软X射线连续谱Z箍缩铝等离子体电子温度诊断

针对强光一号加速器（约1.5 MA,80～100 ns）Z箍缩铝丝阵实验设计和研制了一套弯晶谱仪,采用邻苯二甲酸氢铊（TlAP）晶体对辐射能谱进行色散,用X射线胶片记录连续辐射谱型,谱仪测谱范围为1.8～3.0 keV。以第10084发次平面型铝丝阵负载实验为例,获得了具有轴向分辨的时间积分辐射谱型,对其中某一热斑处的数据进行处理得到了该区域等离子体时间积分电子温度约为520(135%)eV。     

时间分辨晶体谱仪在Z箍缩等离子体中的应用

在装置阳加速器上,使用椭圆弯晶谱仪对Al丝阵Z箍缩实验的X射线辐射特性进行了研究。在谱仪结构中,使用椭圆面的晶体作为分光元件,采用PIN阵列作为记录元件实现时间分辨测量,同时用成像板记录时间积分结果。在Al丝阵Ｚ箍缩实验中,获得了时间分辨的Al等离子体Ｋ壳层辐射谱,用基于碰撞-辐射模型的K壳层线辐射谱分析程序对Al丝阵Z箍缩的实验数据进行了分析,获得了Al丝阵等离子体的时间分辨的电子温度和时空平均的电子数密度参数。     

柱状锗等离子体状态的时空分辨诊断

在四靶串接X光激光实验中,用时间分辨晶体谱仪记录了类Ne锗共振线及其类Na伴线的时间扫描特性。测出了这些谱线的辐射持续时间(FWHM)约为0.95ns。考察了锗等离子体电子温度T_e随时间的演化,观测到T_e≥400eV的维持时间大于1.2ns。用空间分辨晶体谱仪诊断得到锗等离子体电子温度T_e和电子密度n_e的轴向分布,其平均值T_e=4.9×10~2eV,n_e=1.2×10~(20)/cm~3。     

Z箍缩等离子体均匀色散晶体光谱成像

为了诊断Z箍缩等离子体X射线相关信息,利用自聚焦和均匀色散原理,研制了一种新型的均匀色散弯晶谱仪。晶体分析器采用-石英（1010）,布拉格角为43.4~72.7,利用有效面积为10 mm50 mm的X射线胶片接收光谱信号,实验在中国工程物理研究院阳加速器装置上进行,摄谱元件获得了Z箍缩铝丝阵等离子体的类H及类He谱线。实验结果表明:谱线分布遵循均匀色散条件,所研制均匀色散弯晶谱仪线色散率为-116.198 mm/nm,与理论值-120 mm/nm的相对误差为3.168%,能够用于Z箍缩等离子体X射线的光谱学研究。     

线状锗等离子体X射线线谱的时间分辨测量

用自行研制的X射线条纹晶体谱仪首次测量了线状锗等离子体的X射线时间分辨谱。给出了类Ne-锗L线共振线的时间演化过程,并用类Ne-锗L线共振线与其双电子俘获伴线的相对强度比粗估了锗等离子体的电子温度及其随时间的变化,实验给出了X光激光增益区介质的电子温度为400～760eV,同时给出了电子温度保持相对恒定的时间不小于90ps(电子温度变化小于2％)。     

激光等离子体电子温度的时间分辨诊断

本文描述在LF-11激光装置上进行的线状锗等离子体电子温度时间分辨诊断的实验。在实验中利用时间分辨X射线晶体谱仪测量了线状锗等离子体X射线的时间分辨谱,并借助碰撞辐射模型(CR模型),由类Ne锗L线特征线相对强度比确定出锗等离子体的电子温度及其时间演化过程。并与用部分局部热平衡模型(PLTE)得出的结果做了比较。     

用于诊断激光等离子体X射线的双通道椭圆弯晶谱仪

利用从一个焦点发出的光线经过椭圆面反射后汇聚于另一个焦点及布拉格衍射的特点,研制了双通道椭圆弯晶谱仪(以下简称"弯晶谱仪").采用独特的双通道结构能够对高温等离子体所发出的X射线同时进行空间和时间分辨测量,测量的波长范围为0.2～2 nm,布拉格角的覆盖范围是30°～67.5°.阐述了弯晶谱仪的基本结构.重点介绍了对LiF分光晶体进行的X射线衍射实验及在"星光Ⅱ" 激光装置上进行的激光打靶实验.得到了钛等离子体X射线的发射谱图像,经过分析,发现弯晶谱仪的空间分辨率能够达到0.0011 nm.最后,提出对弯晶分析器的特性、制作工艺及检测方法还必须进行进一步的深入研究.     

