The present invention relates to a mass spectrometer, in particular, to a mass spectrometer characterized by a connection structure for electrically connecting an electrode and a power source included in the mass spectrometer.
As an example of mass spectrometer, a time-of-flight mass spectrometer is described in Patent Literature 1. In this time-of-flight mass spectrometer 90, as shown in
Thus, the time-of-flight mass spectrometer 90 includes various electrodes for forming electric fields, and a predetermined voltage is applied to each electrode. For example, the reflection electrode 94 is connected via connection lines 97 to a power source board 95 disposed on a side of the flight space 93. The power source board 95 is connected via vacuum feedthroughs 96 to a power source 99 disposed outside of the time-of-flight mass spectrometer 90.
Patent Literature 1: JP 2014-165053 A
Patent Literature 2: JP 2015-118887 A (FIGS. 1 to 4)
Patent Literature 3: U.S. Pat. No. 5,689,111 A (FIG. 2)
Patent Literature 4: U.S. Pat. No. 6,812,453 B2
For the power source board 95, a printed board is normally used, and each of the connection lines 97, which connects the power source board 95 to each electrode, is electrically connected by soldering. Each of the reflection electrodes 94 is normally formed of a metal plate such as aluminum or stainless steel, and each of the reflection electrodes 94 and each of the connection lines 97 are electrically connected by spot welding. On the other hand, since a rotating member such as a fin rotates at high speed inside of the vacuum pump 80, which is used to evacuate the inside of the time-of-flight mass spectrometer 90 as described earlier, the time-of-flight mass spectrometer 90 is vibrated due to the vibration generated by this rotation. If the reflection electrode 94 and the connection line 97 are not adequately fixed by spot welding, a problem arises in that this vibration may separate the reflection electrode 94 and the connection line 97. Besides the vibration by the vacuum pump 80, vibration or impact at the time of transportation may also separate the reflection electrode 94 and the connection line 97. In particular, in a case of a stacked electrode formed of a number of electrodes and connected to the connection lines by conventional spot welding and the like such as the reflection electrode 94 of the time-of-flight mass spectrometer described in Patent Literature 1, when one of the connection lines 97, through which voltage is applied to each electrode, is separated, it is difficult to reconnect or repair it on site. In addition, in a case where fixation of such a spot welding section is not adequate, there is a problem that, even if electrical contact itself is maintained, the contact state is poor, voltage applied from the power source 99 is likely to become unstable due to vibration of the vacuum pump or the like, and the mass accuracy, the mass resolution, and the sensitivity of the mass spectrometer become unstable.
Such a problem has occurred also in the extrusion electrode 921 and the grid electrode 922. In addition, such a problem can also occur in the stacked ion guide electrode that is an acceleration electrode in a flight space described in Patent Literature 2 and in the stacked ion guide electrode provided on the near side of the ion introduction section described in Patent Literature 3. In addition, a similar problem may occur in, other than a time-of-flight mass spectrometer, various stacked electrodes used for a mass spectrometer, such as the multi-aperture ion guide electrode disclosed in Patent Literature 4.
The problem to be solved by the present invention is to provide a mass spectrometer that is capable of maintaining a good connection state of the electrode and the power source even if vibration or impact due to transport or vibration due to the rotation drive mechanism or the like are applied and capable of reconnecting with ease even if the connection between the electrode and the power source is separated.
A mass spectrometer according to the present invention provided in order to solve the problem mentioned above includes:
a) an electrode;
b) a power source section that supplies electric power to the electrode with a predetermined voltage and/or current;
c) a connection line formed of a conductive wire rod having elasticity for electrically connecting the electrode and the power source section;
d) a connector section provided at one end of the connection line;
e) a seat provided in the electrode to be contacted with the connector section;
f) a fixation section provided in the connection line to be fixed to the power source section; and
g) a spring section formed between the connector section and the fixation section of the connection line or in the connector section and for urging the connector section to the seat.
In the mass spectrometer according to the present invention, the fixation section of the connection line is fixed to the power source section and the connector section contacts the seat of the electrode, and hence the power source section and the electrode are electrically connected via the connection line. Here, since the connector section is urged to the seat by the spring section, the connector section is pressed to the seat by the urging force of the spring section, and the connector section and the seat are not separated even if an ordinary vibration is applied to the device. In addition, if a vibration that exceeds the frictional force of this connector section is applied, the connector section absorbs the vibration by being displaced, and thus, while maintaining good electrical connection, no excessive force is applied to the connection line and the connector section. If a greater vibration is applied, the connector section is separated, which causes the electrical connection to be cut off, but the worse situations are avoided such as disconnection of the connection line and damage of the connecting section (connector section). Then, in such a case, reconnection can be made easily without soldering, welding, and the like.
The power source section supplies electric power with a predetermined voltage and/or current to the electrode, and normally includes an electric circuit that adjusts electric power from a commercial power source or a battery to the predetermined voltage and/or current. In addition, in a case of distributing electric power to a plurality of electrodes, the power source section may include an electric circuit for the distribution. The fixation section of the connection line can be fixed to a printed board on which those electric circuits are formed, for example. In that case, it is possible to effect the fixation to the printed board by inserting a connection line into a hole provided on the printed board and soldering the connection line to the printed board.
