular, are of importance for the calculation of the electron capture rates at the core-collapse stage of presupernovae. The $B$(GT) strengths were further compared with $B(M1)$ strengths measured in the ${}^{54}$Fe($e,{e}^{\ensuremath{'}}$)${}^{54}$Fe reaction. In the $M1$ excitation using an electromagnetic probe, isoscalar (IS) and isovector (IV) orbital type operators are active in addition to the IV spin type operator that mediates the GT transitions. The contributions of the IS and IV orbital terms were studied by calculating the ratio of the strengths of analogous $M1$ and GT transitions.

In a program to determine proton induced damage and its effect on relative scintillation efficiency for various yttrium and gadolinium based fluors, materials were selected for high efficiency, fast prompt fluorescence response, and minimal delayed fluorescence. These fluors were exposed to a 45 MeV proton beam at the Indiana University Cyclotron Facility (IUCF) using the High Energy Materials Irradiation Chamber (HEMIC). Data obtained at IUCF indicates that the measured 45 MeV proton dose to reduce the fluorescence brightness to half its original value (half brightness dose - N 1 2 ) was found to be 2.2 to 7.3 times larger than that measured at 3 MeV. The corresponding average 45 MeV half brightness dose values, measured at elevated temperature, were 4.0 to 83.7 times larger than at 3 MeV. Although the interaction cross section for 45 MeV protons is smaller than at 3 MeV, each of the resulting high energy reactions causes more damage to the fluor. This research was completed as part of the Fluorescent Materials and Bonding: Extended Energy program under contract DASG60-90-C-0144 for the U.S. Army Space and Strategic Defense Command (USASSDC).

Double differential cross sections for ([ital p],[ital n]) quasifree scattering on [ital p]-shell nuclei, [sup 6,7]Li, [sup 10,11]B, and [sup 12,13]C, have been measured at an incident proton energy of 186 MeV between [theta][sub lab]=[theta][degree] and [theta][sub lab]=50[degree] in steps of 5[degree]. The normal polarization transfer coefficient, analyzing power, and induced polarization were also measured at [theta][sub lab]=0[degree], 15[degree], and 20[degree] using an incident proton beam of transverse polarization. Calculations by some competing quasifree models are presented and compared with the experimental results.

The spin observable D NN ′ ( θ ) was measured for ( p , n ) at 135 MeV on 16 O, 40 Ca, 48 Ca, and 208 Pb. Data for 16 O and 40 Ca are compared with distorted-wave impulse approximation (DWIA) calculations with Tamm-Dancoff (TDA) wave functions; the D NN ′ data generally agree with the J π distribution (O − , 1 − , 2 − ) predicted for the “spin-dipole” resonance.

The level structure of the odd-odd nucleus 224Ac has been studied by measuring radiations associated with the α-decay of the 22 h 228Pa isotope. The 228Pa activity was produced by the irradiation of Th metal foils with 45 MeV protons. The Pa fraction was subsequently chemically isolated. Alpha singles as well as αγ-, αe-, αγγ-coincidence measurements were performed with thin sources, and a partial level scheme was deduced for the 224Ac. Although the spins of the observed levels have not been uniquely determined, the data establish positive- and negative-parity bands which exhibit characteristics of parity doublets. In particular, two bands at 354 and 360 keV appear to be members of a parity doublet. The similarity in the hindrance factors of α-decays to the 354 and 360 keV levels, which have opposite parities, indicates that the wavefunctions of the two states are very similar, which is a signature for octupole deformation.

Neutron time-of-flight spectra were measured for the [sup 14]C([ital p],[ital n])[sup 14]N reaction at 135 MeV with the beam-swinger system at the Indiana University Cyclotron Facility. Excitation-energy spectra and differential cross sections for the observed excitations in this reaction were extracted over the momentum transfer range from 0 to 2.5 fm[sup [minus]1]. The goal of this work is to identify the 4[sup [minus]] states in [sup 14]N and to determine the isovector transition strengths. The identification of the 4[sup [minus]] states is based on comparisons of the theoretical differential cross sections, performed in a DWIA formalism, with the experimental cross sections and with information from the [sup 14]C([ital e],[ital e][prime]) reaction. Isospin assignments are based primarily on comparisons of the measured ([ital p],[ital n]) and ([ital e],[ital e][prime]) isovector strengths. Candidate 4[sup [minus]] states are identified at excitation energies of 8.49 MeV ([ital T]=0), 13.76 MeV and 19.49 MeV ([ital T]=1), and 26.61 MeV ([ital T]=2) in the [sup 14]C([ital p],[ital n])[sup 14]N reaction, and the isovector strengths for the transitions leading to these states re extracted. The observed excitation energies and isovector strengths are in good agreement with the analog [ital T]=1 and [ital T]=2 4[sup [minus]] states observedmore » in the ([ital e],[ital e][prime]) reaction. The experimental results are compared with results from shell-model calculations.« less

