Bio-rad Laboratories, Inc.

Ciphergen Biosystems, Inc.

Craig A Keller

Michael G Youngquist

Steve Miller

Steve Waltman

Fiona L Plows

A device for dynamically biasing an ion optic element, for example, in a mass spectrometer. The device includes a voltage source, a first ion optical element coupled with the voltage source, a second ion optical element resistively coupled with the first ion optical element; and a pulse generator capacitively coupled with the second ion optical element. The pulse generator is configured to apply a series of pulses to the second ion optical element. In steady state operation, a dynamic voltage bias is generated between the first ion optical element and the second ion optical element. The dynamic voltage bias is controllable by controlling the characteristics of the applied pulses, such as the pulse width, pulse amplitude, and pulse repetition rate of the applied pulses.

Dynamic biasing of ion optics in a mass spectrometer

Signal amplifiers having a non-linear transfer function. A high speed (high bandwidth) circuit with a non-linear transfer function over a limited range of input signal is provided. By appropriate choice of components, the non-linear transfer function can be used to accurately approximate any monotonic function such as a square root transfer function. In another aspect, a piecewise non-linear circuit arrangement using a set of non-linear sub-circuits is provided to accurately generate a desired non-linear transfer function over an extended dynamic range of input signal. In one implementation of such a circuit, each of the sub-circuits approximates the desired non-linear function over a portion of the input range.

Non-linear signal amplifiers and uses thereof in a mass spectrometer device

Laser desorption/ionization time-of-flight mass spectrometer ('LDI-TOF-MS') devices, and methods, that accurately measure the mass of analytes contained in a sample and which also measure the quantities of analytes present in a sample in a consistent manner from instrument-to-instrument and over time on a single instrument. In particular, the invention provides LDI-TOF-MS devices and methods in which: 1) the energy of the laser pulse and the area of the sample illuminated (fluence) is consistent and controlled so as to produce consistent conditions for analyte desorption and ionization; 2) the mass analyzer behaves in a reproducible manner; and 3) the detection system produces a signal that consistently represents the arrival of ions of different masses.

Laser desorption and ionization mass spectrometer with quantitative reproducibility

An improved electron multiplier bias network that limits the response of the multiplier when the multiplier is faced with very large input signals, but then permits the multiplier to recover quickly following the large input signal. In one aspect, this invention provides an electron multiplier, having a cathode that emits electrons in response to receiving a particle, wherein the particle is one of a charged particle, a neutral particle, or a photon; an ordered chain of dynodes wherein each dynode receives electrons from a preceding dynode and emits a larger number of electrons to be received by the next dynode in the chain, wherein the first dynode of the ordered chain of dynodes receives electrons emitted by the cathode; an anode that collects the electrons emitted by the last dynode of the ordered chain of dynodes; a biasing system that biases each dynode of the ordered chain of dynodes to a specific potential; a set of charge reservoirs, wherein each charge reservoir of the set of charge reservoirs is connected with one of the dynodes of the ordered chain of dynodes; and an isolating element placed between one of the dynodes and its corresponding charge reservoir, where the isolating element is configured to control the response of the electron multiplier when the multiplier receives a large input signal, so as to permit the multiplier to enter into and exit from saturation in a controlled and rapid manner.

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Menlo Park, CA, United States of America

Craig A Keller