Method and apparatus

Abstract

One aspect of the present disclosure provides a method of reducing electrical measurement noise in a detection device configured to detect ion arrival at a collector electrode wherein the detection device includes an air conveyor providing an air flow in the device, the method includes operating the air conveyor at an operating level to provide the flow of air; reducing operation of the air conveyor during a quiet period; and operating the detection device to allow ions to travel to be detected by the collector electrode during the quiet period.

Description

Technical Field

[0001] This invention relates to methods and apparatus, and more particularly to methods and apparatus for detecting ions, which can be used in systems for detecting and / or analyzing substances of interest. More specifically, this disclosure relates to methods and apparatus for reducing measurement noise when detecting ions at a collector electrode. Background Technology

[0002] Various systems, such as physical measurement and trace detection devices, spectrometers, and other types of physical instruments, rely on the detection of charge to sense ions arriving at the detector's electrodes. These electrodes can be referred to as collector electrodes.

[0003] Examples of such systems include ion mobility spectrometers and mass spectrometers. One example of a type of mass spectrometer is the so-called "time-of-flight" mass spectrometer, TOF-MS. Various such systems exist.

[0004] Ion mobility spectrometry (IMS) identifies materials from a sample of interest by ionizing them (e.g., molecules, atoms, etc.) and measuring the time it takes for the resulting ions to travel a known distance through a countercurrent of drift gas under a known electric field. Typically, this time is measured from the time the ion gate (which may also be called the ion gate) opens to the time it takes for the ions to reach a detector such as a Faraday cup.

[0005] The time of flight of each ion is related to its mobility. Ion mobility is related to its mass and geometry. Therefore, by measuring the time of flight of an ion, its identity can be inferred. These times of flight can be displayed digitally and / or graphically as a spectrum.

[0006] Some IMS units include detectors that collect ions to measure their time of flight, making them identifiable. This can be done in the presence of drift gas, allowing the migration effect to separate the ions. Ion mobility spectrometers typically include at least some electromechanical actuators and other types of actuators, including motors. These can be used for things like operating fans and air conveyors, as well as other types of air boosters. These can be used to provide a flow of drift gas through the drift chamber and to operate a pressure pulse generator, which is used for sampling using a pinhole or other type of sampling inlet. Various types of IMS devices exist—including some types of differential mobility spectrometers (DMS) and field asymmetric IMS devices (FAIMS)—where the mechanisms for resolving mobility characteristics differ. Many of these also have mechanical components, for reasons similar to those outlined above.

[0007] Time-of-flight mass spectrometry (TOF-MS) can measure mass-to-charge ratio by the time it takes for a substance to travel through a chamber under an electric field, without the presence of drift gas. Typically, a mass spectrometer includes at least some electromechanical actuators and other types of actuators, including motors for air delivery functions such as the operation of a vacuum pump, providing sample flow, and other applications. Summary of the Invention

[0008] The aspects and examples of the invention are set forth in the claims and are intended to solve the problem of measurement noise caused by mechanical vibrations in detection devices such as ion mobility spectrometers and mass spectrometers.

[0009] In one aspect, a method for reducing electrical measurement noise in a detection device configured to detect ions arriving at a collector electrode is provided, wherein the detection device includes an air conveyor for providing an airflow within the device, the method comprising: The air booster is operated at the operating level to provide the airflow; Reduce the operation of the air conveyor for a quiet period; and The detection device is operated to allow ions to travel so that they can be detected by the collector electrodes during the quiet period.

[0010] The collector electrode may have capacitance that is affected by mechanical vibrations caused by the air delivery system. For example, one or more capacitive elements (e.g., conductive elements and / or charge-carrying elements) may be assembled with the collector electrode. Mechanical vibrations of this assembly may cause corresponding changes in the collector electrode capacitance. Airflow can be associated with the operation of the detection device, for example, it may perform functions upon which the detection method used by the device depends. As an example, it may provide airflow through the pneumatic system of the device, for example, it may be used to provide a drift gas flow in an IMS system. As another example, it may operate a pump to provide a depressurization zone, such as the vacuum chamber of a TOF-IMS system.

[0011] The quiet period can begin during the waiting period before the detection equipment is operated. The waiting period can be selected to allow changes in the collector's capacitance caused by vibrations from the air conveyor to the collector to be reduced below a threshold level.