The ([sup 3]He,[ital t]) charge-exchange reaction has been studied at [ital E]([sup 3]He)=200 MeV and angles near 0[degree] on targets of [sup 117]Sn and [sup 120]Sn. Fragmentation of the giant Gamow-Teller resonance into separate components of the particle-hole type has been observed in good agreement with theoretical predictions. These components are connected with what is usually referred to in the literature as direct-, core-polarization-, and back-spin-flip Gamow-Teller strength. The observed cross sections near [theta]=0[degree] suggest contributions from the isovector spin-flip interaction as well as the isovector tensor interaction. A theoretically predicted configuration splitting of the main Gamow-Teller component into two components involving the 1[ital h][sub 11/2] neutron orbital could not uniquely be identified. The data are compatible, though, with such a splitting since the observed widths of the main Gamow-Teller components in [sup 117]Sb and [sup 120]Sb exceed the predicted splittings.

The $^{12}\mathrm{C}$(n,p${)}^{12}$B reaction was studied using the white neutron source at the Los Alamos Meson Physics Facility/Weapon Neutron Research Center with a continuous incident neutron energy from 60 to 260 MeV. Double differential cross sections were measured in the angular range 11\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$\ensuremath{\le}37\ifmmode^\circ\else\textdegree\fi{}. Using the neutron time-of-flight facility at the Indiana University Cyclotron Facility, we also studied the $^{12}\mathrm{C}$(p,n${)}^{12}$N reaction at ${\mathit{E}}_{\mathit{p}}$=186 MeV and the $^{12}\mathrm{C}$(p\ensuremath{\rightarrow},n\ensuremath{\rightarrow}${)}^{12}$N reaction at ${\mathit{E}}_{\mathit{p}\ensuremath{\rightarrow}}$=160 and 186 MeV. Double differential cross sections were measured between ${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$=0\ifmmode^\circ\else\textdegree\fi{} and ${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$=50\ifmmode^\circ\else\textdegree\fi{} in 5\ifmmode^\circ\else\textdegree\fi{} steps. Spin observables ${\mathit{D}}_{\mathit{N}\mathit{N}}$, ${\mathit{A}}_{\mathit{Y}}$, and P were measured at ${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$=5\ifmmode^\circ\else\textdegree\fi{},9\ifmmode^\circ\else\textdegree\fi{},13\ifmmode^\circ\else\textdegree\fi{} with ${\mathit{E}}_{\mathit{p}\ensuremath{\rightarrow}}$=160 MeV and ${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$=15\ifmmode^\circ\else\textdegree\fi{},20\ifmmode^\circ\else\textdegree\fi{} with ${\mathit{E}}_{\mathit{p}\ensuremath{\rightarrow}}$=186 MeV. Angular distributions of differential cross section and spin observables for low-lying transitions in the residual nuclei are compared with disorted-wave impulse approximation (DWIA) calculations. A multipole decomposition analysis was performed to study the giant dipole and giant spin-dipole resonances. The contributions of the quasifree reaction in the giant resonance region was subtracted. The empirical results of energy distributions for dipole (\ensuremath{\Delta}L=1) transition are compared with DWIA calculations using nuclear structure information obtained with a conventional shell model and also with a random phase approximation.

