We are studying the feasibility of utilizing Kα x-ray sources in the range of 20 to 100 keV as a backlighters for imaging various stages of implosions and high aerial density planar samples driven by the NIF laser facility. The hard x-ray Kα sources are created by relativistic electron plasma interactions in the target material after a radiation by short pulse high intensity lasers. In order to understand Kα source characteristics such as production efficiency and brightness as a function of laser parameters, we have performed experiments using the 10 J, 100 fs JanUSP laser. We utilized single-photon counting spectroscopy and x-ray imaging diagnostics to characterize the Kα source. We find that the Kα conversion efficiency from the laser energy at 22 keV is ~3 x 10-4.
The Linac Coherent Light Source (LCLS) is a 1.5 to 15 A- wavelength free-electron laser (FEL), currently proposed for the Stanford Linear Accelerator Center (SLAC). The photon output consists of high brightness, transversely coherent pulses with duration <300 fs, together with a broad spontaneous spectrum with total power comparable to the coherent output. The output fluence, and pulse duration, pose special challenges for optical component and diagnostic designs. We discuss some of the proposed solutions, and give specific examples related to the planned initial experiments.
LOTIS is a rapidly slewing wide-field-of-viewtelescope which was designed and constructed to search for simultaneous gamma- ray burst (GRB) optical counterparts. This experiment requires a rapidly slewing (less than 10 sec), wide-field-of-view (greater than 15 degrees celsius), automatic and dedicated telescope. LOTIS utilizes commercial tele-photo lenses and custom 2048 X 2048 CCD cameras to view a 17.6 X 17.6 degree field of view. It can point to any part of the sky within 5 sec and is fully automated. It is connected via Internet socket to the GRB coordinate distribution network which analyzes telemetry from the satellite and delivers GRB coordinate information in real-time. LOTIS started routine operation in Oct. 1996. In the idle time between GRB triggers, LOTIS systematically surveys the entire available sky every night for new optical transients. This paper will describe the system design and performance.
The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared region. More than 1.7 million images of the moon, earth and space were returned from this mission. Two star tracker stellar compasses (star tracker camera + stellar compass software) were included on the spacecraft, serving a primary function of providing angle updates to the guidance and navigation system. These cameras served as a secondary function by providing a wide field of view imaging capability for lunar horizon glow and other dark-side imaging data. This 290 g camera using a 576 X 384 FPA and a 17 mm entrance pupil, detected and centroided stars as dim and dimmer than 4.5 mv, providing rms pointing accuracy of better than 100 (mu) rad pitch and yaw and 450 (mu) rad roll. A description of this light-weight, low power star tracker camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission's primary objective for flight qualifying the sensors for future Department of Defense flights.
The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth, and space were returned from this mission. The long-wave-infrared (LWIR) camera supplemented the UV/visible and near-infrared mapping cameras providing limited strip coverage of the moon, giving insight to the thermal properties of the soils. This camera provided approximately 100 m spatial resolution at 400 km periselene, and a 7 km across- track swath. This 2.1 kg camera using a 128 X 128 mercury-cadmium-telluride (MCT) FPA viewed thermal emission of the lunar surface and lunar horizon in the 8.0 to 9.5 micrometers wavelength region. A description of this lightweight, low power LWIR camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission's primary objective for flight qualifying the sensors for future Department of Defense flights.
The Clementine mission provided the first ever complete, systematic surface mapping of the moon from the ultra-violet to the near-infrared regions. More than 1.7 million images of the moon, earth, and space were returned from this mission. The near-infrared (NIR) multi- spectral camera, one of two workhorse lunar mapping cameras (the other being the UV/visible camera), provided approximately 200 m spatial resolution at 400 km periselene, and a 39 km across-track swath. This 1.9 kg infrared camera using a 256 X 256 InSb FPA viewed reflected solar illumination from the lunar surface and lunar horizon in the 1 to 3 micrometers wavelength region, extending lunar imagery and mineralogy studies into the near infrared. A description of this lightweight, low power NIR camera along with a summary of lessons learned is presented. Design goals and preliminary on-orbit performance estimates are addressed in terms of meeting the mission's primary objective for flight qualifying the sensors for future Department of Defense flights.
This article describes the Clementine UV/Visible (UV/Vis) multispectral camera, discusses design goals and preliminary estimates of on-orbit performance, and summarized lessons learned in building and using the sensor. While the primary objective of the Clementine Program was to qualify a suite of 6 light-weight, low power imagers for future Department of Defense flights, the mission also has provided the first systematic mapping of the complete lunar surface in the visible and near-IR spectral regions. The 410 g, 4.65 W UV/Vis camera uses a 384 X 288 frame-transfer silicon CCD FPA and operates at 6 user-selectable wavelength bands between 0.4 and 1.1 micrometers . It has yielded lunar imagery and mineralogy data with up to 120 m spatial resolution (band dependent) at 400 km periselene along a 39 km cross-track swath.
We have developed an astronomical imaging system that incorporates a total of eight 2048 X 2048 pixel CCDs into two focal planes, to allow simultaneous imaging in two colors. Each focal plane comprises four 'edge-buttable' detector arrays, on custom Kovar mounts. The clocking and bias voltage levels for each CCD are independently adjustable, but all the CCDs are operated synchronously. The sixteen analog outputs (two per chip) are measured at 16 bits with commercially available correlated double sampling A/D converters. The resulting 74 MBytes of data per frame are transferred over fiber optic links into dual-ported VME memory. The total readout time is just over one minute. We obtain read noise ranging from 6.5 e- to 10 e- for the various channels when digitizing at 34 Kpixels/sec, with full well depths (MPP mode) of approximately 100,000 e- per 15 micrometers X 15 micrometers pixel. This instrument is currently being used in a search of gravitational microlensing from compact objects in our Galactic halo, using the newly refurbished 1.3 m telescope at the Mt. Stromlo Observatory, Australia.
This paper describes an automated calibration system that we developed to calibrate JR flight cameras for a series of sub-orbital experiments. Short schedules as well as concern over cryo-cooler lifetimes dictated a totally automated calibration system that obtained as much data as possible over a short period of time. The data must be as complete as possible since the cameras are not recovered. For this reason the system calibrates each pixel individually. The output of the calibration is a set of calibration coefficients which convert the gray level output of the camera into physical units of radiance (Watts/cm2-str-.tm). We have calibrated Hughes 256x256 pixels PtSi cameras and 128x128 pixels HgCd cameras and Amber 128x128 pixels JnSb cameras. These cameras put out 8 bit digital data and sync signal at a given camera setting. This paper describes the calibration acquisition system and shows the results for the Hughes 256x256 PtSi camera.
We are developing a real-time-multiple-target-tracking system using a wide-field-of-view (WFOV) camera The high resolution WFOV camera was conceived as part of the Strategic Defense Initiative Research at Lawrence Livermore National Laboratory. The camera system consists of a lens made of concentric solid blocks of index matching glasses, CCDs arrayed on the focal plane, and a custom VLSI image processor to extract the targets. References 1 and 2 describe the basic design of the WFOV camera and the prototype system that we have constructed. In this paper, we will briefly review the existing prototype system, the on-going effort to cover the full field of view using digital CCD cameras, the production of custom VLSI chips developed to extract centroids in real time, and the implementation of transputers to run the tracking algorithms.