This is an ion-producing source having a distinct chemical ionization configuration and a distinct electron impact configuration. In this source, a hollow chamber including an ion source and a source of sample molecules receives a hollow, slidable cylindrical member having a chemical ionization chamber within it. Orifices in the chamber and the cylindrical member connect the chemical ionization source chamber to the electron source and to the sample molecule source when the cylindrical member is pulled to one position. When the cylindrical member is pulled to another position, the slidable cylindrical member and the inside walls of the chamber define the ionization region to which the electron source and the sample molecule source are directly connected. By moving the cylindrical member, the ionization source can be changed from a chemical ionization source to an electron impact source.
An ionizer for ionizing a sample by bombardment with energetic particles. The ionizer incudes an ion chamber and an adjacent gas discharge region formed with an electrode cooperating wih the ion chamber. Said region serving to discharge a gas to form neutral and charged gas particles. The cooperation of the electrode and chamber accelerates the charged particles and causes charged and uncharged particles to flow into the ion chamber to strike and ionize a sample in the ion chamber.
A combined ion source capable of operating either in an electron-impact-ionization mode or in a chemical ionization mode and being quickly shiftable from one mode to the other, consists of a cavity into which either a sample gas can be introduced to be ionized alone or together with a reaction gas introduced into the cavity, the cavity having at least one opening for the introduction of ionizing particles, or radiation, into the cavity and another opening for the discharge of ions, with a flexible band covering the exterior surface of the cavity between the openings, the band having suitable patterns of openings, each of which patterns cooperates with the various openings to provide a specific combination of openings and at the same time adjusting the width of each opening used in each combination.
An ionizer adapted to be placed in a vacuum envelope for providing ions of a sample to be analyzed is disclosed herein and includes an electron source, ion accelerating and focusing electrodes and an interchangeable ionization chamber including a first opening for allowing electrons to enter the chamber and an exit opening to allow ions to exit said chamber. The ionization chamber is supported in cooperative relationship with the electron source and accelerating and focusing electrodes whereby electrons enter the chamber through the first opening and form sample ions in the chamber which then exit the chamber through the exit opening toward said accelerating and focusing electrodes.
The apparatus and method of the present invention multiplexes or gates particle beams to provide continuous data collection useful in time-of-flight mass spectrometry. The multiple particle beams are gated or combined to achieve an overall 100% duty cycle. This allows continuous data collection, thereby realizing the full advantages of abundance sensitivity and mass resolution in time-of-flight mass spectrometry.
A method and apparatus for mass spectrometry employing tandem chemical ionization (CI) and electron impact (EI) ionization chambers with independent ionizing electron sources, both CI and EI ions being produced simultaneously. Through electronic shuttering either the CI or EI ions may be transmitted to the mass spectrometer while the ions of the other type are dispersed and rejected. The shuttering being accomplished very rapidly relative to the mass scan rate, which is in turn fast with respect to temporal variations in sample material composition. The two interwoven ion sequences are demultiplexed and smoothed into independent and effective simultaneous CI and EI mass spectrum channels.
