Abstract: A gas tight cell receives an unmetered stream of sample gas. The cell is divided into a reaction chamber, as drift chamber and an ion collector chamber by transverse shutter grids normally carrying an ion repellent charge. The inlet of a chromatograph analytical column is connected to the outlet of the cell ion collector chamber. Inert gas admitted to the ion collector chamber is divided into a drift gas stream and into an oppositely directed carrier gas stream. The drift gas flows from the collector chamber through the drift chamber and out the reaction chamber. The carrier gas flows from the collector chamber through a deionizer into the chromatograph column. An electrostatic field urges sample gas ions from the reaction chamber toward the ion collection chamber. The ions are blocked from entering or exiting from the intervening drift chamber by the charge on the shutter grids.

Abstract: In a quadrupole ion store or ion trap type mass spectometer, significantly improved mass selection is achieved by simultaneously trapping ions within the mass range of interest and then scanning the applied RF and DC voltages or the frequency .omega. to sequentially render unstable trapped ions of consecutive specific masses. These are passed out through apertures in an end cap to a high gain electron multiplier to provide a signal indicative of the ion mass. Sensitivity and mass resolution is also enhanced by operating the ion trap at a relatively high pressure in the range 1.times.10.sup.-1 to 1.times.10.sup.-5 torr. The presence of collision gas molecules, such as helium, improves sensitivity and mass resolution. In addition, the structure itself is built of stacked units, sealed by O-rings, which are easily disassembled for cleaning.

Abstract: An electrospray ion source for a mass spectrometer capable of generating ions from samples dissolved in a solution comprises a capillary tube through which the said solution is pumped into a first chamber maintained substantially at atmospheric pressure and in which an inert gas is flowing in a direction counter to the flow of the solution, and a small orifice in the end wall of the chamber opposite to and aligned with the capillary. A high potential difference is applied between the capillary and the end wall so that the solution is electrosprayed into the chamber and ions characteristic of the sample are formed. These ions are desolvated to a controllable extent by the inert gas, which may also be heated to improve the efficiency of the process and increase the maximum permissible flow rate of solution. The ions so formed pass through the small orifice into a second chamber maintained at a reduced pressure, and into a mass spectrometer.

Abstract: The invention relates to an ion current measuring device.This device comprises a vacuum chamber, a diaphragm for introducing an ion beam into the chamber, means for collecting the ions from the diaphragm and located at the end of the chamber opposite to the diaphragm, and means for measuring a periodic voltage between the collecting means and the reference earth. It is characterized in that it also comprises means located between the diaphragm and the collecting means, for bringing about a periodic modulation of the intensity of the ion current circulating between the collecting means and a reference earth, the measuring means being current or frequency measuring means.Application to the measurement of ion currents, particularly in mass spectrometry.

Abstract: An improved pulsed-beam time-of-flight mass spectrometer is described whereby the velocities of a plurality of iso-mass ions are equalized (velocity compaction) by subjecting a transiting ion bunch, partially separated into iso-mass ion packets, to a time-dependent and monotonically time-varying acceleration force field. Concurrently, space compaction or space focussing is achieved through a speeding up of the retarded ions (relative to the advanced ions) in a given iso-mass ion packet. The wave-form of the ion accelerating field may be of an exponential-limiting-like form in time and depends on the various physical and voltage parameters associated with the ion source, accelerating grids and ion drift distances. When the acceleration force field is properly contoured in both space and time velocity compaction and space compaction simultaneously are achieved for a wide range of iso-mass ion packets and the mass resolution for heavier mass ions is particularly improved.

Abstract: Apparatus and methods of operation are described for determining, with isotopic selectivity, the number of noble gas atoms in a sample. The analysis is conducted within an evacuated chamber which can be isolated by a valve from a vacuum pumping system capable of producing a pressure of 10.sup.-8 Torr. Provision is made to pass pulses of laser beams through the chamber, these pulses having wavelengths appropriate for the resonance ionization of atoms of the noble gas under analysis. A mass filter within the chamber selects ions of a specific isotope of the noble gas, and means are provided to accelerate these selected ions sufficiently for implantation into a target. Specific types of targets are discussed. An electron measuring device produces a signal relatable to the number of ions implanted into the target and thus to the number of atoms of the selected isotope of the noble gas removed from the gas sample.

