Abstract: A high resolution fast imaging spectrograph is disclosed which provides 400 spatial channels and 100 spectral channels of information. A collimating mirror (10) and a focusing mirror (12) face a plane diffraction grating (14), which is positioned at an acute angle to the perpendicular to the optic axis. An elongated slot (16) is cut through approximately the center of the grating allowing the light source (18) to pass through the slot and onto the collimating mirror. A turning mirror (20), which is placed at the focus of the focusing mirror and adjacent to the slot, directs radiation to a camera mirror (22), which focuses a final image outside the instrument enclosure onto a detector (24). The light source to the instrument is provided by an optical fiber ribbon. The detector will commonly be a CCD or CID 2-D detector, permitting the simultaneous measurement of spectral distribution of a spatial profile.

Abstract: A safety valve for fitting into a compressed gas cylinder to terminate gas flow from the cylinder when a primary gas valve attached to the cylinder port of the cylinder is deflected or severed. The safety valve is independently supported in the cylinder port below the location of the primary gas valve. A threaded housing having a channel for the passage of gas to and from the cylinder is threaded into the cylinder port below the location of the primary gas valve. A poppet seat is provided in the housing. A tubular portion of the threaded housing extends up and fits snugly into the gas passage of the primary gas valve. A cylindrical housing having apertures for the passage of gas is attached to the threaded housing. A poppet is provided in the cylindrical housing, which is biased into the poppet seat by a helical spring. The poppet is held off of the poppet seat by means of a frangible element.

Abstract: An aspheric mirror, for example in the form of an off-axis parabolic mirror or a toric mirror, that includes a first element having a front surface which defines a spherical reflector and a spaced apart rear surface. The spherical reflector includes a constant radius of curvature, an X-axis with an X-axis radius of curvature and a Y-axis with a Y-axis radius of curvature. The first element possesses a first rigidity factor. A second element includes a front surface sized to mate with the rear surface of the first element along an interface zone. The second element possesses a second rigidity factor. An interface contour device produces a differential contour within the interface zone between the first and second elements. The interface contour device is aligned to modify the X-axis radius of curvature of the shperical reflector without significantly modifying the Y-axis radius of curvature.

Abstract: An advanced downhole periodic seismic generator system for transmitting variable frequency, predominantly shear-wave vibration into earth strata surrounding a borehole. The system comprises a unitary housing operably connected to a well head by support and electrical cabling and contains clamping apparatus for selectively clamping the housing to the walls of the borehole. The system further comprises a variable speed pneumatic oscillator and a self-contained pneumatic reservoir for producing a frequency-swept seismic output over a discrete frequency range.