Elastic scattering of protons from [sup 90]Zr in the energy range [ital E][sub [ital p]]=9.8 to 135 MeV is analyzed using a dispersive optical model potential (OMP). In this analysis, a dispersion relation connects the volume integrals of the imaginary and the real parts of the OMP. Best-fit dispersive OMP parameters are obtained from fits to experimental cross section and analyzing power data at each energy, while the volume integrals of the imaginary potential and dispersive correction terms are fixed at the empirical values obtained in the individual proton elastic scattering analyses from 9.8 to 135 MeV. Predictions of the cross section and analyzing power angular distributions from the best-fit dispersive OMP and conventional OMP are obtained, and give similar quality fits to data. A dispersive OMP with parameters that show a smooth energy dependence are determined from fits to the entire data set. Comparison of cross sections and analyzing powers calculated by the dispersive OMP with experimental data at 160 and 185 MeV is also presented. The dispersive OMP with a smooth energy dependence is extended to the negative energy region with the guidance of the known first single-particle and single-hole state energies near the Fermi energy, [ital E][submore » [ital F]]=[minus]6.8 MeV, to provide parameters for the shell model potential. This analysis also provides estimates for single-particle and hole energies [ital E][sub [ital n][ital l][ital j]], root-mean-square radii [ital R][sub [ital n][ital l][ital j]], expectat ion values of the effective mass [l angle][ital m][sup *]/[ital m][r angle][sub [ital n][ital l][ital j]], occupation probabilities [ital N][sub [ital n][ital l][ital j]], absolute spectroscopic factors [ital S][sub [ital n][ital l][ital j]], and spectral functions [zeta][sub [ital n][ital l][ital j]]([ital E][sub [ital x]]) for proton single-particle and single-hole orbits in [sup 90]Zr.« less

The $^{10}\mathrm{B}$(p,n${)}^{10}$C reaction was studied using the Indiana University Cyclotron Facility (IUCF) neutron time-of-flight facilities at an incident proton energy of 186 MeV between ${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$=0\ifmmode^\circ\else\textdegree\fi{} and ${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$=50\ifmmode^\circ\else\textdegree\fi{} in steps of 5\ifmmode^\circ\else\textdegree\fi{}. The IUCF neutron polarimeter was also used to measure polarization observables at ${\mathrm{\ensuremath{\theta}}}_{\mathrm{lab}}$=0\ifmmode^\circ\else\textdegree\fi{}, 15\ifmmode^\circ\else\textdegree\fi{}, and 20\ifmmode^\circ\else\textdegree\fi{} using an incident transverse polarized proton beam. Data for transitions to excited states in $^{10}\mathrm{C}$ below 7 MeV are presented. A multipole decomposition analysis is presented for unresolved states up into the continuum. Distorted wave calculations are presented for positive and negative parity transitions which are compared with data to assess spectroscopies of the $^{10}\mathrm{C}$ excited states.

High-spin, stretched-state excitations were studied in the $^{38}\mathrm{Ar}$(p,n${)}^{38}$K reaction at 135 MeV with the beam-swinger system at the Indiana University Cyclotron Facility. Neutron kinetic energies were measured by the time-of-flight technique with large-volume plastic-scintillator neutron detectors at flight paths ranging from 81 to 131 m. Overall time resolutions of about 825 ps provided energy resolutions from 320 to 450 keV. The target was a 4-cm-long gas cell filled to \ensuremath{\sim}3 atm absolute. Angular distributions were extracted for the low-lying excitations observed at wide angles. A known ${7}^{+}$ state at ${\mathit{E}}_{\mathit{x}}$=3.5 MeV was observed, plus two states at 5.3 and 5.9 MeV, which are tentatively identified as ${6}^{\mathrm{\ensuremath{-}}}$ excitations, based on comparisons with distorted wave Born approximation and sdpf shell-model calculations. The $^{38}\mathrm{K}$ spectrum is in reasonable agreement with the shell-model calculations. In contrast to the analysis of 80 MeV $^{40}\mathrm{Ca}$(d,\ensuremath{\alpha}${)}^{38}$Ar measurements, these results do not indicate a significant problem for the nuclear shell model near A=40.

