S. Sanders

We review the main results obtained by the BRAHMS collaboration on the properties of hot and dense hadronic and partonic matter produced in ultrarelativistic heavy ion collisions at RHIC. A particular focus of this paper is to discuss to what extent the results collected so far by BRAHMS, and by the other three experiments at RHIC, can be taken as evidence for the formation of a state of deconfined partonic matter, the so called quark-gluon-plasma (QGP). We also discuss evidence for a possible precursor state to the QGP, i.e. the proposed Color Glass Condensate.

We review the theoretical background, experimental techniques, and phenomenology of what is known in relativistic heavy ion physics as the Glauber model, which is used to calculate geometric quantities. A brief history of the original Glauber model is presented, with emphasis on its development into the purely classical, geometric picture used for present-day data analyses. Distinctions are made between the optical limit and Monte Carlo approaches, which are often used interchangeably but have some essential differences in particular contexts. The methods used by the four RHIC experiments are compared and contrasted, although the end results are reassuringly similar for the various geometric observables. Finally, several important RHIC measurements are highlighted that rely on geometric quantities, estimated from Glauber calculations, to draw insight from experimental observables. The status and future of Glauber modeling in the next generation of heavy ion physics studies is briefly discussed.

We report on a study of the transverse momentum dependence of nuclear modification factors R(dAu) for charged hadrons produced in deuteron + gold collisions at sqrt[s(NN)]=200 GeV, as a function of collision centrality and of the pseudorapidity (eta=0, 1, 2.2, 3.2) of the produced hadrons. We find a significant and systematic decrease of R(dAu) with increasing rapidity. The midrapidity enhancement and the forward rapidity suppression are more pronounced in central collisions relative to peripheral collisions. These results are relevant to the study of the possible onset of gluon saturation at energies reached at BNL RHIC.

We present spectra of charged hadrons from Au+Au and d+Au collisions at √sNN=200 GeV measured with the BRAHMS experiment at RHIC. The spectra for different collision centralities are compared to spectra from p+¯p collisions at the same energy scaled by the number of binary collisions. The resulting ratios (nuclear modification factors) for central Au+Au collisions at η=0 and η=2.2 evidence a strong suppression in the high pT region (>2 GeV/c). In contrast, the d+Au nuclear modification factor (at η=0) exhibits an enhancement of the high pT yields. These measurements indicate a high energy loss of the high pT particles in the medium created in the central Au+Au collisions. The lack of suppression in d+Au collisions makes it unlikely that initial state effects can explain the suppression in the central Au+Au collisions.Received 3 July 2003DOI:https://doi.org/10.1103/PhysRevLett.91.072305©2003 American Physical Society

We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the 197 Au 1 197 Au reaction at p s NN 200 GeV.For the 5% most central events we obtain dN ch ͞dhj h0 625 6 55 and N ch j 24.7#h#4.7 4630 6 370, i.e., 14% and 21% increases, respectively, relative to p s NN 130 GeV collisions.Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity.These results constrain current models of particle production at the highest RHIC energy.

We have measured rapidity densities dN/dy of pi+/- and K+/- over a broad rapidity range (-0.1 < y < 3.5) for central Au + Au collisions at square root(sNN) = 200 GeV. These data have significant implications for the chemistry and dynamics of the dense system that is initially created in the collisions. The full phase-space yields are 1660 +/- 15 +/- 133 (pi+), 1683 +/- 16 +/- 135 (pi-), 286 +/- 5 +/- 23 (K+), and 242 +/- 4 +/- 19 (K-). The systematics of the strange to nonstrange meson ratios are found to track the variation of the baryochemical potential with rapidity and energy. Landau-Carruthers hydrodynamics is found to describe the bulk transport of the pions in the longitudinal direction.

Transverse momentum spectra and rapidity densities, dN/dy, of protons, antiprotons, and net protons (p−p¯) from central (0%–5%) Au+Au collisions at sNN=200 GeV were measured with the BRAHMS experiment within the rapidity range 0≤y≤3. The proton and antiproton dN/dy decrease from midrapidity to y=3. The net-proton yield is roughly constant for y<1 at dN/dy∼7, and increases to dN/dy∼12 at y∼3. The data show that collisions at this energy exhibit a high degree of transparency and that the linear scaling of rapidity loss with rapidity observed at lower energies is broken. The energy loss per participant nucleon is estimated to be 73±6 GeV.Received 31 December 2003DOI:https://doi.org/10.1103/PhysRevLett.93.102301©2004 American Physical Society

Measurements of the total fusion cross sections for $^{12}\mathrm{C}$ + $^{12}\mathrm{C}$, $^{13}\mathrm{C}$, $^{14}\mathrm{N}$, $^{15}\mathrm{N}$, $^{16}\mathrm{O}$, $^{18}\mathrm{O}$, and $^{19}\mathrm{F}$ and $^{16}\mathrm{O}$ + $^{16}\mathrm{O}$ have been performed over the energy range from 1.5 to 3 times the Coulomb barrier energy. Fusion barrier parameters were extracted for each system. Three systems, $^{12}\mathrm{C}$ + $^{12}\mathrm{C}$, $^{12}\mathrm{C}$ + $^{16}\mathrm{O}$, and $^{16}\mathrm{O}$ + $^{16}\mathrm{O}$, show rather pronounced oscillatory structure in the energy dependence of the fusion cross sections. The maximum fusion cross sections for the systems studied vary by as much as 10-20%, depending on the particular entrance channel. The specific structure of the interacting nuclei clearly does have an effect; the fusion process is not entirely dominated by the macroscopic features of the ion-ion interaction.NUCLEAR REACTIONS, fusion, measured ${\ensuremath{\sigma}}_{\mathrm{fusion}}(E)$; $^{12}\mathrm{C}$ + $^{12}\mathrm{C}$, $7.4<~{E}_{\mathrm{c}.\mathrm{m}.}<~31.2$ MeV; $^{12}\mathrm{C}$ + $^{13}\mathrm{C}$, $7.6<~{E}_{\mathrm{c}.\mathrm{m}.}<~24.9$ MeV; $^{12}\mathrm{C}$ + $^{14}\mathrm{N}$, $15.1<~{E}_{\mathrm{c}.\mathrm{m}.}<~24.0$ MeV; $^{12}\mathrm{C}$ + $^{15}\mathrm{N}$, $8.9<~{E}_{\mathrm{c}.\mathrm{m}.}<~26.7$ MeV; $^{12}\mathrm{C}$ + $^{16}\mathrm{O}$, $12.9<~{E}_{\mathrm{c}.\mathrm{m}.}<~27.0$ MeV; $^{12}\mathrm{C}$ + $^{18}\mathrm{O}$, $11.9<~{E}_{\mathrm{c}.\mathrm{m}.}<~28.0$ MeV; $^{12}\mathrm{C}$ + $^{19}\mathrm{F}$, $11.6<~{E}_{\mathrm{c}.\mathrm{m}.}<~27.1$ MeV; $^{16}\mathrm{O}$ + $^{16}\mathrm{O}$, $14.9<~{E}_{\mathrm{c}.\mathrm{m}.}<~36.0$ MeV; deduced fusion barrier parameters.

The first measurements of xF-dependent single-spin asymmetries of identified charged hadrons, π±, K±, and protons, from transversely polarized proton-proton collisions at 62.4 GeV at RHIC are presented. Large asymmetries are seen in the pion and kaon channels. The asymmetries in inclusive π+ production, AN(π+), increase with xF from 0 to ∼0.25 and AN(π−) decrease from 0 to ∼−0.4. Observed asymmetries for K− unexpectedly show positive values similar to those for K+, increasing with xF, whereas proton asymmetries are consistent with zero over the measured kinematic range. Comparisons of the data with predictions of QCD-based models are presented.Received 7 January 2008DOI:https://doi.org/10.1103/PhysRevLett.101.042001©2008 American Physical Society

We present charged particle densities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at sqrt{s_{NN}}=130 GeV. An integral charged particle multiplicity of 3860+/-300 is found for the 5% most central events within the pseudorapidity range -4.7 <= eta <= 4.7. At mid-rapidity an enhancement in the particle yields per participant nucleon pair is observed for central events. Near to the beam rapidity, a scaling of the particle yields consistent with the ``limiting fragmentation'' picture is observed. Our results are compared to other recent experimental and theoretical discussions of charged particle densities in ultra-relativistic heavy-ion collisions.

A review of the characteristic features found in fully energy-damped, binary decay yields from light heavy-ion reactions with 20≤Atarget+Aprojectile≤80 is presented. The different aspects of these yields that have been used to support models of compound-nucleus (CN) fission and deep-inelastic dinucleus orbiting are highlighted. Cross-section calculations based on the statistical phase space at different stages of the reaction are presented and compared to the experimental results. Although the statistical models are found to reproduce most of the observed experimental behaviors, an additional reaction component corresponding to a heavy-ion resonance or orbiting mechanism is also evident in certain systems. The system dependence of this second component is discussed. The extent to which the binary yields in very light systems (ACN≤32) can be viewed as resulting from a fusion–fission mechanism is explored. A number of unresolved questions, such as whether the different observed behaviors reflect characteristically different reaction times, are discussed.

