Subramanian "Ram" Raman, a distinguished nuclear physicist and senior staff member of the Physics Division at Oak Ridge National Laboratory (ORNL), died April 8, 2003. In June 1966, Raman joined the staff at ORNL working in the Nuclear Data Project. This position provided him insights into important open questions in nuclear structure physics, and the power of "horizontal" compilations of properties across a broad range of nuclei. These insights would guide Raman's research interests throughout his 36-year career at ORNL.As shown by his great variety of publications, Raman's research career was marked by an intense interest in all areas of nuclear physics. He published papers on topics ranging from detailed nuclear structure to giant resonances, to the search for superheavy nuclei, to the scattering of heavy ions. His research resulted in over 200 published papers and over 3000 citations of his work. It is however, his nuclear data evaluations, both horizontal and vertical, that we most often remember. His most often cited papers deal with the evaluation and systematics of nuclear data, and he helped establish many of the "rules" and guidelines for assignment of nuclear level properties. An overview of Raman's work at ORNL is presented.

In the early 90's, it was discovered that a Plasma Focus (PF) system self-creates a plasma-tar et in which high energy-threshold nuclear-reactions occur at high reaction rates. Shoat life radioisotopes (SLR)s such as F-18, F-17, O-15, O-14, N-13 have been generated (10(6) - 10(8) per pulse) with a PF-machine using 7 kJ energy storage to produce the plasmas. beta (-) radioactivity from the SLRs is measured with rugged, Geiger counters inserted into the PF-chamber, and a specific SLR is identified by its half-life. The PF chamber (before discharge) is filled with a mixture of gases that constitutes the latter plasma-target - beam system, e.g., the elements required to produce specific SLRs through nuclear reactions. In this paper, arguments are presented showing that a modest sized PF-machine, using a 50 -75 kJ fast capacitor-bank, when operated at pulse frequencies of 1-10 Hz can produce greater than or equal to 10(9) SLRs/pulse. This paper reports the results of testing a PF as a breeder of SLRs with dual applications for: (i) Secondary Radioactive Nuclear Beams ion-sources (Z < 35), and (ii) as a breeder of radioisotopes for biomedicine (Z less than or equal to 10) and/or PET imaging.

We have made simultaneous measurements of singles ((p) over right arrow,(p) over right arrow') spin-transfer observables and coincident ((p) over right arrow,p' gamma) yields and asymmetries for the 15.11 MeV, 1(+), T=1 state in C-12, at an incident proton bombarding energy of 200 MeV. Data were taken at four proton scattering angles ranging from theta(p)(c.m.)=5.5 degrees to 16.5 degrees. Both vertical (normal to the reaction plane) and horizontal (in-plane) incident beam polarizations were used, which allowed us to extract 16 different observables for this transition. In particular, using the ((p) over right arrow,p' gamma) reaction, we measured the sideways and longitudinal analyzing powers, D-OS and D-OL, which vanish identically in the ((p) over right arrow,p') reaction. Detailed comparisons of all observables to calculations done in both relativistic and nonrelativistic formalisms are presented. Surprisingly, a relativistic description in which knock-on exchange processes are not explicitly included provides the best overall agreement with the data.

The extension of singles (p↘,p↘′) studies to include coincident (p↘,p′γ) measurements can provide new information about the effective nucleon–nucleus interaction. We have therefore made simultaneous measurements of (p↘,p↘′) and (p↘,p′γ) observables for the 15.11 MeV, 1+, T=1 state in 12C at an incident beam energy of 200 MeV. Contained in these coincident observables are determinations of the sideways and longitudinal analyzing powers, D0S and D0L, which must vanish in singles measurements due to parity conservation. With this large data set on a transition with a relatively simple spin sequence, we have, in principle, enough information for a complete determination of the scattering amplitude.

