Long duration x-ray source for laboratory photoionized plasmas*

Long duration, i.e. tens of ns, broadband x-ray sources are important to perform laboratory photoionized plasma experiments relevant to astrophysics. In a series of experiments performed at the OMEGA EP laser facility we have used the Gatling-Gun source to produce an x-ray drive that lasts for 30ns and has a radiation temperature of approximately 90eV. The Gatling-Gun source is comprised of a three Cu hohlraum arrangement. Each holhraum is filled with TPX foam and is driven by a 10ns-square pulsed laser beam with 4.4kJ of UV laser energy¹. The total source duration of 30ns is achieved by driving the three hohlraums sequentially in time. The radiation temperature is monitored with a VISAR diagnostic to check the source’s performance consistency. We present systematic measurements of the radiation temperature and x-ray source performance obtained from VISAR data recorded over two series of experiments performed OMEGA EP. Also, we have used the 4ω probe laser available at OMEGA EP to observe the effect of the Cu/TPX plasma blow off from the hohlraum.

¹D. Martinez, 2017 Annual OLUG Workshop.