David Wayne Bowen

US Patent:

6711234, Mar 23, 2004

Filed:

May 16, 2002

Appl. No.:

10/130586

Inventors:

Neil Loxley - Durham, GB
David Keith Bowen - Denver CO
Ladislav Pina - Prague, CZ

Assignee:

Bede Scientific Instruments Limited - Bowburn

International Classification:

G21K 106

US Classification:

378145, 378 85

Abstract:

This invention relates to a portable apparatus for carrying out X-ray fluorescence spectrometry on specimen materials at a distance from the apparatus. The apparatus comprises an X-ray generating tube, such as a microfocus tube, and two paraboloidal X-ray reflecting mirrors. The first collecting mirror is positioned in close coupled arrangement adjacent to the exit window of the tube, such that it emits parallel X-ray radiation to the second focusing mirror, which is aligned on the axis of and spaced apart from the first mirror ( ). The second mirror ( ) collects the parallel X-ray radiation at its end closest to the first mirror and emits X-ray radiation in a focused beam onto the specimen. The distance between the first and second mirrors is adjusted to suit the distance from the X-ray tube to the specimen. Focal spots on the specimen of diameter less than 15 microns (590.

US Patent:

6782076, Aug 24, 2004

Filed:

Dec 7, 2001

Appl. No.:

10/004785

Inventors:

David Keith Bowen - Denver CO
Matthew Wormington - Littleton CO
Ladislav Pina - Prague, CZ
Petra Feichtinger - Mauerkirchen, AT

Assignee:

Bede Scientific Instruments Limited - Durham

International Classification:

G01N 23207

US Classification:

378 74, 382131

Abstract:

An X-ray topographic system comprises an X-ray generator producing a beam of X-rays impinging on a limited area of a sample such as a silicon wafer. A solid state detector is positioned to intercept the beam after transmission through or reflection from the sample. The detector has an array of pixels matching the beam area to produce a digital image of said limited area. Relative stepping motion between the X-ray generator and the sample produces a series of digital images which are combined together. In optional embodiments, an X-ray optic is interposed to produce a parallel beam to avoid image doubling, or the effect of image doubling is removed by software.

US Patent:

61921033, Feb 20, 2001

Filed:

Jun 3, 1999

Appl. No.:

9/324834

Inventors:

Matthew Wormington - Englewood CO
Charles Panaccione - Littleton CO
Kevin Monroe Matney - Aurora CO
David Keith Bowen - Denver CO

Assignee:

Bede Scientific, Inc. - Englewood CO

International Classification:

G01N 23207

US Classification:

378 73

Abstract:

Evolutionary algorithms are used to find a global solution to the fitting of experimental X-ray scattering data to simulated models. A recombination operator combines two or more parameter vectors from one iteration of simulated scattering data to form a new parameter vector for the next iteration, in a manner such that there is a high probability that the new parameter will better fit the experimental data than any of the parent parameters. A mutation operator perturbs the value of a parent vector, to permit new regions of the error function to be examined, and thereby avoid settling on local minima. The natural selection guarantees that the parameter vectors with the best fitness will be propagated into future iterations.