High-brightness, high-spatial-resolution, 6.151 keV x-ray imaging of inertial confinement fusion capsule implosion and complex hydrodynamics experiments on Sandia's Z accelerator (invited)

When used for the production of an x-ray imaging backlighter source on Sandia National Laboratories' 20 MA, 100 ns rise-time Z accelerator [M. K. Matzen et al., Phys. Plasmas 12, 055503 (2005)], the terawatt-class, multikilojoule, 526.57 nm Z-Beamlet laser (ZBL) [P. K. Rambo et al., Appl. Opt. 44, 2421 (2005)], in conjunction with the 6.151 keV, Mn-Heα curved-crystal imager [D. B. Sinars et al., Rev. Sci. Instrum. 75, 3672 (2004)], is capable of providing a high quality x radiograph per Z shot for various high-energy-density physics experiments. Enhancements to this imaging system during 2005 have led to the capture of inertial confinement fusion capsule implosion and complex hydrodynamics images of significantly higher quality. The three main improvements, all leading effectively to enhanced image plane brightness, were bringing the source inside the Rowland circle to approximately double the collection solid angle, replacing direct exposure film with Fuji BAS-TR2025 image plate (read with a Fuji BAS-5000 scanner), and generating a 0.3-0.6 ns, ∼200 J prepulse 2 ns before the 1.0 ns, ∼1 kJ main pulse to more than double the 6.151 keV flux produced compared with a single 1 kJ pulse. It appears that the 20±5 μm imaging resolution is limited by the 25 μm scanning resolution of the BAS-5000 unit, and to this end, a higher resolution scanner will replace it. ZBL is presently undergoing modifications to provide two temporally separated images ('two-frame') per Z shot for this system before the accelerator closes down in summer 2006 for the Z-refurbished (ZR) upgrade. In 2008, after ZR, it is anticipated that the high-energy petawatt (HEPW) addition to ZBL will be completed, possibly allowing high-energy 11.2224 and 15.7751 keV Kα1 curved-crystal imaging to be performed. With an ongoing several-year project to develop a highly sensitive multiframe ultrafast digital x-ray camera (MUDXC), it is expected that two-frame HEPW 11 and 16 keV imaging and four-frame ZBL 6.151 keV curved-crystal imaging will be possible. MUDXC will be based on the technology of highly cooled silicon and germanium photodiode arrays and ultrafast, radiation-hardened integrated circuitry