JP6536313B2 - Mass spectrometer components - Google Patents

Description

  The present invention relates to a member used to form an ion flight space of a mass spectrometer.

  As one type of mass spectrometer, a time-of-flight mass spectrometer (TOFMS) is known. In a time-of-flight mass spectrometer, ions accelerated by an electric field are introduced from one end of a flight tube, free-fly in the flight tube, and the flight time until a detector provided at the end of the free flight path is reached In accordance with the above, various ions are separated and detected for each mass-to-charge ratio m / z.

  By the way, the principle of being able to separate various ions at every mass-to-charge ratio m / z according to the flight time is based on the premise that the flight distance of ions is constant, this flight distance is It is defined by the length. Therefore, if the length of the flight tube changes with temperature, for example, the flight distance does not remain constant, and the accuracy in identifying the mass-to-charge ratio m / z based on the flight time deteriorates.

  Therefore, various techniques for preventing the change in the length of the flight tube due to the temperature have been conventionally proposed. For example, it has been proposed that the flight tube be placed in a temperature-controlled room kept at a constant temperature inside (see, for example, Patent Document 1). For example, it has also been attempted to form the flight tube of a material having a low coefficient of thermal expansion (for example, invar which is an alloy of Fe and Ni).

JP 2008-157671 A

  However, the method of putting the flight tube in the temperature-controlled room requires equipment (heater, fan, temperature sensor, control unit for controlling temperature control, etc.) to keep the temperature-controlled room and its inside at a constant temperature, The increase in size and manufacturing cost of the mass spectrometer can not be avoided. In addition, the temperature sensor itself placed in the temperature-controlled room also generates heat and affects the temperature of the temperature-controlled room, so it is possible to accurately keep the temperature-controlled room at a constant temperature with high precision. It is not easy to carry out temperature control.

  On the other hand, if the flight tube is formed of a material having a small coefficient of thermal expansion, such as Invar, the length of the flight tube hardly changes with temperature. However, even if it is Invar, its coefficient of thermal expansion is not zero at all. Therefore, even if formed by invar, the length of the flight tube changes slightly depending on the temperature.

  Thus, no effective technique has hitherto existed that can sufficiently prevent the flight tube length from changing with temperature.

In addition, in the mass spectrometer, a member that adversely affects the analysis accuracy by changing the length depending on the temperature exists in addition to the flight tube.
For example, in a mass spectrometer, an einzel lens may be disposed as an ion transport optical system for transporting ions to a flight tube. An ion transport optical system using an einzel lens includes a plurality of (generally three) electrodes arranged along the flight path of ions, and an insulating spacer disposed between adjacent electrodes. If the length of the insulating spacer (length along the flight path of ions) changes with temperature, the uniformity of the electrode spacing can not be secured. If the electrode spacing changes, it is not possible to apply a defined lens action (specifically, for example, a defined acceleration) to the ions, which adversely affects the analysis accuracy.

  The problem to be solved by the present invention is a technique that can avoid deterioration in analysis accuracy due to temperature change of the length of a member used to form the flight space of ions in a mass spectrometer. Offer.

The present invention made to solve the above problems is
A member of a mass spectrometer which separates and accelerates ions accelerated by an electric field and detects each mass-to-charge ratio according to the time of flight to reach a detector, and which is disposed along the flight path of ions There,
A first portion of L1 along the flight path;
It consists of a second part of the length L2 along the flight path, which is arranged next to the first part along the flight path and is made of a material different from the first part,
The length L1 and the length L2 are
Assuming that the linear expansion coefficient of the forming material of the first portion along the flight path is α1, and the linear expansion coefficient of the forming material of the second portion along the flight path is α2.
L1 × α1 + L2 × α2 = 0
It is characterized in that it is set to be

According to this aspect, in the member disposed along the flight path of ions, when the length of the first portion (length along the flight path of ions) is increased by, for example, ΔL due to thermal expansion, the second portion (The length along the flight path of ions) is shortened by the same ΔL due to thermal contraction (ΔL = L1 × α1 × Δθ = −L2 × α2 × Δθ , Δθ is a temperature change ). That is, the thermal expansion width of the first portion is offset by the thermal contraction width of the second portion, and the entire length of the member (length along the flight path of ions) does not change. Therefore, it is avoided that the analysis accuracy of the mass spectrometer is deteriorated due to the temperature change of the length of the member disposed along the flight path of the ions.