Excitation functions for sub- and near-barrier total (complete + incomplete) fusion cross sections are presented for the 6,7Li+59Co reactions. Evaporation residues were identified by their characteristic γ rays and the corresponding yields measured with both the IReS Garel + array at the Vivitron facility and with the São Paulo Ge array at the 8UD Pelletron tandem facility using standard γ-ray techniques. The data extend to medium-mass systems previous works exploring the coupling effects (hindrance versus enhancement) in fusion reactions of both lighter and heavier systems. The results indicate a small enhancement of total fusion for the more weakly bound 6Li at sub-barrier energies, with similar cross sections for both reactions at and above the barrier.Received 24 February 2003DOI:https://doi.org/10.1103/PhysRevC.67.054602©2003 American Physical Society

Fully energy-damped yields from the $^{32}\mathrm{Mg}$ reaction have been measured at center-of-mass energies of ${E}_{\mathrm{c}.\mathrm{m}.=51.6}$ and 60.5 MeV with the use of an experimental arrangement where both of the resulting heavy fragments could be detected in coincidence. Energy, velocity, and angular distributions of the reaction fragments have been determined. The cross sections prior to secondary light-particle emission have been deduced for the breakup of the compound system into different mass channels. These data are discussed in terms of two possible reaction mechanisms: fusion followed by fission and deep-inelastic orbiting.

The BRAHMS experiment at RHIC was conceived to pursue the understanding of nuclear matter under extreme conditions by detailed measurements of charged hadrons over the widest possible range of rapidity and transverse momentum. The experiment consists of two spectrometers with complementary charged hadron detection capabilities as well as a series of global detectors for event characterization. A series of tracking detectors, time-of-flight arms and Cherenkov detectors enables momentum determination and particle identification over a wide range of rapidity and transverse momentum. Technical details and performance results are presented for the various detector subsystems. The performance of the entire system working together is shown to meet the goals of the experiment.

We present ratios of the numbers of charged antiparticles to particles (pions, kaons and protons) in Au + Au collisions at √ sNN = 200 GeV as a function of rapidity in the range y=0-3.While the particle ratios at midrapidity are approaching unity, the K -/K + and p/p ratios decrease significantly at forward rapidities.An interpretation of the results within the statistical model indicates a reduction of the baryon chemical potential from µB ≈ 130MeV at y=3 to µB ≈ 25MeV at y=0.

We present particle spectra for charged hadrons π±, K±, p, and p¯ from pp collisions at s=200 GeV measured for the first time at forward rapidities (2.95 and 3.3). The kinematics of these measurements are skewed in a way that probes the small momentum fraction in one of the protons and large fractions in the other. Large proton to pion ratios are observed at values of transverse momentum that extend up to 4 GeV/c, where protons have momenta up to 35 GeV. Next-to-leading order perturbative QCD calculations describe the production of pions and kaons well at these rapidities, but fail to account for the large proton yields and small p¯/p ratios.Received 22 January 2007DOI:https://doi.org/10.1103/PhysRevLett.98.252001©2007 American Physical Society

Transverse momentum spectra of protons and anti-protons measured in the rapidity range 0<y<3.1 from 0-10% central Au+Au collisions at sqrt{s_{NN}}=62.4 GeV are presented. The rapidity densities, dN/dy, of protons, anti-protons and net-protons N()p-N(pbar) have been deduced from the spectra over a rapidity range wide enough to observe the expected maximum net-baryon density. From mid-rapidity to y=1 the net-proton yield is roughly constant (dN/dy ~ 10),but rises to dN/dy ~25 at 2.3<y<3.1. The mean rapidity loss is 2.01 +-0.16 units from beam rapidity. The measured rapidity distributions are compared to model predictions. Systematics of net-baryon distributions and rapidity loss vs. collision energy are discussed.

Particle production of identified charged hadrons, $\pi^{\pm}$, $K^{\pm}$, $p$, and $\bar{p}$ in Au+Au collisions at $\sqrt(snn) =$ 200 GeV has been studied as a function of transverse momentum and collision centrality at $y=0$ and $y\sim1$ by the BRAHMS experiment at RHIC. Significant collective transverse flow at kinetic freeze-out has been observed in the collisions. The magnitude of the flow rises with the collision centrality. Proton and kaon yields relative to the pion production increase strongly as the transverse momentum increases and also increase with centrality. Particle yields per participant nucleon show a weak dependence on the centrality for all particle species. Hadron production remains relatively constant within one unit around midrapidity in Au+Au collisions at $\sqrt(snn) =$ 200 GeV.

Cross sections for the two-body channels populated in the $^{32}\mathrm{S}$+$^{24}\mathrm{Mg}$ reaction at ${E}_{\mathrm{c}.\mathrm{m}.}=60.8$ MeV have been measured by use of a coincidence technique which allows correction for secondary light-particle evaporation. The data show reaction yields with full equilibration of energy and mass-asymmetry coordinates. These results suggest an asymmetric fission mechanism and are contrary to what is expected from the previously proposed "orbiting" mechanism in light systems.

Charged-particle pseudorapidity densities are presented for the d+Au reaction at √sNN=200 GeV with −4.2≤η≤4.2. The results, from the BRAHMS experiment at BNL Relativistic Heavy-Ion Collider, are shown for minimum-bias events and 0%–30%, 30%–60%, and 60%–80% centrality classes. Models incorporating both soft physics and hard, perturbative QCD-based scattering physics agree well with the experimental results. The data do not support predictions based on strong-coupling, semiclassical QCD. In the deuteron-fragmentation region the central 200 GeV data show behavior similar to full-overlap d+Au results at √sNN=19.4 GeV.Received 21 January 2004DOI:https://doi.org/10.1103/PhysRevLett.94.032301©2005 American Physical Society

Invariant pT spectra and rapidity densities covering a large rapidity range (−0.1<y<3.5) are presented for π± and K± mesons from central Au + Au collisions at sNN=62.4 GeV. The mid-rapidity yields of meson particles relative to their anti-particles are found to be close to unity (π−/π+∼1, K−/K+∼0.85) while the anti-proton to proton ratio is p¯/p∼0.49. The rapidity dependence of the π−/π+ ratio is consistent with a small increase towards forward rapidities while the K−/K+ and p¯/p ratios show a steep decrease to ∼0.3 for kaons and 0.022 for protons at y∼3. It is observed that the kaon production relative to its own anti-particle as well as to pion production in wide rapidity and energy ranges shows an apparent universal behavior consistent with the baryo-chemical potential, as deduced from the p¯/p ratio, being the driving parameter.

The possible occurrence of highly deformed configurations in the $^{40}$Ca di-nuclear system formed in the $^{28}$Si + $^{12}$C reaction is investigated by analyzing the spectra of emitted light charged particles. Both inclusive and exclusive measurements of the heavy fragments (A $\geq$ 10) and their associated light charged particles (protons and $\alpha$ particles) have been made at the IReS Strasbourg {\sc VIVITRON} Tandem facility at bombarding energies of $E_{lab} (^{28}$Si) = 112 MeV and 180 MeV by using the {\sc ICARE} charged particle multidetector array. The energy spectra, velocity distributions, and both in-plane and out-of-plane angular correlations of light charged particles are compared to statistical-model calculations using a consistent set of parameters with spin-dependent level densities. The analysis suggests the onset of large nuclear deformation in $^{40}$Ca at high spin.

Inclusive cross sections for the $^{16}\mathrm{O}$${+}^{40}$Ca reaction leading to fission-like fragments with mass 20\ensuremath{\le}${A}_{\mathrm{fragment}\mathrm{\ensuremath{\le}}}$28, and for the $^{16}\mathrm{O}$${+}^{44}$Ca reaction with 20\ensuremath{\le}${A}_{\mathrm{fragment}\mathrm{\ensuremath{\le}}}$30, have been determined by measurements at seven energies with 69.3\ensuremath{\le}${E}_{\mathrm{lab}{(\mathrm{}}^{16}}$O)\ensuremath{\le}87.3 MeV and for 30\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}${\mathrm{theta}}_{\mathrm{lab}\mathrm{\ensuremath{\le}}60\mathrm{\ifmmode^\circ\else\textdegree\fi{}}}$. The evaporation-residue cross sections were also measured over a limited angular range at the same energies to search for any gross difference between these cross sections for the two systems. No difference was detected outside the experimental uncertainties. The resulting energy spectra and mass distributions for the fission-like yields are shown to be consistent with a fusion-fission reaction mechanism. Although it was not possible to determine the total fission-like cross sections since the apparent mass range of the fission-like yields was greater than that covered by the experiment, the magnitude and energy dependence of the observed fission-like cross sections, as compared to the evaporation-residue cross sections, are also found to be consistent with a fusion-fission mechanism.

