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Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
Azimuthal Correlations As A Test For Centrality In Heavy Ion Collisions, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, G. F. Lynch, Graham F. Peaslee, R. T. De Souza, M. B. Tsang, C. Williams, F. Zhu, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak
Azimuthal Correlations As A Test For Centrality In Heavy Ion Collisions, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, G. F. Lynch, Graham F. Peaslee, R. T. De Souza, M. B. Tsang, C. Williams, F. Zhu, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak
Faculty Publications
Azimuthal correlations of particles emitted in collisions between 197Au target nuclei and projectiles 36Ar (at and 129Xe (at have been measured with the MSU Miniball, a 4π phoswich array with a low detection threshold. Various impact parameter filters, based on the charge-particle multiplicity, transverse energy and midrapidity charge are tested by their ability to suppress collective motion as measured by the azimuthal correlations. The usefulness of a directivity cut in selecting central collisions for these systems is evaluated.
Observation Of Lifetime Effects In Two-Proton Correlations For Well-Characterized Sources, M. A. Lisa, C. K. Gelgke, P. Decowski, W. G. Gong, E. Gualtieri, S. Hannuschke, R. Lacey, T. Li, W. G. Lynch, Graham F. Peaslee, S. Pratt, T. Reposeur, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello
Observation Of Lifetime Effects In Two-Proton Correlations For Well-Characterized Sources, M. A. Lisa, C. K. Gelgke, P. Decowski, W. G. Gong, E. Gualtieri, S. Hannuschke, R. Lacey, T. Li, W. G. Lynch, Graham F. Peaslee, S. Pratt, T. Reposeur, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello
Faculty Publications
Differences between longitudinal and transverse two-proton correlation functions, consistent with finite lifetime effects, are observed for central Ar36+45Sc collisions at E/A=80 MeV. The correlations between two protons emitted with low total momenta are consistent with emission from a source of Gaussian radius r0≊4.7±0.3 fm and characteristic lifetime τ≊25±15 fm/c.
The Onset Of Nuclear Vaporization, M. B. Tsang, W. C. Hsi, W. G. Lynch, D. R. Bowman, C. K. Gelbke, M. A. Lisa, Graham F. Peaslee, G. J. Kunde, M. L. Begemann-Blaich, T. Hoffman, J. Hubele, J. Kempter, P. Kreutz, W. D. Kunze, V. Lindenstruth, U. Lynen, M. Mang, W. F.J. Müller, M. Neumann, B. Ocker, C. A. Ogilvie, J. Pochodzalla, F. Rosenberger, H. Sann, A. Schüttauf, V. Serfling, J. Stroth, W. Trautmann, A. Tucholski, A. Wörner, E. Zude, B. Zwieglinski, S. Aiello, G. Immé, V. Pappalardo, G. Raciti, R. J. Charity, L. G. Sobotka
The Onset Of Nuclear Vaporization, M. B. Tsang, W. C. Hsi, W. G. Lynch, D. R. Bowman, C. K. Gelbke, M. A. Lisa, Graham F. Peaslee, G. J. Kunde, M. L. Begemann-Blaich, T. Hoffman, J. Hubele, J. Kempter, P. Kreutz, W. D. Kunze, V. Lindenstruth, U. Lynen, M. Mang, W. F.J. Müller, M. Neumann, B. Ocker, C. A. Ogilvie, J. Pochodzalla, F. Rosenberger, H. Sann, A. Schüttauf, V. Serfling, J. Stroth, W. Trautmann, A. Tucholski, A. Wörner, E. Zude, B. Zwieglinski, S. Aiello, G. Immé, V. Pappalardo, G. Raciti, R. J. Charity, L. G. Sobotka
Faculty Publications
Multifragmentation has been measured for Au197+197Au collisions at E/A=100, 250, and 400 MeV. The mean fragment multiplicity increases monotonically with the charged particle multiplicity at E/A=100 MeV, but decreases for central collisions with incident energy, consistent with the onset of nuclear vaporization. Molecular dynamics calculations follow some trends but underpredict the observed fragment multiplicities. Including the statistical decay of excited residues improves the agreement for peripheral collisions but worsens it for central collisions.
