Abstract: Methods and apparatus are disclosed for reducing ion reflections between multipole segments in a mass spectrometer by matching the effective potential between the two segments. Mass spectrometers having at least two multipole segments separated from each other along a longitudinal axis of the mass spectrometer such that a boundary region exists through which ions are drawn from an upstream segment to a downstream segment, and wherein each multipole segment further includes a set of spaced-apart rod-shaped electrodes disposed around the longitudinal axis and having a field radius defined by an inscribed circle between the innermost portions of each electrode. Effective potential matching can be achieved by either supplying RF signals of different amplitudes to each segment and/or by modifying the field strength of the segments. In one embodiment, the multipole segments are configured such that the upstream multipole segment has a smaller field radius than the downstream segment.

Abstract: In one aspect, a method of modulating transmission of ions in a mass spectrometer is disclosed, which comprises generating an ion beam comprising a plurality of ions, directing the ion beam to an ion optic positioned in the path of the ion beam, wherein the ion optic includes at least one opening through which the ions can pass, and applying one or more voltage pulses at a selected duty cycle to said ion optic so as to obtain a desired attenuation of brightness of the ion beam passing through the ion optic, where a pulse width of said voltage pulses at said selected duty cycle is determined by identifying a pulse width on a calibration normalized ion intensity versus pulse width relation for said ions that corresponds to said desired attenuation on an ideal normalized ion intensity versus pulse width relation for said ions.

Abstract: Methods and apparatus are disclosed for reducing ion reflections between multipole segments in a mass spectrometer by matching the effective potential between the two segments. Mass spectrometers having at least two multipole segments separated from each other along a longitudinal axis of the mass spectrometer such that a boundary region exists through which ions are drawn from an upstream segment to a downstream segment, and wherein each multipole segment further includes a set of spaced-apart rod-shaped electrodes disposed around the longitudinal axis and having a field radius defined by an inscribed circle between the innermost portions of each electrode. Effective potential matching can be achieved by either supplying RF signals of different amplitudes to each segment and/or by modifying the field strength of the segments. In one embodiment, the multipole segments are configured such that the upstream multipole segment has a smaller field radius than the downstream segment.

Abstract: Apparatus and methods for controlling contamination of components contained within the high-vacuum chambers of mass spectrometer systems are provided. The apparatus and methods employ a beam of neutral gas injected in a contra-flow configuration to incoming particle stream from the ionization chamber. The contra-flow can be in the directly opposite counter-flow direction (e.g., 180 degrees) or at a cross-flow angle to the incoming ion stream (e.g., flowing at an angle between about 10 degrees and 170 degrees). The contra-flow disrupts the axial gas flow and diverts neutral molecules and other undesirable contaminants before they reach the high vacuum stages (e.g., beyond the IQ0 orifice) of the spectrometer. By reducing the transmission of contaminants into the sensitive components housed deep within the mass spectrometer, the present invention can increase throughput, improve robustness, and/or decrease the downtime typically required to vent/disassemble/clean the fouled components.

Abstract: Disclosed is a user terminal for wireless communication with a remote access point. The user terminal may include a mapping module adapted to map one or more input data bits to an uplink symbol, a delay module adapted to apply a delay to the uplink symbol, a transmit module adapted to modulate the delayed symbol into a frequency channel, and an antenna being adapted to transmit the modulated symbol to the access point. The delay can be chosen such that the transmitted symbol arrives at the access point simultaneously with a further symbol modulated into the frequency channel and transmitted by a further user terminal.

Abstract: Disclosed is a wireless communication system comprising a plurality of antennas, a plurality of base stations, each base station being adapted to connect to one or more of the antennas over an available spectrum, and a wireless switching module. The wireless switching module is adapted to allocate one or more portions of the available spectrum to each antenna dependent on a compatibility constraint on the antennas, and assign each antenna for connection to a base station.

Abstract: Disclosed is a user terminal for wireless communication with a remote access point. The user terminal may include a mapping module adapted to map one or more input data bits to an uplink symbol, a delay module adapted to apply a delay to the uplink symbol, a transmit module adapted to modulate the delayed symbol into a frequency channel, and an antenna being adapted to transmit the modulated symbol to the access point. The delay can be chosen such that the transmitted symbol arrives at the access point simultaneously with a further symbol modulated into the frequency channel and transmitted by a further user terminal.

Abstract: Disclosed is a user terminal for wireless communication with a remote access point, the user terminal comprising: a mapping module adapted to map one or more input data bits to an uplink symbol; a delay module adapted to apply a delay to the uplink symbol; a transmit module adapted to modulate the delayed symbol into a frequency channel; and a directional antenna oriented along a dominant path to the access point, the antenna being adapted to transmit the modulated symbol to the access point, wherein the delay is chosen such that the transmitted symbol arrives at the access point simultaneously with a further symbol modulated into the frequency channel and transmitted by a further user terminal.