[0012] Pressure pulsers can be used to move samples of gaseous fluid through a sampling inlet, such as a pinhole, into a detector. The operating amplitude of a pressure pulser can be reduced during quiet periods compared to when the air delivery system is operating at its normal operating level.

[0013] After the quiet period ends, the air delivery system can be increased to return to the operating level.

[0014] This method may include performing a series of operating cycles of the detection device during quiet periods. For example, a sample of gaseous fluid may be obtained via a sampling inlet (e.g., by operation of a pressure pulser) prior to the series of cycles. An ionizer may be operated to generate ions from the sample at the start of each cycle. The method may include maintaining reduced operation of the air delivery system throughout the series of cycles and operating the air delivery system at an operational level prior to obtaining any subsequent samples via the sampling inlet.

[0015] This method may include performing only a single cycle of operating the detection device during a quiet period, and then operating the air conveyor at the operating level before subsequent operating cycles of the detection device.

[0016] This can include obtaining a sample of the gaseous fluid through the sampling inlet before a series of operating cycles of the ion mobility spectrometer, and providing a series of quiet periods corresponding to the series of operating cycles of the ion mobility spectrometer. The air delivery system can return to the operating level between each operating cycle. The air delivery system is in the operating level before obtaining any subsequent sample through the sampling inlet.

[0017] In one aspect, a controller for a detection apparatus is provided, the controller comprising: a control interface for controlling an air delivery unit of the detection apparatus, and for operating the detection apparatus to allow ions to travel for detection by a collector electrode. The controller may be configured to perform any one or more of the methods described herein.

[0018] One aspect of this disclosure includes configuring a controller of a detection device to perform any or more of the methods described herein. Embodiments of this disclosure provide a computer program product configured to program a programmable processor (e.g., a controller of a detection device) to perform any of the methods described or claimed herein. Such a computer program may be encoded in a tangible, non-transitory computer-readable storage medium.

[0019] One aspect of this disclosure provides a detection device including such a controller.

[0020] This disclosure also provides a detection device, including: A collector electrode assembly for detecting ions, wherein the collector electrode assembly is subjected to capacitance changes due to mechanical vibration; The chamber, along which ions travel to reach the collector electrode for detection; A controller is configured to operate the detection device to provide ions that will be detected by the collector device during quiet periods. During the static period, the mechanical vibration of the collector electrode is reduced.

[0021] The controller can be configured to suppress the operation of at least one vibration source of the detection device to provide the reduced mechanical vibration. Vibration sources include air conveyors, such as fans, pumps, or blowers.

[0022] Air delivery systems can be operated to provide airflow into and / or out of a room.

[0023] The detection device may include an ion mobility spectrometer (IMS) unit, with an airflow provided along the drift chamber of the IMS unit, and ions traveling in the drift chamber to be detected by the collector electrode.

[0024] Detection equipment may include mass spectrometers, such as time-of-flight mass spectrometers (TOF-MS), which include a depressurization chamber, an air delivery system that operates to reduce the air pressure inside the chamber, and ions that travel within the depressurization chamber to a collector electrode.

[0025] The controller can be configured to reduce the operation of the air conveyor to provide a quiet period. For example, the controller can be configured such that the quiet period begins during a waiting period prior to the operation of the detection device to provide ions. The controller can be configured such that the waiting period is long enough to allow changes in the collector capacitance caused by collector vibration by the air conveyor to be reduced below a threshold level.

[0026] The controller can be configured to increase the operation of the air conveyor after quiet periods. For example, it can revert the operation of the air conveyor to the level it normally operates to provide the functionality of the detection equipment.

[0027] The detection device may include one or more capacitive elements, such as conductive or charge-carrying elements. Such elements can be capacitively coupled to the collector electrode. For example, these elements can be assembled close enough around the collector electrode to make a significant contribution to the capacitance of the collector electrode. An example of such an element is a shielding electrode, which is arranged to shield the collector electrode from the electric field from the ions, and the change in capacitance is associated with a vibrational change in the spacing between the shielding electrode and the collector electrode.

