Abstract: A cylindrically-shaped auxiliary electrode and a cylindrically-shaped reflecting electrode are located anterior to a spray flow ejected from an ESI ionization probe. An inlet end of a heated capillary extends into the space between the two electrodes. The auxiliary electrode and heated capillary are grounded, while the reflecting electrode is supplied with a direct-current voltage having the same polarity as measurement target ions. As a result, a reflecting electric field which reflects ions originating from sample components and charged droplets, being carried by the spray flow, is created within the space between the two electrodes. A focusing electric field for focusing ions onto the inlet end is also created in an area near the inlet end. The ions originating from sample components are thereby separated from the gas flow and gathered around the inlet end, to be drawn into the heated capillary and sent into a vacuum chamber.

Abstract: A mass spectrometer includes a collision cell (16) converging electrode (18), accelerating electrode (19) and front-side ion lens system (20) which is an electrostatic lens, which are all located within a medium-vacuum region, and a partition wall (22) for separating the medium-vacuum region from a high-vacuum region and an ion transport optical system (23) located within the high-vacuum region. Ions which have been extracted and accelerated by an accelerating electric field created between an exit electrode (16a) and the accelerating electrode (19) are focused into a micro-sized ion-passage opening (19a) by the converging electrode (18). The accelerating electrode (19) blocks a stream of gas, thereby decreasing the chance of contact of ions with gas particles behind the electrode. Additionally, the accelerating electric field imparts a considerable amount of kinetic energy to the ions, thereby preventing the ions from being dispersed even when they come in contact with the gas particles.

Abstract: A mass spectrometer includes a collision cell (16) converging electrode (18), accelerating electrode (19) and front-side ion lens system (20) which is an electrostatic lens, which are all located within a medium-vacuum region, and a partition wall (22) for separating the medium-vacuum region from a high-vacuum region and an ion transport optical system (23) located within the high-vacuum region. Ions which have been extracted and accelerated by an accelerating electric field created between an exit electrode (16a) and the accelerating electrode (19) are focused into a micro-sized ion-passage opening (19a) by the converging electrode (18). The accelerating electrode (19) blocks a stream of gas, thereby decreasing the chance of contact of ions with gas particles behind the electrode. Additionally, the accelerating electric field imparts a considerable amount of kinetic energy to the ions, thereby preventing the ions from being dispersed even when they come in contact with the gas particles.

Abstract: A drift voltage generator applies voltages to a plurality of annular electrodes, respectively, so that a potential distribution ? on an ion beam axis of an accelerating electric field created within a drift region satisfies ?2?/?Z2>0. Trailing ions undergo a higher rate of acceleration than preceding ions, so that a compressing force acts on an ion packet in the direction of the ion beam axis. Consequently, the ion packet is constantly confined to a smaller space in the direction of the ion beam axis, and ions having the same ion mobility form a narrower peak in a spectrum with the horizontal axis representing the drift time, so that the resolving power improves. A control unit switches the applied voltages so that a uniform accelerating electric field is created.

Abstract: A cylindrically-shaped auxiliary electrode and a cylindrically-shaped reflecting electrode are located anterior to a spray flow ejected from an ESI ionization probe. An inlet end of a heated capillary extends into the space between the two electrodes. The auxiliary electrode and heated capillary are grounded, while the reflecting electrode is supplied with a direct-current voltage having the same polarity as measurement target ions. As a result, a reflecting electric field which reflects ions originating from sample components and charged droplets, being carried by the spray flow, is created within the space between the two electrodes. A focusing electric field for focusing ions onto the inlet end is also created in an area near the inlet end. The ions originating from sample components are thereby separated from the gas flow and gathered around the inlet end, to be drawn into the heated capillary and sent into a vacuum chamber.

Abstract: An off-axis ion transport optical system (20) including a front-stage quadrupole ion guide (21), a rear-stage quadrupole ion guide (22), and an ion deflector (23) is disposed inside an intermediate vacuum chamber (2) in a stage next to an ionization chamber (1) maintained at an atmospheric pressure. Both of the quadrupole ion guides (21 and 22) have the same configuration as that of a conventional ion guide that transports ions while trapping the ions using a radio-frequency electric field. The ion deflector (23) includes a pair of parallel flat electrodes (231 and 232) and deflects ions using a direct-current electric field. By causing the deflected ions to reach the ion receiving range of the rear-stage quadrupole ion guide (22), it is possible to efficiency introduce ions while deflecting the ions. Meanwhile, the ions and neutral particles are separated from each other in the ion deflector (23).

