Generation and anisotropy of neutron emission from a condensed Z-pinch
Generation and anisotropy of neutron emission from a condensed Z-pinch
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凝聚 Z 箍缩中子发射的产生和各向异性
DOI：
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发表时间：
2014
期刊：
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通讯作者：
G. Ustroev
中科院分区：
文献类型：
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作者：
Y. Bakshaev;V. Bryzgunov;V. Vikhrev;I. V. Volobuev;S. Dan’ko;E. Kazakov;V. Korolev;D. Klír;A. D. Mironenko;V. Pimenov;E. Smirnova;G. Ustroev
本文介绍了 S-300 设施（2 MA，100 ns）快速 Z 箍缩收缩时产生的中子发射的测量结果。通过使用组合负载来提高能量集中，该组合负载的中心部分是质量密度为 100 mg/cm3、直径为 1-1.5 mm 的微孔氘代聚乙烯颈部。将颈部置于两个直径 5 毫米的琼脂圆柱之间。采用飞行时间法测量了两个轴向和两个径向的中子发射特性。通过蒙特卡罗方法从测量的中子信号中恢复中子谱。在所有实验中，Z 箍缩收缩中等离子体的时空特征都是通过 S-300 设施的诊断综合体测量的，其中包括光学、VUV 和软 X 射线 (SXR) 光谱区域的帧摄影；光学条纹成像； SXR检测；以及时间积分 SXR 摄影。 Z 箍缩收缩中热致密等离子体的形成伴随着硬 X 射线（光子能量 E > 30 keV）、SXR（光子能量 E > 1 keV，持续时间 2-4 ns）和中子发射的产生。揭示了轴向中子能量分布的各向异性。在相对于负载轴呈 0°（阳极上方）、90°、180°（阴极下方）和 270° 角度的四个方向上测量的平均中子能量分别为 2.1 ± 0.1、2.5 ± 0.1、2.6 ± 0.2 和 2.4 ± 0.1 MeV。对于 1 毫米直径的颈部，最大整体中子产额为 6 × 109 个中子。计算了具有高能离子幂律分布的 Z 箍缩的中子发射各向异性。
The paper presents results of measurements of neutron emission generated in the constriction of a fast Z-pinch at the S-300 facility (2 MA, 100 ns). An increased energy concentration was achieved by using a combined load the central part of which was a microporous deuterated polyethylene neck with a mass density of 100 mg/cm3 and diameter of 1–1.5 mm. The neck was placed between two 5-mm-diameter agar-agar cylinders. The characteristics of neutron emission in two axial and two radial directions were measured by the time-of-flight method. The neutron spectrum was recovered from the measured neutron signals by the Monte Carlo method. In all experiments, the spatiotemporal characteristics of plasma in the Z-pinch constriction were measured by means of the diagnostic complex of the S-300 facility, which includes frame photography in the optical, VUV, and soft X-ray (SXR) spectral regions; optical streak imaging; SXR detection; and time-integrated SXR photography. The formation of hot dense plasma in the Z-pinch constriction was accompanied by the generation of hard X-ray (with photon energies E > 30 keV), SXR (with photon energies E > 1 keV and duration of 2–4 ns), and neutron emission. Anisotropy of the neutron energy distribution in the axial direction was revealed. The mean neutron energies measured in four directions at angles of 0° (above the anode), 90°, 180° (under the cathode), and 270° with respect to the load axis were found to be of 2.1 ± 0.1, 2.5 ± 0.1, 2.6 ± 0.2, and 2.4 ± 0.1 MeV, respectively. For a 1-mm-diameter neck, the maximum integral neutron yield was 6 × 109 neutrons. The anisotropy of neutron emission for a Z-pinch with a power-law distribution of high-energy ions is calculated.