Transition From Complete To Incomplete Fusion In Asymmetric Heavy Ion Reactions, K. Hanold, L. G. Moretto, Graham F. Peaslee, G. J. Wozniak, D. R. Bowman, M. F. Mohar, D. J. Morrissey
Transition From Complete To Incomplete Fusion In Asymmetric Heavy Ion Reactions, K. Hanold, L. G. Moretto, Graham F. Peaslee, G. J. Wozniak, D. R. Bowman, M. F. Mohar, D. J. Morrissey
Faculty Publications
Complex fragments with atomic numbers between those of the target and the projectile have been detected from the reactions of 26 and 31 MeV/nucleon Xe129+C, Al, Ti, and Cu. Angular distributions, cross sections, and velocity spectra of these fragments were extracted from the inclusive data. The velocity of the emitting source and Z-total distributions were reconstructed from the twofold coincidence data. These results are used to characterize the emission source of the complex fragments. The results are compared to a geometric incomplete fusion model calculation. Agreement between the model and the data is good.
Impact-Parameter-Selected Two-Proton Intensity Interferometry For 36ar + 45sc At E/A=80 Mev, M. A. Lisa, C. K. Gelbke, W. Bauer, P. Decowski, W. G. Gong, E. Gualtieri, S. Hannuschke, R. Lacey, T. Li, W. G. Lynch, C. M. Mader, Graham F. Peaslee, T. Reposeur, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello
Impact-Parameter-Selected Two-Proton Intensity Interferometry For 36ar + 45sc At E/A=80 Mev, M. A. Lisa, C. K. Gelbke, W. Bauer, P. Decowski, W. G. Gong, E. Gualtieri, S. Hannuschke, R. Lacey, T. Li, W. G. Lynch, C. M. Mader, Graham F. Peaslee, T. Reposeur, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello
Faculty Publications
The momentum dependence of the two-proton correlation function is studied for central and peripheral Ar36+45Sc collisions at E/A=80 MeV. Calculations with the Boltzmann-Uehling-Uhlenbeck transport theory reproduce well the measured momentum dependence of the correlation functions for central collisions, but underpredict the momentum dependence for peripheral collisions.
Sources And Emission Time Scales In E/A=50 Mev 129xe + Natcu Reactions, D. R. Bowman, Graham F. Peaslee, N. Carlin, R. T. De Souza, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, L. Phair, M. B. Tsang, C. Williams, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak, L. G. Moretto
Sources And Emission Time Scales In E/A=50 Mev 129xe + Natcu Reactions, D. R. Bowman, Graham F. Peaslee, N. Carlin, R. T. De Souza, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, L. Phair, M. B. Tsang, C. Williams, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak, L. G. Moretto
Faculty Publications
Velocity distributions and fragment-fragment correlation functions have been measured as a function of charged particle multiplicity for Xe129+natCu collisions at E/A=50 MeV. With increasing multiplicity, the velocity distributions evolve from a pattern exhibiting targetlike and projectilelike sources to an anisotropic distribution centered near the projectile-target center-of-mass velocity. Emission times extracted from the correlation functions are consistent with the decay of a projectilelike source in low multiplicity collisions, but the time scale for fragment emission in the high multiplicity collisions is too short for a separation of sources to occur.
Synthesis Of N-Boc-3-Azabicyclo[3.3.0]Octan-7-One Via Reductive Pauson-Khand Cyclization And Subsequent Conversion To A Novel Diazatricyclic Ring System, Daniel Becker, Daniel L. Flynn
Synthesis Of N-Boc-3-Azabicyclo[3.3.0]Octan-7-One Via Reductive Pauson-Khand Cyclization And Subsequent Conversion To A Novel Diazatricyclic Ring System, Daniel Becker, Daniel L. Flynn
Chemistry: Faculty Publications and Other Works
An intramolecular reductive Pauson-Khand reaction of the hexacarbonyldicobalt complex of N-(tert-butyloxycarbonyl)allylpropargylamine under dry-state adsorption conditions directly afforded the saturated N-BOC-3-azabicyclo[3.3.0]octan-7-one when the reaction was performed under an inert atmosphere. This bicyclic ketone was converted in several steps to the novel octahydro-1-azeto[2′,3′:3,4]cyclopenta[1,2-C]pyrrole ring system as confirmed by single crystal X-ray analysis.
Studies Of The Solid-Phase Pauson-Khand Reaction Selective In-Situ Enone Reduction To 3-Azabicyclo[3.3.0]Oct-Anones, Daniel Becker, Daniel L. Flynn
Studies Of The Solid-Phase Pauson-Khand Reaction Selective In-Situ Enone Reduction To 3-Azabicyclo[3.3.0]Oct-Anones, Daniel Becker, Daniel L. Flynn
Chemistry: Faculty Publications and Other Works
The Smit-Caple DSAC Pauson-Khand cyclization of a series of N-protected allyl propargyl amines in the absence of oxygen gave rise to formation of the saturated azabicyclo[3.3.0]octanones in excellent yields. Standard cyclization in air gave mixtures of saturated and unsaturated ketones.