A high-resolution measurement of fragment-fragment-$\ensuremath{\gamma}$ triple coincidence events in the symmetric and near-symmetric mass exit channels from the ${}^{28}\mathrm{Si}{+}^{28}\mathrm{Si}$ reaction has been undertaken using the EUROGAM Phase II $\ensuremath{\gamma}$-ray spectrometer. The bombarding energy of ${E}_{\mathrm{lab}}{(}^{28}\mathrm{Si})=111.6 \mathrm{MeV}$ has been selected to populate the conjectured ${J}^{\ensuremath{\pi}}{=38}^{+}$ quasimolecular resonance in the ${}^{56}\mathrm{Ni}$ dinuclear system. In the ${}^{28}\mathrm{Si}{+}^{28}\mathrm{Si}$ symmetric mass exit channel, the resonance behavior is clearly verified at the chosen energy. The population of highly excited states in the ${}^{24}\mathrm{Mg},$ ${}^{28}\mathrm{Si},$ and ${}^{32}\mathrm{S}$ nuclei is discussed within a statistical fusion-fission model. Evidence is presented for selective population of states in the ${}^{28}\mathrm{Si}$ fragments arising from the symmetric fission of the ${}^{56}\mathrm{Ni}$ compound nucleus. The enhanced population of the ${K}^{\ensuremath{\pi}}{=3}_{1}^{\ensuremath{-}}$ band of the ${}^{28}\mathrm{Si}$ nucleus, indicative of an oblate deformed shape, suggests that the oblate configuration plays a significant role in the resonant process. Fragment angular distributions for the elastic and low-lying inelastic channels as well as $\ensuremath{\gamma}$-ray angular correlations for the mutual inelastic channel ${(2}^{+}{,2}^{+})$ indicate that the spin orientations of the outgoing fragments are perpendicular to the orbital angular momentum. This unexpected result, which is different from the alignment found for the resonance structures in the ${}^{24}\mathrm{Mg}{+}^{24}\mathrm{Mg}$ and ${}^{12}\mathrm{C}\mathrm{}{+}^{12}\mathrm{C}$ systems, suggests a situation where two oblate ${}^{28}\mathrm{Si}$ nuclei interact in an equator-to-equator stable molecular configuration. A discussion concerning the spin alignment and spin disalignment for different reactions such as ${}^{12}\mathrm{C}\mathrm{}{+}^{12}\mathrm{C},$ ${}^{24}\mathrm{Mg}{+}^{24}\mathrm{Mg},$ and ${}^{28}\mathrm{Si}{+}^{28}\mathrm{Si}$ is presented.

Fusion, strongly damped, quasielastic and elastic scattering yields have been measured for the $^{16,17,18}\mathrm{O}$${+}^{10,11}$B systems at 1 MeV\ensuremath{\le}E/A\ensuremath{\le}4 MeV and $^{19}\mathrm{F}$${+}^{9}$Be at 56 MeV. The significant yields observed for the strongly energy-damped products are attributed to a fusion-fission process. This identification is supported by statistical model calculations based on the transition-state model of fission. The elastic scattering data present enhanced back-angle yields which can be understood in terms of a compound elastic process. These results help to further establish the reaction systematics in this mass region.

All ITER sub-systems of remote handling (RH) classes 1 and 2 have to be remotely maintainable. The maintenance strategy for these components has to ensure system availability after failure or scheduled maintenance. This paper shows how virtual reality (VR) simulation [1] can be used as a tool to analyze the maintenance process, to predict the mean time to repair and to ensure the RH compatibility of one ITER sub-system, the Upper Port Launcher (UPL) [2]. Special emphasis is put on the development of RH procedures and the identification of tooling requirements. The possibility to simulate RH logistics and repair actions in an early stage of the design process allows for the identification of those maintenance actions that require dedicated tests in the Launcher Handling Test Facility at Karlsruhe. The VR analysis, together with dedicated mock-up tests will demonstrate the RH compatibility of the UPL plug, provide input to the design of the Port Plug maintenance area in the ITER Hot Cell, and support the development of RH maintenance tooling.

Fragment-fragment-$\ensuremath{\gamma}$ coincidences have been measured for ${}^{28}\mathrm{Si}{+}^{28}\mathrm{Si}$ at an energy corresponding to the population of a conjectured resonance in ${}^{56}\mathrm{Ni}.$ Fragment angular distributions as well as $\ensuremath{\gamma}$-ray angular correlations indicate that the spin orientations of the outgoing fragments are perpendicular to the orbital angular momentum. This differs from the ${}^{24}\mathrm{Mg}{+}^{24}\mathrm{Mg}$ and the ${}^{12}\mathrm{C}{+}^{12}\mathrm{C}$ resonances, and suggests two oblate ${}^{28}\mathrm{Si}$ nuclei interacting in an equator-to-equator molecular configuration.

Energy-integrated reaction cross sections have been measured at energies ranging from 38 to 80 MeV/nucleon for various exotic neutron-rich isotopes of Al, Si, P, S, Cl, Ar, K, Ca, Sc, and Ti stopping in Si. An experimental technique is employed where Si detectors are used for both particle identification and to serve as the target material. The reduced strong absorption radii ${r}_{0}^{2}$ are deduced and compared with other experimental results. The radius dependence on the neutron number was studied and a trend of increasing reduced radius with neutron excess was found. This behavior is similar to that seen in lighter systems, although less pronounced than found there. The implications of this result on the conjectured existence of neutron halo or skin nuclei is discussed.

The properties of fully energy-damped processes (deep-inelastic orbiting, fusion-evaporation, and fusion-fission processes) have been investigated in the nearly mass-symmetric entrance-channel $^{23}\mathrm{Na}$ + $^{24}\mathrm{Mg}$ reaction leading to the $^{47}\mathrm{V}$ compound nucleus. By comparison with previous data for the mass-asymmetric $^{35}\mathrm{Cl}$ ${+}^{12}$C reaction forming the same compound system at the same excitation energy, no entrance-channel effects are observed in either the evaporation residue or the fusion-fission yields. This is in contrast to the situation with the $^{28}\mathrm{Si}$ ${+}^{12}$C and $^{24}\mathrm{Mg}$ ${+}^{16}$O reactions where an orbiting process is evident. The asymmetrical elemental distributions of the fusion-fission fragments of the massA=47 system are well described by a transition-state model that accounts for the spin and mass-asymmetry dependence of the fission saddle point.

We have measured the distributions of protons and deuterons produced in the 20% most central Au+Au collisions at RHIC ( √ s NN = 200 GeV) over a very wide range of transverse and longitudinal momentum.Near midrapidity we have also measured the distribution of antiprotons and antideuterons.We present our results in the context of coalescence models.In particular we extract the "homogeneity volume" and the average phase-space density for protons and antiprotons.Near central rapidity the coalescence parameter B2(pT ) and the space-averaged phase-space density f (pT ) are very similar for both protons and antiprotons.For protons we see little variation of either B2(pT ) or the space-averaged phase-space density as the rapidity increases from 0 to 3.However, these quantities depend strongly on pT at all rapidities.These results are in contrast to data from lower energy collisions where the proton and antiproton phase-space densities are different at y=0 and both B2 and f depend strongly on rapidity.

The symmetric and near-symmetric mass fission yields from the $^{32}\mathrm{S}$${+}^{24}$Mg reaction have been studied in a particle-particle-\ensuremath{\gamma} coincidence measurement. Evidence is presented for a selective population of states in $^{28}\mathrm{Si}$ fragments arising from the symmetric fission of the $^{56}\mathrm{Ni}$ compound nucleus. A statistical-model calculation of the expected strength to specific mutual excitations of the fission fragments is presented and compared to the experimental results. This calculation is found to describe the structures observed at high excitation energy in the fission Q-value spectra quite well. Analysis of the \ensuremath{\gamma}-ray spectra indicates, however, that a specific set of states in $^{28}\mathrm{Si}$, corresponding to a highly deformed prolate band, is populated more strongly than expected based on a purely spin-weighted, statistical decay of the compound nucleus. It is suggested that the population pattern of states in the fission fragments may reflect nuclear structure effects at the point of scission.

The fully energy-damped yields for the $^{36}\mathrm{Ar}$ + $^{12}\mathrm{C}$ and $^{20}\mathrm{Ne}$ + $^{28}\mathrm{Si}$ reactions at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.}$=47.0 MeV and 45.5 MeV, respectively, are explored using particle-particle-\ensuremath{\gamma} coincidence data. These reactions reach a similar excitation energy of ${\mathit{E}}_{\mathrm{CN}}^{\mathrm{*}}$=59.5 MeV in the $^{48}\mathrm{Cr}$ compound nucleus as was obtained in an earlier particle-particle coincidence study of the $^{24}\mathrm{Mg}$ + $^{24}\mathrm{Mg}$ reaction. The overall mass and total kinetic energy distributions of the fission fragments are found to be well reproduced by statistical-model calculations. These calculations are also found to reproduce structure seen in the excitation-energy spectra for the $^{20}\mathrm{Ne}$ + $^{28}\mathrm{Si}$ and $^{24}\mathrm{Mg}$ + $^{24}\mathrm{Mg}$ exit channels for all three reactions. In previous excitation-function measurements, strong heavy-ion resonance behavior has been observed in elastic and inelastic cross sections for the $^{24}\mathrm{Mg}$ + $^{24}\mathrm{Mg}$ system. There has been speculation that peaks observed in the corresponding excitation-energy spectra at more negative Q values may also be a consequence of this resonance phenomenon. The observation of very similar behavior with the asymmetric-mass entrance channels makes it less likely, though, that the peaks arise from any special configuration of the compound system. Instead, an analysis of the \ensuremath{\gamma}-ray data and the results of statistical-model calculations support the conclusion that most of the observed high-lying structure can be accounted for in terms of statistical fission from a fully energy- and shape-equilibrated compound nucleus. For the $^{24}\mathrm{Mg}$ + $^{24}\mathrm{Mg}$ entrance channel, however, comparisons with the statistical model indicate a reduction of high-angular-momentum partial cross sections, leading to the $^{24}\mathrm{Mg}$ + $^{24}\mathrm{Mg}$ fission channel. For the first time, we are able to deduce the nature of the competition between the resonance and statistical-fission mechanisms in this mass region. \textcopyright{} 1996 The American Physical Society.

