Study of the photonuclear reactions of p-nuclides by means of inorganic scintillation targets

92Mo是钼同位素中最缺乏中子的核素，被认为是通过天体物理核合成的p过程产生的。观测到的~(92)Mo丰度比p过程理论的预测值小几十倍，这是核天体物理学中一个长期存在的问题。造成这种差异的可能原因之一是92Mo(伽马，p)91Nb反应截面的不准确，它还没有被实验测量。我们发展了一种用含钼的无机闪烁体作为活性靶测量92Mo(γ，p)91Nb截面的新方法。利用兵库大学NewSubuu同步辐射装置提供的准单能激光康普顿散射伽马射线束，成功地测量了92Mo(Gamma，p)91Nb反应截面。

92Mo is the most neutron-deficient nuclide in molybdenum isotopes, and is supposed to be produced via the p-process of the astrophysical nucleosynthesis. It has been a long-standing problem in nuclear astrophysics that the observed abundance of 92Mo is smaller by a factor of a few ten than the predicted value of the p-process theory. One of the possible reason for this discrepancy is the inaccuracy of the 92Mo(gamma,p)91Nb reaction cross section which has not been measured experimentally. We developed a new method for measurement of the 92Mo(gamma,p)91Nb cross section by using an inorganic scintillator including molybdenum as an active target. A high-sensitivity photo-activation analysis was also developed, and was successfully used for measurement of the 92Mo(gamma,p)91Nb reaction cross section using a quasi-monoenergetic laser Compton-scattered gamma-ray beam provided at the NewSUBARU synchrotron radiation facility of the University of Hyogo.