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We have made time-resolved spectral measurements above 80 Å from laser-produced plasmas. These are made using a transmission grating spectrograph whose primary components are a cylindrically-curved x-ray mirror for light collection, a transmission grating for spectral dispersion, and an x-ray streak camera for temporal resolution. A description of the instrument and an example of the data are given. We have built a spectrograph to time resolve the spectrum above 80 A from laser-produced plasmas. Several possible schemes using high-powered lasers have been identified that produce x-ray lasing lines in the 80 Å to 300 Å range.1 This spectrograph has been built to measure the output from these targets. The principal components of the spectrograph are a cylindrically-curved x-ray mirror for light collection, a transmission grating for wavelength dispersion, and a soft x-ray streak camera for x ray detection. These have been combined to produce an instrument having high spectral resolution, E/tL > 200, continuous wavelength coverage from 80 A to 300 A, good time resolution, 1,20 psec, and high sensitivity, 1,10 photons/sec-sr. In addition, because an application is to measure x-ray lasing output, we have devised an optical alignment system which can accurately point the instrument to the target with an accuracy of less than one milliradian. A schematic of the instrument design is shown in Fig. 1. X rays from the target are collected and focused at the detection plane by a cylindrically-curved grazing incidence x-ray mirror. The mirror acts like one element of a Kirkpatrick-Baez x-ray microscope producing a line focus perpendicular to the plane of dispersion. 2 The mirror has an eight meter radius of curvature and operates at an angle of incidence of 4°. It is 68 cm from the target midway between the target and detection circle. This produces a magnification of unity. Spherical aberrations for these conditions are estimated to be less than 10 μm, which is much less than target sizes.
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