The member for the mass spectrometer is preferably
The heat capacity of the first part and the heat capacity of the second part are equal.

  According to this aspect, since the heat capacity of the first part and the heat capacity of the second part are equal, when the ambient temperature changes, for example, from θ1 to θ2, the speed of the temperature change of the first part and the temperature of the second part Match the speed of change. That is, not only in the time zone in which the temperature of each portion is constant (time zone of equilibrium state), but also in the time zone in which each portion changes in temperature (time zone of non-equilibrium state) The temperature with the two parts is always almost equal. If the heat capacity of the first portion and the second portion is largely different, one of them heats up (or cools down) faster than the other because one of them heats up (or cools down) faster than the other. Therefore, there is a possibility that the timing when the entire length of the member changes may appear, but when the heat capacity of the first portion and the second portion is equal, such timing does not appear. That is, the entire length of the member (length along the flight path of ions) is always kept constant.

The member for the mass spectrometer is preferably
It is characterized by being a flight tube which forms free flight space of ion inside.

  According to this aspect, since the length of the flight tube (length along the flight path of ions) does not change with temperature, the flight distance uniformity of the ions is secured. Therefore, various ions can be accurately separated at every mass-to-charge ratio m / z according to the time of flight.

The member for the mass spectrometer is preferably
The insulating spacer may be disposed between the plurality of electrodes arranged along the flight path.

  According to this aspect, since the length of the insulating spacer (the length along the flight path of ions) does not change with temperature, a certain distance between the electrodes is secured. Therefore, the defined action can be accurately given to the flying ions.

Moreover, the present invention according to another aspect is
A plurality of mass analyzers arranged along the flight path of ions in a mass spectrometer which separates and accelerates ions accelerated by an electric field and detects each mass-to-charge ratio according to the time of flight to reach the detector. An insulating spacer disposed between the electrodes,
A first portion of L1 along the flight path;
It consists of a second part of the length L2 along the flight path, which is arranged next to the first part along the flight path and is made of a material different from the first part,
The length L1 and the length L2 are
The linear expansion coefficient of the forming material of the first portion along the flight path is α1, the linear expansion coefficient of the forming material of the second portion along the flight path is α2, and the length of the electrode along the flight path is L3 When the linear expansion coefficient along the flight path of the electrode is α3,
L1 × α1 + L2 × α2 + L3 × α3 = 0
It is characterized in that it is set to be

According to this aspect, the length of the first portion of the insulating spacer (length along the flight path of ions) is increased by, for example, ΔL1 due to thermal expansion, and the length of the electrode (length along the flight path of ions) is When the length of the second part is increased by, for example, ΔL3 due to thermal expansion, the width ΔL2 in which the length of the second part is shortened due to heat contraction coincides with ΔL1 + ΔL3 (−ΔL2 = −L2 × α2 × Δθ = L1 × α1 × Δθ + L3 × α3 × Δθ = ΔL1 + ΔL3). Therefore, even if the electrode expands (or shrinks) due to temperature change, the uniformity of the electrode spacing is secured. As a result, it is possible to accurately give a defined action to the flying ions.

  In a member disposed along the flight path of ions and used to form the flight space of ions, the length of the first portion (length along the flight path of ions) is increased by, for example, ΔL due to thermal expansion. When this happens, the length of the second part (length along the flight path of ions) is shortened by ΔL due to heat contraction, so the overall length of the member (length along the flight path of ions) does not change . Therefore, it is avoided that the analysis accuracy of the mass spectrometer degrades due to the change of the length of the member depending on the temperature.

It is a figure which shows the structure of a mass spectrometer typically. It is a sectional side view of a flight tube. It is a partial side sectional view of an acceleration electrode. It is a fragmentary sectional side view of the acceleration electrode which concerns on another aspect. It is a figure which shows typically the structure of the mass spectrometer which concerns on another aspect.

