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September 2001

The Laboratory
in the News

Commentary by
Jan Tulk

Zeroing In
on Genes

Big Glass for
a Big Laser

Lasershot Makes
Its Mark

Tracking the
Global Spread
of Advanced






Abraham P. Lee, William J. Benett, Daniel L. Schumann, Peter A. Krulevitch, Joseph P. Fitch
Apparatus for Loading Shape Memory Gripper Mechanisms
U.S. Patent No.6,240,630 B1
June 5, 2001
A method and apparatus for loading deposit material, such as an embolic coil, into a shape-memory polymer (SMP) gripping and release mechanism. The apparatus enables the application of uniform pressure to secure a grip by the SMP mechanism on the deposit material via the differential pressure between, for example, vacuum within the SMP mechanism and hydrostatic water pressure on the exterior of the SMP mechanism. The SMP tubing material of the mechanism is heated to above the glass transformation temperature (Tg) while reshaping and is subsequently cooled to below Tg to freeze the shape. The heating or cooling may, for example, be provided by the same water applied for pressurization, or the heating can be applied by optical fibers attached to the SMP mechanism for directing, say, a laser beam to the tubing. At a point of use, the deposit material is released from the SMP mechanism by reheating the SMP material to above the Tg, thereby returning the material to its initial shape. The reheating of the shape-memory material may be carried out by injecting heated fluid (water) through an associated catheter or by sending laser light through optical fibers.

Richard F. Post
Apparatus and Method for Reducing Inductive Coupling between Levitation and Drive Coils within a Magnetic Propulsion System
U.S. Patent No. 6,250,230 B1
June 26, 2001
An apparatus and method for reducing inductive coupling between levitation and drive coils within a magnetic levitation system. A pole array has a magnetic field. A levitation coil is positioned so that in response to motion of the magnetic field of the pole array, a current is induced in the levitation coil. A first drive coil having a magnetic field coupled to drive the pole array also has a magnetic flux that induces a parasitic current in the levitation coil. A second drive coil having a magnetic field is positioned to attenuate the parasitic current in the levitation coil by canceling the magnetic flux of the first drive coil that induces the parasitic current. Steps in the method include generating a magnetic field with a pole array for levitating an object; inducing current in a levitation coil in response to motion of the magnetic field of the pole array; generating a magnetic field with a first drive coil for propelling the object; and generating a magnetic field with a second drive coil for attenuating effects of the magnetic field of the first drive coil on the current in the levitation coil.

Luis E. Zapata, Lloyd Hackel
Lamp System for Uniform Semiconductor Wafer Heating
U.S. Patent No.6,252,203 B1
June 26, 2001
A lamp system with a soft, high-intensity output is provided over a large area by water cooling a long-arc lamp inside a diffuse reflector of polytetrafluorethylene and titanium dioxide white pigment. The water is kept clean and pure by a 1-micrometer particulate filter and an activated charcoal–ultraviolet irradiation system that circulates, deionizes, and biologically sterilizes the coolant water at all times, even when the long-arc lamp is off.

Tser-Yuan Yang, Edward I. Moses, Christine Hartmann-Siantar
FALCON: Automated Optimization Method for Arbitrary Assessment Criteria
U.S. Patent No. 6,260,005 B1
July 10, 2001
FALCON is a method for automatic multivariable optimization of arbitrary assessment criteria that can be applied to numerous fields where outcome simulation is combined with optimization and assessment criteria. A specific implementation of FALCON is for automatic radiation therapy treatment planning. In this application, FALCON implements dose calculations into the planning process and optimizes available beam delivery modifier parameters to determine the treatment plan that best meets clinical decision-making criteria. FALCON is described in the context of the optimization of external-beam radiation therapy and intensity modulation radiation therapy, but the concepts could also be applied to internal (brachytherapy) radiotherapy. The radiation beams could consist of photons or any charged or uncharged particles. The concept of optimizing source distributions can be applied to complex radiography (for example, flash x ray or proton) to improve the imaging capabilities of facilities proposed for science-based stockpile stewardship.

Jeffrey D. Morse, Robert J. Contolini
Adhesion Layer for Etching of Tracks in Nuclear Trackable Materials
U.S. Patent No. 6,261,961 B1
July 17, 2001
A method for forming nuclear tracks having a width on the order of 100 to 200 nanometers in nuclear trackable materials, such as polycarbonate (LEXAN), without causing delamination of the polycarbonate. The adhesion film may be composed of a metal such as chromium, nickel, gold, platinum, or titanium or composed of a dielectric having a stable surface, such as silicon dioxide, silicon nitride, or aluminum oxide. The adhesion film can either be deposited on top of the gate metal layer, or if the properties of the adhesion film are adequate, it can be used as the gate layer. Deposition of the adhesion film is achieved by standard techniques, such as sputtering or evaporation.

David R. Shafer
Reflective Optical Imaging Method and Circuit
U.S. Patent No. 6,262,826 B1
July 17, 2001
An optical system compatible with short-wavelength (extreme-ultraviolet) radiation comprising four reflective elements for projecting a mask image onto a substrate. The four optical elements are characterized in order from object to image as convex, concave, convex, and concave mirrors. The optical system is particularly suited for step-and-scan lithography methods. The invention increases the slit dimensions associated with ringfield scanning optics, improves wafer throughput, and allows higher semiconductor device density.

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UCRL-52000-01-9 | September 25, 2001