硬X射线透射晶体谱仪的设计性能参数

激光等离子体相互作用高分辨硬X射线光谱的测量通常采用柱面透射弯晶谱仪实现。利用几何光学模型对柱面透射弯晶谱仪的关键技术参数进行了理论计算和数值模拟,给出了谱仪弯晶曲率半径、光源到晶体的距离、光源尺寸和探测器的位置等因素对谱仪测谱范围和分辨能力的影响情况,分析了光谱分辨水平随能点的变化。分析结果表明:晶体曲率半径对测谱范围和谱分辨能力影响大,在光源尺寸较小时,随着探测器与罗兰圆距离的增加,谱线之间距离增加的速度大于光谱线宽增加的速度,使得分辨能力增加。     

CO2激光锡等离子体极端紫外及可见光光谱

利用CO2激光烧蚀锡靶产生等离子体,当入射到靶面的单个脉冲能量为400mJ,半峰全宽(FWHM)为75ns时,使用光谱仪和增强型电荷耦合器件(ICCD)采集了等离子体的时间分辨光谱。在局域热平衡假设下,利用谱线的斯塔克展宽和五条Sn II谱线的相对强度计算并得到了等离子体电子密度、电子温度和辐射谱线强度随时间的变化规律;利用掠入射极端紫外平场光栅光谱仪,结合X射线CCD同时探测了光源在6.5～16.8nm波段的时间积分极端紫外辐射光谱。实验结果表明:激光点燃等离子体早期的100ns内有很强的连续谱,此后才能分辨出明显的原子和离子线状谱。在延时0.1～2.0μs的时间区间内,等离子体中的电子温度和密度分别在2.3～0.5eV和7.6×1017～1.2×1016 cm-3范围内,均随时间经历了快速下降,然后再较缓慢下降的过程。激光锡等离子体极端紫外不可分辨辐射跃迁光谱峰值中心位于13.5nm,FWHM为1.1nm。     

双驱动x射线激光等离子体能谱特性研究

用时间积分空间分辨的平晶千电子伏谱仪测量了钽激光等离子体发射波长范围为045— 075nm的软x射线能谱，精确测量和准确辨认出类镍、类钴和类铁离子的共振线及类镍离子 的内壳层跃迁线-对实验结果处理，获得了辐射线谱的强度-通过谱线比率的诊断推断脉冲激 光时差对等离子体状态的影响，至少也可部分解释激光上能级的粒子数及等离子体的 电离程度- 关键词： 离子谱特性 软x线能谱强度 谱线辨认     

Detection of the spectra of multicharged ions with time resolution and the determination of the parameters of the hot component of the plasma in the case of the magnetic implosion of multiwire arrays

The dynamics of the hot component of the plasma of imploding multiwire arrays has been analyzed using the time behavior of the X-ray spectral lines of multicharge ions. The spectra of H- and He-like aluminum ions with nanosecond time resolution have been detected using electron-optical chronography in experiments on the implosion of multiwire arrays by mega-ampere currents. The simultaneous appearance of the resonance lines of H- and He-like ions implies that the hot plasma whose electron temperature is higher than 0.5 keV has existed on the axis before the implosion of the main mass of the liner. The further dynamics of the intensity of the lines is primarily attributed to an increase in the mass of the emitting plasma.     

Spectral analysis of K-shell X-ray emission of magnesium plasma produced by ultrashort high-intensity laser pulse irradiation

Spectral analysis of K-shell X-ray emission of magnesium plasma, produced by laser pulses of 45 fs duration, focussed up to an intensity of ～10¹⁸ W cm^?2, is carried out. The plasma conditions prevalent during the emission of X-ray spectrum were identified by comparing the experimental spectra with the synthetic spectra generated using the spectroscopic code PrismSPECT. It is observed that He-like resonance line emission occurs from the plasma region having sub-critical density, whereas K-α emission arises from the bulk solid heated to a temperature of 10 eV by the impact of hot electrons. K-α line from Be-like ions was used to estimate the hot electron temperature. A power law fit to the electron temperature showed a scaling of I ^0.47 with laser intensity.     

Orbital Electron Capture Rate and Time Modulation of H- and He-like Ions in a Storage-Ring

We have studied in a heavy ion storage ring the orbital electron capture decays of H- and He-like ¹⁴⁰Pr and ¹⁴²Pm ions and found that the H-like ions with one electron in the K-shell decay 1.49(8) and 1.44(6) times faster, than the corresponding He-like ions with two electrons in the K-shell. This result is explained by spin statistics due to the hyperfine structure of the H-like ions.     

AlK壳层等离子体辐射谱模型的比对

碰撞辐射模型的比对研究对校验发展等离子体辐射谱模型、提高等离子体参数的诊断精度具有重要意义. 基于Al等离子体, 对常用的辐射模型代码FAC和FLYCHK K壳层辐射谱模型开展了比对研究, 详细比较了它们的离子丰度、特征线强度、谱发射率曲线和吸收系数曲线等特征, 并根据各能态的速率方程, 从FAC和FLYCHK模型的结构特点出发, 分析了造成这些差异的原因. FAC 和FLYCHK计算得到的类H、类He离子n=2, n=3激发态数密度有显著差异, 进而引起特征线发射率及其比值(He-IC/He-αup, He-βup/H-βup)的差异, 从而对等离子体参数的诊断结果产生影响. 除了模型中采用的能级结构和碰撞辐射过程速率外, 计算结果显著地受到FAC 和FLYCHK 模型结构的影响. n=2激发态数密度的差异是由FAC和FLYCHK分别采用能级和超组态(组态)的方式构建n=2激发态的速率方程而引起的, 而FAC代码忽略了n=3与更高激发态之间的碰撞耦合过程, 是引起n=3激发态数密度差异的原因. 主要特征线的吸收系数与基态能级的数密度相关, 受到激发态数密度的影响较小, 因此与谱发射率曲线相比, FAC和FLYCHK计算结果的差异更小.     