The fully energy-damped yields from the $^{35}\mathrm{Cl}$${+}^{12}$C reaction have been systematically investigated using particle-particle coincidence techniques at a $^{35}\mathrm{Cl}$ bombarding energy of \ensuremath{\sim}8 MeV/nucleon. The fragment-fragment correlation data show that the majority of events arises from a binary-decay process with rather large numbers of secondary light-charged particles emitted from the two excited exit fragments. No evidence is observed for ternary break-up events. The binary-process results of the present measurement, along with those of earlier, inclusive experimental data obtained at several lower bombarding energies are compared with predictions of two different kinds of statistical model calculations. These calculations are performed using the transition-state formalism and the extended Hauser-Feshbach method and are based on the available phase space at the saddle point and scission point of the compound nucleus, respectively. The methods give comparable predictions and are both in good agreement with the experimental results thus confirming the fusion-fission origin of the fully damped yields. The similarity of the predictions for the two models supports the claim that the scission point configuration is very close to that of the saddle point for the light $^{47}\mathrm{V}$ compound system. The results also give further support for the specific mass-asymmetry-dependent fission barriers needed in the transition-state calculation. \textcopyright{} 1996 The American Physical Society.

Mass and velocity distributions have been measured for the evaporation residue and fusion-fission products from the $^{16}\mathrm{O}$${+}^{40}$Ca reaction at 214 MeV. Comparisons of Monte Carlo statistical evaporation simulations to the observed angle and mass dependences of the evaporation-residue velocity distributions were used to set limits on the maximum complete-fusion cross section and to extract information about the magnitude and character of incomplete-fusion processes. The extracted value of the complete fusion evaporation-residue cross section is discussed in the framework of previous results and existing models.

The BRAHMS collaboration has measured transverse momentum spectra of pions, kaons, protons, and antiprotons at rapidities 0 and 3 for Cu+Cu collisions at $\sqrt{{s}_{\mathit{\text{NN}}}}=200$ GeV. As the collisions become more central the collective radial flow increases while the temperature of kinetic freeze-out decreases. The temperature is lower and the radial flow weaker at forward rapidity. Pion and kaon yields with transverse momenta between 1.5 and $2.5 \mathrm{GeV}/c$ are suppressed for central collisions relative to scaled $p+p$ collisions. This suppression, which increases as the collisions become more central, is consistent with jet quenching models and is also present with comparable magnitude at forward rapidity. At such rapidities, initial state effects may also be present and persistence of the meson suppression to high rapidity may reflect a combination of jet quenching and nuclear shadowing. The ratio of protons to mesons increases as the collisions become more central and is largest at forward rapidities.

Fission yields for the $^{64}\mathrm{Zr}$ reaction at laboratory energies between 240 and 300 MeV have been measured. ``Elastic scattering'' angular distributions were also obtained and used to deduce the generalized total reaction cross sections. The competition between fission and light-particle evaporation from the compound nucleus is well reproduced by statistical-model calculations. However, the calculated neutron multiplicities for this reaction are larger than those previously measured. Possible reasons for this discrepancy are discussed.

We present spectra of charged pions and protons in 0–10% central Au + Au collisions at sNN=200GeV at mid-rapidity (y=0) and forward pseudorapidity (η=2.2) measured with the BRAHMS experiment at RHIC. The spectra are compared to spectra from p+p collisions at the same energy scaled by the number of binary collisions. The resulting nuclear modification factors for central Au + Au collisions at both y=0 and η=2.2 exhibit suppression for charged pions but not for (anti-) protons at intermediate pT. The p¯/π− ratios have been measured up to pT∼3GeV/c at the two rapidities and the results indicate that a significant fraction of the charged hadrons produced at intermediate pT range are (anti-) protons at both mid-rapidity and η=2.2.

Compound-nucleus fusion and binary-reaction mechanisms have been investigated for the ${}^{35}$Cl+${}^{24}$Mg system at an incident beam energy of E${}_{\mathrm{lab}}$= 282 MeV. Charge distributions, inclusive energy spectra, and angular distributions have been obtained for the evaporation residues and the binary fragments. Angle-integrated cross sections have been determined for evaporation residues from both the complete and incomplete fusion mechanisms. Energy spectra for binary fragment channels near the entrance-channel mass partition are characterized by an inelastic contribution that is in addition to a fully energy damped component. The fully damped component which is observed in all the binary mass channels can be associated with decay times that are comparable to, or longer than, the rotation period. The observed mass-dependent cross sections for the fully damped component are well reproduced by the fission transition-state model, suggesting a fusion followed by fission origin. The present data cannot, however, rule out the possibility that a long-lived orbiting mechanism accounts for part or all of this yield.

Fully-energy-damped yields from the $^{16,17,18}\mathrm{O}$${+}^{10,11}$B and $^{19}\mathrm{F}$${+}^{9}$Be reactions at ${\mathit{E}}_{\mathrm{lab}}$5 MeV/nucleon have been identified and attributed to the process of the heavy-ion fusion followed by compound-nucleus fission. The large cross sections observed for these yields while in excess of those expected based on the conventional rotating liquid drop model are nonetheless found to be consistent with calculations using fission barrier energies more appropriate for light systems. An alternative explanation of the observed yields, based on the formation of a dinucleus orbiting complex, fails to account for the experimental results. This work offers the most compelling evidence yet obtained of the occurrence of fission process in light, s-d shell nuclei.

The fully energy-damped cross sections of the $^{24}\mathrm{Mg}$${+}^{24}$Mg reaction at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.}$=44.4 MeV have been measured for all of the major fission channels. High-resolution Q-value spectra have been obtained for the large-angle yields in the $^{24}\mathrm{Mg}$${+}^{24}$Mg and $^{20}\mathrm{Ne}$${+}^{28}$Si channels. Calculations based on the transition-state model are found to reproduce the fully damped cross sections in all of the observed mass channels. The pronounced structure that is observed in the excitation-energy spectra for the more symmetric mass channels, even for the strongly damped yields, is shown to be qualitatively reproduced by assuming a spin-weighted population of the fragment states. There is no evidence, however, that the structure of the nascent fission fragments at scission may influence the population of states in the fragments. These results, taken together with earlier measurements of the resonance behavior of this system, suggest the coexistence of fission from the normal, compact compound nucleus with that from the deformed configurations believed to be responsible for the resonance behavior.

We have measured \ensuremath{\gamma} rays in coincidence with $^{12}\mathrm{C}$ fragments from the fission of $^{56}\mathrm{Ni}$ produced with the $^{32}\mathrm{S}$${+}^{24}$Mg reaction at ${\mathit{E}}_{\mathrm{lab}}$=140 MeV. These data provide insight into the fission process in this light system by giving information about the energy and spin sharing between the $^{12}\mathrm{C}$ and $^{44}\mathrm{Ti}$ fragments, and the spin alignment of the lighter, $^{12}\mathrm{C}$ fragment. The spin transfer and the nuclear ``temperature'' at scission deduced from this measurement can be related to the compound-nucleus spin and potential energy at scission. The results indicate a statistical decay process consistent with the predictions of the transition-state model employing newer estimates of the spin- and mass-asymmetry-dependent saddle-point energies and corresponding shapes. No evidence is found for the spin alignment of the $^{12}\mathrm{C}$ fragments, contrary to what might be expected for a deep-inelastic scattering origin of the fully energy damped yields.

Purpose The Joint European Torus (JET) is the flagship for European Fusion Research. This study seeks to address the issue of the need for remote handling in the process of recreating nuclear fusion as a limitless source of clean energy. Design/methodology/approach Describes in detail the JET remote handling system with its “man in the loop” approach providing the operator with “remote hands” inside the JET Torus. Findings Finds that the increase in requirement for remote operations has necessitated rationalization of task procedures and their associated paper work. Originality/value This paper opens the gates for increasing productivity, broadening the scope of remote handling procedures, increasing operating loads and reducing downtime.

Abstract The organisation of remote handling (RH) operations in fusion environments is increasingly critical as the number of tasks, components and tooling that RH operations teams must deal with inexorably rises. During the recent JET EP1 RH shutdown the existing virtual reality (VR) and procedural database systems proved essential for visualisation and tracking of operations, particularly due to the increasing complexity of remote tasks. A new task planning system for RH operations is in development, and is expected to be ready for use during the next major shutdown, planned for 2009. The system will make use of information available from the remote operations procedures, the RH equipment human–machine interfaces, the on-line RH equipment control systems and also the virtual reality (VR) system to establish a complete database for the location of plant items and RH equipment as RH operations progress. It is intended that the system be used during both preparation and implementation of shutdowns. In the preparations phase the system can be used to validate procedures and overall logistics by allowing an operator to increment through each operation step and to use the VR system to visualise the location and status of all components, manipulators and RH tools. During task development the RH operations engineers can plan and visualise movement of components and tooling to examine handling concepts and establish storage requirements. In the implementation of operations the daily work schedules information will be integrated with the RH operations procedures tracking records to enable the VR system to provide a visual representation of the status of remote operations in real time. Monitoring of the usage history of items will allow estimates of radiation dosage and contaminant exposure to be made. This paper describes the overall aims, structure and use of the system, discusses its application to JET and also considers potential future developments.

