Multi-imaging X-ray Streak Research Articles

One-dimensional and multichannels multi-imaging x-ray streak camera for imploded core plasma of shell-cone target

Recently one-dimensional and multichannels multi-imaging x-ray streak camera (1D+McMIXS) has been proposed as an ultrafast diagnostic tool for imploded core plasma of shell-cone target. This diagnostic system can provide much more information of core plasma dynamics, such as the shell trajectory before the maximum compression, two dimensional (2D) x-ray images, and 2D map of electron temperature. The 1D+McMIXS was used in an implosion experiment of a shell target with a cone for fast ignition at Gekko XII laser facility. The interaction between the core plasma and the tip of the cone was observed and revealed some detailed structures. A series of time-resolved 2D x-ray images were reconstructed and a nominal temperature evolution was also mapped.

Multi-imaging x-ray streak camera for ultrahigh-speed two-dimensional x-ray imaging of imploded core plasmas (invited)

Ultrahigh-speed two-dimensional x-ray imaging by using an image sampling technique on an x-ray streak camera has been developed and applied to observe the imploded core plasmas of inertial confinement fusion targets. Various one-dimensional and two-dimensional sampling techniques of two-dimensional images were compared, and the multi-imaging x-ray streak camera (MIXS), was found to be one of the most successful schemes. MIXS was used in an implosion experiment of a shell target with a cone for fast ignition at the OMEGA laser facility. Nonuniform structure in imploded core plasma dynamics was clearly observed with temporal and spatial resolutions of 10 ps and 10−20 μm, respectively.

Development of wide-field, multi-imaging x-ray streak camera technique with increased image-sampling arrays

In order to enlarge the field of view of a multi-imaging x-ray streak (MIXS) camera technique [H. Shiraga et al., Rev. Sci. Instrum. 66, 722 (1995)], which provides two-dimensionally space-resolved x-ray imaging with a high temporal resolution of ∼10 ps, we have proposed and designed a wide-field MIXS (W-MIXS) by increasing the number of image-sampling arrays. In this method, multiple cathode slits were used on the photocathode of an x-ray streak camera. The field of view of the W-MIXS can be enlarged up to 150–200 μm instead of ∼70 μm for a typical MIXS with a spatial resolution of ∼15 μm. A proof-of-principle experiment with the W-MIXS was carried out at the Gekko-XII laser system. A cross-wire target was irradiated by four beams of the Gekko-XII laser. The data streaked with the W-MIXS system were reconstructed as a series of time-resolved, two-dimensional x-ray images. The W-MIXS system has been established as an improved two-dimensionally space-resolved and sequentially time-resolved technique.

Two-dimensional sampling-image x-ray streak camera for ultrafast imaging of inertial confinement fusion plasmas

Ultrafast two-dimensional (2D) x-ray imaging with a temporal resolution better than 10 ps is of great importance in diagnosing the final stages of the imploded core plasmas of inertial confinement fusion (ICF) targets. The multi-imaging x-ray streak camera (MIXS) has been one of such imaging techniques. Recently, we have proposed another scheme, a 2D sampling-image x-ray streak camera method (2D-SIXS). In this scheme, a 2D image is sampled two dimensionally with a set of sampling points distributed regularly over the whole image on a cathode plate of an x-ray streak camera. The sampled image is streaked, and then, reconstructed to form the time-resolved 2D images like movie pictures. In this article, we report results of our proof-of-principle experiments of 2D-SIXS scheme performed at Gekko-XII glass laser system. A gold-coated spherical target was irradiated by three beams (0.53 μm) of Gekko-XII laser. Streaked data of 2D-SIXS were obtained and a series of time-resolved 2D x-ray images were successfully reconstructed. 2D-SIXS is suitable for very fast, short-lived, and small x-ray sources such as a hot spark in the ICF plasma as well as short-pulse-laser-produced plasmas.

Time-resolved, two-dimensional electron-temperature distribution of laser-imploded core plasmas

We have developed a multichannel, multiimaging x-ray streak camera technique to measure two-dimensional electron-temperature distributions with a high temporal resolution by adding a multichannel spectrum selection capability to a multiimaging x-ray streak camera technique, and applied it to direct-drive implosion experiments with partially coherent light at Gekko-XII laser facility. It was found that electron-temperature distributions in the laser-imploded core plasmas of ICF targets had low-mode nonuniform structures changing with a temporal scale of 20 ps, and the abrupt drop of the electron temperature appeared in the deceleration phase. We have compared temporal profiles of the experimentally observed x-ray intensity and electron-temperature with those predicted by a one-dimensional hydrodynamic code “ILESTA” to investigate the hot spark heating in the core plasmas.

One- and two-dimensional fast x-ray imaging of laser-driven implosion dynamics with x-ray streak cameras

One- (1D) and two-dimensional (2D) x-ray imaging techniques with x-ray streak cameras have been developed and utilized for investigating implosion dynamics of laser fusion targets. Conventional streaked 1D images of the shell motion of the imploding target was recorded together with the time-resolved 2D multi-imaging x-ray streak images of the core shapes on the same x-ray streak camera. Precise comparison of the core dynamics between the experimental and simulation results was performed with an accuracy of 30 ps by fitting the trajectories of the x-ray emission from the imploding shell.

Ultrafast two-dimensional x-ray imaging with x-ray streak cameras for laser fusion research (invited)

Ultrafast two-dimensional x-ray imaging is required for diagnosing laser-driven inertial confinement fusion plasmas. Image sampling technique with x-ray streak cameras can meet this requirement. Multi-imaging x-ray streak camera method (MIXS) with temporal and spatial resolutions of 10 ps and 15 μm, respectively, has been developed and successfully utilized for diagnosing the uniformity and heating process of the imploded core plasmas. The two-dimensional sampling-image x-ray streak camera method is also presented. Two types of spectroscopic applications of the MIXS have been developed recently. One is multichannel MIXS, which has three MIXS channels with various spectral responses for time-resolved two-dimensional temperature measurement of the plasmas. Another is monochromatic MIXS for temperature, density, and mixing measurement, in which monochromatic images with Bragg crystals are coupled to MIXS.

Ultra-fast 2-dimensional X-ray imaging with a 10-ps resolution for use in laser fusion research

2-dimensional x-ray imaging of the laser fusion target is now possible with 10-ps temporal resolution by using recently developed multi-imaging x-ray streak (MIXS) technique. Structures in the x-ray image of the laser-imploded core, symmetry and size, were found to be rapidly changing with 10-ps time scale.

マルチイメージX線ストリークカメラを用いた超高時間分解2次元X線画像計測法によるレーザー核融合プラズマの研究 : 情報入力,情報ディスプレイ

マルチイメージX線ストリークカメラを用いた超高時間分解2次元X線画像計測法によるレーザー核融合プラズマの研究 : 情報入力,情報ディスプレイ