共查询到19条相似文献,搜索用时 93 毫秒
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超强超短脉冲激光诱发大尺度氘团簇聚变 总被引:3,自引:3,他引:0
利用低温脉冲气阀获得了平均含有3×103氘原子的氘团簇。在飞秒激光装置上实现了氘团簇聚变,每发中子产额为1×103。中子产额对激光功率密度敏感,保持激光能量不变,随着激光焦斑的变大,DD聚变中子产额逐渐增加,最大值出现在激光焦斑为470 mm时;继续增大激光焦斑,没有观察到中子信号。实验结果还表明激光氘团簇聚变发生的区域主要是激光辐照的等离子体热区,此区域内邻近氘团簇库仑爆炸发射的高能氘离子碰撞引发聚变反应。 相似文献
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本文主要研究了超强超短激光与Ar团簇相互作用过程中X射线能谱、K壳层光子产额、能量转换效率以及激光对比度对X射线光子产额的影响.实验中得到K壳层的光子产额约为1× 1011/发,能量转换效率约为2.8× 10-5.同时观测到较强预脉冲离化团簇会导致预电离,产生膨胀等离子体,然而主脉冲与膨胀的等离子体相互作用的强度较未膨胀时降低了,从而导致K壳层光子产额降低,而使用高对比度的激光能增加X射线光子产额. 相似文献
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通过超短脉冲激光与合适的介质相互作用,在普通光学实验室中可以产生聚变中子,经过特殊设计的固体靶结构和特殊安排的级联过程,亚TW激光即可引发光核反应产生中子,通过台面超强激光与固体靶相互作用利用对离子的自导通道径向加速机制,可获得较多的高能离子和较多的中子产率,由于超强激光辐照下大的团簇爆炸时可获得大量高能离子,团簇靶实验中实现的中子产率比相似激光能量的固体靶实验高两个量级,文章讨论了上述三种产生中 相似文献
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描述了包含共线的光电子速度成像仪,以及与双阀激光溅射团簇源联用的时间飞行质谱装置.为了避免预混气体,两个脉冲阀和一个反应通道被用来产生反应负离子.共线的光电子成像仪采用了改进的速度成像透镜系统,它的能量分辨率优于3%.此外还报道了Si4-团簇在532和355 nm,以及Si3C- 团簇在532 nm的光电子速度成像.从实验图像中可以获得光电子能谱和各向异性参数.从Si4-团簇能谱上获得了中性的Si4团簇的基态和第一激发态的振动频率分别为330和312 cm-1.初步的实验结果证明这套光电子成像装置对研究团簇负离子的电子结构以及光脱附动力学非常有效. 相似文献
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采用激光溅射法制备了同位素标记的氧化锰团簇正离子Mnm18On+,并研究了其在快速流动反应管中与硫化氢在热碰撞条件下的反应,氧化锰团簇正离子与硫化氢反应前后的质量分布与强度变化由飞行时间质谱仪检测.实验表明,绝大多数氧化锰团簇正离子可与硫化氢发生氧-硫交换反应产生水分子,反应通式为:Mnm18On++H2S→Mnm18On-1S++H218O.通过密度泛函理论计算了氧化锰团簇正离Mn2O2+、Mn2O3+和Mn2O4+与H2S反应的机理,结果显示,在这些反应体系中氧-硫交换反应通道同时具有热力学和动力学优势,印证了实验中观察到的现象.气相团簇研究发现的氧-硫交换反应与相关凝聚相体系反应结果一致 相似文献
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在20TW激光器上进行了超短超强激光与金属Cu膜靶的相互作用实验,当靶厚度不同时,采用CR39核径迹探测器测量了质子发射的空间分布和产额;使用Thomson磁谱仪测量了靶背法线方向质子束的能量分布。测量结果表明:质子产额为10
5~10
6每发;质子束沿靶背法线方向发射,与入射激光方向无关,并且存在较小的发射立体角,在一定能量处出现截止,截止能量的大小与靶厚度有关。 相似文献
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采用简化库仑爆炸模型对强激光脉冲照射氘代乙烷团簇发生的库仑爆炸过程进行数值模拟,研究了氘代乙烷团簇爆炸产生的氘核动能、中子产额与团簇尺寸的关系,且与氘代甲烷团簇产生的氘核动能及中子产额进行了比较.研究表明,尺寸为5 nm的氘代乙烷团簇在发生库仑爆炸后氘核的最大动能为20.96 keV,获得的中子产额为6.31×105,比同尺寸氘代甲烷团簇产生的氘核最大动能及中子产额更大.因此相对于氘代甲烷团簇,大尺寸的氘代乙烷团簇更适合作为激光驱动团簇库仑爆炸获得高额中子的靶材,这与报道的实验推论相一致. 相似文献
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Effect of laser spot size on fusion neutron yield in laser--deuterium cluster interactions 下载免费PDF全文
The effect of the laser spot size on the neutron yield of table-top nuclear fusion from explosions of a femtosecond intense laser pulse heated deuterium clusters is investigated by using a simplified model, in which the cluster size distribution and the energy attenuation of the laser as it propagates through the cluster jet are taken into account. It has been found that there exists a proper laser spot size for the maximum fusion neutron yield for a given laser pulse and a specific deuterium gas cluster jet. The proper spot size, which is dependent on the laser parameters and the cluster jet parameters, has been calculated and compared with the available experimental data. A reasonable agreement between the calculated results and the published experimental results is found. 相似文献
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超快中子探测器是ICF聚变反应速率测量系统的核心部件。利用蒙特卡罗粒子输运工具包Geant4模拟了一种超快中子探测器——BC-422型闪烁探测器的中子探测过程,计算出了几种厚度的BC-422型闪烁体的探测效率、输出光信号强度和时间分辨力;对比了闪烁体的2种不同反射表面对输出光信号强度和时间分辨力的影响。计算的结果显示:设计适当的BC-422型闪烁探测器能够测量的最低中子产额在108量级,对DT中子的信号时间分辨力好于20 ps,对DD中子的信号时间分辨力达到30 ps,能够用于大型激光装置及其原型的聚变反应速率测量。 相似文献
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Nuclear fusion from Coulomb explosions of deuterated methane clusters subjected to ultraintense femtosecond laser pulses 下载免费PDF全文
This paper reports that Coulomb explosions taken place in the
experiment of heteronuclear deuterated methane clusters
