scholarly journals Рентгеновские лазеры в потоках кластеров и в наноструктурированных мишенях

2019 ◽  
Vol 127 (7) ◽  
pp. 74
Author(s):  
Е.П. Иванова
Keyword(s):  
Steady State ◽  
Model Potential ◽  
Zero Approximation ◽  
Quasi Steady State ◽  
X Ray ◽  
Water Window ◽  
Xenon Cluster ◽  
Relativistic Perturbation Theory ◽  
Window Region ◽  
Cluster Flow

AbstractThe paper presents a brief review of recent works concerning the modeling of X-ray lasers in cluster flows and in nanostructured targets. Calculations of the atomic characteristics are based on relativistic perturbation theory with a model potential of zero approximation. Two new results are discussed: (1) it is shown that a subpicosecond X-ray laser with λ = 41.8 nm formed in a xenon cluster flow can serve as an alternative to a free-electron laser and (2) in heavy Ni-like ions ( Z ≥ 60), the ionization of ions and recombination of electrons are balanced at electronic temperatures ≥1500 eV; thus, the state of a Ni-like ion is quasi-steady-state. The inversions of many transition levels of an X-ray laser are also quasi-steady-state. The possibility of experimental observation of X-ray lasers based on 3 p ^54 d ^104 p [ J = 0] – 3 p ^63 d ^94 p [ J = 1] intrashell transitions in Gd^36+ with wavelengths in the water window region is discussed.

Soft X‐ray Detectors Based on SnS Nanosheets for the Water Window Region

2021 ◽  
pp. 2105038
Author(s):  
Babar Shabbir ◽  
Jingying Liu ◽  
Vaishnavi Krishnamurthi ◽  
R. A. W. Ayyubi ◽  
Kevin Tran ◽  
...  
Keyword(s):  
X Ray ◽  
Water Window ◽  
Window Region

scholarly journals Time dependence of the inversion condition and optimized X-ray emission in recombining laser-produced plasmas

1995 ◽  
Vol 13 (3) ◽  
pp. 403-421 ◽  
Author(s):  
W. Brunner ◽  
R.W. John
Keyword(s):  
Steady State ◽  
Population Density ◽  
Critical Density ◽  
Time Behavior ◽  
Quasi Steady State ◽  
Time Duration ◽  
X Ray ◽  
Optimal Population ◽  
Inversion Condition ◽  
Short Times

The recombination X-ray laser scheme is considered in the case of recombining plasmas produced by laser pulses which are short to such a degree that the condition for inversion in X-ray transitions of the ions is essentially time-dependent. Using an analytic four-level model, applicable for H-like and Li-like ions, we calculate the inversion conditions for the 4→3, 3→2, and 2→l transitions in H-like ions as functions of time. As we have already shown, a drastic change occurs, especially for the 3→2 transition. To achieve inversion, for short times the free-electron density as a function of the temperature Te, Neinv(Te), must be greater than a critical density Nesh (Te), Neinv(Te) > Nesh(Te), whereas for longer times in the quasi-steady state, Neinv(Te) must be smaller than a critical density Neqv(Te), Neinv(Te) < Nequ(Te). We also consider the evolution of the inversion condition in the intermediate time domain. The time duration of the existence of the short-time 3→2 inversion condition–in the time interval from the initial state with unoccupied lower levels to the quasi-steady state—is in the main determined by t α 1/A21; for example, one has t ≈ 730 fs for Na.In a plasma produced in particular by optical-field ionization, during the initial cascade populating the excited levels, an inversion may be possible in the 2→1 resonance line transition in the transient regime. The inversion in this transition is of interest especially because of the arising possibility to achieve X-ray gain at shorter wavelengths. In the transient case, an inversion occurs for a small time depending on the temperature Te and the density N.In addition, we discuss generally the time behavior of the population densities (especially of N3) and show that an optimal population density occurs, on the one hand, for very short times (fs region, depending on Z). On the other hand, however, the optimal (ion-)density-temperature relation is determined via a time of the optimal population density required with regard to the experimental conditions.

scholarly journals High Reflectance Nanoscale V/Sc Multilayer for Soft X-ray Water Window Region

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Qiushi Huang ◽  
Qiang Yi ◽  
Zhaodong Cao ◽  
Runze Qi ◽  
Rolf A. Loch ◽  
...  
Keyword(s):  
X Ray ◽  
Water Window ◽  
Window Region ◽  
High Reflectance

Generation of a coherent x ray in the water window region at 1 kHz repetition rate using a mid-infrared pump source

