Large laser and pulsed power facilities at national labs such as LLNL have afforded the scientific community significant experience with measuring high-energy-density plasmas and with developing routine, reliable, and accurate diagnostic suites. NIF’s diagnostic development benefits from those decades of experience and from the involvement of organizations such as the University of Rochester’s Laboratory for Laser Energetics, Massachusetts Institute of Technology, General Atomics, National Security Technologies, and the atomic energy agencies in the United Kingdom and France.
NIF is equipped with an array of nuclear, optical, and x-ray diagnostics that together provide over 400 channels for experimental data. New instruments are added regularly. (A comprehensive list, current as of the time of publication, is available in Appendix E.) Optical diagnostics measure the backscattered light’s power, spectrum, and angular distribution of visible light to determine the energy balance of an experiment as well as the implosion velocity of the fuel capsule, laser–plasma interactions, and instabilities that affect the target performance. Hard and soft x-ray emission detectors with micron-scale and picosecond-scale resolution characterize laser and target performance by measuring target self-emission or by using the x-rays to probe or radiograph dense matter. Nuclear diagnostics signal the presence of high-energy neutrons and gamma radiation and measure physical properties such as neutron yield, ion temperature, bang time, core temperature, and reaction history.
NIF diagnostics are either deployed to a fixed location in the Target Chamber/Bay or fielded on a DIM (diagnostic instrument manipulator). DIMs are two-stage telescoping devices capable of inserting, retracting, positioning, and aligning a diagnostic instrument in the Target Chamber, from the interior wall to Target Chamber Center (TCC). DIMs can fit in a number of designated Target Chamber ports, but three are currently mounted in three locations: one in the Target Chamber north pole (0-0) and two on its equatorial plane (90-78 and 90-315); see Section 5.3. DIMs also provide a standard set of utilities, cables, and controls to support operation of all DIM-based diagnostic instruments. Additionally, there are two target and diagnostic manipulators (TANDMs, see Section 5.4.3) on the chamber’s equatorial plane (90-124 and 90-348).
Facility-provided diagnostics data locations are listed in Table 6-1. Table 6-2 lists key DIM snouts and appendages that can be used in conjunction with a DIM-based detector. Figure 5-3 shows the location of the DIMs, target positioners, and major fixed diagnostics. Appendix E identifies the NIF diagnostics and detectors currently available. The diagnostic location is given in terms of chamber coordinates. Diagnostics labeled “DIM” may be placed in any of the DIMs. If an instrument at a fixed location requires a pinhole or filter on a DIM, this is noted.
| Location | Diagnostic | Diagnostic Description | Facility-Provided Automated Data Analysis Outputs |
|---|---|---|---|
| TC090-315 | VISAR | Velocimetry Interferometer System for Any Reflector: Streak image for reflections from shock waves and surfaces | Streak image that is cross-timed and corrected for background, flat field, saturated pixel, and warp. |
| Q31B, Q36B, Q33B |
FABS/NBI | Full Aperture Backscatter and Near Backscatter Imager: Spectrometers, static, and streak image detectors for energy balance and backscattered energy | Estimated backscattered energy to each cone. |
| TC007-090 | SPIDER | Streaked Polar X-Ray Imager: for measuring x-ray burn history | Cross-timed x-ray bang time and burn width. Corrected and cross-timed streak image. |
| TC090-100 (TC000-000) |
DIXI | Dilation X-Ray Imager: For high temporal resolution imaging of implosion shape and time history | Camera image corrected for warp, saturated pixel, flat field, and background. Image plate data is fade corrected. |
| TC090-078, TC000-000, TC090-315, TC090-124, TC090-348 |
GXD, HGXD |
Gated X-Ray and Hardened Gated X-Ray Detectors for imaging of implosion shape and time history | Timing of gated pulses. Image plate data is fade corrected. Film data is linearized. |
| TC090-078, TC090-124 |
AXIS | AXIS is a gated imager platform optimized for dual ARC projection radiography. | Timing of gated pulses. Image plate data is fade corrected. Film data is linearized. |
| TC090-089 | ARIANE | ARIANE is a gated x-ray detector measuring x-ray output at yields up to ~1E16 neutrons from TCC. | Timing of gated pulses. Image plate data is fade corrected. Film data is linearized. |
| TC090-078, TC000-000, TC090-315, TC090-124, TC090-348 |
DISC | DIM Insertable Streak Camera: for measuring implosion velocity on backlit shots | Streak image that is cross-timed and corrected for background, flat-field, saturated pixel, and warp. |
| TC090-315, TC090-078, TC090-124 |
SLOS | Single-Line-of-Sight Imager is a DIM-based fast, multi-frame x-ray imaging system with variable temporal resolution. | |
| TC000, TC090-315, TC090-078 |
OTS-D | Optical Thomson Scattering Diagnostic for local, time-resolved density, flow, and temperature measurements of under-dense plasmas. | Calibrates the streak image in wavelength and time for both EPW and IAW spectrometers. |
| TC018-123, TC161-326 |
SXI | Static X-Ray Imager: for imaging radiation drive through the laser entrance holes | Corrected reoriented camera image (and estimate of laser entrance hole (LEH) size using camera image). |
| TC090-110 | FFLEX | Filter Fluorescer: hard x-ray detector for measuring electron preheat | Hot electron temperatures. |
| TC143-274, TC064-350 |
DANTE1, DANTE2 | Soft x-ray detector for hohlraum drive and temperature | Voltage traces at each x-ray energy cross-timed and corrected for scope, attenuation, and cabling. |
| TC064-020 | GRH | Gamma Reaction History: nuclear burn history and fuel density | Gamma bang time and burn width. Scope traces cross-timed and corrected. |
| TC090-315 | NIS | Neutron Imaging System | System provides unprocessed images from the cameras and oscilloscope displays for the timing signals. |
| TC090-124 | NIS3 | Neutron Imaging System | System provides unprocessed images from the cameras and oscilloscope displays for the timing signals. |
| TC161-056, TC116-316, TC090-174, TC064-136, TC064-309 |
NTOF | Neutron Time of Flight: for measuring prompt and downscattered neutrons at several locations around the target | Yield and ion temperature of DT or DD peak. |
Table 6-1. Instruments for which automated data reduction is available.