The decay of excited $^{16}\mathrm{O}$ projectiles into the four alpha particle exit channel has been investigated. The projectiles, with bombarding energies of E/A=25 MeV, were excited through peripheral interactions with $^{159}\mathrm{Tb}$ target nuclei. A 4\ensuremath{\pi} counter was used to detect both the projectile alpha particles and the light charged particles evaporated from the target nucleus. Criteria for selecting true $^{16}\mathrm{\ensuremath{\alpha}}$ events with the minimum contamination from incorrectly identified events were examined. The distribution of relative angles between the four alpha particles in their center of mass frame was compared to simulations of $^{16}\mathrm{O}$ decay by sequential decay mechanisms. The relative angles were shown to be consistent with a sequential evaporation mechanism if a nonzero angular momentum is assumed for the excited projectile. The momentum distribution of the alpha particles in the reaction plane was examined and found to be anisotropic for high projectile excitation energies. This anisotropy was shown to be consistent with Coulomb interactions between the first emitted alpha particle and the target nucleus, which would indicate that the lifetime of the projectile is very short, on the order of ${10}^{\mathrm{\ensuremath{-}}22}$ s.

We have measured the scattering of 375-MeV O-17 ions by isotopes of Pb-204, Pb-206, Pb-208 to investigate the isospin character of transitions to low-lying 2+ and 3- states. The data were analyzed using the deformed optical potential model. The 2+ collective strength, which is concentrated in a single state at 4.085 MeV in Pb-208, is observed to fragment in both Pb-204 and Pb-206. The differential cross sections for excitation of the collective 2+ and 3- states are well reproduced by model calculations in which it is assumed that M(n)/M(p) = N/Z (i.e., isoscalar character). Angular distributions for the lowest-lying 2+ states in Pb-203, Pb-206 are significantly different from those for the higher-lying collective 2+ states, and can be reproduced with M(n)/M(p) almost-equal-to 2.5. The data are compared with random-phase-approximation calculations including pairing, and good agreement is found within estimated uncertainties.

Decay studies of giant multipole resonances are discussed, emphasizing the role of Coulomb excitation with intermediate energy heavy ions, which can provide very large cross sections for both isoscalar and isovector resonances. We discuss measurement of the photon decay of one and two phonon giant resonances, reporting results where available. It is pointed out throughout the presentation that the use of E1 photons as a tag'' provides a means to observe weakly excited resonances that cannot be observed in the singles spectra. 30 refs., 16 figs., 1 tab.

Differential cross sections are reported for elastic scattering and for exciting the 2(1)+ (1.81 MeV), 2(2)+ (2.94 MeV), 4(1)+ (4.32 MeV), and the 4(2)+ (4.90 MeV) states of Mg-26 from Mg-26 (200 MeV) + Pb-208 scattering. In addition, we have measured complete particle-gamma angular correlations for the 2(1)+ --> 0(1)+, 2(2)+ --> 2(1)+, and 4(2)+ --> 2(1)+ gamma-decays. Coupled-channels analysis was performed to extract E2 and E4 matrix elements. For the ground-state rotational band we find M(E2;0(1)+ <--> 2(1)+) = -16.79 +/- 0.13 e fm2, M(E4;0(1)+ <--> 4(2)+) = +95 +/- 10 e fm4, and Q2(2(1)+) = -20.9 +/- 1.9 e fm2, where we have identified the 4(2)+ (4.90 MeV) state as a member of the ground-state band rather than the 4(1)+ (4.32 MeV) state. The 2(2)+ (2.94 MeV) state is not well accounted for by the asymmetric-rotor model.