[0028] The quiet periods described herein can be provided by reducing the operation of the air conveyor, which can be achieved by reducing the power or speed of the air conveyor operation. This can be done by shutting down the air conveyor or otherwise stopping its operation. Attached Figure Description

[0029] Embodiments of this disclosure will now be described in detail with reference to the accompanying drawings, in which: Figure 1 A cross-sectional view of an ion mobility spectrometer is shown; Figure 2 It shows in such as Figure 1 or Figure 5 A flowchart of a method for reducing measurement noise in the detection device shown; Figure 3 It shows in such as Figure 1 or Figure 5 Another flowchart of a method for reducing measurement noise in the detection device shown; Figure 4 It shows in such as Figure 1 or Figure 5 Another flowchart of a method for reducing measurement noise in the detection equipment shown; Figure 5 A highly schematic view of different testing equipment is shown.

[0030] In the accompanying drawings, the same reference numerals are used to denote the same elements. Detailed Implementation

[0031] The embodiments described below present different types of detection devices in which the methods of this disclosure can be implemented. These methods offer particular advantages in detection devices that include ion mobility spectrometry measurement capabilities, where a collector electrode can be used to detect the arrival of ions, and where mechanical vibration of the collector electrode can generate particular problems of vibration-induced capacitance fluctuations. This is especially likely to occur in systems where components surrounding the collector electrode include conductive elements. The embodiments also offer significant advantages in mass spectrometry analysis devices, where a considerable structure can exist and can withstand considerable mechanical vibration.

[0032] Therefore, embodiments of this disclosure provide quiet periods during which mechanical vibrations of the collector electrode assembly are reduced, and the detection device is operated to allow ions to travel for detection by the collector electrodes during the quiet periods. Various implementations are being considered, as will become apparent in the following disclosure.

[0033] Figure 1 The ion mobility spectrometer includes a reaction zone 102, an ionization source 104 for ionizing the gaseous fluid in the reaction zone 102, an ion gate 105, a collector electrode 118 such as a Faraday cup, and a controller 120. The ion mobility spectrometer also includes a drift zone 103, drift electrodes 103a and 103b, a screen grid 117, an air conveyor 122, a drift gas inlet 119, and a drift gas outlet 121.

[0034] The spectrometer includes a housing, such as tube 101. A reaction zone 102 is located inside one end of the housing 101 and is separated from the collector electrode 118 by a drift zone 103. The reaction zone 102 is separated from the drift zone 103 by an ion gate 105. The housing 101 includes an inlet 108 for allowing a sample of gaseous fluid (e.g., vapor and / or gas and / or aerosol) to be introduced into the reaction zone 102.

[0035] An ionization source 104 is disposed within the housing and is used to generate ions to ionize the gaseous fluid sample in the reaction zone 102. Figure 1 In the example shown, ionization source 104 includes a corona point. Embodiments of this disclosure may use a dual-point corona ionization source.

[0036] A voltage distribution can be provided in the drift region 103 using a series of drift electrodes 103a, 103b spaced apart along the drift region 103. Although Figure 1 Not shown, a reflector or other electrodes may be arranged to extend the voltage distribution into the reaction region 102. Between the reaction region 102 and the detector 118, the distributed voltage varies spatially (e.g., with displacement along the cell in the drift direction) to provide an electric field that moves ions along the cell 100 toward the collector 118. The electric field along the drift region 103 and / or the reaction region 102 may be uniform and / or known.

[0037] A screen grid 117 is disposed between the drift region and the collector electrode, and is typically closely adjacent to the collector electrode. It is connected to a controller 120. The controller is configured to maintain the voltage of the screen grid 117 at a selected electrothermal level to protect the collector electrode 118 from mirror charge effects associated with ions approaching the collector electrode from the drift region 103. To help prevent peak broadening, the screen grid 117 is typically positioned close to the collector electrode 118, and is typically positioned parallel to the collector electrode. The screen grid may extend along the axis of the drift chamber across a portion of the center of the collector electrode. For example, the screen grid may substantially cover the entire collector electrode to protect it from mirror charge effects from approaching ions.

[0038] As a result, the screen gate is one of the largest contributors to the collector electrode capacitance. However, other contributions may exist to this capacitance, such as those related to any other conductive and / or charge-carrying elements in the assembly surrounding the collector electrode but not at the same DC potential. This assembly may be referred to herein as the collector electrode assembly. The capacitance of the collector electrode assembly can be generated by the screen gate and / or other conductive and / or charge-carrying elements mounted sufficiently close to the collector electrode assembly, which significantly contribute to the apparent capacitance of the collector electrode.