The polarization ({ital P}) and the analyzing power ({ital A}) were measured for the {sup 48}Ca({ital p},{ital n}){sup 48}Sc reaction at 135 MeV. Of special interest is the difference ({ital P}{minus}{ital A}) in these two quantities for the transitions to the two 1{sup +} states at 2.52 and 16.8 MeV. Because of the difference in the predominant one-particle--one-hole configurations for these two states, viz., ({ital f}{sub 7/2},{ital f}{sub 7/2}{sup {minus}1}) and ({ital f}{sub 5/2},{ital f}{sub 7/2}{sup {minus}1}), respectively, qualitative differences in {ital P}{minus}{ital A} are predicted based on nonlocal exchange contributions. The experimental results agree qualitatively with these predicted differences, but there are significant quantitative differences indicating that other effects contribute as well.

Elastic scattering of deuterons from $^{208}\mathrm{Pb}$ in the energy range ${\mathit{E}}_{\mathit{d}}$=9 to 79.2 MeV is analyzed using a dispersive optical model potential (OMP). In this analysis, a dispersion relation connects the volume integrals of the imaginary and the real parts of the OMP. Best-fit dispersive OMP parameters are obtained from fits to experimental cross-section and analyzing power data at one energy, and dispersive OMP parameters with a smooth energy dependence are determined from fits to the entire data set. Comparisons, showing fits of similar quality, of the predictions of the cross sections and analyzing powers given by the best-fit dispersive OMP and standard OMP are presented. Dispersive OMP parameters with a smooth energy dependence also give a good description of the experimental data.

Isovector stretched-state excitations were studied in the (p,n) reaction at 136 MeV on the self-conjugate s-d shell nuclei $^{20}\mathrm{Ne}$, $^{24}\mathrm{Mg}$, $^{28}\mathrm{Si}$, and $^{32}\mathrm{S}$. The measurements were performed in three separate experiments using the beam-swinger neutron time-of-flight facility at the Indiana University Cyclotron Facility. Neutrons were detected in large-volume plastic scintillation detectors located in three detector stations at 0\ifmmode^\circ\else\textdegree\fi{}, 24\ifmmode^\circ\else\textdegree\fi{}, and 45\ifmmode^\circ\else\textdegree\fi{} with respect to the undeflected beam line; the flight paths varied from 75 to 134 m. Overall time resolutions of about 825 ps provided energy resolutions of about 320 keV in the first two stations and about 425 keV in the third station. Both (${\mathit{d}}_{5/2}$,${\mathit{d}}_{5/2}^{\mathrm{\ensuremath{-}}1}$)${5}^{+}$ 0\ensuremath{\Elzxh}\ensuremath{\omega} and (${\mathit{f}}_{7/2}$,${\mathit{d}}_{5/2}^{\mathrm{\ensuremath{-}}1}$)${6}^{\mathrm{\ensuremath{-}}}$ 1\ensuremath{\Elzxh}\ensuremath{\omega} stretched-state excitations are observed in the (p,n) reaction on $^{20}\mathrm{Ne}$, $^{24}\mathrm{Mg}$, and $^{28}\mathrm{Si}$.For the (p,n) reaction on $^{32}\mathrm{S}$, only the ${6}^{\mathrm{\ensuremath{-}}}$ strength is observed. The states are identified by comparison of the extracted angular distributions with distorted-wave impulse-approximation calculations and by comparison with known analog states observed in inelastic scattering. In the $^{20}\mathrm{Ne}$ and $^{24}\mathrm{Mg}$(p,n) reactions, the majority of the ${5}^{+}$ strength is observed in single states at low excitation energy; the strengths are described well by full s-d shell-model calculations. A weak ${5}^{+}$ state is observed in the $^{28}\mathrm{Si}$(p,n${)}^{28}$P reaction that corresponds to the strength expected if there is \ensuremath{\sim}1/3 of a hole in the ${\mathit{d}}_{5/2}$ proton orbital. The ${6}^{\mathrm{\ensuremath{-}}}$ 1\ensuremath{\Elzxh}\ensuremath{\omega} strength is fragmented in all four reactions. Less than 60% of the strength expected in the extreme single-particle-hole model is observed in each case. The observed ${6}^{\mathrm{\ensuremath{-}}}$ strengths and distributions in the $^{28}\mathrm{Si}$ and $^{32}\mathrm{S}$(p,n) reactions are described well by large-basis shell-model calculations.

