Violent collisions and multifragment final states in the 40Ca+40Ca reaction at 35 MeV/nucleon.-猫眼课题宝

DOI：

10.1103/physrevc.50.2017

发表时间：

1994-10

期刊：

Physical review. C, Nuclear physics

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通讯作者：

中科院分区：

其他

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作者：

Hagel;Gonin;Wada;Natowitz;Haddad;Lou;Gui;Utley;Xiao;Li;Nebbia;Fabris;Prete;Ruiz;Drain;Chambon;Cheynis;Guinet;Hu;Demeyer;Pastor;Giorni;Llères;Stassi;Viano;Gonthier

用4 π多探测器AMPHORA测量了35 MeV/核子[sup 40]Ca与[sup 40] Ca碰撞产物的产额分布和能谱。事件的高多重性（[ge]10），其中[ge]85%的总入口通道原子序数被检测到已被隔离，并发现导致最激烈的碰撞，导致激发能量接近6 MeV/核子。这些碰撞的很大一部分导致多碎片的最终状态。实验数据与各种模型的结果的详细比较表明，统计模型，允许系统的扩展或治疗的多碎片过程作为一个同时拆卸是更成功的比正常的顺序二进制模型在再现的产量数据和事件的复杂性固有的多碎片事件。量子分子动力学（QMD）计算发现，提供一般良好的协议与数据，但高估了质子和中子的排放。如果使用适当的加力燃烧室去激发分离的初级QMD碎片，则一致性显著提高。这种混合计算的敏感性之间的动力计算和加力燃烧室的假设匹配时间进行了探讨。实验过滤的QMD计算提供了与实验观测值的良好一致性，表明这项工作中观察到的最复杂的事件不是来自最中心的碰撞，其通过轻粒子发射衰减更多，而是来自撞击参数[ital B]/[ital B][sub max]=0.5的区域。这表明角动量效应在多碎片衰变模式中起着重要作用。本文的结果与600 MeV/核子[sup 197]Au与Cu的中等碰撞参数碰撞中的射弹碎裂结果的比较表明，在两个非常不同的反应系统中产生了相似的多重碎裂系统。«少

The 4[pi] multidetector AMPHORA has been used to measure yield distributions and energy spectra for products of the collisions in the reactions of [sup 40]Ca with [sup 40]Ca at 35 MeV/nucleon. Events of high multiplicity ([ge]10) for which [ge]85% of the total entrance channel atomic number is detected have been isolated and found to result from the most violent collisions which lead to excitation energies near 6 MeV/nucleon. A large fraction of these collisions lead to multifragment final states. A detailed comparison of the experimental data with results of various models indicates that statistical models which allow for expansion of the system or treat the multifragmentation process as a simultaneous disassembly are more successful than normal sequential binary models at reproducing the yield data and the event complexity inherent in the multifragment events. Quantum molecular dynamic (QMD) calculations are found to provide generally good agreement with the data but overestimate the proton and neutron emission. The agreement is significantly improved if an appropriate afterburner is used to deexcite the separated primary QMD fragments. The sensitivity of such hybrid calculations to the assumed matching time between the dynamical calculation and the afterburner has been explored. The experimentally filtered QMD calculations whichmore » provide good agreement with the experimental observables suggest that the most complex events observed in this work come not from the most central collisions, which decay more by light particle emission, but from a region of impact parameter [ital b]/[ital b][sub max]=0.5. This suggests that angular momentum effects play an important role in the multifragment decay modes. A comparison of the present results with those for projectile fragmentation in intermediate impact parameter collisions of 600 MeV/nucleon [sup 197]Au with Cu indicates that a similar multifragmenting system is produced in the two very different reaction systems.« less

Violent collisions and multifragment final states in the 40Ca+40Ca reaction at 35 MeV/nucleon.

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