Generation and characterization of a bright X-ray source using picosecond laser

High-resolution soft X-ray spectra of H-like and He-like ions were produced from laser irradiated silicon and aluminum targets. Plasma size was about 100 μm. X-ray spectra were analyzed to determine plasma parameters. We compared the line shape of resonance transitions and their intensity ratios to corresponding dielectronic satellites and the intensities of the inter combination lines of He-like ions, with the results of model calculations. Such comparison gave average values of the electron density N _e=(1?1.9)×10²¹ cm^?3 and the electron temperature T _e=460–560 eV for Si plasmas and about 560 eV for Al plasmas produced by the first and the second laser harmonics. According to our estimations, more than 10¹² photons were produced within the resonance line spectral width and in the solid angle 2π steredian during the total decay period.     

Al激光等离子体电子温度的时间分辨诊断

 将门控分幅相机与平面晶体谱仪耦合，构成时间分辨光谱测量系统，对Al激光等离子体的K壳层发射谱进行测量，获得了相对入射激光延迟约1ns，积累时间约200ps的光谱信号。利用稳态碰撞-辐射平衡（CRE）近似条件下的等离子体光谱辐射动力学模型，给出了Al激光等离子体Ly-β线与He-β线强度比以及Ly-γ线与He-γ线强度比与电子温度的函数关系。在此基础上，根据实验谱线强度比，得到激光强度为2.319×10¹⁴，1.937×10¹⁴和3.946×10¹⁴ W/cm²时，等离子体冕区电子温度分别为1.190(1±27%)，1.165(1±27%)和1.525(1±27%)keV。     

Band tunable X-ray flat crystal spectrometer for laser-produced plasma spectroscopy measurements

An updated design of a band-tunable flat crystal spectrometer is presented. The new configuration contributes to a broad spectral coverage with greater resolving power, a strong rejection of hard X-ray backgrounds, and decreased sensitivity to source broadening for an extended source. To verify the performance of the spectrometer, spectral lines were measured using a potassium acid phthalate crystal for highly ionized species of aluminum or silicon, and the results were compared by measuring H- and He-like Al and Si lines by rotating the crystal to selected Bragg angles, at the Shenguang II laser facility. The observed energy-coverage range is consistent with the theoretical predictions, as well as with the measured spectral resolution of ~300.     

On the role of prepulses during solid target heating by picosecond laser pulses

X-ray emission spectra of the plasma created at the surface of magnesium, aluminum, copper, and zinc targets heated by 1-ps laser pulses with a peak power density of up to 10¹⁶ W/cm² were measured. The effect of a picosecond prepulse on the spectra was studied for various power densities and intensity contrasts of the main laser pulse. It is established that the emission spectra of laser plasmas are weakly affected by a change from 10⁵ to 10⁷ in the main pulse contrast relative to the first prepulse. Variations in the parameters of emission from aluminum and magnesium plasmas were calculated using relative intensities and widths of the resonance lines of H-and He-like ions and their two-electron satellite peaks.     

作为X激光增益介质的激光等离子体特性

本文报道利用具有空间分辨能力的透射光栅谱仪对以三体复合泵浦实现锂离子(Si~(11+)X光自发辐射放大的增益介质——硅激光等离子体特性的研究。结果表明,等离子体5～100A范围软X线辐射主要来自类氦离子(Si~(12+))到(S~(11+))复合辐射和Si~(11+)(n=3→n=2)跃迁发射的贡献,且它们辐射的最大强度距靶面130μm,对应的电子密度3×10~(20)cm~(-3)与Si~(11+)+1s~23d能级的粒子数相对丰度比36;实验中还观察到Si~(11+)(1s~23d-1s~22p)跃迁发射存在着明显的自吸收现象。     

极化X光谱诊断铝激光等离子体的电子密度

为了准确诊断激光等离子体的电子密度,提出了一种基于极化光谱的类氦共振线与互组合线相对强度比诊断电子密度的方法.该法考虑了激光等离子体发射的X射线存在极化的特性,用极化光谱理论对测量的类氦共振线和互组合线光谱相对强度比进行精密校正,再推导等离子体的电子密度.在2×10 J激光装置上进行了实验,使用极化PET（002）晶体谱仪测量了Al类氦离子光谱,利用光谱的极化特性推出Al等离子体的电子密度约为1.5×1020 cm－3.结果表明极化X光谱推导等离子体电子密度方法适合激光高温高密等离子体诊断.