共查询到17条相似文献,搜索用时 46 毫秒
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物理学家利用高能粒子加速器进行了多方面的研究,但高能粒子加速器庞大且耗资巨大。随着超短超强激光的发展,现在的激光的功率密度可达到10^22W/cm^2。许多实验室利用不同功率密度的激光与固体靶、薄膜靶及气体等相互作用,进行加速产生高能粒子的研究。其中,利用超短超强激光与薄膜薄相互作用加速产生质子是一重要的研究课题,利用超热电子加速产生超热电子, 相似文献
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近年来,随着CPA(脉冲啁啾放大)等技术的发展,激光功率有了很大提高,超短脉冲激光器及超短脉冲激光与物质相互作用的研究已发展成为当今世界最热门最前沿的领域。日前,基于CPA技术的超短脉冲激光系统已经达到PW(1015)量级。紫外超短脉冲激光在强场物理及惯性约束核聚变快速点火等研究中具有无可比拟的优势,在小型超快中子源、激光化学、激光生物学等众多领域有着广泛应用。 准分子激光器在放大超短脉冲方面具有独特的优势。基于它的气体性质和饱和能量低、超短脉冲放大过程中的非线性效应小,可不采用CPA路线而直接将超短脉冲激光放大到1019W/cm2,甚至更高。它还可以提供一个信噪比高达1010的干净脉冲,这对于激光靶物理实验非 相似文献
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采用飞秒激光与金属薄膜靶相互作用,测量了前向(靶背方向)发射的快电子和快质子.实验显示:快电子主要沿靶背法线附近发射且有较大的发散角,这与PIC模拟的结果一致;快质子发射方向与快电子大体一致,但其发散角远小于快电子.原因在于电子产生和加速在靶前(激光辐照面),在输运中受过密等离子体和靶的散射;而质子来源于靶背的含H污染物,并由靶法线鞘加速机制(TNSA)加速,未受散射地到达探测器.快电子和快质子能谱给出的快电子有效温度和质子最大能量较好地满足定标关系Emax=αTh,其中α≈2. 相似文献
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双脉冲打靶实验中传统光路的能量损失大,会使能量密度降低一个数量级。由于光学实验平台空间有限,镜子又多,调节和搭建复杂,实验调节和测得结果的准确性很低。于是搭建了一个新的可调控的光路,使实验效率和准确性大大提高。 相似文献
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Proton acceleration induced by a high-intensity ultraviolet laser interaction with a thin foil target was studied on an ultra-short KrF laser amplifier called LLG50 in China Institute of Atomic Energy(CIAE).The ultraviolet laser produced pulses with a high-contrast of 109,duration of 500 fs and energy of 30 mJ.The p-polarized laser was focused on a 2.1 μm gold foil by an of-axis parabola mirror(OAP) at an incident angle of 45°.The laser intensity was 1.2×1017W/cm2.The divergence angle for proton energy of 265 keV or higher was 30°,which was recorded by a CR39 detector covered with 2 μm aluminum foil in the target normal direction.The maximum proton energy recorded by a CR39 detector covered with a 4 μm aluminum foil was 440 keV,and the proton energy spectrum was measured by a proton spectrometer.The ultraviolet laser acquires a relatively lower hot electron temperature,which can be ascribed to the proportional relationship of Iλ2,but a higher hot electron density because of the higher laser absorption and critical density.Higher electron density availed to strengthen the sheath electric field,and increased the proton acceleration. 相似文献
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《等离子体科学和技术》2015,17(6):458-460
Proton acceleration experiments were carried out by a 1.2 x 101s W/cm2 ultra-short laser interaction with solid foil targets.The peak proton energy observed from an optimum target thickness of 7μm in our experiments was 2.1 MeV.Peak proton energy and proton yield were investigated for different foil target thicknesses.It was shown that proton energy and conversion efficiency increased as the target became thinner,on one condition that the preplasma generated by the laser prepulse did not have enough shock energy and time to influence or destroy the target rear-surface.The existence of optimum foil thickness is due to the effect of the prepulse and hot electron transportation behavior on the foil target. 相似文献
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超短超强激光与固体靶相互作用可产生显著的X射线剂量,其辐射防护问题是辐射防护和激光等离子体物理的学科交叉问题,对超短超强激光装置安全运行至关重要。为验证清华大学所提出的剂量评估公式,对超短超强激光与固体靶作用所产生的X射线剂量开展了实验研究。设计了用于屏蔽靶室内超热电子和散射光子的屏蔽结构,仅测量超热电子和固体靶作用所产生的X射线剂量,并开展蒙特卡罗模拟评估其屏蔽效果。基于星光 Ⅲ激光装置对不同激光功率密度(7×1018~4×1019 W/cm2)下不同角度上的X射线剂量开展了实验测量,并与不同的剂量评估公式结果进行了比较分析,实验中还对不同剂量测量探测器的响应进行了比较。计算结果表明,所设计的屏蔽结构能很好地屏蔽超热电子和散射光子。实验结果表明,清华大学所提出的剂量评估公式较文献公式能更好地与实验结果吻合。随激光功率密度的增加,前向的X射线剂量较侧向增加得更快。 相似文献
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LI Ye-jun WANG Lei-jian XI Xiao-feng ZHANG Hai-feng ZHANG Ji TANG Xiu-zhang 《中国原子能科学研究院年报》2005,(1):136-136
Effects of experimental conditions to laser pulse laser with atomic clusters are investigated. same backing gas pressure. The size of cluster absorption coefficient at the interaction of ultra-short Big clusters are easily formed for high Z rare gases at is large at high backing gas pressure, 相似文献