Inclusive measurements of electromagnetic dissociation of 197Au targets.
Inclusive measurements of electromagnetic dissociation of 197Au targets.
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197Au 目标电磁离解的包容性测量。
DOI：
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发表时间：
1993
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通讯作者：
Hill
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作者：
Aumann;Kratz;Stiel;Sümmerer;Brüchle;Schädel;Wirth;Fauerbach;Hill
用活化法测量了1.7GeV/核子的[sup 20]Ne和1GeV/核子的[sup 86]Kr、[sup 197]Au和[sup 209]Bi离子束对[sup 197]Au靶的电磁解离截面。我们观察到实验数据和简单的Weizsaecker-Williams计算之间的系统差异：对于最重的射弹，计算高估了1[ital n]截面，而2[ital n]和3[ital n]截面系统地低估了。偏差可以显着减少，但是，通过计算，包括isoscillation和isovector巨四极激发以及激发多声子态的可能性。本研究最重要的实验结果是观察到了[sup 197] Au和[sup 209]Bi射弹从[sup 197]Au中去除三个中子的大截面，这只能用双声子巨偶极激发的主要贡献来解释。对于几乎定量再现所有观察到的[ital xn]通道，我们必须假设一个更高的激发概率约为2倍的双巨偶极共振相比，谐波的方法。
Cross sections for the electromagnetic dissociation of [sup 197]Au targets by 1.7 GeV/nucleon [sup 20]Ne and 1 GeV/nucleon [sup 86]Kr, [sup 197]Au, and [sup 209]Bi beams have been measured by an activation method. We observe systematic discrepancies between the experimental data and a simple Weizsaecker-Williams calculation: For the heaviest projectiles, the calculation overpredicts the 1[ital n] cross sections, whereas the 2[ital n] and 3[ital n] cross sections are systematically underpredicted. The deviations can be significantly reduced, however, by calculations including isoscalar and isovector giant quadrupole excitations as well as the possibility to excite multiphonon states. The most important experimental result of the present study is the observation of large cross sections for three-neutron removal from [sup 197]Au with [sup 197]Au and [sup 209]Bi projectiles which can only be explained by a dominant contribution from two-phonon giant dipole excitation. For an almost quantitative reproduction for all [ital xn] channels observed, we have to assume a higher excitation probability by roughly a factor of 2 for the double giant dipole resonance as compared to the harmonic approach.