New cross-section and analyzing-power data are presented for elastic and inelastic scattering of 200-MeV protons from $^{7}\mathrm{Li}$, which has a ${\frac{3}{2}}^{\ensuremath{-}}$, $T=\frac{1}{2}$ ground state. A microscopic foldingmodel optical potential, obtained by convoluting a Pauli-corrected effective nucleon-nucleon ($\mathrm{NN}$) interaction with $^{7}\mathrm{Li}$ ground-state densities constrained by weak and electromagnetic data, produces a satisfactory description of the elastic data. The effects of the nonspherical terms in the optical potential, estimated via the distorted-wave approximation (DWA), are appreciable. The inelastic transitions leading to the ${\mathrm{\textonehalf{}}}^{\ensuremath{-}}$, $T=\frac{1}{2} \mathrm{and} {\frac{7}{2}}^{\ensuremath{-}}$, $T=\frac{1}{2}$ states at 0.48 and 4.63 MeV, respectively, are also examined within the framework of the microscopic folding model and the DWA. Transition potentials are generated by convoluting the effective $\mathrm{NN}$ interaction considered with target transition densities constrained by weak, electromagnetic, and low-energy proton and neutron scattering data. These potentials are employed in DWA calculations along with the folded optical potential that is consistent with the transition potentials. These self-consistent calculations also provide a good description of the inelastic data. The results provide a clear indication that there are important shape differences between the $^{6}\mathrm{Li}$ and $^{7}\mathrm{Li}$ radial densities and that the two inelastic transitions in $^{7}\mathrm{Li}$, which are primarily quadrupole in character, have $\frac{{\ensuremath{\rho}}_{2n}^{m}}{{\ensuremath{\rho}}_{2p}^{m}}\ensuremath{\approx}0.9 \mathrm{and} 0.9\ensuremath{-}1.2$, respectively.

Cross section and analyzing power measurements for the scattering of 180 MeV protons are used to investigate the structure of $^{9}\mathrm{Be}$. Data were collected for 24 states below 21 MeV of excitation. Detailed line-shape analysis was used to isolate several broad states. Most notably, the dependence of apparent peak position upon momentum transfer was used to separate the strong resonance listed as 6.76 MeV in standard compilations into two contributions identified as the 7/${2}^{\mathrm{\ensuremath{-}}}$ member of the ground-state rotational band, located at 6.38 MeV, and the 9/${2}^{+}$ weak-coupling state, located at 6.76 MeV. Calculations of proton scattering were made using a density-dependent effective interaction in the local density approximation. The quadrupole contribution to elastic scattering was included in distorted wave Born approximation and found to have an important effect upon the analyzing power. For states dominated by a single multipolarity, neutron transition densities were fitted to (p,p') data and compared with the corresponding proton transition densities fitted to (e,e') data. We find that excitation of the rotational states and the 9/${2}^{+}$ state are essentially isoscalar. Shell model calculations were performed in the full 0\ensuremath{\Elzxh}\ensuremath{\omega} and 1\ensuremath{\Elzxh}\ensuremath{\omega} model spaces. Suggested assignments for most states are made by comparisons of shell model calculations with data for both (p,p') and (e,e'). Similar calculations for analog states observed with the $^{9}\mathrm{Be}$(p,n${)}^{9}$B reaction at 135 MeV support the proposed assignments. Finally, several relatively narrow states are observed between 18 and 21 MeV that are candidates for positive-parity states with T=3/2.

Gamow-Teller (GT) strength distributions were studied in the ({ital p},{ital n}) reaction at 136 MeV on the self-conjugate {ital s}-{ital d} shell nuclei {sup 20}Ne, {sup 24}Mg, and {sup 28}Si. The measurements were performed in two separate experiments with the beam-swinger neutron time-of-flight facility at the Indiana University Cyclotron Facility. The flight paths were 91 and 131 m, respectively, for the two experiments. The neutrons were detected in large-volume plastic-scintillation detectors. The overall time resolutions were about 825 ps; this provided energy resolutions from 300 to 400 keV. GT strength was identified as {Delta}{ital l}=0 contributions in transitions to discrete final states and also in the background and continuum. The 0{degree}, {Delta}l=0 cross sections were converted to {ital B}(GT) units using a universal'' conversion formula calibrated to ({ital p},{ital n}) reactions on other even-even {ital s}-{ital d} shell nuclei. The resulting {ital B}(GT) distributions were compared with full {ital s}-{ital d} shell-model predictions. The distribution for {sup 24}Mg is described well, but the distributions for {sup 20}Ne and {sup 28}Si are described poorly. The total {ital B}(GT) strength observed in discrete states (up to 12 MeV of excitation) for each reaction is 65{plus minus}10 % of that predicted. If onemore » considers {ital B}(GT) strength observed in the continuum above a calculated quasi-free-scattering background, the strength increases to 70--100 % of that predicted. If one considers {ital B}(GT) strength in an analysis of the full continuum (up to {similar to}20 MeV), the entire amount predicted may be observed. These results are consistent with that observed in other light nuclei.« less