Embodiments of the present invention will be described with reference to the attached drawings.
<1. Mass spectrometer 100>
The entire configuration of the mass spectrometer 100 will be described with reference to FIG. FIG. 1 is a view schematically showing the configuration of a mass spectrometer 100. As shown in FIG.

  The mass spectrometer 100 is a time-of-flight mass spectrometer (TOFMS) that allows free-flying ions accelerated by an electric field and separates and detects each mass-to-charge ratio according to the time of flight to reach the detector. .

  The mass spectrometer 100 comprises an ion source 10 for generating ions. As the ion source 10, for example, an ion source by matrix-assisted laser desorption ionization (MALDI = Matrix Assisted Laser Desorption / Ionization) method can be adopted. In this case, the ion source 10 has a stage 1 on which the sample plate 9 is placed on the upper surface, a laser irradiation unit 2 that emits a laser beam, and a sample 90 formed on the sample plate 9 while reflecting the laser beam. And a reflecting mirror 3 for collecting light. However, the ion source 10 is not limited to the MALDI ion source, and may be, for example, a laser desorption ion source, a desorption electrospray ion source, a plasma desorption ion source, or the like.

  A mass analysis unit 20 is disposed above the stage 1. The mass analysis unit 20 includes a flight tube 4 forming a free flight space V of ions therein, and an ion detector 5. Further, between the stage 1 and the mass analysis unit 20, an extraction electrode 6 for forming an electric field for extracting ions generated from the sample 90 upward from the vicinity of the generation position by being irradiated with laser light; An acceleration electrode 7 is provided to apply acceleration energy to the extracted ions. Specifically, the acceleration electrode 7 is, for example, an insulating spacer 72 disposed between a plurality of (generally, three) electrodes 71 arranged along the flight path F of ions and the adjacent electrodes 71. And (so-called Einzel lens). In the illustrated example, two ring-shaped insulating spacers 72 having different diameters are provided between the adjacent electrodes 71.

  The operation of the mass spectrometer 100 will be described. The sample 90 is mounted on the sample plate 9 in advance with a matrix that is a substance that easily absorbs and ionizes laser light. The sample contained in the sample 90 is ionized by irradiating the sample 90 placed on the sample plate 9 with the laser light emitted from the laser irradiation unit 2.

  The generated ions are extracted upward by the electric field formed by the extraction electrode 6, are given acceleration energy by the acceleration electrode 7, and are introduced into the flight tube 4. The ions introduced into the flight tube 4 fly freely in the free flight space V without being affected by the electric field and reach the ion detector 5. In the free flight space V, ions with smaller mass-to-charge ratios have higher flight speeds, so among various types of ions that have started flight almost simultaneously, the ions with smaller mass-to-charge ratios are sequentially reached the detector 5 and detected. It will be.

  As described above, in the mass analysis unit 20, various ions accelerated substantially simultaneously by the electric field are introduced into the free flight space V formed in the flight tube 4, and fly in the free flight space V to reach the ion detector 5. Various ions are separated according to mass (strictly, mass-to-charge ratio m / z) according to the time (flight time) until In the ion detector 5, a detection signal corresponding to the amount of ions to be reached is continuously obtained. Therefore, after converting the flight time to mass, the mass spectrum with the horizontal axis as the mass axis and the vertical axis as the signal intensity axis is Can be created.

<2. Members arranged along the flight path F of ions>
As described above, in the mass spectrometer 100, various members are disposed along the flight path F of ions. A member disposed along the flight path F of ions is often a member used to form, for example, a flight space of ions, and the length of the member (length along the flight path F of ions; In the description of the term “length”, it is often a problem that “the length along the flight path F of the ion” changes depending on temperature unless otherwise noted. For example, the insulating spacer 72 of the flight tube 4 and the acceleration electrode 7 corresponds to such a member.

  For example, the identification of the mass to charge ratio m / z based on the time of flight can not be made accurate unless the flight distance at which the ions fly freely is constant. Therefore, if the length of the flight tube 4 changes with temperature, the mass-to-charge ratio m / z can not be identified accurately.

  Also, for example, in the acceleration electrode 7, if the distance between the plurality of (three in the illustrated example) electrodes 71 arranged along the flight path F of the ions is not constant, the lens action (for example, acceleration) determined for the ions You will not be able to give Therefore, even when the length of the insulating spacer 72 disposed between the electrodes 71 changes due to temperature, the mass-to-charge ratio m / z can not be identified accurately.