[0039] The controller 120 is also connected to control the air conveyor 122. The air conveyor 122 typically includes a fan, pump, or air conveyor or other suitable air delivery device. It is connected to the drift air inlet via an air circulation system, such as a suitable duct. Typically, the air conveyor is mounted in or to the detector such that mechanical vibrations generated by the operation of the air conveyor can be transmitted to the collector assembly through the detection device itself.

[0040] The controller 120 operates the air conveyor 122 to supply a drift gas flow into the drift zone via the drift gas inlet. The drift gas then flows downwards from the collector electrode 118 toward the reaction zone 102 along the drift zone 103. It exits the drift zone via the drift gas outlet, from where it can be recycled back to the air conveyor. The drift gas may also pass through a cleaning and / or drying stage, such as using molecular sieves.

[0041] The operation of the air delivery unit 122 can be a source of mechanical vibration, which can be transmitted through the body of the ion mobility spectrometer to the collector electrode 118 and / or surrounding components including conductive or charge-carrying elements. These vibrations can cause relative displacement between these elements and the collector electrode. As a result, the capacitance of the collector electrode can exhibit corresponding changes due to the dependence of capacitance on spacing.

[0042] Ion gate 105 includes two electrodes 106 and 107 coupled to controller 120 to provide a barrier voltage between the two electrodes 106 and 107. When gate 105 is “closed,” this barrier voltage prevents ions from moving from the reaction region into the drift region of the IMS, and in the open state, ions can move toward the detector into the drift region. Ion gate 105 may include a Tyndall-Powell, Bradbury-Nielsen, or other type of gate. Gate electrodes 106 and 107 may each include an elongated conductor, and the elongated conductor of the first gate electrode 106 may be aligned with the elongated conductor of the second gate electrode 107 in the drift direction. The elongated conductors of each gate electrode 106 and 107 may be arranged as a grid, such as a mesh, for example, triangular, rectangular, hexagonal, or other regular or irregular grid. Gate electrodes 106 and 107 do not need to be separated in the drift direction. For example, they can be coplanar, in which case the slender conductors can be intersecting each other, for example, they can be interleaved or interwoven.

[0043] The controller 120 may include a control interface for controlling the air delivery unit and other parts of the IMS unit. Examples of the control interface may include serial or parallel interfaces, as well as synchronous and asynchronous interfaces. Through these or other means, the controller 120 is connected to the ion gate 105 and the collector electrode for sensing ions arriving at the collector electrode. The controller 120 may also be connected to operate the ionization source 104.

[0044] Now refer to Figure 2 Describe the operation of the device. A sample of a gaseous fluid (e.g., vapor) is provided to the reaction zone. This can be accomplished by operating a pressure pulser or other device or sampling. Controller 120 provides pulses or a sequence of pulses to ionization source 104 to generate ions. These ions are mixed with the sample to produce sample ions. During this process, controller 120 operates air delivery device 200 at an operating level to provide an airflow along drift chamber 103. This airflow can be used to keep the drift chamber “clean,” for example, by inhibiting the flow or diffusion of neutral samples from the reaction zone into the drift chamber.

[0045] The controller 120 then provides a quiet period 202 during which mechanical vibration of the collector electrodes (and / or any surrounding components that contribute to their apparent capacitance) is reduced. This can be achieved by reducing the operation of the air conveyor and / or other sources of mechanical vibration. One way to do this is to reduce the operating speed or power of the air conveyor. This can be achieved simply by shutting it off, but merely reducing the operating speed / power is sufficient to reduce vibration, so the air conveyor does not always need to be completely shut off. This reduced operation of the air conveyor provides the quiet period.

[0046] During this quiet period, controller 120 can operate detection device 204 to allow ions to travel for detection by collector electrode 118.

[0047] In a typical operating cycle, after a gate delay (following the operation of the ionizer), controller 120 opens the ion gate to the gate width, allowing the ion cloud to enter drift region 103, where it travels against the drift gas stream to collector electrode 118. As the ions travel along the drift chamber, they become separated due to their different mobilities, causing them to arrive at collector electrode 118 at different times. Collector electrode 118 is connected to the controller, allowing the controller to detect 206 the charge associated with the arrival of ions at collector electrode 118. This signal is used to provide an ion spectrum characterizing the operating cycle of the IMS device. Controller 120 can operate the IMS device to provide a series of such cycles, for example, multiple operating cycles for each sample. The resulting spectra can be combined, for example, by averaging.