Background: The strength of electron capture for medium mass nuclei has a significant effect on the evolution of supernovae. There is insufficient knowledge of these strengths and very little data for important radioactive nuclei. Purpose: Determine whether it is feasible to obtain EC strength from studies of ${T}_{o}+1$ excitations in ($p$, $n$) reactions, and whether this might yield information for radioactive nuclei. Methods: Cross sections for the $^{58,60,62,64}\mathrm{Ni}$($p$, $n$)$^{58,60,62,64}\mathrm{Cu}$ reactions were measured over the angular range of $0.3{}^{\ensuremath{\circ}}$ to $11.6{}^{\ensuremath{\circ}}$ at 134.3 MeV using the IUCF neutron time-of-flight facility. Results: The ${T}_{o}+1$ excitations in $^{60,62}\mathrm{Ni}$ were identified by comparison with inelastic proton scattering spectra, their $B$(GT) were extracted, and the corresponding electron capture rates in supernovae were calculated. Data from the TRIUMF ($n$, $p$) experiments at 198 MeV were reanalyzed; the electron capture rates for the reanalyzed data are in moderately good agreement with the higher resolution ($p$, $n$) results, but differ in detail. The possibility of future measurements with radioactive nuclei was considered. Conclusions: It may be possible to obtain low-lying electron capture strength for radioactive nuclei by studying ($p$, $n$) reactions in inverse kinematics.

Zero-degree cross sections have been measured for the {sup 11}B({ital p},{ital n}){sup 11}C reaction at bombarding energies of {ital E}{sub {ital p}}=160, 200, 494, 644, and 795 MeV. In addition, spectra have been obtained at laboratory scattering angles of 3{degree} and 5{degree} at 494 MeV, and the transverse spin-flip probability at zero degrees has been measured for {ital E}{sub {ital p}}=160 MeV. These data are used to obtain estimates of the Gamow-Teller transition strength to final states in {sup 11}C up to an excitation energy of {ital E}{sub {ital x}}{approx equal}14 MeV. The uncertainty (1 standard deviation) in the extracted transition strengths is estimated to be in the range (2--8)%. Measured cross sections for the first four excited states in {sup 11}C have been compared to distorted-wave impulse approximation calculations. In this comparison, no evidence is found in the cross-section data for certain effects associated with knock-on exchange and noncentral interactions.

Differential cross sections and analyzing powers were measured for $^{17}\mathrm{O}$(d\ensuremath{\rightarrow},t${)}^{16}$O with polarized deuterons of 89 MeV. States of $^{16}\mathrm{O}$ up to 22.89 MeV excitation energy have been studied with an overall resolution of 60 keV. Discrimination between analyzing powers (${\mathit{A}}_{\mathit{y}}$) for different j transfers was found to be very good. The unique ${\mathit{A}}_{\mathit{y}}$(\ensuremath{\theta}) shapes were used to deduce ${\mathit{p}}_{1/2}$-${\mathit{p}}_{3/2}$ mixing ratios for those levels where it was significant. We find unexpectedly strong mixing for the 6.130 MeV, ${3}^{\mathrm{\ensuremath{-}}}$, and 8.872 MeV, ${2}^{\mathrm{\ensuremath{-}}}$, levels. Exact finite-range distorted-wave Born approximation calculations were used to identify l transfers and to extract spectroscopic strengths. Up to 23 MeV excitation, pickup strength is dominated by 1p transfer; less than 2% of the observed particle-hole strength results from 2s, 1d, or 1f transfer. Twelve particle-hole matrix elements for (${\mathit{p}}_{1/2}^{\mathrm{\ensuremath{-}}1}$${\mathit{d}}_{5/2}$) and (${\mathit{p}}_{3/2}^{\mathrm{\ensuremath{-}}1}$${\mathit{d}}_{5/2}$) configurations have been deduced. Comparison with previous work shows general agreement except for the T=0,${\mathit{J}}^{\mathrm{\ensuremath{\pi}}}$=${3}^{\mathrm{\ensuremath{-}}}$ term.

