Complex fragment emission at 50 MeV/u: Compound nuclei forever?

Bowman, D. R.; Kehoe, W. L.; Charity, R. J.; McMahan, M. A.; Moroni, A.; Bracco, A.; Bradley, S. T.; Iori, I.; McDonald, R. J.; Mignerey, A. C.; Moretto, L.G.; Namboodiri, M.N.; Wozniak, G.J.

doi:10.1016/0370-2693(87)91432-8

Cited by 57 publications

(7 citation statements)

References 17 publications

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“…A similar case has been studied both experimentally and theoretically [5]. Figure 1 shows the mass yields obtained for these three cases.…”

Section: Illustrative Resultsmentioning

confidence: 96%

“…Accepting the fact that the timing of fragment production is the main difference in our two models, it is easy to see that the models will coincide when the multiplicity of heavy fragments decreases to two or one. Furthermore, the Coulomb effects at this low multiplicities will be exactly the same in the two cases giving a back-to-hack push between heavy fragments and since both mechanisms split a compound nucleus, source velocity studies as those of Bowman et al [5] and Moretto and Wozniak [9] a~e bound to describe the binary nature of the fragment production.…”

Section: Excitation Energy Dependencementioning

confidence: 99%

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Multifragmentation versus sequential fission: Observable differences?

López

Randrup

1989

Nuclear Physics A

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“…A similar case has been studied both experimentally and theoretically [5]. Figure 1 shows the mass yields obtained for these three cases.…”

Section: Illustrative Resultsmentioning

confidence: 96%

Section: Excitation Energy Dependencementioning

confidence: 99%

Multifragmentation versus sequential fission: Observable differences?

López

Randrup

1989

Nuclear Physics A

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“…There is a single cluster that evaporates up to 2500 atoms. This is the region of the "compound nucleus for ever" which is emphasized so much by Moretto [2]. However, its temperature is higher than the canonical transition temperature T tr and these events are inaccessible to the canonical ensemble.…”

Section: Introductionmentioning

confidence: 95%

Microcanonical Thermostatistics, the basis for a New Thermodynamics, “heat can flow from cold to hot”, and nuclear multifragmentation. The correct treatment of Phase Separation after 150 years of statistical mechanics

Gross¹

2007

AIP Conference Proceedings

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Equilibrium statistics of finite Hamiltonian systems is fundamentally described by the microcanonical ensemble (ME) [1]. Canonical, or grandcanonical partition functions are deduced from this by Laplace transform. Only in the thermodynamic limit are they equivalent to ME for homogeneous systems. Therefore ME is the only ensemble for non-extensive/inhomogeneous systems like nuclei or stars where the lim N →∞,ρ=N/V =const does not exist. Conventional canonical thermo-statistic is inapplicable for non-extensive systems. This has far reaching fundamental and quite counter-intuitive consequences for thermo-statistics in general: Phase transitions of first order are signaled by convexities of S(E, N, Z,Here the heat capacity is negative. In these cases heat can flow from cold to hot! The original task of thermodynamics, the description of boiling water in heat engines can be treated. Consequences of this basic peculiarity for nuclear statistics as well for the fundamental understanding of Statistical Mechanics in general are discussed. Experiments on hot nuclei show all these novel phenomena in a rich variety. The close similarity to inhomogeneous astro physical systems will be pointed out.

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“…It was the result of experiments and theoretical thoughts especially in nuclear physics that paved the way to a new and much deeper understanding of equilibrium statistical mechanics and phase transitions in "Small" systems. I want to remind the pioneering attempts on nuclear multifragmentation, experimentally by the references [5][6][7][8][9][10][11][12][13], where finally Moretto [14] gave a concluding overview on the experimental situation of multifragmentation, even though he initially doubted the very existence of this new phenomenon in the paper entitled: "Complex fragment emission at 50 MeV/u -compound nuclei for ever" [15]. This development was soon theoretically accompanied and stimulated: [16][17][18][19][20][21][22][23][24][25][26][27][28] and others.…”

Section: Thermo-statistics As Geometry and Topology Of The Mechanicalmentioning

confidence: 99%

Phase transitions in “small” systems – A challenge for thermodynamics

Gross¹

2001

Nuclear Physics A

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Traditionally, phase transitions are defined in the thermodynamic limit only. We propose a new formulation of equilibrium thermo-dynamics that is based entirely on mechanics and reflects just the geometry and topology of the N-body phase-space as function of the conserved quantities, energy, particle number and others. This allows to define thermo-statistics without the use of the thermodynamic limit, to apply it to "Small" systems as well and to define phase transitions unambiguously also there. "Small" systems are systems where the linear dimension is of the characteristic range of the interaction between the particles. Also astrophysical systems are "Small" in this sense. Boltzmann defines the entropy as the logarithm of the area W (E, N) = e S(E,N ) of the surface in the mechanical N-body phase space at total energy E. The topology of S(E, N) or more precisely, of the curvature determinant D(E, N) = ∂ 2 S/∂E 2 * ∂ 2 S/∂N 2 − (∂ 2 S/∂E∂N) 2 allows the classification of phase transitions without taking the thermodynamic limit. The topology gives further a simple and transparent definition of the order parameter. Attention: Boltzmann's entropy S(E) as defined here is different from the information entropy c.f. [1] and can even be non-extensive and convex.

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Complex fragment emission at 50 MeV/u: Compound nuclei forever?

Cited by 57 publications

References 17 publications

Multifragmentation versus sequential fission: Observable differences?

Multifragmentation versus sequential fission: Observable differences?

Microcanonical Thermostatistics, the basis for a New Thermodynamics, “heat can flow from cold to hot”, and nuclear multifragmentation. The correct treatment of Phase Separation after 150 years of statistical mechanics

Phase transitions in “small” systems – A challenge for thermodynamics

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