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arXiv 0907.5045nucl-th
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~(239)Pu(n,f)瞬发中子的逐事件研究

Event-by-event study of prompt neutrons from 239Pu(n,f)

R. Vogt, J. Randrup, J. Pruet, W. Younes

摘要:

本文采用最近发展起来的Monte Carlo模型,研究了~(240)Pu在热中子到低于二次机会裂变阈值的中子作用下的裂变。目前对裂变中发射的瞬发中子平均数的测量,加上对中子能谱的不太精确的测量,对微观计算的预测提出了非常精细的限制。特别是,新生碎片的总激发能必须指定在1兆电子伏,以避免与平均中子多重性的测量不一致。蒙特卡罗裂变模型与统计似然分析的结合也为裂变中子数据的评价提供了一个强有力的工具。特别重要的是裂变谱,它在确定反应堆临界性方面起着关键作用。我们表明,我们的方法可以用来开发一个估计的裂变谱的不确定性比目前的实验不确定性小几倍,传出中子能量高达2兆电子伏。

英文摘要:

Employing a recently developed Monte Carlo model, we study the fission of 240Pu induced by neutrons with energies from thermal to just below the threshold for second chance fission. Current measurements of the mean number of prompt neutrons emitted in fission, together with less accurate measurements of the neutron energy spectra, place remarkably fine constraints on predictions of microscopic calculations. In particular, the total excitation energy of the nascent fragments must be specified to within 1 MeV to avoid disagreement with measurements of the mean neutron multiplicity. The combination of the Monte Carlo fission model with a statistical likelihood analysis also presents a powerful tool for the evaluation of fission neutron data. Of particular importance is the fission spectrum, which plays a key role in determining reactor criticality. We show that our approach can be used to develop an estimate of the fission spectrum with uncertainties several times smaller than current experimental uncertainties for outgoing neutron energies up to 2 MeV.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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