Yacouba Q Diawara

US Patent:

6455987, Sep 24, 2002

Filed:

Jan 12, 1999

Appl. No.:

09/228375

Inventors:

Roger Durst - Middleton WI
Yacouba Diawara - Madison WI

Assignee:

Bruker Analytical X-Ray Systems, Inc. - Madison WI

International Classification:

H01J 4300

US Classification:

313103R, 313399, 313532, 313528, 250207

Abstract:

An electron multiplication apparatus uses a matrix of dielectric particles interspersed with conductive particles. Typically a porous layer of metal oxide and relatively inert metal, the material provides high electron count rates while maintaining good temperature stability. The layer is located between a cathode and an anode that together provide desired voltage differentials. A mesh is also used on a side of the matrix layer opposite the cathode to conduct surface charge away from the matrix, while providing an intermediate voltage potential between that of the anode and the cathode. A voltage source is used to generate the voltage potentials for each of the anode, cathode and mesh layer, and the resulting electric fields provide a device that may be used in the detection of high energy particles and photons, such as x-rays. A preferred method of fabricating the material involves the codeposition of a metal prone to oxidation and a relatively inert metal to form a porous layer. A subsequent oxidization step results in a metal oxide being intermingled with a conductive material.

US Patent:

7639783, Dec 29, 2009

Filed:

Jun 2, 2008

Appl. No.:

12/131341

Inventors:

Yacouba Diawara - Madison WI, US
Bruce L. Becker - Madison WI, US
Roger D. Durst - Middleton WI, US
Menyhert Kocsis - Venon, FR

Assignee:

Bruker AXS, Inc. - Madison WI

International Classification:

H05G 1/64
G01N 23/20

US Classification:

378 988, 378 71

Abstract:

An X-ray detector is formed with a geometry in the form of a spherical polygon, including an entrance window, a grid and an anode. The spherical polygonal entrance window and the grid form a spherical polygonal drift region between them. The electric field in this region is radial and eliminates parallax broadening. A spherical polygonal amplification region between a resistive anode on an insulating support and the grid allows very high gas amplification and good protection against spark discharges. A readout electrode on the back side of the anode insulator detects induced charges and protects the readout electronics against sparks.

US Patent:

7928400, Apr 19, 2011

Filed:

Aug 4, 2008

Appl. No.:

12/185565

Inventors:

Yacouba Diawara - Madison WI, US
Roger D. Durst - Middleton WI, US
Sergei A. Medved - Madison WI, US
Vladislav N. Sedov - Fitchburg WI, US
Donald P. Lesher - Warren OH, US

Assignee:

Bruker AXS, Inc. - Madison WI

International Classification:

H01L 27/146
H01L 31/09

US Classification:

25037009, 25037001, 378 5, 378 6

Abstract:

A detection system for wavelength-dispersive and energy-dispersive spectrometry comprises an X-ray detector formed from a solid-state avalanche photodiode with a thin entrance window electrode that permits the efficient detection of X-rays scattered from “light” elements. The detector can be tilted relative to the incident X-rays in order to increase the detection efficiency for X-rays scattered from “heavy” elements. The entrance window may be continuous conductive layer with a thickness in the range of 5 to 10 nanometers or may be a pattern of conductive lines with “windowless” areas between the lines. A signal processing circuit for the avalanche photodiode detector includes an ultra-low noise amplifier, a dual channel discriminator, a scaler and a digital counter. A linear array of avalanche photodiode detectors is used to increase the count rate of the detection system.

