Murata Isao, Otani Yuki, Sato Fuminobu
Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871, Japan.
Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871, Japan.
Appl Radiat Isot. 2015 Dec;106:75-7. doi: 10.1016/j.apradiso.2015.07.034. Epub 2015 Jul 28.
Proton-lithium (p-Li) reaction is being examined worldwide as a candidate nuclear production reaction for accelerator based neutron source (ABNS) for BNCT. In this reaction, the emitted neutron energy is not so high, below 1 MeV, and especially in backward angles the energy is as low as about 100 keV. The intensity measurement was thus known to be difficult so far. In the present study, a simple method was investigated to monitor the absolute neutron intensity of the p-Li neutron source by employing the foil activation method based on isomer production reactions in order to cover around several hundreds keV. As a result of numerical examination, it was found that (107)Ag, (115)In and (189)Os would be feasible. Their features found out are summarized as follows: (107)Ag: The most convenient foil, since the half life is short. (115)In: The accuracy is the best at 0°, though it cannot be used for backward angles. And (189)Os: Suitable nuclide which can be used in backward angles, though the gamma-ray energy is a little too low. These would be used for p-Li source monitoring depending on measuring purposes in real BNCT scenes.
质子-锂（p-Li）反应作为基于加速器的硼中子俘获疗法（BNCT）中子源的候选核反应，正在全球范围内进行研究。在该反应中，发射的中子能量不高，低于1 MeV，特别是在背角方向，能量低至约100 keV。因此，到目前为止，强度测量一直被认为是困难的。在本研究中，研究了一种简单的方法，通过采用基于同质异能素产生反应的箔活化法来监测p-Li中子源的绝对中子强度，以覆盖几百keV左右的能量范围。数值研究结果表明，（107）Ag、（115）In和（189）Os是可行的。发现它们的特性总结如下：（107）Ag：最方便的箔，因为半衰期短。（115）In：在0°时精度最佳，但不能用于背角方向。以及（189）Os：适合用于背角方向的核素，尽管γ射线能量有点太低。在实际的BNCT场景中，这些将根据测量目的用于p-Li源监测。