Excitation functions have been measured for the $^{24}\mathrm{Mg}$($^{16}\mathrm{O}$, $^{12}\mathrm{C}$)$^{28}\mathrm{Si}$ reaction populating states in $^{28}\mathrm{Si}$ with $6.4\ensuremath{\le}{E}_{x}\ensuremath{\le}10$ MeV over the energy range $24\ensuremath{\le}{E}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\le}36$ MeV. At each incident beam energy, cross sections were measured at three angles over the range $17\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}{\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\le}21\ifmmode^\circ\else\textdegree\fi{}$. More complete angular distributions with $10\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}{\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}\ensuremath{\le}50\ifmmode^\circ\else\textdegree\fi{}$ were measured at ${E}_{\mathrm{c}.\mathrm{m}.}=30.5 \mathrm{and} 32.6$ MeV. Resonance-like structures are observed in the excitation functions and strongly correlate with those seen previously at forward angles for the $^{24}\mathrm{Mg}$($^{16}\mathrm{O}$, $^{12}\mathrm{C}$)$^{28}\mathrm{Si}$(g.s.) transition. Estimates are made for the partial decay widths of the resonance at ${E}_{\mathrm{c}.\mathrm{m}.}=30.8$ MeV to the excited states in $^{28}\mathrm{Si}$. Using different background assumptions, between 5% and 40% of the total width of this resonance can be atrributed to $^{12}\mathrm{C}$+$^{28}\mathrm{Si}$* (${E}_{x}&lt;10$ MeV) decays.NUCLEAR REACTIONS $^{24}\mathrm{Mg}$($^{16}\mathrm{O}$, $^{12}\mathrm{C}$)$^{28}\mathrm{Si}$* ($6.4&lt;~{E}_{x}&lt;~10$ MeV); $24&lt;~{E}_{\mathrm{c}.\mathrm{m}.}&lt;~36$ MeV; measured $\ensuremath{\sigma}(E, \ensuremath{\theta})$; DWBA analysis; deduced partial widths.

This paper presents an introduction of a novel development to a multi-functional mobile platform for agriculture applications. This is achieved through a reinvention process of a mechatronic design by spinning off space robotic technologies into terrestrial applications in the AgriRover project. The AgriRover prototype is the first of its kind in exploiting and applying space robotic technologies in precision farming. To optimize energy consumption of the mobile platform, a new dynamic total cost of transport algorithm is proposed and validated. An autonomous navigation system has been developed to enable the AgriRover to operate safely in unstructured farming environments. An object recognition algorithm specific to agriculture has been investigated and implemented. A novel soil sample collecting mechanism has been designed and prototyped for on-board and in situ soil quality measurement. The design of the whole system has benefited from the use of a mechatronic design process known as the Tiv model through which a planetary exploration rover is reinvented into the AgriRover for agricultural applications. The AgriRover system has gone through three sets of field trials in the UK and some of these results are reported.

Excitation functions have been measured at 0\ifmmode^\circ\else\textdegree\fi{} and 180\ifmmode^\circ\else\textdegree\fi{} for the $^{24}\mathrm{Mg}$${(}^{16}$O${,}^{12}$C${)}^{28}$ Si(g.s.) reaction, and at 180\ifmmode^\circ\else\textdegree\fi{} for the $^{24}\mathrm{Mg}$${(}^{16}$O${,}^{12}$C${)}^{28}$ Si(${2}^{+}$) reaction over the energy range 36 MeV\ensuremath{\le}${E}_{\mathrm{c}.\mathrm{m}.}$\ensuremath{\le}54 MeV. Angular distributions were measured at ${E}_{\mathrm{c}.\mathrm{m}.}$=35.5 and 36.2 MeV where, for the latter energy, much of the angular range between 0\ifmmode^\circ\else\textdegree\fi{} and 180\ifmmode^\circ\else\textdegree\fi{} was covered. These data, combined with earlier measurements at lower energies, establish that the reaction cross section is strongly influenced by resonances of the compound system over a large energy range. At the higher energies, however, both the energy averaged cross section and the resonance amplitudes fall off sharply. An attempt is made to reproduce the observed structure in the $^{28}\mathrm{Si}$(g.s.) 0\ifmmode^\circ\else\textdegree\fi{} and 180\ifmmode^\circ\else\textdegree\fi{} excitation functions by fitting to the data a band of Breit-Wigner resonances with an energy dependence proportional to J(J+1). The general behavior of the 0\ifmmode^\circ\else\textdegree\fi{} and 180\ifmmode^\circ\else\textdegree\fi{} yield is well reproduced by this procedure, even though there are twice as many resonance poles as there are clear bumps in the data. Some regularity is evident in the resulting resonance parameters, although the fitted resonance amplitudes show greater scatter than expected for a nuclear molecular band.

An excitation function for the 40Ca${(}^{16}$O${,}^{28}$${\mathrm{Si}}^{\mathrm{*}}$${)}^{28}$${\mathrm{Si}}^{\mathrm{*}}$ reaction has been measured between 74.925\ensuremath{\le}${E}_{\mathrm{lab}\mathrm{\ensuremath{\le}}}$77.25 MeV in 75-keV steps for 30\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}${\mathrm{theta}}_{\mathrm{lab}\mathrm{\ensuremath{\le}}60\mathrm{\ifmmode^\circ\else\textdegree\fi{}}}$. $Q----value and angular distributions were measured at each beam energy. Intermediate width (\ensuremath{\Gamma}\ensuremath{\simeq}200 keV) structures are present in the excitation function at the 3--5 % level of the cross section. An analysis of the present excitation function, together with one previously obtained for the inclusive elastic and inelastic $^{28}\mathrm{Si}$ scattering yields, indicates that the structures in the two excitation functions are correlated at an 80% confidence level. This suggests that the process responsible for the resonances is of compound-nuclear origin.

Particle production of charged kaons in central Au+Au collisions at has been studied as a function of rapidity by the BRAHMS collaboration at RHIC. The kaon spectral shapes are described well by an exponential in transverse mass for the rapidity range of 0 ⩽ yK ⩽ 3.3 with smoothly decreasing inverse slopes as the rapidity increases. For the charged kaon to pion ratios, while there is no significant rapidity dependence for the K+/π+ ratio, the K−/π− ratio shows a significant decrease from y ≈ 1 towards higher rapidities. The systematics of K−/K+ and ratios in the measured rapidity range demonstrates a strongly correlated behaviour which can be described by thermal–statistical models.

The proton spectra from pion- and photon-induced reactions on $^{12}\mathrm{C}$ at the $\ensuremath{\Delta}(\frac{3}{2},\frac{3}{2})$ resonance are found to be very similar in shape, and in their variation with angle. It seems reasonable to assume that these protons arise from a common reaction mechanism ($\ensuremath{\Delta}$ production) for the two projectiles. The absolute cross sections for producing protons with pions and with photons are in roughly the same ratio as the total inelastic pion yield to the total photopion yield.

HiPER is the European Project for Laser Fusion that has been able to join 26 institutions and signed under formal government agreement by 6 countries inside the ESFRI Program of the European Union (EU). The project is already extended by EU for two years more (until 2013) after its first preparatory phase from 2008. A large work has been developed in different areas to arrive to a design of repetitive operation of Laser Fusion Reactor, and decisions are envisioned in the next phase of Technology Development or Risk Reduction for Engineering or Power Plant facilities (or both). Chamber design has been very much completed for Engineering phase and starting of preliminary options for Reactor Power Plant have been established and review here.

Abstract The quality, functionality and performance of the virtual reality (VR) system used at JET for preparation and implementation of remote handling (RH) operations has been progressively enhanced since its first use in the original JET remote handling shutdown in 1998. As preparation began for the JET EP2 (Enhanced Performance 2) shutdown it was recognised that the VR system being used was unable to cope with the increased functionality and the large number of 3D models needed to fully represent the JET in-vessel components and tooling planned for EP2. A bespoke VR software application was developed in collaboration with the OEM, which allowed enhancements to be made to the VR system to meet the requirements of JET remote handling in preparation for EP2. Performance improvements required to meet the challenges of EP2 could not be obtained from the development of the new VR software alone. New methodologies were also required to prepare source, CATIA models for use in the VR using a collection of 3D software packages. In collaboration with the JET drawing office, techniques were developed within CATIA using polygon reduction tools to reduce model size, while retaining surface detail at required user limits. This paper will discuss how these developments have played an essential part in facilitating EP2 remote handling task development and examine their impact during the EP2 shutdown.

The proton-to-pion ratios measured in the BRAHMS experiment for Au+Au and p+p collisions at $\sqrt{s_{NN}}$ = 62.4 and 200 GeV are presented as a function of transverse momentum and collision centrality at selected pseudorapidities in the range of 0 to 3.8. A strong pseudorapidity dependence of these ratios is observed. We also compare the magnitude and p_T-dependence of the p/pi ratios measured in Au+Au collisions at \rootsnn{200} and $\eta \approx 2.2$ with the same ratio measured at \rootsnn{62.4} and $\eta = 0$. The great similarity found between these ratios throughout the whole p_T range (up to 2.2 GeV/$c$) is consistent with particle ratios in A+A collisions being described with grand-canonical distributions characterized by the baryo-chemical potential \mibn. At the collision energy of 62.4 GeV, we have observed a unique point in pseudorapidity, $\eta = 3.2$, where the p/pi+ ratio is independent of the collision system size in a wide p_T-range of $0.3 \le p_{T} \le 1.8$ GeV/$c$.

Inclusive as well as exclusive energy spectra of the light charged particles emitted in the 28Si(Elab = 112.6 MeV) + 28Si, 12C reactions have been measured at the Strasbourg VIVITRON facility in a wide angular range 150 – 1500, using the ICARE multidetector array. The observed α-particle energy spectra are generally well reproduced by the statistical model using a spin-dependent level density parameterisation. The results suggest significant deformation effects at high spin.

