Gregory A Mulhollan

8298029, Oct 30, 2012

Feb 11, 2011

12/931839

Gregory A. Mulhollan - Austin TX, US
John C. Bierman - Austin TX, US

H01J 9/50

445 2, 25049224

A method by which negative electron affinity photocathodes (), single crystal, amorphous, or otherwise ordered, can be made to recover their quantum yield following exposure to an oxidizing gas has been discovered. Conventional recovery methods employ the use of cesium as a positive acting agent (). In the improved recovery method, an electron beam (), sufficiently energetic to generate a secondary electron cloud (), is applied to the photocathode in need of recovery. The energetic beam, through the high secondary electron yield of the negative electron affinity surface (), creates sufficient numbers of low energy electrons which act on the reduced-yield surface so as to negate the effects of absorbed oxidizing atoms thereby recovering the quantum yield to a pre-decay value.

20030063707, Apr 3, 2003

Oct 1, 2001

09/682633

Gregory Mulhollan - Dripping Springs TX, US

H01J035/06

378/134000

An X-radiation source can comprise an electron emission layer and an anode layer. In an embodiment the anode layer may be no more than approximately 1000 microns from the emission layer or include an anode region that laterally surrounds a hole extending through the anode layer. In one embodiment, a plurality of electron emission tips, extraction gate electrodes and anode regions may be used. When the anode regions comprise different materials, a plurality of wavelengths may be emitted. In another embodiment, a monolithic structure can be formed using processing operations similar to those used in conventional semiconductor device manufacturing. The X-radiation source can be relatively small and may have uses in applications with confined spaces, such as medical applications.

20090322222, Dec 31, 2009

Jan 26, 2009

12/321805

Gregory A. Mulhollan - Dripping Springs TX, US
John C. Bierman - Austin TX, US

H01J 40/06

313542

A method by which photocathodes (), single crystal, amorphous, or otherwise ordered, can be surface modified to a robust state of lowered and in best cases negative, electron affinity has been discovered. Conventional methods employ the use of Cs () and an oxidizing agent (), typically carried by diatomic oxygen or by more complex molecules, for example nitrogen trifluoride, to achieve a lowered electron affinity (). In the improved activation method, a second alkali, other than Cs (), is introduced onto the surface during the activation process, either by co-deposition, yo-yo, or sporadic or intermittent application. Best effect for GaAs photocathodes has been found through the use of Li () as the second alkali, though nearly the same effect can be found by employing Na (). Suitable photocathodes are those which are grown, cut from boules, implanted, rolled, deposited or otherwise fabricated in a fashion and shape desired for test or manufacture independently supported or atop a support structure or within a framework or otherwise affixed or suspended in the place and position required for use.

20120255364, Oct 11, 2012

Apr 9, 2012

13/506280

Gregory A. Mulhollan - Dripping Springs TX, US
John C. Bierman - Austin TX, US
Robert E. Kirby - Cupertino CA, US

G01L 21/12

73753, 73700

A method by which titania, or other composition, nanotube arrays, grown anodically or otherwise, can be made to meter vacuum pressure through hydrogen absorption has been discovered. The nanotube array () is fixed onto a demountable or permanently affixed flange, through which electrical current can be passed. By metering the current () for an allowable range of bias voltages (), a resistance value () can be obtained. This resistance is related to the hydrogen pressure () through cross-calibration at the overlap with conventional gauges. Conventional gauges require free electrons for ionization of gas molecules, directly contributing to the pressure in the vacuum volume. The present invention avoids that complication by relying on the absorption of hydrogen. The method associated with this embodiment includes the mounting, bias, current measurement, restoration and boosting techniques all compatible with the operation of a vacuum vessel at very high, ultra-high and extreme-high vacuum levels.

20150202564, Jul 23, 2015

Jan 21, 2014

14/159812

Robert E. Kirby - Cupertino CA, US
Gregory A. Mulhollan - Dripping Springs TX, US
John C. Bierman - Austin TX, US

B01D 53/22

A method by which a gold-coated palladium foil, singly or in combination with metal oxides, can be made to permanently remove hydrogen gas from an attached vacuum chamber, either electrically-passive or electrically-active has been discovered. The foil assembly () is secured onto a demountable or permanently affixed flange (), through which hydrogen gas passes via permeation (), from the vacuum chamber being pumped (), to atmosphere. Palladium combined with a metal oxide (), secondary metal layer (), gold coating () and an applied voltage () increases the pumping speed. Methods associated with this claim include the foil mounting and sealing, configuring film composition and applying requisite bias voltage.