[0048] The quiet period can begin with a waiting period before the detection equipment is operated. Typically, the waiting period is chosen to be long enough to reduce vibrations in the collector caused by vibration sources such as air conveyors to below a threshold level. The relevant threshold can be selected based on the specific details of the device and / or the desired measurement accuracy. After an operating cycle (or a series of cycles) has been completed, the controller 120 can return the operation of the air conveyor 122 to the operating level at 208. This can help prevent neutral sample vapor from diffusing or flowing into the drift zone.

[0049] Figure 3 Examples are shown Figure 1 The operating procedure of the apparatus is illustrated. In this method, a pressure pulser (300) is operated to obtain a sample and ionize it. Then, the operation of any vibration source (e.g., an air conveyor) is reduced (302) to provide a quiet period. The spectrometer is then controlled to perform a series of operating cycles (305) before the vibration source returns (308) to its normal operating level. Since these cycles are all taken from a single sample, the spectra obtained from this series of operating cycles can be combined by summing them, for example, to provide an average value.

[0050] Figure 4 Another method of operation is shown. In this method, a pressure pulser is operated at 400 to obtain a sample, and then the operation of any vibration source (e.g., an air conveyor) is reduced at 402. The spectrometer is then controlled to perform an operating cycle at 405 before the vibration source (e.g., the air conveyor) returns to its operating level at 408. The controller can then reduce the operation of the vibration source at 402 again, performing another operating cycle at 405, and then returning the vibration source to its operating level at 408 before each subsequent operating cycle. During the intervals between cycles, additional neutral samples can be introduced into the reaction zone for ionization. When the pressure pulser is used between consecutive quiet periods, the power applied to the pressure pulser can be reduced compared to when the air conveyor is operating at its operating level. Therefore, embodiments of this disclosure can relate to systems in which the operation of an air conveyor providing a drift gas flow is reduced during certain periods, and during these quiet periods, the power level of each operation of the pressure pulser is also reduced compared to the level used when the air conveyor is operating normally.

[0051] Figure 5 Another detection device is shown. Figure 5 The detection device 500 shown is a time-of-flight mass spectrometer (TOF-MS). The device includes a decompression chamber 503, an air delivery system 522, a collector electrode 518, a controller 520, an ion source 506, and an inlet 508. The device 500 also includes an assembly of conductive and / or charge-carrying elements 517 adjacent to the collector electrode.

[0052] Ion source 506 includes the ion source to be analyzed and is connected to depressurization chamber 503 via inlet 508, which may include a capillary inlet or an ion funnel or other suitable means for delivering ions to depressurization chamber 503.

[0053] Air delivery unit 522 is connected to controller 520 and is arranged in fluid communication with pressure reduction chamber 503. Air delivery unit 522 can be operated to reduce the air pressure in pressure reduction chamber 503, for example, in the manner of a vacuum pump.

[0054] Collector electrode 518 is positioned at the end of chamber 503 opposite to inlet 508 for ion detection. The collector electrode and assemblies 518, 517 are subjected to mechanical vibration due to the operation of air conveyor 522. This may cause changes in capacitance.

[0055] Chamber 503 may include a vacuum chamber and may provide one or more electrodes along the chamber to allow ions to travel from the inlet to the collector electrodes for detection. These, along with other components such as a screen grid, may provide assembly 517.

[0056] A controller 520 is connected to operate the ion source 506 with / or inlet 508 for controlling the inlet. Therefore, the controller is operable to allow or prevent ions from entering the depressurization chamber to provide ions that will be detected by the collector electrodes. The controller is also connected to an air delivery system and is operable to control the operation of the air delivery system—for example, to reduce or increase the power / speed of the air delivery system and / or to turn it on and off.

