Abstract: An injection seeded modular gas discharge laser system capable of producing high quality pulsed laser beams at pulse rates of about 4,000 Hz or greater and at pulse energies of about 5 mJ or greater. Two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. The chambers can be controlled separately permitting separate optimization of wavelength parameters in the master oscillator and optimization of pulse energy parameters in the amplifying chamber. A preferred embodiment in an ArF excimer laser system configured as a MOPA and specifically designed for use as a light source for integrated circuit lithography. In the preferred MOPA embodiment, each chamber comprises a single tangential fan providing sufficient gas flow to permit operation at pulse rates of 4000 Hz or greater by clearing debris from the discharge region in less time than the approximately 0.25 milliseconds between pulses.

Abstract: A grating based line narrowing unit for gas discharge lasers with increased beam expansion to produce smaller bandwidths. The grating has a grating surface larger than 100 cm2 and is a replica grating produced from a master grating produced with a lithography process on a single crystal substrate. In preferred embodiments, a beam from the chamber of the laser is expanded with four prism beam expanders. The large grating, much larger than gratings historically produced from diamond lined gratings, permit substantial reductions in bandwidth while maintaining laser efficiency. A narrow band of wavelengths in the expanded beam is reflected from a grating in a Littrow configuration back via the bi-directional beam expanders into the laser chamber for amplification.

Abstract: A high resolution spectral measurement device. A preferred embodiment presents an extremely narrow slit function in the ultraviolet range and is very useful for measuring bandwidth of narrow-band excimer lasers used for integrated circuit lithography. Light from the laser is focused into a diffuser and the diffused light exiting the diffuser illuminates an etalon. A portion of its light exiting the etalon is collected and directed into a slit positioned at a fringe pattern of the etalon. Light passing through the slit is collimated and the collimated light illuminates a grating positioned in an approximately Littrow configuration which disburses the light according to wavelength. A portion of the dispursed light representing the wavelength corresponding to the selected etalon fringe is passed through a second slit and monitored by a light detector. When the etalon and the grating are tuned to the same precise wavelength a slit function is defined which is extremely narrow such as about 0.

Abstract: A high resolution etalon-grating monochromator. A preferred embodiment presents an extremely narrow slit function in the ultraviolet range and is very useful for measuring bandwidth of narrow band excimer lasers used for integrated circuit lithography. Light from the laser is focused into a diffuser and the diffused light exiting the diffuser illuminates an etalon. A portion of its light exiting the etalon is collected and directed into a slit positioned at a fringe pattern of the etalon. Light passing through the slit is collimated and the collimated light illuminates a grating positioned in an approximately Littrow configuration which disburses the light according to wavelength. A portion of the dispursed light representing the wavelength corresponding to the selected etalon fringe is passed through a second slit and monitored by a light detector. When the etalon and the grating are tuned to the same precise wavelength a slit function is defined which is extremely narrow such as about 0.

Abstract: A first double pass etalon based spectrometer. In a preferred embodiment a second etalon matched to the first double pass etalon is used to produce extremely precise fringe data. Spectral components of a diffused beam are angularly separated as they are transmitted through an etalon. A retroreflector reflects the transmitted components back through the etalon. Twice transmitted spectral components are directed through a second etalon and focused onto a light detector which in a preferred embodiment is a photo diode array. The spectrometer is very compact producing the extremely precise fringe data permitting bandwidth measurements with precision needed for microlithography for both &Dgr;&lgr;FWHM and &Dgr;&lgr;95%.

Abstract: A catadioptric anamorphic beam expanding telescope expands an optical beam in a first axis substantially perpendicular to the beam propagation axis, and deflects it in a plane substantially perpendicular to the first axis. The beam expanding telescope can include reflective, refractive, and combined reflective/refractive elements. An embodiment includes an off axis convex spheric reflector and an off axis combined reflective/reflective optical element, commonly known as a Mangin mirror, incorporating a refractive first surface and a reflective rear surface, which compensate for aberrations introduced by the off axis deflection of the beam. The telescope is particularly useful for deep ultraviolet (DUV) applications at wavelengths shorter than about 250 nm. In some applications, the telescope illuminates a diffraction grating or other wavelength dispersive element, aligned to retroreflect a preferential wavelength, thereby providing wavelength narrowing.

