Activation Cross section measurements for 5〜7 MeV Neutrons produced with d-D reaction

为名古屋大学的Van de Graaf（VdG）加速器KN-3750研制了一个静电三重态四极透镜和一个光束偏转器。用VdG加速器测量了D(D,n)^3He反应产生的3-5 MeV中子的活化截面。为了聚焦直径为5mm的d2气体靶的Haver箔（2.2μm^t）小于靶窗的d^+光束，研制了一种静电三重态四极透镜。通过施加±3kV的电压，可以使光束光斑聚焦约2mm，这是用石英光束观察器观察到的。因此，它可以减少在非期望区域产生的散射中子，并认为它保持了中子良好的单二向性。另一方面，为了测量所产生的核的半衰期短于1秒的激活截面，还研制了一种束偏转器，以便从范德格拉夫加速器中产生脉冲中子。通过在两个电极之间施加20kV，产生脉冲宽度约为30ms的d^+束。通过测量^<27>Al（p,γ）反应，在光束关闭条件下根本没有观察到提示γ射线。利用四极透镜和束流偏转器，预定用VdG加速器测量短寿命核的中子激活截面。

An electrostatic-triplet quadrupole lens and a beam deflector have been developed for a Van de Graaf(VdG) accelerator KN-3750 at Nagoya University.Activation cross section has been measured with 3-5 MeV neutrons produced with D(d,n)^3He reactions by using a VdG accelerator. In order to focus the d^+ beam smaller than the target window made of Haver foil (2.2μm^t) of the D_2 gas target whose size is 5mm diameter, an electrostatic-triplet quadrupole lens has been developed. By applying the voltage of ± 3kV, it could focus the beam spot about 2 mm, this was observed with a quartz beam viewer. As the result, it can reduce the scattered neutron which generated in undesired area, and it considered to keep good monodiromacity of the neutron.On the other hand, in order to measure the activation cross section of which half-lives of produced nuclei is shorter than 1 s, a beam deflector has been also developed in order to generate pulsed neutrons from the Van de Graaf accelerator. By applying 20kV between two eletrodes, it makes d^+ beam whose pulse width about 30 ms. By measuring the ^<27>Al(p,γ) reaction, the prompt γ-rays were not observed at all with beam-off condition. By using the quadrupole lens and the beam deflector, neutron activation cross sections for short lived-nuclei are scheduled to measure with VdG accelerator.