Nanosecond-gated hybrid complementary metal-oxide semiconductor imaging sensors are a powerful tool for temporally gated and spatially resolved measurements in high energy density science, including inertial confinement fusion, and in laser diagnostics. However, a significant oscillating background excited by photocurrent has been observed in image sequences during testing and in experiments at the National Ignition Facility (NIF). Characterization measurements and simulation results are used to explain the oscillations as the convolution of the pixel-level sensor response with a sensor-wide RLC circuit ringing. Data correction techniques are discussed for NIF diagnostics, and for diagnostics where these techniques cannot be used, a proof-of-principle image correction algorithm is presented.

A new generation of gated x-ray detectors at the National Ignition Facility has brought faster, enhanced imaging capabilities. Their performance is currently limited by the amount of signal they can be operated with before space charge effects in their electron tube start to compromise their temporal and spatial response. We present a technique to characterize this phenomenon and apply it to a prototype of such a system, the Single Line Of Sight camera. The results of this characterization are used to benchmark particle-in-cell simulations of the electrons drifting inside the detector, which are found to well reproduce the experimental data. These simulations are then employed to predict the optimum photon flux to the camera, with the goal to increase the quality of the images obtained on an experimental campaign while preventing the appearance of deleterious effects. They also offer some insights into some of the improvements that can be brought to the new pulse-dilation systems being built at Lawrence Livermore National Laboratory.

The hardened single line of sight camera has been recently characterized in preparation for its deployment on the National Ignition Facility. The latest creation based on the pulse-dilation technology leads to many new features and improvements over the previous-generation cameras to provide better quality measurements of inertial confinement fusion experiments, including during high neutron yield implosions. Here, we present the characterization data that illustrate the main performance features of this instrument, such as extended dynamic range and adjustable internal magnification, leading to improved spatial resolution.

We describe a method of analyzing gate profile data for ultrafast x-ray imagers that allows pixel-by-pixel determination of temporal sensitivity in the presence of substantial background oscillations. With this method, systematic timing errors in gate width and gate arrival time of up to 1 ns (in a 2 ns wide gate) can be removed. In-sensor variations in gate arrival and gate width are observed, with variations in each up to 0.5 ns. This method can be used to estimate the coarse timing of the sensor, even if errors up to several ns are present.

Characterization data for the Icarus 2 hybrid-CMOS (hCMOS) imager using near-infrared (NIR) laser pulses is presented. The Icarus 2 hCMOS imagers are four-frame burst mode cameras, with a 1024 x 512 pixel array and 25μm spatial resolution. Designed and built by Sandia National Laboratory for the Ultra-Fast X-ray Imager (UXI) program where they have been used to capture X-ray images at LLNL’s National Ignition Facility and during HED physics experiments. Temporal and spatial characterization is performed using NIR, 1053nm and 1064nm, laser pulses ranging from 43-ps to 20ns. Specific results include gate response, internal reflections, off-gate sensitivity, side-to-side timing skew, and response to a characteristic NIF-like laser pulse. Comparisons between a commercial gated, intensified CCD camera and a commercial time-integrated CMOS camera are included when relevant.

The temporal response of a microchannel plate photomultiplier tube used in the suite of neutron time of flight (nToF) diagnostics at the National Ignition Facility has been characterized to reduce uncertainty in, and understanding of, shot parameters obtained from nTOF data. A short pulse laser, neutral density glass filters, and electrical attenuators were used to gather statistically significant samples of photodetector impulse response functions (IRF) in rapid succession. Individual components have been absolutely calibrated to minimize systematic uncertainties. The zeroth (collected charge), first (transit time), and second central moments (transit time spread) of the IRF were calculated as either the bias voltage or the amount of light incident on the detector was varied. Timing reference was provided by a monitor photodiode viewing a pickoff of the incident laser pulse. The primary sources of uncertainty are jitter in the monitor photodiode and the statistical variation across our measurement period. The spreads in the first moment, with respect to the timing photodiode, and the square root of the second central moment were found to be less than 50 ps and 150 ps, respectively.

In this paper characterization data for two versions of a gated hybrid-CMOS image sensor are presented. These sensors, referred to as Icarus and Icarus 2, are two and four frame burst mode cameras respectively, with 1024 x 512 pixel array and 25μm spatial resolution. Designed and built by Sandia National Laboratory for the Ultra-Fast X-ray Imager (UXI) program, they have been used to capture X-ray images at LLNL’s National Ignition Facility and during High Energy Density Physics (HEDP) experiments. Performance data including timing mode, oscillator performance, and gate widths for the Icarus series sensors is covered; this is the first reported data for the four frame Icarus 2 sensors. Additional impacts on device performance due to diode passivation layer for low energy electron sensitivity and low signal linearity are presented. A discussion of oscillator performance, bond wire inductance, and linear response is also covered.

The Daedalus camera is a second-generation imager for the Ultra-Fast X-ray Imager (UXI) program, achieving 1 ns, time-gated, multi-frame image sets for High Energy Density (HED) physics experiments. Daedalus includes a 1024 x 512 pixel array with 25 μm spatial resolution with three frames of storage per pixel with three times larger full well (1.5 million e-) than the last generation camera, Icarus. Daedalus incorporates an improved timing generation and distribution concept to facilitate broader user configurability and application space while improving timing resolution to 1 ns. Electrical timing measurements demonstrated 1 nanosecond shutters. Analog dynamic range is sufficient to provide the expected full well. Read noise of 210 e- has been measured, exceeding design goals. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.