Abstract: The ion accelerator for an ion mobility detector cell is comprised of a ceramic tube coated inside with a thick film resistor composition across which a voltage potential difference is impressed to provide an ion accelerating electrical field gradient within the tube.

Abstract: An ion mobility detector in which selectivity and sensitivity is enhanced by converting through surface interactions sample gas or vapor to a form more readily ionized or by converting through surface interactions interferent gas or vapor to a form less readily ionized. To accomplish the conversion, samples may be passed through a catalytically reactive filter prior to injection into the detector reaction region; exposed to a reactive coating placed on the surface of a permeable membrane prior to diffusion therethrough into the reaction region or exposed to a reactive coating placed on the interior walls of the reaction region.

Abstract: An atomic or molecular beam detector is disclosed wherein the beam to be detected is coupled through a chopper to form a spatially modulated beam which is then directed at the pressure sensitive surface of a small sensitive microphone. The electrical output signal of this microphone is coupled to a phase-sensitive detector in order to detect the energy that is present in the signal at the frequency corresponding to the chopping rate. In the specific embodiment disclosed, a light beam is also coupled through the chopper in order to develop a second electrical signal which is mixed with the electrical output of the microphone and then coupled through a low pass filter to provide a DC signal when the atomic or molecular beam is present.

Abstract: A detector for trace quantities of chemical species in the atmosphere includes a pump for drawing an atmospheric sample through transfer means which transfer species molecules present in the sample to a dry carrier gas circulating in a closed gas flow circuit including the transfer means, an ionmobility type detector, filters and a circulating pump; the filters remove water molecules and species molecules from the carrier gas. The carrier gas may be air. The arrangement inhibits water vapor reaching the detector and reducing its sensitivity to the chemical species.

Abstract: An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatilizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vilicon unit.

Abstract: Two converging molecular beams are introduced alternately into the inlet of a mass spectrometer by utilizing a chopping wheel apparatus to alternately pass the two molecular beams to the inlet of the mass spectrometer.

Abstract: The spark source spectrographic analysis process and apparatus utilizes an ion source with two electrodes connected to electrical excitation means making it possible to produce discharges between them and means for directing the ions formed in this source to a mass spectrograph, together with means which make it possible for the spectrograph only to analyze the ions produced by discharges having a given direction.

Abstract: The ion beam from a field desorption source in a double focusing magnetic mass spectrometer is monitored by disabling the electric sector of the mass analyzer such that the ion beam is not deflected. An opening is provided in the wall of the electric sector such that the undeflected ion beam may pass therethrough to a detector. This permits the characteristics of the field desorption source to be ascertained more quickly and easily so that a mass analysis may be performed. The monitor may be operated automatically to vary a characteristic of the field desorption source until ions are detected. Thereafter, the electric sector is energized and an analysis performed.

Abstract: An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vidicon unit.

Abstract: The invention relates to a nonmagnetic time-of-flight mass spectrometer whose analyzer chamber accommodates a pulsed ion source, an ion detector and an ion reflecting system disposed on one and the same ion-optical axis. The ion detector and the ion reflecting system are disposed on opposite sides of the ion source. The ion source comprises a source wherein all electrodes are transparent to the ions studied.

Abstract: A pulsed neutron system includes an accelerator tube having a target, an ionization section, and a replenisher for supplying accelerator gas. The power supplied to the replenisher is controlled to maintain the ionization pulse time duration within the upper and lower limits of a time window. A comparator compares the ionization pulse time duration to the upper and lower limits of the time window and produces an output pulse which is utilized by an operational amplifier to operate a stepping motor in one direction if the ionization pulse time duration exceeds the upper limit of the time window and in a reverse direction if the ionization pulse time duration is below the lower limit of the time window. The stepping motor positions a variable autotransformer which increments the voltage applied to the replenisher to change the ionization pulse time duration if it does not fall within the upper and lower limits of the time window.

Abstract: The ion beam from a field desorption source in a double focusing magnetic mass spectrometer is monitored by disabling the electric sector of the mass analyzer such that the ion beam is not deflected. An opening is provided in the wall of the electric sector such that the undeflected ion beam may pass therethrough to a detector. This permits the characteristics of the field desorption source to be ascertained more quickly and easily so that a mass analysis may be performed. The monitor may be operated automatically to vary a characteristic of the field desorption source until ions are detected. Thereafter, the electric sector is energized and an analysis performed.