[0057] In operation, air delivery unit 522 operates at an operating level to provide reduced air pressure in the chamber. Then, compared to the operating level, the controller reduces the operation of the air delivery unit, for example, by shutting it off to provide a quiet period. During the quiet period, while mechanical vibrations of the collector electrodes are reduced, the controller operates the inlet to allow ions to enter the depressurized chamber, enabling the ions to travel along the depressurized chamber to the collector electrodes. When the chamber is evacuated or at least under depressurization, the flight time of the ions to the collector provides an indication of their mass-to-charge ratio. A series of such operating cycles can be performed before the controller returns the air delivery unit to its operating level.

[0058] In the context of the above disclosure, it will be understood that various embodiments are conceivable. The principles of this disclosure have been explained with reference to ion mobility spectrometry and time-of-flight mass spectrometry, but they can be applied to other types of detection devices, such as differential mobility spectrometry, field asymmetric IMS (FAIMS) devices, and any other devices in which collector electrodes are used to detect ion arrival. This is particularly advantageous where sensitive measurement of ion arrival time is required. The use of pressure pulsers and pinhole inlets has been described, but other types of inlets, such as membrane inlets, can also be used. Quiet periods have been described by reducing the operation of vibration sources, but in some embodiments, vibration of the collector electrode can be reduced by applying counter-vibration to the collector electrode assembly. For example, a controller may be connected to a vibration provider and configured to detect vibration of the collector assembly, and also configured to control the vibration provider to apply compensating vibrations, such as vibrations opposite in phase to the detected vibrations. These embodiments may employ active noise cancellation principles and other active methods to reduce vibration of the collector electrode and / or any surrounding conductive or charge-carrying elements assembled therewith.

[0059] In the context of this disclosure, various other embodiments will be apparent to those skilled in the art. Any feature of any of the examples disclosed herein may be combined with any selected features of any of the other examples described herein. For example, features of a method may be implemented in appropriately configured hardware, and the specific hardware configuration described herein may be adopted in a method implemented using other hardware.

[0060] From the foregoing discussion, it will be understood that the embodiments shown in the figures are merely exemplary and include features that can be generalized, removed, or replaced as described herein and in the claims. Referring generally to the accompanying drawings, it will be understood that the schematic functional block diagrams are used to indicate the functionality of the systems and devices described herein. However, it will be understood that functionality need not be divided in this way and should not be construed as implying any particular hardware architecture other than the hardware described and claimed below. The functionality of one or more elements shown in the figures may be further subdivided and / or distributed throughout the device of this disclosure. In some embodiments, the functionality of one or more elements shown in the figures may be integrated into a single functional unit.

[0061] In some examples, the functionality of the controller may be provided by a general-purpose processor that can be configured to perform any of the methods described herein. In some examples, the controller may include digital logic, such as a field-programmable gate array (FPGA), FPGA, application-specific integrated circuit (ASIC), digital signal processor (DSP), or any other suitable hardware. In some examples, one or more memory elements may store data and / or program instructions for implementing the operations described herein. Embodiments of this disclosure provide a tangible, non-transitory storage medium including program instructions operable to program a processor to perform any one or more of the methods described and / or claimed herein and / or to provide data processing apparatus as described and / or claimed herein. The controller may include analog control circuitry that provides at least a portion of the control functionality. An embodiment provides an analog control circuitry configured to perform any one or more of the methods described herein.

[0062] The above embodiments should be understood as illustrative examples. Further embodiments are conceivable. It should be understood that any feature described with respect to any embodiment can be used alone or in combination with other described features, and can also be used in combination with one or more features of any other embodiment, or in any combination with any other embodiment. Furthermore, equivalents and modifications not described above may be employed without departing from the scope of the invention as defined in the appended claims.

Claims

1. A method for reducing electrical measurement noise in a detection device configured to detect ions arriving at a collector electrode, wherein the detection device includes an air conveyor for providing an airflow within the device, the method comprising: The air conveyor is operated at the operating level to provide the airflow; Reduce the operation of the air conveyor for a quiet period of time; as well as The detection device is operated to allow ions to travel so that they can be detected by the collector electrodes during the quiet period.

2. The method according to claim 1, wherein, The quiet period begins during the waiting period before the detection equipment is operated.

3. The method according to claim 2, wherein, The waiting period is selected to allow changes in the collector's capacitance caused by vibrations from the air conveyor to the collector to be reduced below a threshold level.

4. The method according to claim 2 or 3, wherein, During the quiet period, a pressure pulse is used to move the sample into the detector with a reduced amplitude.