Abstract: The present invention provides an excimer laser capable of producing a high quality pulsed laser beam at pulse rates of about 4,000 Hz at pulse energies of about 5 mJ or greater. A preferred embodiment is an ArF excimer laser specifically designed as a light source for integrated circuit lithography. An improved wavemeter with special software monitors output beam parameters and controls a very fast PZT driven tuning mirror and the pulse power charging voltage to maintain wavelength and pulse energy within desired limits. In a preferred embodiment two fan motors drive a single tangential fan which provides sufficient gas flow to clear discharge debris from the discharge region during the approximately 0.25 milliseconds between pulses.

Abstract: A multi-service user interface that facilitates access to and exchange of information between two or more people when communicating remotely over a broadband network. The interface allows users to move data on a display using gesture motions. Each gesture motion corresponds to a predetermined function. In addition, the interface includes visible reactive zones where a user can move data to implement a specific activity such as, sending a message to another person over the network or removing certain data from the display.

Abstract: A system and method of density detection in a target object involve irradiating the target object, detecting a first and second discrete number of photons penetrating the target object through respective first and second prescribed volumes and entering respective first and second radiation detectors. First and second numbers of photons detected by the first and second radiation detectors are counted, and a display output signal is generated in response to the first and second numbers. A graphical representation of the densities within the first and second volumes of the target object is displayed.

Abstract: A grating based line narrowing unit with bi-directional beam expansion for line narrowing lasers. In a preferred embodiment a beam from the chamber of the laser is expanded in the horizontal direction with a three-prism beam expander and is expanded in the vertical direction with a single prism. A narrow band of wavelengths in the expanded beam is reflected from a grating in a Littrow configuration back via the two beam expanders into the laser chamber for amplification.

Abstract: A first double pass etalon based spectrometer. In a preferred embodiment a second etalon matched to the first double pass etalon is used to produce extremely precise fringe data. Spectral components of a diffused beam are angularly separated as they are transmitted through an etalon. A retroreflector reflects the transmitted components back through the etalon. Twice transmitted spectral components are directed through a second etalon and focused onto a light detector which in a preferred embodiment is a photo diode array. The spectrometer is very compact producing the extremely precise fringe data permitting bandwidth measurements with precision needed for microlithography for both &Dgr;&lgr;FWHM and &Dgr;&lgr;95%.

Abstract: Radioactive therapeutic seeds include a substantially radiotransparent cylindrical capsule containing a radioactive isotope and, in particular embodiments, a radiopaque or MRI-visible marker. Each of the embodiments is designed to provide a substantially isotropic distribution of radiation. In one embodiment, the isotope is deposited on the outer surface of a hollow radiolucent tube and a collar is provided about a central portion of the tube. The capsule comprises two tubular halves positioned over the tube with the open ends of the halves forming an interference fit with the collar and welded thereabout. In another embodiment, the isotope bearing structure is a plurality of radiolucent spheres provided with a thin coating of silver to facilitate the adhesion of the isotope thereto. The spheres are provided in two capsule halves which are welded closed about a plug have an axial radiopaque marker therein.

Abstract: Radioactive therapeutic seeds include a substantially radiotransparent cylindrical capsule provided with a radioactive isotope, a radiopaque marker, and an engagement structure adapted to engage tissue surrounding the seeds at the implant site. The engagement structure is also preferably adapted to releasably engage the inside of a delivery needle prior to implantation. The engagement structure is preferably adapted to prevent axial longitudinal movement and axial rotation of a seed about its longitudinal axis when the seed is implanted. According to a preferred embodiment of the invention, the engagement structure includes three spring elements which are biased away from the seed capsule and which provide positive fixation in the tissue, and also frictionally engage the inside of the needle.