  In the mass spectrometer 100, each of the flight tube 4 and the insulating spacer 72, which are members disposed along the flight path F of the ion and whose length is a problem that changes with temperature, is a first portion And the second part formed next to the first part along the flight path F of the ions and formed of a material different from the first part, so that its length is prevented from changing due to temperature doing. Hereinafter, specific configurations of the flight tube 4 and the insulating spacer 72 will be described.

<2-1. Flight tube 4>
A side sectional view of the flight tube 4 is schematically shown in FIG. As shown here, the flight tube 4 is formed by bringing the first portion 41 and the second portion 42 into contact with each other along the extending direction (that is, along the flight path F of the ions). ing. That is, each of the first portion 41 and the second portion 42 is in the form of a straight cylinder, and is disposed such that the central axes thereof coincide with each other. One end of the first portion 41 and one end of the second portion 42 Are joined by welding, for example.

One of the material forming the first portion 41 (hereinafter referred to as "first material") and the material forming the second portion 42 (hereinafter referred to as "second material") is a material having a positive coefficient of linear expansion. And the other is a material having a negative coefficient of linear expansion. As a material having a negative coefficient of linear expansion, specifically, bismuth lanthanide nickel oxide _{(Bi 1-x Ln x NiO} 3), bismuth-nickel-iron oxide _{(BiNi 1-x Fe x O} 3) , Silicon oxide, manganese nitride, nickel oxide, zirconium tungstate, tungsten oxide, aluminum titanate, iron oxide, carbon fiber, and the like.

The length of the first portion 41 along the flight path F of ions (denoted "L1") and the length of the second portion 42 along the flight path F of ions (denoted "L2") are the first material Of linear expansion coefficient (linear expansion coefficient along the flight path F) is α1, and linear expansion coefficient of the second material (linear expansion coefficient along the flight path F) is α2,
L1 × α1 + L2 × α2 = 0 (Equation 1)
It is set to be In the case where the linear expansion coefficient is given by “α = (dL / dθ) / L ₀ ” (where θ is temperature, L is length, L ₀ is length at 0 ° C.), and (Expression 1) L1 is the length at 0 ° C. of the first portion 41, and L2 is the length at 0 ° C. of the second portion 42.

Therefore, as shown in the figure, when the length of the first portion 41 is increased by, for example, thermal expansion due to, for example, a temperature change Δθ, the length of the second portion 42 is increased by the same ΔL due to thermal contraction. It becomes short (ΔL = L1 × α1 × Δθ = −L2 × α2 × Δθ). That is, the thermal expansion width of the first portion 41 is offset by the thermal contraction width of the second portion 42, and the overall length of the flight tube 4 does not change. Since the length of the flight tube 4 does not change with temperature, the flight distance of the ions can be maintained constant. Therefore, in the mass spectrometer 100, various ions can be accurately separated at every mass-to-charge ratio m / z according to the time of flight.

  Here, in the flight tube 4, for example, the thickness of the first portion 41 (the thickness in the direction orthogonal to the length direction, and the same applies to the following) d1 and the thickness d2 of the second portion 42 are adjusted to each other. The heat capacity of the first portion 41 and the heat capacity of the second portion 42 are equal.

  Therefore, when the ambient temperature changes, for example, from θ1 to θ2, the speed of the temperature change of the first portion 41 matches the speed of the temperature change of the second portion 42. That is, not only the time zone in which the temperature of each portion 41 and 42 is constant (time zone of equilibrium state), but also the time zone in which the temperature of each section 41 and 42 is changing (time zone of non-equilibrium state) However, the temperatures of the first portion 41 and the second portion 42 are always almost equal. If the heat capacities of the first portion 41 and the second portion 42 are largely different, one of them heats up (or cools down) faster than the other, so that one shrinks faster (or thermal expansion) than the other. The timing at which the entire length of the flight tube changes may appear, but here the timing does not appear because the heat capacities of the first portion 41 and the second portion 42 are equal. That is, the entire length of the flight tube 4 is always kept constant.