The distributions in mass, energy and angle of fully damped fragments from the A≈80 system produced in the symmetric 40Ca+40Ca reaction at 197 and 231 MeV and in the asymmetric 28Si+50Cr reaction at 150 MeV have been studied. The mass distributions show a strong entrance channel dependence. A discussion in terms of barriers calculated using the finite-range liquid drop model suggests a fast-fission mechanism previously only ascribed to much heavier systems.

The intrinsic quadrupole moment Q(0) of superdeformed rotational bands in A approximately 150 nuclei depends on the associated single-particle configuration. We have derived an empirical formula based on the additivity of effective quadrupole moments of single-particle orbitals that describes existing measurements from (142)Sm to (152)Dy. To further test the formula, the predicted Q(0) moments for two superdeformed bands in (146)Gd of 14.05 eb were confronted with a new measurement yielding 13.9+/-0.4 eb and 13.9+/-0.3 eb, respectively. This excellent agreement provides empirical evidence of extreme single-particle behavior in highly deformed, collective systems.

An array of 40 tiles of thin plastic scintillators is used to construct the outer layer of the charged particle multiplicity detector for the BRAHMS experiment at the Relativistic Heavy Ion Collider (RHIC). Each tile is a square with 12cm long sides and 5mm thickness. The light from each of the scintillators is collected by wavelength shifting fibers embedded on the periphery. The light collection is uniform within 5% over the tile with the edge effect limited to 4mm along the edge. The response is found to be linear in the high-multiplicity environment at RHIC with Au+Au beams at sNN of 200GeV.

Elliptic flow has been measured by the BRAHMS experiment as a function of transverse momentum and pseudorapidity for the Au+Au reaction at GeV. Identified-particle v2(η, pt) values were obtained with the two BRAHMS spectrometers at pseudorapidities η≈ 0, 1 and 3.4. The results show that the differential v2(η, pt) values for a given particle type are essentially constant over the covered pseudorapidity range. It is suggested that the dominant cause of the observed fall-off of the integral v2 values going away from mid-rapidity is a corresponding softening of the particle spectra.

We performed an experiment to search for the two-phonon octupole vibrational state in {sup 208}Pb. Thick targets of {sup 208}Pb, {sup 209}Bi, {sup 58,64}Ni, and {sup 160}Gd were bombarded with 1305 MeV beams of were bombard {sup 208}Pb supplied by ATLAS. Gamma rays were detected using the Argonne-Notre Dame BGO gamma-ray facility, consisting of 12 Compton-suppressed germanium detectors surrounding an array of 50 BGO scintillators. We identified some 30 known gamma rays from {sup 208}Pb in the spectra gated by the 5{sup -} {yields} 3{sup -} and 3{sup -} {yields} 0{sup +} transitions in {sup 208}Pb. In addition, after unfolding these spectra for Compton response, we observed broad coincident structures in the energy region expected for the 2-phonon states. Furthermore, we confirmed the placement of a 2485 keV line observed previously in {sup 207}Pb and find no evidence consistent with the placement of this line in {sup 208}Pb. We are currently in the process of investigating the origin of the broadened lines observed in the spectra, extracting the excitation probability of states in {sup 208}Pb, and determining the relative probability of mutual excitation and neutron transfer in this reaction. An additional experiment is also being performed to collect much highermore » statistics germanium-germanium coincidence data for the thick {sup 208}Pb target.« less

Mass, energy, charge and angular distributions from fully damped reactions of the 40Ca + 40Ca system have been measured at 197 and 231 MeV, in both singles and coincidence. The data display features of compound nucleus fission. Comparison with similar, but asymmetric systems, however, shows an entrance-channel dependence which invalidates a fusion-fission description. A discussion in terms of fission barriers calculated using the finite-range liquid drop model suggests a fast-fission mechanism. Re-analyses of systems studied in the literature are presented in terms of the finite-range liquid drop model, indicating fast fission — a process previously assumed only to be relevant for heavier systems — to be significant in most cases. Furthermore, using the finite-range liquid drop model, we find that the systematic behaviour of the mass distributions from systems where complete fusion-fission is expected to be dominant is well described in terms of the revised locus of the Businaro-Gallone transition from symmetric to asymmetric fission.

The properties of binary fragments produced in the 35Cl+24Mg fusion reaction at a beam energy of ELab≈8MeVA have been investigated by measurement of inclusive energy spectra, angular distributions and angular correlations between heavy fragments and evaporated charged particles. The fully damped components can be ascribed to a fusion-fission process.

Abstract Highlights of the results obtained by the CMS experiment at the LHC on collective flow and dihadron correlations in PbPb collisions are presented. At lower transverse momenta of the outgoing particles and for a wide range of collision centralities, the 2 nd - through 6 th -order Fourier components of the azimuthal distribution have been found using different analysis techniques with different sensitivities to non-flow and flow fluctuation effects. An ultra-central collision trigger allows the Fourier components to be extended to a region of centrality where initial-state effects are expected to be small. A high- p T single-track trigger has allowed the elliptic anisotropy ( ν 2 ) and higher-orderharmonics to be explored up to ≈ 60 GeV/c , as a function of pseudorapidity and collision centrality. The CMS results provide new information on both the hydrodynamic properties of the medium at low p T and the path-length dependence of in-medium parton energy loss at high p T . By subtracting the long-range in pseudorapidity anisotropy components arising from hydrodynamic flow from dihadron correlation results, it is possible to gain further insight into the medium effect on dijets. This is done with a study of the “near-side” and “away-side” yields of dijets measured in PbPb collisions compared to those found in pp collisions.

Evidence that the fully energy-damped binary products observed in the 18O + 10,11B reactions originate from a fusion-fission process, rather than through a deep-inelastic orbiting mechanism, is presented. The relative importance of the fusion-fission process in these very light systems is supported by experimental results that indicate a statistically equilibrated fission process and also by model calculations. This conclusion is contrary to that reached in a recent publication discussing the same data.

Fusion and breakup in reactions involving weakly bound nuclei A. Szanto de Toledo”, F.A. Souza”, C. Beckb, S.J. Sandersc, M.G. Munhoza, J Takahashi”, N. Carlin”, A.A.P. Suaide”, M.M. de Moura” and E.M. Szanto” “Instituto de Fisica - Universidade de Slo Paulo, Deptartamento de Fisica Nuclear, Laboratorio Pelletron, CP 66318, 05315-970, Sao Paulo - SP, Brazil bCentre National de la Recherche Scientifique Universitd Louis Pasteur, 23 rue du Loess, B.P. 28, F-67037 Strasbourg Cedex 2, France ‘University of Kansas, Lawrence, KS 66045, USA The effect of collective degrees of freedom on the fusion process has been extensively investigated over the past few years [l]. A significant enhancement of the sub-barrier fu- sion cross section is often found as compared to the predictions of one-dimensional barrier penetration models. This enhancement is understood in terms of dynamical processes involving couplings to collective inelastic excitations of the target and/or projectile. A precise determination of the “barrier distributions” leading to the enhancement requires an understanding of the dominant channels that couple to the fusion channel[2]. However, in the case of reactions where at least one of the colliding nuclei has a sufficiently low binding energy so that breakup becomes an important process, conflicting experimental and theoretical results have been reported [3-111. The many questions regarding the influence of breakup become more relevant with the recent availability of radioactive beams and the renewed interest in super-heavy element formation. Radioactive ion beams are likely to produce intense breakup yields. In the fusion processes, and more specifically in the fusion of weakly bound nuclei, that can be used in super-heavy element studies, two different and independent processes can be distinguished both experimentally and theoretically. One, denoted as “Complete Fusion” (CF), is associated with the capture of all of the projectile constituents by the target. The other, denoted as “Incomplete Fusion” (ICF) or Partial Fusion, occurs when part of the projectile is captured by the target and the remaining part escapes. “Total Fusion” is understood as the sum of these two processes (CF + ICF). In order to avoid misinterpre- tations, a clear definition of the experimental and theoretical quantities being compared is essential. This is the main difficulty in comparing data and/or calculations from different authors. Depending on the theoretical approach, different results are achieved. If fusion occurs incoherently, i.e., with possible breakup of the incoming particle [4,5], the survival probability of this particle prior to fusion, is lower than unity, resulting in a decrease in the effective entrance-channel flux and a corresponding reduction of the fusion cross section. On the other hand, if the breakup channel is coupled coherently to the fusion channel, as expected in references [3,6], entrance barrier fluctuations will lead to an effective lowering

The effect of breakup in the fusion cross section in terms of suppression versus enhancement, discussed in a conflicting way in the literature is addressed. Data and theoretical predictions available in the literature are compared. Excitation functions of the sub- and near-barrier fusion cross-sections for a wide variety of light and heavy systems are presented and interpreted. We have measured fusion excitation functions and breakup correlation functions for the medium weight systems 6Li + 59Co and 7Li + 59Co. These measurements help to establish the influence of the projectile breakup on the fusion process at near-barrier energies and contribute to the determination of how the mass of the target affects the breakup role. The results indicate a light fusion enhancement at sub-barrier energies and a geometry dominated cross section at barrier energies.