Abstract: A system and method of density detection in a target object involve irradiating the target object, detecting a first and second discrete number of photons penetrating the target object through respective first and second prescribed volumes and entering respective first and second radiation detectors. First and second numbers of photons detected by the first and second radiation detectors are counted, and a display output signal is generated in response to the first and second numbers. A graphical representation of the densities within the first and second volumes of the target object is displayed.

Abstract: Radioactive therapeutic seeds include a seed capsule, a radioactive isotope, and a radiopaque marker. According to one embodiment of the invention, the radiopaque marker is a silver wire coil and the isotope is coated on the surface of the coil. According to a first method of the invention, the therapeutic dosage of the seed is adjusted during manufacture by expanding or contracting the coil before it sized and deposited in the capsule. According to second embodiment, the radiopaque marker is a silver rod and the isotope is coated on a radiotransparent coil which is placed over the rod. According to a third embodiment, the isotope is coated on a plurality of rings which are stacked on a radiopaque rod. According to a second method of the invention, the therapeutic dosage of the seed is adjusted during manufacture by stacking a mixture of radio-inactive rings with radioactive rings on the radiopaque rod before the capsule is sealed.

Abstract: A portable, self-contained, electronic radioscopic imaging system uses a pulsed X-ray source, a remote X-ray sensor, and a self-contained, display and controller unit to produce, store, and/or display digital radioscopic images of an object under investigation. An X-ray image sensor configured to spatially sense X-ray radiation pulses includes a pixel clock generator, an integrating CCD camera imager operating in a progressive scan mode providing a discrete pixel readout cycle of sensed X-ray radiation pulses, a sample and hold circuit for sampling the discrete pixel readout responsive to the pixel clock, and an analog to digital converter for digitizing each pixel as the discrete pixel readout is sampled. A digital video transmission system controller board controls the X-ray source for acquiring digitized samples from the X-ray image sensor.

Abstract: Radioactive therapeutic seeds include a substantially cylindrical capsule containing a radioactive isotope and, preferably, a radiopaque marker. According to one embodiment, the capsule is made of titanium or stainless steel, the isotope is deposited on the surface of a hollow cylinder and a titanium or stainless steel tube is disposed inside the hollow cylinder. The capsule is sealed by swaging the end of the capsule against the inner tube and welding the swaged end and tube. The inner tube facilitates swaging and protects the contents of the capsule from the heat of welding. In alternate embodiments, a radiopaque marker is disposed inside the inner tube or the cylinder bearing the radioisotope is radiopaque.

Abstract: An implantable brachytherapy device includes a biocompatible outer capsule containing a radiation shielding element and a radioactive isotope between the shielding element and the wall of the outer capsule. When the device is at body temperature, radiation is emitted by the isotope through the wall of the outer capsule. When a predetermined amount of energy is applied to the device, the shielding element is adapted to at least partially surround the isotope, and thereby at least partially prevent the transmission of radiation through the outer capsule.

Abstract: Radioactive therapeutic seeds include a two part seed capsule, a radioactive isotope, and, preferably, a radiopaque marker. According to the invention, the seed capsule has an outer part, and an inner part which fits into the outer part and which carries the radioactive isotope. The capsule is sealed by welding the end(s) of the inner part to the end(s) of the outer part. According to one embodiment, the outer part of the seed capsule is a cylinder with one open end and one closed end. The inner part of the seed capsule has a reduced diameter portion which carries the isotope and a larger diameter portion which mates with the open end of the cylinder. According to another embodiment, the outer part of the seed capsule is a cylinder with two open ends. The inner part has a reduced diameter portion which carries the isotope and two larger diameter portions which mate with the open ends of the cylinder.

Abstract: In a video conference system, participants are provided with a greater sense of presence. A pair of monitors are positioned at each location and provide a presence view image and a shared space image of the other location. With this system, participants can overlap their finger pointing at a shared image while maintaining eye-to-eye contact.