Abstract: An off-axis ion transport optical system (20) including a front-stage quadrupole ion guide (21), a rear-stage quadrupole ion guide (22), and an ion deflector (23) is disposed inside an intermediate vacuum chamber (2) in a stage next to an ionization chamber (1) maintained at an atmospheric pressure. Both of the quadrupole ion guides (21 and 22) have the same configuration as that of a conventional ion guide that transports ions while trapping the ions using a radio-frequency electric field. The ion deflector (23) includes a pair of parallel flat electrodes (231 and 232) and deflects ions using a direct-current electric field. By causing the deflected ions to reach the ion receiving range of the rear-stage quadrupole ion guide (22), it is possible to efficiency introduce ions while deflecting the ions. Meanwhile, the ions and neutral particles are separated from each other in the ion deflector (23).

Abstract: Within an intermediate vacuum chamber next to an ionization chamber maintained at atmospheric pressure, an electrode group of a radio-frequency carpet composed of a plurality of concentrically arranged ring electrodes is placed before a skimmer, with its central axis coinciding with that of an ion-passing hole. Each ring electrode has a circular radial sectional shape. Radio-frequency voltages with mutually inverted phases are applied to the ring electrodes neighboring each other in the radial direction. Additionally, a different level of direct-current voltage is applied to each ring electrode to create a potential which is sloped downward from the outer ring electrode to the inner ring electrode. The circular cross section of the electrode produces a steep pseudo-potential near the electrode and thereby increases the repulsive force which acts on the ions to repel them from the electrode.

Abstract: A drift voltage generator applies voltages to a plurality of annular electrodes, respectively, so that a potential distribution ? on an ion beam axis of an accelerating electric field created within a drift region satisfies ?2?/?Z2>0. Trailing ions undergo a higher rate of acceleration than preceding ions, so that a compressing force acts on an ion packet in the direction of the ion beam axis. Consequently, the ion packet is constantly confined to a smaller space in the direction of the ion beam axis, and ions having the same ion mobility form a narrower peak in a spectrum with the horizontal axis representing the drift time, so that the resolving power improves. A control unit switches the applied voltages so that a uniform accelerating electric field is created.

Abstract: Within an intermediate vacuum chamber next to an ionization chamber maintained at atmospheric pressure, an electrode group of a radio-frequency carpet composed of a plurality of concentrically arranged ring electrodes is placed before a skimmer, with its central axis coinciding with that of an ion-passing hole. Each ring electrode has a circular radial sectional shape. Radio-frequency voltages with mutually inverted phases are applied to the ring electrodes neighboring each other in the radial direction. Additionally, a different level of direct-current voltage is applied to each ring electrode to create a potential which is sloped downward from the outer ring electrode to the inner ring electrode. The circular cross section of the electrode produces a steep pseudo-potential near the electrode and thereby increases the repulsive force which acts on the ions to repel them from the electrode.

Abstract: When ions introduced between repeller electrode and extraction electrode are accelerated through flight space, orthogonal acceleration power supply portion applies a designated voltage to a plurality of acceleration electrodes in such a way as to form an acceleration field wherein potential distribution ? along central axis of the acceleration area becomes ?2?/?Z2<0. When ions traverse an acceleration field with this manner of axial potential distribution, in addition to force in the acceleration direction, force pressing towards central axis acts on ions situated away from central axis. This causes ions to be fired through flight space while being focused, and hence to reach detector more efficiently. This makes it possible to improve measurement sensitivity without adding a focusing lens or the like.

Abstract: An ion entrance opening (15) for introducing ions into an orbit (C) along a sector-shaped electric field entrance optical axis (A) from outside is provided in an outer electrode (11a) of a main electrode (11) for producing a sector-shaped electric field for forming the orbit (C). In order to correct the disturbance in the sector-shaped electric field due to the provision the ion entrance opening (15), three electrode correction electrodes (20) are aligned in the direction of the sector-shaped electric field entrance optical axis (A). By appropriately adjusting each of the direct-current voltages applied to the electrode correction electrodes (20), the equipotential lines in the sector-shaped electric field can be substantially the same as in the case where the ion entrance opening (15) is not provided. This configuration can alleviate the shift of the orbit of ions flying along the orbit (C).

Abstract: Provided is a time-of-flight mass spectrometer having a reflectron which eliminates energy dependency of the flight time of ions having the same m/z while ensuring a high degree of design freedom. An electric field created by the reflectron is virtually divided into a decelerating region for decelerating ions and a reflecting region for reflecting ions. For an ion having a mass-to-charge ratio which has departed with initial energy higher than Ud, the total flight time required for the ion to travel through a free-flight region and the decelerating region into the reflecting region and return will be equal to the total flight time required for an ion of the same mass-to-charge ratio to make a round trip in which the ion turns around at a point of the reference potential value at the boundary between the decelerating region and the reflecting region or in the decelerating region.

Abstract: One virtual rod electrode (11) is composed by arraying a plurality of plate electrodes (111, . . . , 118) along an ion beam axis, and a quadrupole ion optical element (1) is constructed by arranging four virtual rod electrodes (11, 12, 13 and 14) around an ion beam axis C. A voltage-applying unit alternately applies two radio-frequency voltages having a phase difference of 180 degrees for each of the plate electrodes in one virtual rod electrode. By this voltage application, the quadrupole component of the radio-frequency electric field created within a space surrounded by the four virtual rod electrodes is decreased, while higher-order multipole components are increased. The quadrupole component yields high ion convergence and mass selectivity, while the higher-order components provide high ion transmission efficiency and ion acceptance.