The influence on the fusion process of coupling to collective degrees of freedom has been explored. The significant enhancement of the fusion cross section at sub-barrier energies was compared to predictions of one-dimensional barrier penetration models. This was understood in terms of the dynamical processes arising from strong couplings to collective inelastic excitations of the target and projectile. However, in the case of reactions where at least one of the colliding nuclei has a sufficiently low binding energy, for breakup to become an important process, conflicting model predictions and experimental results have been reported in the literature. Excitation functions for sub- and near-barrier total (complete + incomplete) fusion cross sections have been measured for the 6,7Li+59Co reactions. Elastic scattering as well as breakup/transfer yields have also been measured at several incident energies. Results of Continuum-Discretized Coupled-Channel (Cdcc) calculations describe reasonably well the experimental data for both reactions at and above the barrier. A systematic study of 4,6He induced fusion reactions with a three-body Cdcc method is presented. The relative importance of breakup and bound-state structure effects on total fusion (excitation functions) is particularly investigated. The four-body Cdcc model is being currently developed.

The ITER plant will require fully remote maintenance during its operational life. For this to be effective, safe and efficient the plant will have to be developed in accordance with remote handling (RH) compatibility requirements. A system for ensuring RH compatibility on plant designed for Tokamaks was successfully developed and applied, inter alia, by the authors when working at the JET project. The experience gained in assuring RH compatibility of plant at JET is now being applied to RH relevant ITER plant. The methodologies required to ensure RH compatibility of plant include the standardization of common plant items, standardization of RH features, availability of common guidance on RH best practice and a protocol for design and interface review and approval. The protocol in use at ITER is covered by the ITER Remote Maintenance Management System (IRMMS) defines the processes and utilization of management controls including Plant Definition Forms (PDF), Task Definition Forms (TDFs) and RH Compatibility Assessment Forms (RHCA) and the ITER RH Code of Practice. This paper will describe specific examples where the authors have applied the methodology proven at JET to ensure remote handling compatibility on ITER plant. Examples studied are: ELM coils (to be installed in-vessel behind the Blanket Modules) – handling both in-vessel, in Casks and at the Hot Cell as well as fully remote installation and connection (mechanical and electrical) in-vessel. Neutral beam systems (in-vessel and in the NB Cell) – beam sources, cesium oven, beam line components (accessed in the NB Cell) and Duct Liner (remotely replaced from in-vessel). Divertor (in-vessel) – cooling pipe work and remotely operated electrical connector. The RH compatibility process can significantly affect plant design. This paper should therefore be of interest to all parties who develop ITER plant designs.

A large-acceptance Bragg curve spectrometer with a longitudinal electron collection field and a segmented anode has been constructed and tested. The effects on the charge resolution of the entrance angle and entrance position of the incident particle have been studied. Simulations have been done in order to isolate the contribution to the overall detector performance of the signal-shaping electronics from that of the intrinsic design of the detector.

The possible occurence of highly deformed configurations is investigated in the $^{40}$Ca and $^{56}$Ni di-nuclear systems as formed in the $^{28}$Si+$^{12}$C,$^{28}$Si reactions by using the properties of emitted light charged particles. Inclusive as well as exclusive data of the heavy fragments and their associated light charged particles have been collected by using the {\sc ICARE} charged particle multidetector array. The data are analysed by Monte Carlo CASCADE statistical-model calculations using a consistent set of parameters with spin-dependent level densities. Significant deformation effects at high spin are observed as well as an unexpected large $^{8}$Be cluster emission of a binary nature.

Single and multinucleon transfer yields for the ${}^{136}{\mathrm{X}\mathrm{e}+}^{64}\mathrm{Ni}$ reaction at a scattering energy $\ensuremath{\approx}5%$ above the Coulomb barrier energy are studied using particle--\ensuremath{\gamma}-ray coincidence data. $Q$-value and scattering-angle distributions are extracted for the stronger channels. A fast transfer mechanism dominates the yields to these channels over an extended $Q$-value range, leading to a concentration of the cross section near the grazing angle. Analysis of the angular distributions based on a semiclassical barrier penetration model suggests that the single-nucleon and two-neutron exchange channels are dominated, respectively, by direct and two-step sequential transfer from the ground or low-lying excited states of the participating nuclei. The multiproton transfer channels have angular distributions that indicate a more complex mechanism, although direct cluster transfer from an excited configuration cannot be fully discounted. In a separate analysis, the relative population of different mass channels is found to be in general agreement with the expectations of a ``random walk'' model of particle exchange.

Results from the BRAHMS Collaboration for the inaugural physics run with the relativistic heavy ion collider (RHIC), Au + Au collisions at √sNN = 130 GeV in the late summer of 2000, and some results of the very first data from the summer of 2001 at √sNN = 200 GeV are presented. Here the main focus is on the determination of the pseudorapidity distribution of charged particles as a function of collision centrality and on the measurement of the antiproton to proton and the K− to K+ ratios as a function of rapidity. The pseudorapidity density at midrapidity reaches dN(ch)/dη = 553 ± 36 for the most central collisions (0–5%) at √sNN = 130 GeV; the corresponding number for a higher energy is dN(ch)/dη = 632 ± 36, demonstrating an increase in multiplicity of about 14%. The measured antiproton/proton ratios peak at midrapidity around N()/N(p) = 0.64 ± 0.06 and drop to 0.41 ± 0.04 at y ≈ 2 for √sNN = 130 GeV reactions; the K− to K+ ratios are 0.90 ± 0.06 (y ≈ 0) and 0.83 ± 0.1 (y ≈ 2.5).

A strong azimuthal flow signature at RHIC suggests rapid system equilibration leading to an almost perfect fluid state. The longitudinal extent of the flow behavior depends on how this state is formed and can be studied by measuring the pseudorapidity and transverse momentum dependence of the second Fourier component (ν2(pT)) of the azimuthal angular distribution. We report on a measurement of identified-particle ν2 as a function of pT(0.5−2.0 GeV/c), centrality (0-25%, 25-50%), and pseudorapidity (0⩽η<3.2) for sNN=200 GeV Au+Au collisions. The BRAHMS spectrometers are used for particle identification (π, K, p) and momentum determination and the BRAHMS global detectors are used to determine the corresponding reaction-plane angles. The results are discussed in terms of the pseudorapidity dependence of constituent quark scaling and in terms of models that develop the complete (azimuthal and radial) hydrodynamic aspects of the forward dynamics at RHIC.

Single-nucleon transfer cross sections have been measured for the $^{48}$Ti${+}^{104}$Ru reaction over a large angular range at an energy near the Coulomb barrier. Evidence has been found previously in \ensuremath{\gamma}-ray studies for superdeformed shapes in the compound system ${(}^{152}$Dy) reached by this reaction. Reaction channels which couple to these shapes may experience interaction time delays, which would be revealed experimentally by broadened angular distributions. Although an enhancement is found in the forward angle $^{49}\mathrm{Ti}$ yields, this enhancement is small and may reflect uncertainties in the analysis.

The BRAHMS collaboration has measured transverse momentum spectra of pions, kaons, protons and antiprotons at rapidities 0 and 3 for Cu+Cu collisions at $\sqrt{s_{NN}} = 200$ GeV. As the collisions become more central the collective radial flow increases while the temperature of kinetic freeze-out decreases. The temperature is lower and the radial flow weaker at forward rapidity. Pion and kaon yields with transverse momenta between 1.5 and 2.5 GeV/c are suppressed for central collisions relative to scaled $p+p$ collisions. This suppression, which increases as the collisions become more central is consistent with jet quenching models and is also present with comparable magnitude at forward rapidity. At such rapidities initial state effects may also be present and persistence of the meson suppression to high rapidity may reflect a combination of jet quenching and nuclear shadowing. The ratio of protons to mesons increases as the collisions become more central and is largest at forward rapidities.

We report on the CMS measurements of charged-hadron anisotropic azimuthal distributions from PbPb collisions at √ s NN = 2.76 TeV.The results are presented as a function of transverse momentum, centrality and pseudorapidity over a wide kinematic region.For low transverse momentum particles (p T < 3 GeV/c ) the azimuthal behavior is believed to be dominated by the hydrodynamic flow of the expanding medium created in the reaction.We characterize this behavior in terms of the first-order term of a Fourier expansion of the azimuthal angular distribution as determined using the event-plane, cumulant, and Lee-Yang zeros methods.For high transverse momentum particles (p T > 8 GeV/c) the azimuthal asymmetry reflects the energy loss of highenergy partons moving through the medium.This is studied using the event-plane method.In both cases the azimuthal asymmetry can be related to the initial geometry of the hot and dense matter created in the reaction.These results provide constraints on theoretical descriptions of the early dynamics of heavy-ion reactions at the LHC and the transport properties through the medium created by these reactions.

The Department of Physics and Astronomy at the University of Kansas seeks applicants for a tenure-track assistant professor position in the field of experimental condensed matter physics.The position is expected to begin as early as August 18, 2012.Candidates who complement the existing programs in condensed matter physics, in particular with regard to basic energy science, are encouraged to apply.A Ph.D. or ABD in Physics or a closely related

Corrosion and gas hydrate formation are flow assurance problems that can cause serious safety problems in deep water environments. One aspect that has been given less attention is the corrosion behavior of materials in salinity environment where gas hydrate formation and CO2 (sweet) corrosion can both occur. This type of environment is common in oil and gas deep water environments. The aim of this work is to investigate the effects of CO2-saturated salinity environment on Ni-Mo alloys at gas hydrate formation temperatures using electrochemical, SEM/EDX, and XRD surface characterization techniques. The immersion test solutions were sweet low-salinity (CO2 + 1 wt% salt + 5 oC) and sweet high- salinity (CO2 + ~24 wt% salt + 5 oC) environments, respectively. The as-deposited Ni-Mo alloy coating has the highest corrosion resistance of 33.28 kΩ cm2. The corrosion resistance dropped to 14.36 kΩ cm2 and 11.11 kΩ cm2 after 20 hrs of immersion in the sweet low-salinity and sweet high-salinity test solutions respectively. From grazing incidence XRD, the (111) reflection peak of the Ni-Mo coating was depressed and broaden after immersion in both test solutions due to increase in oxide layer formation on the surface of the Ni-Mo coating. SEM revealed a cracked surface morphology after immersion in sweet high-salinity test solution and elemental analysis shows the presence of oxygen after immersion in both test solutions. The oxygen content increased from 1.70 wt% after immersion in sweet low-salinity test solution to 2.37 wt% after immersion in sweet high-salinity test solution.