Multifragment Emission In 36ar +197au And 129xe + 197au Collisions, W. Bauer, D. R. Bowman, N. Carlin, N. Colonna, R. T. De Souza, C. K. Gelbke, W. G. Gong, K. Hanold, Y. D. Kim, M. A. Lisa, W. G. Lynch, M. A. Mcmahan, L. G. Moretto, Graham F. Peaslee, L. Phair, M. B. Tsang, C. Williams, G. J. Wozniak, F. Zhu
Multifragment Emission In 36ar +197au And 129xe + 197au Collisions, W. Bauer, D. R. Bowman, N. Carlin, N. Colonna, R. T. De Souza, C. K. Gelbke, W. G. Gong, K. Hanold, Y. D. Kim, M. A. Lisa, W. G. Lynch, M. A. Mcmahan, L. G. Moretto, Graham F. Peaslee, L. Phair, M. B. Tsang, C. Williams, G. J. Wozniak, F. Zhu
Faculty Publications
Multifragment disintegrations observed in 36Ar+197Au and 129Xe+197Au collisions are compared with theoretical predictions.
Expansion Effects In Intermediate Energy Heavy-Ion Reactions, R. T. De Souza, D. Fox, W. A. Friedman, L. Phair, D. R. Bowman, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu
Expansion Effects In Intermediate Energy Heavy-Ion Reactions, R. T. De Souza, D. Fox, W. A. Friedman, L. Phair, D. R. Bowman, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu
Faculty Publications
Transverse kinetic energy spectra of fragments in the reaction 36Ar + 197Au are used to probe the multifragmentation mechanism at intermediate energies. The mass dependence of the average transverse kinetic energy is examined in the context of the statistical decay of an expanding, emitting source. The role of source expansion during emission is explored. Results suggest the onset of volume emission at the highest incident energy.
Extraction Of The Multifragmentation Time Scale In Intermediate Energy Heavy-Ion Reactions, D. Fox, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu
Extraction Of The Multifragmentation Time Scale In Intermediate Energy Heavy-Ion Reactions, D. Fox, R. T. De Souza, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu
Faculty Publications
The spatial and temporal extent of a system decaying by multifragment emission is deduced. Two-particle intermediate mass fragment correlation functions measured for central Ar36+197Au collisions at E/A=50–110 MeV indicate a rapid decay, <75 fm/c, of the highly excited system. Furthermore, the behavior of the correlation function at large relative velocities suggests that considerable charge loss occurs prior to fragment emission.
Complex Fragment Production In 139la-Induced Reactions At 35, 40, 45, And 55 Mev/Nucleon, P. Roussel-Chomaz, N. Colonna, Y. Blumenfeld, B. Libby, Graham F. Peaslee, D. N. Delis, K. Hanold, M. A. Mcmahan, J. C. Meng, Q. C. Sui, G. J. Wozniak, L, G. Moretto, H. Madani, A. A. Marchetti, A. C. Mignery, G. Guarino, N. Santoruvo, I. Iori, S. Bradley
Complex Fragment Production In 139la-Induced Reactions At 35, 40, 45, And 55 Mev/Nucleon, P. Roussel-Chomaz, N. Colonna, Y. Blumenfeld, B. Libby, Graham F. Peaslee, D. N. Delis, K. Hanold, M. A. Mcmahan, J. C. Meng, Q. C. Sui, G. J. Wozniak, L, G. Moretto, H. Madani, A. A. Marchetti, A. C. Mignery, G. Guarino, N. Santoruvo, I. Iori, S. Bradley
Faculty Publications
Complex fragment emission (Z>3) has been studied in the reactions of 35, 40, 45 and 55 MeV/u139La+X. Charge, angular, and energy distributions were measured inclusively and in coincidence with other complex fragments, and were used to extract source rapidities, velocity distributions, and cross sectins. Multifragment events increase with both bombarding energy and entrance-channel mass asymmetry. The excitation functions for multifragment events rise strongly with excitation energy. These excitation functions are independent of the target-projectile combination and bombarding energy suggesting, the formation of an intermediate nuclear system, whose decay properties depend mainly on its excitation energy and angular momentum.