Abstract: Provided is a time-of-flight mass spectrometer having a reflectron which eliminates energy dependency of the flight time of ions having the same m/z while ensuring a high degree of design freedom. An electric field created by the reflectron is virtually divided into a decelerating region for decelerating ions and a reflecting region for reflecting ions. For an ion having a mass-to-charge ratio which has departed with initial energy higher than Ud, the total flight time required for the ion to travel through a free-flight region and the decelerating region into the reflecting region and return will be equal to the total flight time required for an ion of the same mass-to-charge ratio to make a round trip in which the ion turns around at a point of the reference potential value at the boundary between the decelerating region and the reflecting region or in the decelerating region.

Abstract: A measurement is performed in a no-passing mode, in which ions having different masses are prevented from making a complete turn through a loop orbit, to obtain a time-of-flight spectrum without the passing of ions having different masses (S1 and S2). From the time of flight and other information of the peaks appearing on the time-of-flight spectrum (S3), the number of turns and the time of flight in the loop-turn mode are predicted. Based on this prediction, a set of segments are defined on a time-of-flight spectrum in the loop-turn mode. The time widths of those segments are determined taking into account the spreads of the time widths of the aforementioned peaks. Since the number of turns is unique within each segment, the numbers of turns and the masses of the peaks can be uniquely determined as long as none of the segments overlap each other.

Abstract: One virtual rod electrode is composed by a plurality of electrode plane plates arranged in the ion optical axis direction, and four virtual rod electrodes are arranged around the ion optical axis to form a virtual quadrupole rod type ion transport optical system (30). In one virtual rod electrode, the interval between the adjacent electrode plane plates is set to be large in the anterior area (30A) and small in the posterior area (30B). As the interval between electrodes becomes larger, high-order multipole field components increase and therefore the ion acceptance is increased, which enables an efficient acceptance of ions coming from the previous stage. On the other hand, if the interval between electrodes is small, the quadrupole field components relatively increase and the ion beam's convergence is improved. Therefore, ions can be effectively introduced into a quadrupole mass filter for example in the subsequent stage, which contributes to the enhancement of the mass analysis' sensitivity and accuracy.

Abstract: A basic ion optical system (2) in which the temporal focusing of ions is ensured includes a plurality of sector-shaped electrodes (11, 12, 13, and 14), an ion injection slit (15), and an ion ejection slit (16), which are placed on the same plane. A plurality of basic ion optical systems (2) are placed in such a manner as to be mutually separated at predetermined intervals in the direction approximately orthogonal to their planes. The ion ejection slit (16) of the lower-stage basic ion optical system (2) and the ion injection slit (15) of the next-stage basic ion optical system (2) are connected to each other via another basic ion optical system (3) in which the temporal focusing of the ions is ensured. Accordingly, the flight distance can be elongated while assuredly achieving the temporal focusing of the ions as an entire ion optical system (1), and a three-dimensional space can be efficiently utilized to compactify the ion optical system (1).

Abstract: One cycle of loop orbit is formed by two identical time-focusing unit structures (T1 and T2). Each of the time-focusing unit structures (T1 and T2) has a time-focusing point (P1) at the injection side and a time-focusing point (P2) at the ejection side. Each of them also has an injection-side free flight space (11) with a length of L1 and an ejection-side free flight space (12) with a length of L1, respectively anterior and posterior to a basic ion optical element (10) for causing ions to fly along a substantially arc-shaped orbit. Another basic ion optical element (30) having the same configuration as that of the basic ion optical element (10) is inserted to the injection-side free flight space (11) so that the distance between the ejection end of the basic ion optical element (30) and the injection end of the basic ion optical element (10) is L1?. The length L0 of the free flight space for injecting ions to the basic ion optical element (30) is set to be the value obtained by L0=2(L1+L2)?(L1?+L2).

Abstract: An ion entrance opening (15) for introducing ions into an orbit (C) along a sector-shaped electric field entrance optical axis (A) from outside is provided in an outer electrode (11a) of a main electrode (11) for producing a sector-shaped electric field for forming the orbit (C). In order to correct the disturbance in the sector-shaped electric field due to the provision the ion entrance opening (15), three electrode correction electrodes (20) are aligned in the direction of the sector-shaped electric field entrance optical axis (A). By appropriately adjusting each of the direct-current voltages applied to the electrode correction electrodes (20), the equipotential lines in the sector-shaped electric field can be substantially the same as in the case where the ion entrance opening (15) is not provided. This configuration can alleviate the shift of the orbit of ions flying along the orbit (C).