2009 ◽  
Vol 34 (11) ◽  
pp. 1747 ◽  
Author(s):  
Hui Xiong ◽  
Han Xu ◽  
Yuxi Fu ◽  
Jinping Yao ◽  
Bin Zeng ◽  
...  
Keyword(s):  
Repetition Rate ◽  
Mid Infrared ◽  
X Ray ◽  
Water Window ◽  
Pump Source ◽  
Window Region

scholarly journals Towards GW-Scale Isolated Attosecond Pulse Far beyond Carbon K-Edge Driven by Mid-Infrared Waveform Synthesizer

2018 ◽  
Vol 8 (12) ◽  
pp. 2451 ◽  
Author(s):  
Yuxi Fu ◽  
Hua Yuan ◽  
Katsumi Midorikawa ◽  
Pengfei Lan ◽  
Eiji Takahashi
Keyword(s):  
Single Cycle ◽  
High Order Harmonic Generation ◽  
Mid Infrared ◽  
X Ray ◽  
Water Window ◽  
High Order Harmonic ◽  
Optical Parametric ◽  
Isolated Attosecond Pulse ◽  
Window Region ◽  
The Continuum

We discuss the efficient generation of intense “water window” (0.28–0.54 keV) isolated attosecond pulses (IAPs) using a mid-infrared (MIR) waveform synthesizer. Our numerical simulations clearly indicate that not only a longer-wavelength driving laser but also a weak control pulse in the waveform synthesizer helps extend the continuum cutoff region and reduce the temporal chirp of IAPs in high-order harmonic generation (HHG). This insight indicates that a single-cycle laser field is not an optimum waveform for generating the shortest IAP from the veiwpoints of reducing the attochirp and increasing the efficiency of HHG. By combining a waveform synthesizer technology and a 100 mJ MIR femtosecond pulse based on a dual-chirped optical parametric amplification (DC-OPA) method, a gigawatt-scale IAP (55 as with 10 nJ order) in the water window region can be generated even without attochirp compensation. The MIR waveform synthesizer is highly beneficial for generating a shorter IAP duration in the soft X-ray region because there are no suitable transparent dispersive materials that can be used for compressing the attochirp.

Thermal and temporal stability of V/Sc multilayer mirror for the soft X-ray water window region

Vacuum ◽  
2017 ◽  
Vol 146 ◽  
pp. 187-193 ◽  
Author(s):  
Qiang Yi ◽  
Qiushi Huang ◽  
Jinshuai Zhang ◽  
Xiangmei Wang ◽  
Runze Qi ◽  
...  
Keyword(s):  
Temporal Stability ◽  
X Ray ◽  
Multilayer Mirror ◽  
Water Window ◽  
Window Region

Numerical experiments on the PF1000 plasma focus device operated with nitrogen and oxygen gases

2017 ◽  
Vol 31 (16) ◽  
pp. 1750167 ◽  
Author(s):  
M. Akel ◽  
Sh. Ismael ◽  
S. Lee ◽  
S. H. Saw ◽  
H. J. Kunze
Keyword(s):  
Plasma Focus ◽  
Numerical Experiments ◽  
Oxygen Plasma ◽  
Stored Energy ◽  
X Ray ◽  
Water Window ◽  
Energy Formula ◽  
Window Region ◽  
Cooling Effects ◽  
Radiative Collapse

The indicative values of reduced Pease–Braginskii (P–B) currents are estimated for a nitrogen and oxygen plasma focus. The values of depletion times indicate that in N2 and O2 with estimated 3–4% of pinch energy radiating away over the duration of the pinch, we may expect some cooling effects leading to small reductions in radius ratio. In other gases with higher atomic number, the pinch duration is much more than the depletion time, so radiative contraction may be anticipated. The Lee model was employed to study the soft X-ray from PF1000 operated with nitrogen and oxygen. We found nitrogen soft X-ray yield in the water window region of 3.13 kJ, with the corresponding efficiency of 0.9% of the stored energy [Formula: see text], while for the oxygen it was found to be [Formula: see text] = 4.9 kJ, with the efficiency of 1.4% [Formula: see text]. The very modest enhancement of compression (radius ratios around 0.1) in the pinches of these two gases gives rise to rather modest pinch energy densities (PEDs) under 109 Jm[Formula: see text]. This is in contrast to Kr or Xe where it had been shown that the radiative collapse leads to radius ratios of 0.007 and 0.003, respectively, with PEDs going to large values considerably exceeding 10[Formula: see text] Jm[Formula: see text].

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