Abstract: Disclosed is a wireless backhaul network for a communications system. The network comprises a congregate node connected to the communications system; a plurality of access points, each access point having associated amounts of incident bidirectional traffic to be conveyed to and from the congregate node; and a plurality of bidirectional wireless links adapted to convey the traffic between the access points and the congregate node. The congregate node is configured to allocate spectrum to each directional component of each link within a predetermined available spectrum for the conveyance of the traffic, wherein the allocation is dependent on the amounts of traffic at the respective access points.

Abstract: Disclosed is a user terminal for wireless communication with a remote access point, the user terminal comprising: a mapping module adapted to map one or more input data bits to an uplink symbol; a delay module adapted to apply a delay to the uplink symbol; a transmit module adapted to modulate the delayed symbol into a frequency channel; and a directional antenna oriented along a dominant path to the access point, the antenna being adapted to transmit the modulated symbol to the access point, wherein the delay is chosen such that the transmitted symbol arrives at the access point simultaneously with a further symbol modulated into the frequency channel and transmitted by a further user terminal.

Abstract: A user terminal for wireless communication with a remote access point can include a mapping module, a delay module, a transmit module, and a directional antenna. The mapping module can be used to map one or more input data bits to an uplink symbol. The delay module can be used to apply a delay to the uplink symbol. The transmit module can be used to modulate the delayed symbol into a frequency channel. The directional antenna can be oriented along a dominant path to the access point, and the antenna is used to transmit the modulated symbol to the access point. The delay is chosen such that the transmitted symbol arrives at the access point simultaneously with a another symbol that is modulated into the frequency channel and transmitted by another user terminal.

Abstract: A mass spectrometer system can include a mass analyzer operable to mass transmit streams of ions to a detector in a mass dependent fashion for measurement of ion flux intensity. An ion attenuator can be located in the extraction region between the mass analyzer and detector, downstream of the mass analyzer, and can be operable to provide selective attenuation of the ion beam by attenuating ion flux intensity also in mass dependent fashion. Higher concentration ions can be selected and attenuated, while other lower concentration ions can be left unattenuated. Different ions can be attenuated to different degrees. Locating the ion attenuator downstream of the mass analyzer so that the ion beam is already mass differentiated when attenuated can avoid mass discriminatory effects associated with ion beam attenuators. Selective attenuation of only certain ions but not others can extend the dynamic range of the detector without necessarily sacrificing detector sensitivity.

Abstract: Disclosed is a method of communicating a complex vector, using one or more index bits, the method comprising quantizing the complex vector using a codebook, the codebook comprising a plurality of complex vectors mapped from real vectors that lie on a reflected simplex where the simplex is of dimension one less than twice the length of the complex vector; indexing the quantized vector to form the one or more index bits; and transmitting the index bits to the transmitter, thereby communicating the complex vector.

Abstract: Methods for improved separation of ions from an ion trap employing a combination of low pressure and low amplitude ion excitation, including methods for removing, from an ion trap ion population, ions having a m/z value neighboring that of an ion of interest, mass spectrometry methods providing improved resolution of ion detection, and programmable apparatus programmed with instructions therefor.

Abstract: Disclosed is a wireless backhaul network for a communications system. The network comprises a congregate node connected to the communications system; a plurality of access points, each access point having associated amounts of incident bidirectional traffic to be conveyed to and from the congregate node; and a plurality of bidirectional wireless links adapted to convey the traffic between the access points and the congregate node. The congregate node is configured to allocate spectrum to each directional component of each link within a predetermined available spectrum for the conveyance of the traffic, wherein the allocation is dependent on the amounts of traffic at the respective access points.

Abstract: Disclosed is a wireless communication system comprising a plurality of antennas, a plurality of base stations, each base station being adapted to connect to one or more of the antennas over an available spectrum, and a wireless switching module. The wireless switching module is adapted to allocate one or more portions of the available spectrum to each antenna dependent on a compatibility constraint on the antennas, and assign each antenna for connection to a base station.

Abstract: Methods for fragmenting ions in an ion trap are described.

Abstract: Disclosed is a user terminal for wireless communication with a remote access point, the user terminal comprising: a mapping module adapted to map one or more input data bits to an uplink symbol; a delay module adapted to apply a delay to the uplink symbol; a transmit module adapted to modulate the delayed symbol into a frequency channel; and a directional antenna oriented along a dominant path to the access point, the antenna being adapted to transmit the modulated symbol to the access point, wherein the delay is chosen such that the transmitted symbol arrives at the access point simultaneously with a further symbol modulated into the frequency channel and transmitted by a further user terminal.

Abstract: Methods for fragmenting ions retained in an ion trap are described. In various embodiments, a non-steady-state pressure of a neutral collision gas of less than about 5×10?4 Torr and an excitation amplitude of less than about 500 mV (peak to ground) is used to fragment ions with greater than about 80% fragmentation efficiency. In various embodiments, duration of ion excitation is greater than about 25 ms.

Abstract: Methods for improved separation of ions from an ion trap employing a combination of low pressure and low amplitude ion excitation, including methods for removing, from an ion trap ion population, ions having a m/z value neighboring that of an ion of interest, mass spectrometry methods providing improved resolution of ion detection, and programmable apparatus programmed with instructions therefor.