Transmission grating streaked spectrometer for the diagnosis of soft x-ray emission from ultrahigh intensity laser heated targets

A free-standing gold transmission grating with a period of 5000 Å has been coupled to a soft x-ray sensitive streak camera with a limiting temporal resolution of 10 ps. The streak camera is equipped with a caesium iodide transmission photocathode and observations have been made in the 10–100 Å regime. For a small source (200 μm diameter) the spectral resolution is predicted to be around 2.5 Å. This has been confirmed by examination of the Lyman-α line in hydrogen-like laser heated boron. A recorded linewidth of 2.44 Å is demonstrated. The instrument has been used to diagnose the soft x-ray emission from a plastic (CH) foil target heated by an ultra-intense (2×1020 W cm−2) laser pulse.