2-2. Insulating spacer 72>
A partial side sectional view of the acceleration electrode 7 is schematically shown in FIG. As described above, the acceleration electrode 7 is an insulating spacer disposed between the three electrodes 71 arranged along the extension direction (that is, along the flight path F of the ions) and the adjacent electrodes 71. And 72. The insulating spacer 72 is a member for positioning while insulating each electrode 71.

  The insulating spacer 72 is formed by bringing the first portion 721 and the second portion 722 into contact along the extending direction (that is, along the flight path F of the ions). That is, each of the first portion 721 and the second portion 722 is a ring-shaped member having a uniform thickness, for example, in a plan view, and one main surface of the first portion 721 and one main surface of the second portion 722 And are joined by welding, for example.

  Also in the insulating spacer 72, as in the flight tube 4, one of the material forming the first portion 721 (first material) and the material forming the second portion 722 (second material) has a positive coefficient of linear expansion. The other is a material having a negative coefficient of linear expansion. The length of the first portion 721 along the flight path F of ions (denoted "L1") and the length of the second portion 722 along the flight path F of ions (denoted "L2") are Assuming that the linear expansion coefficient of one material (linear expansion coefficient along the flight path F) is α1, and the linear expansion coefficient of the second material (linear expansion coefficient along the flight path F) is α2, the above (Equation 1) is It is set to be established. Here, for convenience of explanation, the length of the first portion 721 is indicated by L1 and the length of the first portion 41 of the flight tube 4 is also indicated by L1 in the above, but the first portion of the insulating spacer 72 It goes without saying that the length 721 and the length of the first portion 41 of the flight tube 4 may be different from each other. The same applies to L2. The same applies to the following description.

Therefore, as shown in the figure, when the length of the first portion 721 is lengthened by, for example, thermal expansion due to temperature change Δθ, for example, the length of the second portion 722 is the same length ΔL due to thermal contraction. It becomes short (ΔL = L1 × α1 × Δθ = −L2 × α2 × Δθ). That is, the thermal expansion width of the first portion 721 is offset by the thermal contraction width of the second portion 722, and the entire length of the insulating spacer 72 does not change. Since the length of the insulating spacer 72 does not change with temperature, the uniformity of the distance between the electrodes 71 is ensured. Therefore, the defined action can be accurately given to the flying ions.

  Also in the insulating spacer 72, as in the flight tube 4, for example, the cross-sectional area of the first portion 721 (the cross-sectional area cut in the direction orthogonal to the length direction, the same applies hereinafter) and the cross-sectional area of the second portion 722 It is preferable that the heat capacity of the first portion 721 and the heat capacity of the second portion 722 be equalized by adjustment. According to this configuration, as described above, not only in the time zone in which the temperature of each portion 721 and 722 is constant, but also in the time zone in which the temperature of each portion 721 and 722 changes, The temperature with the two portions 722 is always approximately equal, and the entire length of the insulating spacer 72 (and hence the distance between the electrodes 71) is always kept constant.

<2-3. Insulating spacer 72a>
FIG. 4 schematically shows a partial side sectional view of the acceleration electrode 7a including the insulating spacer 72a according to another aspect. Similarly to the insulating spacer 72 described above, the insulating spacer 72a is also brought in contact with the first portion 721a and the second portion 722a along the extending direction (that is, along the flight path F of the ions). It is formed.

Similarly to the insulating spacer 72 described above, one of the material (first material) for forming the first portion 721a and the material (second material) for forming the second portion 722a of the insulating spacer 72a also has a linear expansion coefficient The other is a material having a negative coefficient of linear expansion. The length of the first portion 721a along the flight path F of ions (denoted "L1") and the length of the second portion 722a along the flight path F of ions (denoted "L2") are The linear expansion coefficient (linear expansion coefficient along the flight path F) of one material is α1, the linear expansion coefficient of the second material (linear expansion coefficient along the flight path F) is α2, the ions 71 along the flight path F When the length is L3 and the linear expansion coefficient of the electrode 71 (linear expansion coefficient along the flight path F) is α3, then
L1 × α1 + L2 × α2 + L3 × α3 = 0 (Equation 2)
It is set to be