The excitation and electromagnetic decay of the giant resonance region (8--15 MeV) in $^{208}\mathrm{Pb}$ have been measured with the $^{208}\mathrm{Pb}$${(}^{17}$O${,}^{17}$O') reaction at 84 MeV/nucleon. The study of coincidences between scattered $^{17}\mathrm{O}$ ions and photon decays to the $^{208}\mathrm{Pb}$ ground state, including angular correlations, serves to isolate the isovector giant dipole resonance and enable us to investigate the mechanisms of its excitation and decay in detail. The angular correlations and yields are accounted for quantitatively by a pure Coulomb excitation model of the reaction process. The distribution in energy of the ground-state photon decay cross section is well described by an approximate application of the multistep theory of nuclear reactions. The photon coincidence measurements enable us to extract the differential cross sections for the 10.6-MeV giant quadrupole and 13.9-MeV monopole resonances with low uncertainty. An analysis of the Coulomb-nuclear interference for the 10.6-MeV excitation indicates that the ratio of neutron to proton matrix elements, ${\mathit{M}}_{\mathit{n}}$/${\mathit{M}}_{\mathit{p}}$, is 1.7\ifmmode\pm\else\textpm\fi{}0.4, consistent with a predominantly isoscalar character for the giant quadrupole resonance.

The scattering of 84-MeV/nucleon $^{17}\mathrm{O}$ ions by $^{118}\mathrm{Sn}$ has been studied. Inelastic cross sections for excitation of the 2.327-MeV state (${3}^{\mathrm{\ensuremath{-}}}$), the giant quadrupole resonance, and the giant monopole resonance are reproduced by distorted-wave approximation calculations using the deformed potential model and assuming isoscalar transitions. A minimum predicted in the angular distribution at ${\mathrm{\ensuremath{\theta}}}_{\mathrm{c}.\mathrm{m}.}$=1.9\ifmmode^\circ\else\textdegree\fi{} from utilization of the small B(E2)\ensuremath{\uparrow} strength suggested by ${\mathrm{\ensuremath{\pi}}}^{+}$/${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$ scattering is not apparent in the data.

Differential cross section measurements have been made for the giant resonance region (13.2--40 MeV) in $^{40}\mathrm{Ca}$ using 500 MeV protons with an experimental energy resolution of 70 keV. Fine structure was observed in this energy region. After fixing the energy weighted sum rule depletion for the isovector giant dipole resonance at 70%, energy weighted sum rules of 70\ifmmode\pm\else\textpm\fi{}14 % for the isoscalar giant quadrupole resonance and 15\ifmmode\pm\else\textpm\fi{}3 % for the isoscalar giant hexadecapole resonance were deduced. All of these energy weighted sum rule depletions agree well with theoretical predictions and results from other experiments.

A vibrational collective model has been used to analyze 15 bound states in $^{40}\mathrm{Ca}$ excited by inelastic scattering of 500 MeV polarized protons. It is shown that for those states which have surface peaked charge transition densities the collective model describes the shape and magnitude of the angular distributions quite well. The hadronic deformation lengths extracted are shown to be constant over the incident proton energy range of 25--800 MeV with the exception of data at 185 MeV. The average values for the hadronic deformation lengths are used to calculate the ratio of the neutron to proton multipole matrix elements for five states. Elastic scattering and the ${3}_{1}^{\mathrm{\ensuremath{-}}}$, ${2}_{1}^{+}$, and ${5}_{1}^{\mathrm{\ensuremath{-}}}$ transitions have also been studied using the relativistic collective model.

Differential cross sections for exciting the low-lying states in $^{24}\mathrm{Mg}$ by heavy-ion inelastic scattering were measured with a new technique that uses a 4\ensuremath{\pi} \ensuremath{\gamma}-ray detector in coincidence with charged-particle detectors. The resulting data were subjected to a coupled-channels analysis to obtain a set of E2 and E4 matrix elements for exciting the ${2}_{1}^{+}$(1.37 MeV), ${4}_{1}^{+}$(4.12 MeV), and ${2}_{2}^{+}$(4.24 MeV) states of $^{24}\mathrm{Mg}$ as well as the interconnecting and self-coupling matrix elements for these states. Our results disagree with electron scattering measurements for the charge shape of $^{24}\mathrm{Mg}$. The data on the ${2}_{2}^{+}$(4.24 MeV) state is not well accounted for by the asymmetric rotor model.