Leco Corporation

Ted J Casper

Gordon C Ford

Joel C Mitchell

Kim Alvin Marshall

Sara K Casper

Brad Rush

Jason Griesbach

Timothy A Hall

The embodiments of the invention include a method for controlling plasma conditions of a glow discharge system using the integrated electron (or ion) pulse area extracted from the total lamp current. The method of using an integrated electron/ion pulse area for controlling plasma conditions allows for controlled analysis of conductive, non-conductive and layered materials without the need for estimation of plasma voltages. The method allows for control of sputter rates and plasma emissions that cannot be achieved using other methods such as capacitive divider calculations where actual thicknesses and dielectric constants are not known or predefined.

System and method of determining effective glow discharge lamp current

A resonant power supply () for use with high inductive loads includes an input rectifier () and a switching inverter formed using a plurality of parallel connected half bridge networks for switching the voltage provided from the input rectifier (). A transformer () is used whose primary is connected to the switching inverter and whose secondary is connected to load such as a crucible (). A capacitor () is used in series with the primary of the transformer () for resonating the inductance in the secondary circuit at the frequency of the switching inverter to provide maximum power transfer to the crucible ().

Resonant power supply for use with high inductive loads and method of providing same

An analytical induction furnace and method for combusting conductive sample materials () utilizing a crucible for holding a sample within the induction furnace. Less than one gram of accelerator material is then inserted into the crucible with the sample and the induction furnace is activated for a predetermined time period () for thoroughly combusting the sample and accelerator. In some instances, no accelerator is required with the sample at frequencies of approximately 4.5 MHz. The invention provides for the induction furnace that is actuated in an RF frequency range between 2-9 MHz with little to no accelerator for thoroughly melting the sample for use in an analytical instrument.

Induction furnace operating in a range from 2-9 MHz for providing analytical samples and method of same

A transformer assembly () for use with an internal load () includes a transformer core () having a primary winding (). A first electrode () and second electrode () are used for contacting an internal load (). A secondary circuit is formed that includes the first electrode (), the second electrode () and conductors () positioned between the first electrode () and second electrode (). The transformer assembly () is arranged so that the conductors () surround the primary winding (), transformer core (), the first electrode () and second electrode (). The transformer assembly () may be used in an electrode furnace or other high current and voltage applications requiring high efficiency in a small package.

Transformer assembly using an internal load and method for forming same

Circuits for correcting base line shift of the detector coupling circuit of a TOFMS provide gain and impedance characteristics that compensate for the AC coupling effect of the detector. In one circuit, base line correction is achieved by injecting a current equal to that which flows due to the buildup charge in the detectors AC coupling network. In another circuit, the current source drives an integrator which is coupled to the signal path to reduce the detector AC coupling effects. In another circuit, a low noise amplifier utilizes a feedback network that reduces the detector AC coupling effects. In yet another circuit, an operational amplifier is employed to reduce the detector AC coupling effects.

Base line restoration circuit

A pulse jitter reduction circuit employs a low jitter system clock coupled to synchronize a pulse generating device and an ultra low jitter flip-flop to generate substantially jitter-free trigger signals employed to generate high voltage pulses for a flight tube of a time-of-flight mass spectrometer. By eliminating time fluctuations due to jitter in the triggering signal, the predictability of the arrival time of ions along a flight tube of a time-of-flight mass spectrometer is greatly improved, thereby improving the resolution of the mass spectrometer.

Last stage synchronizer system

A non-conductive isolator for supporting a sample to be analyzed by radio frequency energy induced glow discharge techniques has a conductive ring for coupling a source of radio frequency energy to the same surface of a sample which is in direct contact with the induced glow discharge. An adapter kit for converting a direct current glow discharge analysis apparatus to a radio frequency energy induced flow discharge is also disclosed as well as the method of analyzing non-conductive and sample conductive using a source of RF energy coupled to the same sample surface being analyzed.

Glow discharge analytical instrument for performing excitation and

A multiple frequency plasma torch activation circuit includes a system driver circuit with a pair of different frequency sources and a selector switch which allows one of the sources to be coupled to a splitter assembly which applies signals to a pair of independent power amplifiers having their outputs applied to a combiner assembly and to the plasma torch inductor. A detector circuit provides signals to a power control circuit which includes forward and reflected power monitoring and an impedance matching circuit for optimum coupling of the frequencies to the inductive load.

Growing community of inventors

West Bend, WI, United States of America

Ted J Casper