The spring section can be formed by winding the connection line in the form of torsion spring or helical spring. In addition, the spring section may be provided between the connector section and the fixation section, separately from the connector section, so that the connector section is urged to the seat of the electrode, or the spring section itself can be used as a connector section by winding the connection line multiple times and by sandwiching the seat of the electrode between two neighboring winding sections.
It is desirable that the connector section and the seat have an insertion structure in which one is male and the other is female. Due to this, it is more difficult for the connector section to be separated from the seat.
The connection structure of the electrode and the power source of a mass spectrometer according to the present invention can preferably be applied to a stacked electrode used for transporting an ion in a flight space of a time-of-flight mass spectrometer. Examples of such a stacked electrode include an electrode in which a plurality of acceleration electrodes are stacked, an electrode in which an extrusion electrode, and extraction electrode, and a plurality of acceleration electrodes are stacked, a reflection electrode (reflectron), and a stacked electrode provided on the near side of the ion introducing section. In addition, the connection structure of the electrode and the power source of the mass spectrometer according to the present invention can preferably be used for an ion guide electrode and a reflection electrode used not only in the time-of-flight mass spectrometer but also in the general mass spectrometer.
According to a mass spectrometer according to the present invention, a connection line with a power source section is hardly separated from an electrode even if a vibration is applied, and a good connection state of the electrode and the power source can be maintained. In addition, even if the connection between the electrode and the power source is separated, the electrode and the power source can be easily reconnected.
A mass spectrometer according to an embodiment of the present invention is described with reference to the attached drawings.
The reflection electrode 14 is made up of a plurality of plate-like electrodes 141 formed by metal plates of stainless steel stacked at predetermined intervals. In each of the plate-like electrodes 141, except for the one in the rearmost end, is provided in the center with a hole through which the ion is allowed to pass. An outer edge of each of the plate-like electrodes 141 is provided with a rectangular-shaped seat 1411 that protrudes outward (
The power source board 15 is a printed board on which an electric circuit 151 is formed to convert a power source voltage from the power source 19 into a predetermined voltage and to apply it to each of the plate-like electrodes 141.
A connection line 17 is formed of a conductive wire rod having elasticity, and as shown in
As shown in
The connector section 173 and the seat 1411 have an insertable structure in which the former and the latter correspond to the female and the male, respectively.
Due to a structure similar to each of the plate-like electrodes 141 of the reflection electrode 14, the extrusion electrode 121 and the grid electrode 122 are also connected with a power source board provided in the proximity of them.
Next, the operation of the time-of-flight mass spectrometer 10 is described. Firstly, inside of the housing 20 is put into a high-vacuum state by the vacuum pump 30. Then, voltage is applied from the power source 19 to each of the electrodes. Once the ion to be measured is introduced into the ion introducing section 11, it is transported in the following manner due to an electric field formed by each of the electrodes. First, the ion is accelerated towards the flight space 13 due to an electric field formed by the extrusion electrode 121 and the grid electrode 122. The accelerated ion flies in the flight space 13, turns back due to a reflection electric field formed by the reflection electrode 14, flies again in the flight space 13, and reaches the ion detector 18. Based on the time from when the acceleration of the ion is started to when the ion enters the ion detector 18, a mass-to-charge ratio of the ion can be measured.
When the vacuum pump 30 is operated, vibration generated by the rotation mechanism in the vacuum pump 30 is transmitted to the entire time-of-flight mass spectrometer 10. Due to this, the reflection electrode 14, the power source board 15, and the like are vibrated, and since the spring section 172 urges the connector section 173 to the seat 1411 of the plate-like electrodes 141, the connector section 173 and the seat 1411 are not separated even if an ordinary vibration is applied and a good electrical contact is maintained in a state where the contact resistance between the connector section 173 and the seat 1411 is restrained. For this reason, the electrical field in the reflection electrode 14 becomes stable, and it is thus possible to prevent the mass accuracy, the mass resolution, and the sensitivity from becoming unstable.
Even if a greater vibration is applied and the connector section 173 is separated from the seat 1411, the reflection electrode 14, the connection line 17, and the like are not damaged. In addition, after the connection is cut off, reconnection is made possible with ease by a worker on the site inserting the connector section 173 into the seat 1411.
While in the embodiment described above, the connector structure in which the seat 1411 is male and the connector section 173 is female is adopted, the connector section may be male and the seat may be female.
Next, another connection structure of the reflection electrode 14, the power source board 15, and the connection line 17 is described with reference to
The second modification of connection structure of the reflection electrode 14, the power source board 15, and the connection line 17 is shown in
The third modification of connection structure of the reflection electrode 14, the power source board 15, and the connection line 17 is shown in
While in the embodiment described above, the power source board is disposed inside of the housing, the power source board may be disposed outside the housing. In this case, as shown in
While only a connection structure of a reflection electrode and a power source section for the electrode has been described, a similar connection structure can also be applied to a power source section and another electrode that contributes to transport of an ion in a flight space, such as an extrusion electrode and a grid electrode. For example, as shown in
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Number | Date | Country |
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2014-165053 | Sep 2014 | JP |
2015-118887 | Jun 2015 | JP |
Number | Date | Country | |
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20200075305 A1 | Mar 2020 | US |