US Patent:

8153988, Apr 10, 2012

Filed:

Jul 28, 2010

Appl. No.:

12/844960

Inventors:

Yacouba Diawara - Oak Ridge TN, US
Menyhert Kocsis - Venon, FR

Assignee:

UT-Battelle, LLC - Oak Ridge TN

International Classification:

G01T 3/06

US Classification:

25039011

Abstract:

A neutron detector employs a porous material layer including pores between nanoparticles. The composition of the nanoparticles is selected to cause emission of electrons upon detection of a neutron. The nanoparticles have a maximum dimension that is in the range from 0. 1 micron to 1 millimeter, and can be sintered with pores thereamongst. A passing radiation generates electrons at one or more nanoparticles, some of which are scattered into a pore and directed toward a direction opposite to the applied electrical field. These electrons travel through the pore and collide with additional nanoparticles, which generate more electrons. The electrons are amplified in a cascade reaction that occurs along the pores behind the initial detection point. An electron amplification device may be placed behind the porous material layer to further amplify the electrons exiting the porous material layer.

US Patent:

20070272872, Nov 29, 2007

Filed:

May 24, 2006

Appl. No.:

11/439657

Inventors:

Vladimir A. Joshkin - Madison WI, US
Yacouba Diawara - Madison WI, US
Roger D. Durst - Middleton WI, US

Assignee:

Bruker AXS, Inc. - Madison WI

International Classification:

G01T 1/20

US Classification:

25037011

Abstract:

An X-ray detector includes one or more photodetectors embedded in scintillating material. The photodetectors may have a needle-like, a column-like, or a ridge-like structure. The scintillating material is applied over the photodetector which can either be a p−i−n type diode, an n−i−p type diode, a Schottky diode, or an avalanche diode.

US Patent:

6340819, Jan 22, 2002

Filed:

Aug 9, 1999

Appl. No.:

09/370769

Inventors:

Roger D. Durst - Middleton WI
Sean N. Carney - Madison WI
Yacouba Diawara - Madison WI
Rudolph Shuvalov - Madison WI

Assignee:

Bruker AXS, Inc. - Madison WI

International Classification:

G01J 528

US Classification:

250374, 250397

Abstract:

A detection apparatus for detecting an electron cloud includes a resistive anode layer with a detection plane upon which the electron cloud is incident. The resistive layer is capacitively coupled to a readout structure having a conductive grid parallel to the detection plane. Charge on the resistive layer induces a charge on the readout structure, and currents in the grid. The location of the induced charge on the readout structure corresponds to the location on the detection plane at which the electron cloud is incident. Typically, the detection apparatus is part of a detector, such as a gas avalanche detector, in which the electron cloud is formed by conversion of a high-energy photon or particle to electrons that undergo avalanche multiplication. The spacing between the anode layer and the readout structure is selected so that the width of the charge distribution matches the pitch between conductive segments of the grid. The resistivity of the anode layer is selected to be low enough to support the highest bandwidth of the readout electronics, but high enough to allow penetration of the charge through the anode layer to the readout structure.

US Patent:

20140353511, Dec 4, 2014

Filed:

Jan 15, 2013

Appl. No.:

14/376018

Inventors:

- Oak Ridge TN, US
Yacouba Diawara - Oak Ridge TN, US
Cornelius Donahue, JR. - Knoxville TN, US
Christopher A. Montcalm - Oak Ridge TN, US
Richard A. Riedel - Knoxville TN, US
Theodore Visscher - Powell TN, US

Assignee:

UT-Battelle, LLC - Oak Ridge TN

International Classification:

G01T 3/06

US Classification:

250362, 250361 R

Abstract:

For each photomultiplier tube in an Anger camera, an R×S array of preamplifiers is provided to detect electrons generated within the photomultiplier tube. The outputs of the preamplifiers are digitized to measure the magnitude of the signals from each preamplifier. For each photomultiplier tube, a corresponding summation circuitry including R row summation circuits and S column summation circuits numerically add the magnitudes of the signals from preamplifiers for each row and for each column to generate histograms. For a P×Q array of photomultiplier tubes, P×Q summation circuitries generate P×Q row histograms including R entries and P×Q column histograms including S entries. The total set of histograms include P×Q×(R+S) entries, which can be analyzed by a position calculation circuit to determine the locations of events (detection of a neutron).