Differential-cross-section distributions for the {sup 7}Li({ital p},{ital n}){sup 7}Be(g.s.+0.43-MeV) reaction have been measured for {ital E}{sub {ital p}}=80, 120, 160, 200, 494, 644, and 795 MeV. These distributions have been integrated and normalized to independent values for the total cross section obtained from parametrizations of {sup 7}Li({ital p},{ital n}) activation measurements. Zero-degree cross sections obtained from this normalization are reported.

New cross section and analyzing power data are presented for elastic and inelastic scattering of 200 MeV protons from {sup 6}Li. The elastic data are well described by a standard, spherical, 12-parameter phenomenological Woods-Saxon (WS) optical potential. Microscopic folding-model optical potentials, obtained by convoluting free and Pauli-corrected effective nucleon-nucleon ({ital NN}) interactions with {sup 6}Li ground-state densities constrained by electromagnetic data, produce satisfactory descriptions of the elastic data. The effects of the spin-spin optical potential, estimated via the distorted wave approximation (DWA), are small but not negligible. The inelastic transitions leading to the 3{sup +},{ital T}=0 state at 2.18 MeV and the 0{sup +},{ital T}=1 state at 3.56 MeV are also examined within the framework of the microscopic folding model using the DWA. Transition potentials are generated by convoluting the two effective {ital NN} interactions considered with target transition densities constrained by weak and electromagnetic data. These are employed in DWA calculations using both folded optical potentials consistent with the transition potentials and the WS optical potential. The self-consistent calculation with the Pauli-corrected interaction provides a good description of the data for the 3{sup +} excitation. The results for the 0{sup +} excitation provide a clear indication that shell modelmore » configurations outside the {ital p} shell are important for a complete description of this transition.« less

Differential cross section angular distributions for the $^{6,7}\mathrm{Li}$(p,n${)}^{6,7}$Be reactions have been measured at energies between 60 and 200 MeV. The experimental angular distributions are analyzed using a microscopic distorted wave impulse approximation. The results of self-consistent microscopic distorted wave calculations based on a complete set of weak and electromagnetic data for the mass 6 and 7 systems are also presented. Total observed Gamow-Teller strength up to about 40 MeV excitation energy is reported. Energy dependence of the \ensuremath{\sigma}\ensuremath{\tau} and \ensuremath{\tau} effective interaction terms are presented up to 200 MeV. The measured (p,n) cross sections for the $^{7}\mathrm{Be}$ (g.s.) and $^{7}\mathrm{Be}$ (0.43 MeV) transitions are used to obtain the branching ratio of the $^{7}\mathrm{Be}$ (g.s.) decay to the g.s. and 0.478 MeV states in $^{7}\mathrm{Li}$. Zero degree polarization transfer (${\mathit{D}}_{\mathit{N}\mathit{N}}$) data at ${\mathit{E}}_{\mathit{p}}$=80, 120, 160, and 200 MeV are reported for the $^{6}\mathrm{Li}$(p,n${)}^{6}$Be (g.s.) and for the $^{7}\mathrm{Li}$(p,n${)}^{7}$Be (g.s.+0.43 MeV) reactions. Energy dependence of total and zero degree differential cross section for the $^{7}\mathrm{Li}$(p,n${)}^{7}$Be (g.s.+0.43 MeV) transitions are reported. Finally a comparison is presented for the (n,p), (p,p'), and (p,n) reaction in $^{6}\mathrm{Li}$ populating isospin triplets.