Gas hydrate formation and corrosion can cause serious safety and flow assurance problems in deep water environments. One aspect that has been given less attention is the corrosion behavior of materials in salinity environment where gas hydrate formation and CO 2 (sweet) corrosion can simultaneously occur. This type of environment is common in oil and gas deep water environments. The aim of this work is to investigate the corrosion behavior of Ni-Mo alloy coatings in an environment containing salt and dissolved CO 2 gas at gas hydrate formation temperature (5 o C). Even though materials exposed to deep water operations can still experience corrosion at gas hydrate temperatures (low temperatures), previous research have done similar studies in room or higher temperatures using other test materials. Ni-Mo coatings were selected as the test material due to its excellent corrosion resistance in aggressive environments and serves as a based material for many oil and gas materials. A specialty designed jacketed glass cell was used to conduct the immersion test. The immersion test solutions were sweet low-salinity (CO 2 + 1 wt% salt + 5 o C) and sweet high-salinity (CO 2 + ~24 wt% salt + 5 o C) test solutions, respectively. The as-deposited Ni-Mo alloy coating has the highest corrosion resistance of 33.28 kΩ cm 2 . The corrosion resistance dropped to 14.36 kΩ cm 2 and 11.11 kΩ cm 2 after 20 hrs of immersion in the sweet low-salinity and sweet high-salinity test solutions, respectively. From grazing incidence XRD, the (111) reflection peak of the Ni-Mo coating was depressed and broaden after immersion in both test solutions due to increase in oxide layer formation on the surface Ni-Mo coating. SEM revealed a cracked surface morphology after immersion in sweet high-salinity test solution and elemental analysis shows the presence of oxygen after immersion in both test solutions, which is an indication of the formation of oxygen containing compounds on the surface of the Ni-Mo coating. The oxygen content increased from 1.70 wt% after immersion in sweet low-salinity test solution to 2.37 wt% after immersion in sweet high-salinity test solution. This work provides a new corrosion design consideration and solution, and will help in designing models and corrosion prediction software used for simulating materials exposed to salinity environment where gas hydrate formation and CO 2 corrosion can both occur. Incorporating this consideration into corrosion design of pipeline will improve offshore pipeline performance and serve as a baseline for initial corrosion allowance for materials exposed to this type of environment. Figure 1

Casimir interactions play an important role in the dynamics of nanoscale objects. Here, we investigate the noncontact transfer of angular momentum at the nanoscale through the analysis of the Casimir torque acting on a chain of rotating nanoparticles. We show that this interaction, which arises from the vacuum and thermal fluctuations of the electromagnetic field, enables an efficient transfer of angular momentum between the elements of the chain. Working within the framework of fluctuational electrodynamics, we derive analytical expressions for the Casimir torque acting on each nanoparticle in the chain, which we use to study the synchronization of chains with different geometries and to predict unexpected dynamics, including a rattleback-like behavior. Our results provide new insights into the Casimir torque and how it can be exploited to achieve efficient noncontact transfer of angular momentum at the nanoscale, and therefore have important implications for the control and manipulation of nanomechanical devices.

Fusion cross section excitation functions were measured for the 6,7 Li+ 59 Co systems (12 ≤ E lab ≤ 26M eV ) aiming the investigation of the effect of the breakup process on the fusion cross section.The experimental method consisted on the detection of γ-rays from the evaporation residues.Coupled channels calculations have been performed for both systems.The comparison to the experimental results support the conclusion that there is neither supression nor enhancement at energies above the coulomb barrier.A slight enhancement at energies below the barrier is observed for the 6 Li+ 59 Co cross section over the one for 7 Li+ 59 Co.In order to better quantify the effect of the breakup process, coincidence measurements for the breakup products are being performed.

Resumen en: A summary of BRAHMS results is presented. Emphasis is placed on data for which measurements at forward rapidities are necessary for interpretation. This ...

The BRAHMS experiment at RHIC has measured pions, kaons and protons and their antiparticles over a wide range of rapidity and transverse momenta. Au+Au collisions, d+Au and p+p interactions have been studied. From the net-proton rapidity distribution a stopping power of 73% can be deduced for central Au+Au collisions. The rapidity distributions of produced particles exhibit Gaussian shapes. At midrapidity the nuclear modification factor for central Au+Au collisions shows a strong pion suppression at intermediate transverse momenta; a suppression which is even stronger at forward rapidities. The nuclear modification factor for d+Au changes from a Cronin-like enhancement of charged hadrons at midrapidity to a suppression at forward rapidities.

We present recent results obtained by the BRAHMS experiment at the Relativistic Heavy Ion Collider (RHIC) for the systems of Au + Au and Cu + Cu at \rootsnn{200} and at 62.4 GeV, and p + p at \rootsnn{200}. Nuclear modification factors for Au + Au and Cu + Cu collisions are presented. Analysis of anti-particle to particle ratios as a function of rapidity and collision energy reveal that particle populations at the chemical freeze-out stage for heavy-ion reactions at and above SPS energies are controlled by the baryon chemical potential. From the particle spectra we deduce significant radial expansion ($\beta \approx $ 0.75), as expected for systems created with a large initial energy density. We also measure the elliptic flow parameter $v_2$ versus rapidity and \ptn. We present rapidity dependent $p/\pi$ ratios within $0 < y < 3$ for Au + Au and Cu + Cu at \rootsnn{200}. \Raa is found to increase with decreasing collision energy, decreasing system size, and when going towards more peripheral collisions. However, \Raa shows only a very weak dependence on rapidity (for $0 < y < 3.2$), both for pions and protons.

Results from the BRAHMS collaboration for Au+Au collisions at √SNN = 200 GeV are presented, focussing on the measurement of the net-proton rapidity distribution, the determination of the pseudorapidity distribution of charged particles and on the rapidity distributions of pions and kaons.

When arranged in a periodic geometry, arrays of metallic nanostructures are capable of supporting collective modes known as lattice resonances. These modes, which originate from the coherent multiple scattering between the elements of the array, give rise to very strong and spectrally narrow optical responses. Here, we show that, thanks to their collective nature, the lattice resonances of a periodic array of metallic nanoparticles can mediate an efficient long-range coupling between dipole emitters placed near the array. Specifically, using a coupled dipole approach, we calculate the Green tensor of the array connecting two points and analyze its spectral and spatial characteristics. This quantity represents the electromagnetic field produced by the array at a given position when excited by a unit dipole emitter located at another one. We find that, when a lattice resonance is excited, the Green tensor is significantly larger and decays more slowly with distance than the Green tensor of vacuum. Therefore, in addition to advancing the fundamental understanding of lattice resonances, our results show that periodic arrays of nanostructures are capable of enhancing the long-range coupling between collections of dipole emitters, which makes them a promising platform for applications such as nanoscale energy transfer and quantum information processing.

The possible occurence of highly deformed configurations is investigated in the $^{40}$Ca and $^{56}$Ni di-nuclear systems as formed in the $^{28}$Si + $^{12}$C and $^{28}$Si + $^{28}$Si reactions, respectively, by using the properties of emitted light charged particles. Inclusive as well as exclusive data of the heavy fragments (A $\geq$ 6) and their associated light charged particles (p, d, t, and $α$-particles) have been collected at the IReS Strasbourg VIVITRON Tandem facility with two bombarding energies $E_{lab}(^{28}$Si) = 112 and 180 MeV by using the ICARE charged particle multidetector array, which consists of nearly 40 telescopes. The measured energy spectra, velocity distributions, in-plane and out-of-plane angular correlations are analysed by Monte Carlo CASCADE statistical-model calculations using a consistent set of parameters with spin-dependent level densities. Although significant deformation effects at high spin are needed, the remaining disagreement observed in the $^{28}$Si + $^{12}$C reaction for the S evaporation residue suggests an unexpected large unstable $^{8}$Be cluster emission of a binary nature.

The BRAHMS experiment will measure semi-inclusive spectra of identified charged particles over an extended range of rapidity and transverse momentum. These data will be used to characterize both the `hard' and `soft' scattering components of reactions at RHIC energies in both the central- and large-rapidity regions. This talk presents an overview of the BRAHMS experiment.

The intrinsic quadrupole moment Q0 of superdeformed rotational bands in A∼150 nuclei depends on the associated single-particle configuration. We have derived an empirical formula based on the additivity of effective quadrupole moments of single-particle orbitals that describes existing measurements from 142Sm to 152Dy. To further test the formula, the predicted Q0 moments for two superdeformed bands in 146Gd of 14.05 eb were confronted with a new measurement yielding 13.9±0.4 eb and 13.9±0.3 eb respectively. This excellent agreement provides empirical evidence of extreme single-particle behavior in highly deformed, collective systems.