Transient response for automatic gain control with multiple intensity thresholds for image-intensified camera
This paper describes the transient response of an automatic gain control (AGC) with multiple thresholds for intensity in an image-intensified camera. Similar examples have flown in intensified-video systems used in satellites. This paper completes the development of a stable AGC with an improved transient response over the system described in a previous work. The improved transient response uses the integrated scene brightness at various intensity thresholds.
Initial results from a photon-counting intensified CCD development
We present a progress report on the development of intensified charge coupled devices (ICCDs) used in both analog mode with CCD integrating the output of an MCP and in photon counting mode where single MCP events are centroided to subpixel accuracy by the CCD and readout electronics. Spatial resolutions of 36 lp/mm have been achieved using a 15 micrometer pitch MCP in the analog mode. In the photon counting mode, individual MCP pores with the same spacing have been easily resolved indicating spatial resolutions of less than 10 micrometer. A discussion of the centroiding algorithms are presented, as well as a description of the electronic designs that will increase the diffuse event rate of the photon counting ICCD to 50,000 events/sec.
An analytical approach to the design of electrodes in high-power, fast-transverse-flow CO2 lasers
Abstract Usually, the design of the electrodes of fast-transverse-flow CO 2 lasers relies more on experimental data than on theoretical analysis. Traditional systems sustain a stable, high-power discharge but the current distribution generates a peaked, non-uniform small-signal-gain pattern. We present a theoretical model suitable for the design of electrodes that achieves a quasi uniform gain distribution. The analysis, based on a two-temperature model and the gas-transport equations, computes the electron density that supports a flat gain pattern. Combining the desired electron density with the electron-balance equations, the model determines the required electric field. The results were used to design a new set of electrodes for a home-made fast transverse flow CO 2 laser. A stable, large volume discharge ( 4 × 8 × 90 cm 3 ) with very good uniformity was obtained. The resulting gain distribution was registered in a bi-dimensional map. The peak gain rose from 1.2 m - 1 , attained with the old electrode set, to 1.6 m - 1 with the new one and the gain showed a homogeneous profile.