5. The method according to any one of the preceding claims, comprising increasing the operation of the air delivery unit to the operating level after the quiet period.

6. The method according to any one of claims 1 to 5, wherein the detection device comprises an ion mobility spectrometer (IMS) unit, the airflow being provided along the drift chamber of the ion mobility spectrometer, and the ions traveling in the drift chamber to be detected by the collector electrode.

7. The method according to any one of claims 1 to 5, wherein, The detection device includes a mass spectrometer, such as a time-of-flight mass spectrometer (TOF-MS) including a decompression chamber, wherein the air delivery unit operates to reduce the air pressure in the chamber, and the ions travel in the decompression chamber to the collector electrode.

8. The method according to any one of claims 1 to 7, comprising performing a series of cycles of operating the detection device during the quiet period.

9. The method of claim 8, further comprising operating a sampling inlet to obtain a sample of the gaseous fluid to be ionized, to provide the ions prior to the series of cycles.

10. The method of claim 9, further comprising maintaining the air delivery unit in reduced operation during the series of cycles, and operating the air delivery unit at the operation level prior to any subsequent operation of the sampling inlet.

11. The method according to any one of claims 1 to 7, comprising performing only a single cycle of operating the detection device during the quiet period, and operating the air conveyor at the operating level prior to a subsequent operating cycle of the detection device.

12. The method of claim 11, further comprising operating a sampling inlet to obtain a sample of the gaseous fluid to be ionized, to provide the ions prior to a series of cycles of operating the ion mobility spectrometer, and Provides a series of quiet periods corresponding to a series of operating cycles of the ion mobility spectrometer, and optionally an air delivery system at the operating level between each operating cycle.

13. The method of claim 9, 10, 11 or 12, comprising operating the air delivery unit at the operation level prior to any subsequent operation at the sampling inlet.

14. A controller for a detection device, the controller comprising: A control interface for controlling the air delivery unit of the detection device and the IMS unit of the spectrometer, and for operating the detection device to allow ions to travel for detection by the collector electrodes; as well as Control logic configured to perform the method described in any of the preceding claims.

15. A detection device comprising the controller of claim 14.

16. A testing device, comprising: A collector electrode assembly for detecting ions, wherein the collector electrode assembly is subjected to capacitance changes due to mechanical vibration; The chamber, along which ions travel to reach the collector electrode for detection; A controller is configured to operate the detection device to provide ions detected by the collector device during quiet periods. During the quiet period, the mechanical vibration of the collector electrodes is reduced.

17. The testing equipment according to claim 16, wherein, The controller is configured to suppress the operation of at least one vibration source of the detection device to provide reduced mechanical vibration, such as an air conveyor including a fan.

18. The testing equipment according to claim 17, wherein, The air delivery unit operates to provide airflow into and / or out of the chamber.

19. The testing equipment according to claim 18, wherein, The detection device includes an ion mobility spectrometer (IMS) unit, the airflow being provided along the drift chamber of the IMS unit, and the ions traveling in the drift chamber to be detected by the collector electrodes.

20. The testing equipment according to claim 19, wherein, The detection device includes a mass spectrometer, such as a time-of-flight mass spectrometer (TOF-MS), which includes a depressurization chamber, an air delivery unit that operates to reduce the air pressure in the chamber, and the ions that travel in the depressurization chamber to the collector electrode.

21. The detection device of claim 19 or 20, wherein the controller is configured to reduce the operation of the air conveyor to provide the quiet period.

22. The testing equipment according to claim 21, wherein, The quiet period begins as a waiting period before the detection device provides the ions, for example, wherein the waiting period is selected to allow changes in the collector's capacitance due to vibrations of the air delivery system to the collector to be reduced below a threshold level, for example, wherein the controller is configured to increase the operation of the air delivery system to an operating level after the quiet period.

23. The detection apparatus according to any one of claims 16 to 22, comprising a shielding electrode arranged to shield the collector electrode from the electric field from the ions, and wherein a change in capacitance is associated with a vibrational change in the distance between the shielding electrode and the collector electrode.

24. The method according to any one of claims 1 to 13, or the detection apparatus according to any one of claims 14 to 23, wherein reducing the operation of the air conveyor includes stopping the operation.

25. A computer program product configured to program a programmable controller of a detection device to perform the method according to any one of claims 1 to 13 or 23.

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