Therefore, for example, when the length of the first portion 721a is increased by ΔL1 due to, for example, thermal expansion due to a temperature change Δθ, and the length of the electrode 71 is increased by ΔL3 due to, for example, thermal expansion, the length of the second portion 722a The width ΔL2 which is shortened due to heat contraction coincides with ΔL1 + ΔL3 (−ΔL2 = −L2 × α2 × Δθ = L1 × α1 × Δθ + L3 × α3 × Δ3 = ΔL1 + ΔL3). That is, even if the electrode 71 expands (or contracts) due to temperature change, the uniformity of the distance between the electrodes 71 is secured. Therefore, the defined action can be accurately given to the flying ions.

  In the insulating spacer 72a, for example, the heat capacity of the first portion 721a, the heat capacity of the second portion 722a, and the heat capacity of each electrode 71 are adjusted by adjusting the cross-sectional area of the first portion 721a and the cross-sectional area of the second portion 722a, respectively. It is preferable that and are equal. According to this configuration, not only in the time zone in which the temperature of each portion 721a and 722a and each electrode 71 is constant, but also in the time zone in which the temperature of each portion 721a and 722a and each electrode 71 changes. The temperature of the portion 721a, the second portion 722a, and each electrode 71 is always approximately equal, and the distance between the electrodes 71 is always kept constant.

<3. Other Embodiments>
Although the mass spectrometer 100 according to the above embodiment is a mode (so-called linear TOFMS) in which ions are caused to fly linearly in the free flight space V, the present invention is of a type in which the flight trajectory of ions is reversed. The present invention can also be applied to a mass spectrometer (so-called reflectron TOFMS) or a mass spectrometer (so-called multi-turn TOFMS) of a type in which ions are caused to repeatedly fly along a circular orbit.

  FIG. 5 schematically shows an example of the configuration of a mass spectrometer 100a of the type in which the flight trajectory of ions is reversed. In the figure, the same elements as the elements of the mass spectrometer 100 according to the above embodiment are indicated by the same reference numerals and the description thereof will be omitted.

  The mass spectrometer 100 a includes a reflectron (reflector) 8 that causes ions to fly back by the action of a direct current electric field. Specifically, the reflectron 8 has, for example, a structure in which a plurality of plate-like electrodes 81 having a hole formed in the center are arranged at regular intervals via insulating spacers 82. Then, for example, a voltage is applied to each of the electrodes 81 such that the potential increases with distance from the ion source 10 based on the potential distribution by the electrical resistance. As a result, a gradient electric field is formed in the interior of the reflectron 8, and the ions flying in the free flight space V linearly and reaching the interior of the reflectron 8 are reflected by the gradient electric field.

  In the same way as the flight tube 4 and the insulating spacer 72 described above, the insulating spacer 82 included in the reflectron 8 is also disposed along the flight path F of ions, and a member whose length varies with temperature is a problem. is there. Therefore, by forming this insulating spacer 82 from the first portion and the second portion which is disposed adjacent to the first portion along the flight path F of the ions and is formed of a material different from the first portion, It is avoided that the length changes with temperature.

  Specifically, the insulating spacer 82 is formed by bringing the first portion 821 and the second portion 822 into contact along the extending direction (that is, along the flight path F of the ions). . That is, each of the first portion 821 and the second portion 822 is a ring-shaped member having a uniform thickness, for example, in a plan view, and one main surface of the first portion 821 and one main surface of the second portion 822 And are joined by welding, for example.

Also in the insulating spacer 82, as in the flight tube 4 etc., one of the material forming the first portion 821 (first material) and the material forming the second portion 822 (second material) has a positive coefficient of linear expansion. The other is a material having a negative coefficient of linear expansion. The length of the first portion 821 along the flight path F of ions (denoted "L1") and the length of the second portion 822 along the flight path F of ions (denoted "L2") are Assuming that the linear expansion coefficient of one material (linear expansion coefficient along the flight path F) is α1, and the linear expansion coefficient of the second material (linear expansion coefficient along the flight path F) is α2, the above (Equation 1) is It is set to be established. Therefore, even if the temperature changes, the entire length of the insulating spacer 82 does not change, and the uniformity of the distance between the electrodes 81 is secured.

