Power law behavior of the isotope yield distributions in the multifragmentation regime of heavy ion reactions

Journal Article · Mon Nov 15 00:00:00 EST 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.82.054602· OSTI ID:21499179

Huang, M ^[1]; Wada, R; Hagel, K; Barbui, M; Bottosso, C; Materna, T; Natowitz, J B; Qin, L; Rodrigues, M R. D.; Sahu, P K; Schmidt, K J ^[2]; Chen, Z ^[1]; Keutgen, T ^[3]; Kowalski, S ^[4]; Bonasera, A ^[2]; Wang, J ^[1]

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1. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)
2. Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States)
3. FNRS and IPN, Universite Catholique de Louvain, B-1348 Louvain-Neuve (Belgium)
4. Institute of Physics, Silesia University, Katowice (Poland)

Isotope yield distributions in the multifragmentation regime were studied with high-quality isotope identification, focusing on the intermediate mass fragments (IMFs) produced in semiviolent collisions. The yields were analyzed within the framework of a modified Fisher model. Using the ratio of the mass-dependent symmetry energy coefficient relative to the temperature, a{sub sym}/T, extracted in previous work and that of the pairing term, a{sub p}/T, extracted from this work, and assuming that both reflect secondary decay processes, the experimentally observed isotope yields were corrected for these effects. For a given I=N-Z value, the corrected yields of isotopes relative to the yield of {sup 12}C show a power law distribution Y(N,Z)/Y({sup 12}C){approx}A{sup -}{tau} in the mass range 1{<=}A{<=}30, and the distributions are almost identical for the different reactions studied. The observed power law distributions change systematically when I of the isotopes changes and the extracted {tau} value decreases from 3.9 to 1.0 as I increases from -1 to 3. These observations are well reproduced by a simple deexcitation model, with which the power law distribution of the primary isotopes is determined to be {tau}{sup prim}=2.4{+-}0.2, suggesting that the disassembling system at the time of the fragment formation is indeed at, or very near, the critical point.

• OSTI ID: 21499179
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 82, Issue 5; Other Information: DOI: 10.1103/PhysRevC.82.054602; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CARBON 12
COLLISIONS
DE-EXCITATION
DISTRIBUTION
HEAVY ION REACTIONS
MASS
NUCLEAR DECAY
NUCLEAR FRAGMENTATION
SYMMETRY
CARBON ISOTOPES
DECAY
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
ISOTOPES
LIGHT NUCLEI
NUCLEAR REACTIONS
NUCLEI
STABLE ISOTOPES