John A Stringer

US Patent:

6380742, Apr 30, 2002

Filed:

Jul 27, 2001

Appl. No.:

09/916964

Inventors:

John Stringer - Longmont CO
Charles E. Bronnimann - Fort Collins CO

Assignee:

Varian, Inc. - Palo Alto CA

International Classification:

G01V 300

US Classification:

324322, 324318, 324307

Abstract:

An NMR probe, lacking electrical balance in respect of the RF coil thereof, includes a conducting shield of axial extent greater than /4 from the ground plane closure of said shield of the probe ( being the highest resonant frequency of interest), the components of the probe other than the coil being confined to the axial region less than /4 from the ground plane and spaced apart from the shield.

US Patent:

7081753, Jul 25, 2006

Filed:

Jul 26, 2004

Appl. No.:

10/899830

Inventors:

Charles G. Mullen - Fort Collins CO, US
John A. Stringer - Longmont CO, US
Knut G. Mehr - San Francisco CA, US

Assignee:

Varian, Inc. - Palo Alto CA

International Classification:

G01V 3/00

US Classification:

324318, 324321, 324322

Abstract:

A sample probe and apparatus are provided for magnetic resonance experiments. The probe includes a coil simultaneously tunable to at least two different frequencies. The coil includes a section having a scroll configuration and defines a core into which a sample can be inserted. A multi-resonant circuit transmits RF energy to the coil at two or more different frequencies for exciting nuclei of the sample. The apparatus includes a coil having a scroll configuration. RF transmission circuitry transmits RF energy to the coil at two or more different frequencies. RF receiving circuitry receives an RF signal responsive to excitation. A coil is magnetically coupled with a sample at an RF frequency.

US Patent:

7541807, Jun 2, 2009

Filed:

Jul 19, 2007

Appl. No.:

11/880001

Inventors:

John Stringer - Longmont CO, US

Assignee:

Varian, Inc. - Palo Alto CA

International Classification:

G01V 3/00

US Classification:

324307, 324309

Abstract:

A rotor drive apparatus includes a rotor and a stator. The stator has a gas injection orifice located on the axis about which the rotor spins. The gas injection orifice communicates with a bearing gap formed between a tapered surface of the rotor and an axially spaced tapered surface of the stator. A gas is flowed from the gas injection orifice through the bearing gap, thereby establishing a center-fed, radial-outflow gas bearing supporting the rotor during rotation. In one implementation, a separate flow of drive gas is fed to drive flutes of the rotor to drive rotation. In another implementation, the center-fed, radial-outflow gas flow is additionally utilized to impinge against the drive flutes to actuate the rotation.