The $^{54}\mathrm{Fe}$(p,n${)}^{54}$Co reaction was studied at 135 MeV by the time-of-flight technique. Neutrons were detected with an energy resolution of 245 keV in large-volume, mean-timed counters at a flight path of 125 m. The forward-angle spectra are dominated by the excitation of ${1}^{+}$ states with characteristic \ensuremath{\Delta}l=0 angular distributions peaked at 0\ifmmode^\circ\else\textdegree\fi{}. The strengths of the ${1}^{+}$ excitations are interpreted as being equivalent to Gamow-Teller (GT) strengths excited in beta decay. This strength is observed to be highly fragmented; GT strength is identified in more than 30 states. The B(GT-) strength is obtained relative to the Fermi strength B(F) assumed to be concentrated in the ${0}^{+}$, isobaric-analog ground state. The total B(GT-) strength observed in discrete states, combined with the B(GT+) strength obtained from the (n,p) reaction, yields a lower limit of 48 percent of the 3(N-Z) sum rule. Inclusion of \ensuremath{\Delta}l=0 strength in the background and continuum above a quasifree scattering background increases this lower limit to 73 percent. If one considers the \ensuremath{\Delta}l=0 strength observed in the full background and continuum up to ${\mathit{E}}_{\mathit{x}}$=25 MeV, the entire sum rule may be satisfied. The observed distribution of GT strength is in good agreement with a truncated 1f-2p shell-model calculation.

The $^{45}\mathrm{Sc}$(p,n${)}^{45}$Ti reaction was studied at 135 MeV with a beam-swinger system. Neutron kinetic energies were measured by the time-of-flight technique, with neutron detectors located in three detector stations at 0\ifmmode^\circ\else\textdegree\fi{}, 24\ifmmode^\circ\else\textdegree\fi{}, and 45\ifmmode^\circ\else\textdegree\fi{} with respect to the undeflected beam. Flight paths of 131.0, 131.1, and 81.3 m were used. The overall timing resolution was about 825 ps, providing energy resolutions of 320 keV in the first two stations and 520 keV in the third. The wide-angle spectra are dominated by a complex at ${\mathit{E}}_{\mathit{x}}$=4.3 MeV. The angular distribution for this complex is fitted well by a distorted-wave impulse approximation calculation for an assumed ${\mathit{J}}^{\mathrm{\ensuremath{\pi}}}$=17/${2}^{\mathrm{\ensuremath{-}}}$,19/${2}^{\mathrm{\ensuremath{-}}}$ (\ensuremath{\pi}${\mathit{f}}_{7/2}^{2}$,\ensuremath{\nu}${\mathit{f}}_{7/2}^{\mathrm{\ensuremath{-}}1}$) doublet. The spectra and angular distribution are consistent with (p,${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$) excitations of the same states and are in good agreement with a full 1f-2p shell-model calculation. The 17/${2}^{\mathrm{\ensuremath{-}}}$,19/${2}^{\mathrm{\ensuremath{-}}}$ strength predicted by distorted-wave impulse approximation calculations using these shell-model wave functions is in good agreement with the experimental measurements.

Isospin is a good quantum number under the assumption that the nuclear interaction is charge independent. An analogous structure of excited states is expected for nuclei with the same mass number A but with different z components T{sub z} of the isospin T, where T{sub z}=(N-Z)/2. The analogous structure has been studied for the isobaric nuclei {sup 58}Ni and {sup 58}Cu by comparing the transitions from the {sup 58}Ni ground state (initial isospin T{sub i}=1 and J{sup {pi}}=0{sup +}) to the M1 and the Gamow-Teller (GT) states (J{sup {pi}}=1{sup +}) in {sup 58}Ni and {sup 58}Cu, respectively. For this purpose, proton inelastic scattering (p,p{sup '}) at E{sub p}=160 MeV and the charge-exchange ({sup 3}He,t) reaction at 140 MeV/nucleon were both measured at 0 deg., exciting final states with isospin T{sub f}=1 and 2 and T{sub f}=0, 1, and 2, respectively. High energy and scattering-angle resolutions were achieved by applying complete beam matching techniques. On the basis of the correspondence between excitation energies and transition strengths, isospin values T{sub f}=1 and 2 of analog GT and M1 states were identified. The distribution of T{sub f}=2 states was also compared with results of {sup 58}Ni(d,{sup 2}He), {sup 58}Ni(t,{sup 3}He), and {sup 58}Ni(n,p)more » experiments, in which only T{sub f}=2 states are excited. The obtained GT strength distribution is compared with the results of shell-model calculations.« less