((CD4)2) in a gas jet subjected to intense femtosecond
laser pulses (170mJ, 70fs) have led to table-top laser driven DD
nuclear fusion. The clusters produced in supersonic expansion had an
average size of about 5nm in radius and the laser intensity used
was 3×1017W/cm2.The measured maximum and average
energies of deuterons produced in the laser--cluster interaction were
60 and 13.5keV, respectively. From DD collisions of energetic
deuterons, a yield of 2.5(±0.4)×104 fusion neutrons
of 2.45MeV per shot was realized, giving rise to a neutron
production efficiency of about 1.5×105 per joule of
incident laser pulse energy. Theoretical calculations were performed
and a fairly good agreement of the calculated neutron yield with
that obtained from the present experiment was found. 相似文献
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G. L. Chen H. Y. Lu C. Wang J. S. Liu R. X. Li G. Q. Ni Z. Z. Xu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(2):303-307
We propose a plasma channel scheme to obtain an improved
table-top laser driven fusion neutron yield as a result of explosions of
large deuterium clusters irradiated by an intense laser pulse. A cylindrical
plasma channel is created by two moderate intensity laser prepulses at the
edge of a deuterium cluster jet along which an intense main laser pulse
propagates several nanoseconds later. With the aid of this plasma channel,
the main laser pulse will be allowed to deposit its energy into the central
region of the deuterium gas jet where the cluster sizes are larger and the
atomic density is higher. The plasma channel formation and its impact on the
deuterium ion energy spectrum and the consequent fusion neutron yield have
been investigated. The calculated results show that a remarkable increase of
the table-top laser driven fusion neutron yield would be expected. 相似文献
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Zweiback J Smith RA Cowan TE Hays G Wharton KB Yanovsky VP Ditmire T 《Physical review letters》2000,84(12):2634-2637
Recent experiments on the interaction of intense, ultrafast laser pulses with large van der Waals bonded clusters have shown that these clusters can explode with substantial kinetic energy. By driving explosions in deuterium clusters with a 35 fs laser pulse, we have accelerated ions to sufficient kinetic energy to produce DD nuclear fusion. By diagnosing the fusion yield through measurements of 2.45 MeV fusion neutrons, we have found that the fusion yield from these exploding clusters varies strongly with the cluster size, consistent with acceleration of deuterons via Coulomb explosion forces. 相似文献
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Neutrons (2.45MeV) from deuterium cluster fusion induced by the intense femtosecond (3Ors) laser pulse are experimentally demonstrated. The average neutron yield 103 per shot is obtained. It is found that the yield slightly increases with the increasing laser spot size. No neutron can be observed when the laser intensity I 〈 4.3 × 10^15 W/cm^2. 相似文献
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利用瑞利散射方法研究了超声喷流Ar-CH4混合团簇和超声喷流Ar-H2混合团簇的特性.通过测量不同混合比例和不同背压下所形成混合团簇的散射信号发现,当用Ar气和CH4的混合气体进行超声喷流时很容易形成Ar-CH4混合团簇,当Ar气含量为50%时混合团簇尺度最大且大于相同气压下纯Ar团簇尺度和纯CH4团簇尺度.实验发现,与纯H2团簇只能在低温条件下获得不同,常温下即可形成Ar-H2混合团簇,实现了常温下含氢团簇的获取,从而有效降低了制备成本.在H2含量大于40%时混合团簇开始形成并在60%时达到最大尺度.含氢(氘)混合团簇在氢(氘)团簇的基础上引入了更重的异核Ar元素,在激光氘团簇聚变实验中它将进一步加速氘离子从而获得更高的能量,并具有更高的中子产额和聚变效率. 相似文献
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在神光Ⅲ主机装置上,利用已经建成的两个激光束组,开展了激光间接驱动内爆物理磨合实验,是神光Ⅲ主机装置首次出中子实验。实验采用1400μm×2100μm黑腔,500μm的塑料靶丸充1 MPa的DD燃料,激光从黑腔两端55°注入。实验获得的最高中子产额为9.7×108。实验结果表明,实验黑腔的耦合效率约为50%;使用的黑腔偏长,靶丸被压缩为"薄饼形";中子产额和激光能量正相关;中子发射峰值时刻主要依赖于烧蚀层厚度。 相似文献