  The length L1 of the first portion 821 along the flight path F of ions and the length L2 of the second portion 822 along the flight path F of ions are the linear expansion coefficient of the first material (along the flight path F). Linear expansion coefficient α1; linear expansion coefficient of the second material (linear expansion coefficient along flight path F) α2; length of each electrode 81 along ion flight path F L3: linear expansion coefficient of electrode 81 When the linear expansion coefficient) along the flight path F is α3, the above (Equation 2) may be set to hold. In this case, as described above, even if the electrode 81 expands (or contracts) due to a temperature change, the uniformity of the distance between the electrodes 81 is secured.

  Also in the insulating spacer 82, for example, by adjusting the cross sectional area of the first portion 821 and the cross sectional area of the second portion 822 to each other, the heat capacity of the first portion 821 and the heat capacity of the second portion 822 are equal. Is preferred. According to this configuration, as described above, since the temperatures of the first portion 821 and the second portion 822 are always secured to be substantially equal, the entire length of the insulating spacer 82 is always kept constant.

  Further, by adjusting the cross-sectional area of the first portion 821 and the cross-sectional area of the second portion 822 respectively, the heat capacity of the first portion 821 and the heat capacity of the second portion 822 become equal to the heat capacity of each electrode 81. Is also preferable. According to this configuration, as described above, since the temperatures of the first portion 821, the second portion 822, and the electrode 81 are ensured to be almost equal at all times, the distance between the electrodes 81 is always kept constant.

DESCRIPTION OF SYMBOLS 1 stage 2 laser irradiation part 3 reflective mirror 4 flight tube 41 1st part 42 2nd part 5 ion detector 6 lead-out electrode 7, 7a acceleration electrode 71 electrode 72, 72a insulation spacer 721, 721a 1st part 722, 722a 2nd Part 8 Reflectron 81 Electrode 82 Insulating spacer 821 First part 822 Second part 10 Ion source 20 Mass spectrometer 100, 100a Mass spectrometer L1 Length L2 of first part along flight path Second part of flight Path of length L3 electrode along the flight path Length α1 of the first material along the flight path Linear expansion coefficient α2 of the second material along the flight path Line of linear expansion coefficient α3 of the second material along the flight path Expansion rate F flight path

Claims (4)

A member of a mass spectrometer which separates and accelerates ions accelerated by an electric field and detects each mass-to-charge ratio according to the time of flight to reach a detector, and which is disposed along the flight path of ions There,
A first portion of L1 along the flight path;
It consists of a second part of the length L2 along the flight path, which is arranged next to the first part along the flight path and is made of a material different from the first part,
The length L1 and the length L2 are
Assuming that the linear expansion coefficient of the forming material of the first portion along the flight path is α1, and the linear expansion coefficient of the forming material of the second portion along the flight path is α2.
L1 × α1 + L2 × α2 = 0
Is set in such a way that,
A member for a mass spectrometer , wherein a heat capacity of the first part and a heat capacity of the second part are equal . It is a member for mass spectrometry according to claim 1 ,
The member is
A member for a mass spectrometer characterized in that it is a flight tube that forms free flight space of ions inside. It is a member for mass spectrometry according to claim 1 ,
The member is
A member for a mass spectrometer, which is an insulating spacer disposed between a plurality of electrodes arranged along the flight path. A plurality of mass analyzers arranged along the flight path of ions in a mass spectrometer which separates and accelerates ions accelerated by an electric field and detects each mass-to-charge ratio according to the time of flight to reach the detector. An insulating spacer disposed between the electrodes,
A first portion of L1 along the flight path;
It consists of a second part of the length L2 along the flight path, which is arranged next to the first part along the flight path and is made of a material different from the first part,
The length L1 and the length L2 are
The linear expansion coefficient of the forming material of the first portion along the flight path is α1, the linear expansion coefficient of the forming material of the second portion along the flight path is α2, and the length of the electrode along the flight path is L3 When the linear expansion coefficient along the flight path of the electrode is α3,
L1 × α1 + L2 × α2 + L3 × α3 = 0
Is set in such a way that,
An insulating spacer , wherein a heat capacity of the first part, a heat capacity of the second part, and a heat capacity of the electrode are equal .

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