Patent Description:
As methods for analyzing the concentration of ions within a solution, there are a coulometric titration method, a flame photometry method, an ion-selective electrode method, and the like. The ion-selective electrode method is widely used for the measurement of the concentration of ions within a biological sample and the like, since the concentration of ions within the sample can be quantitated only by inserting an ion-selective electrode together with a reference electrode in a sample solution. Since an ion concentration measuring device using an ion-selective electrode method has advantages that the ion concentration measuring device quickly performs measurement and is easily downsized and does not require a hazardous substance such as a propane gas and is safe, the ion concentration measuring device is embedded in a clinical inspection analysis device to be used in a hospital, an inspection center, or the like and is used.

For the clinical inspection analysis device, information (individual identification codes, usage periods, and usage statuses, and the like) on the device, conditions of use, and the like are demanded to be stored for the purpose of reducing medical errors and for quick handling upon the occurrence of the errors. To meet the demand, a method for implementing a storage medium storing the information in a cartridge with an ion-selective electrode has been proposed (for example, Patent Literature <NUM>). According to this method, when a device fails, the cartridge removed from the failed device is attached to another device, and the device to which the cartridge has been attached takes over the information stored in the storage medium and can continuously performs measurement.

When the method described in Patent Literature <NUM> is used, it is necessary that a data storage region that is a semiconductor memory or the like be included in the cartridge with the ion-selective electrode. When data is to be written to the data storage region, noise and heat are generated and may affect the data to be written. As a method for suppressing an effect of the noise generated in the data writing, there is a method in which a time period for measuring the potential of the ion-selective electrode does not overlap a time period for writing data to a memory (Patent Literature <NUM>). It is Patent Literature <NUM> from which the pre-characterising part of claim <NUM> starts out. Related art is disclosed in <CIT> and <CIT>.

In the invention described in Patent Literature <NUM>, how to control the semiconductor memory for a time period for which data is not written is not specially mentioned. However, regarding a sensor having a high-resistance portion such as a liquid film type ion-selective electrode, even in a state in which data writing to the memory is stopped, noise generated by turning on a power source of the memory affects a measurement result. In addition, it is known that heat is generated from the memory during the time when power is supplied to the semiconductor memory and this heat affects potential measurement.

The present invention has been devised under the foregoing circumstances and aims to suppress an effect of noise and heat generated from a memory on a measurement result in an ion concentration measuring device that uses an ion detection element for outputting a potential corresponding to the concentration of ions.

This problem is solved by an ion concentration measuring device as set forth in the appended claims.

An ion concentration measuring device according to the invention includes a cartridge having an ion detection element and a memory and supplies power to the memory in a time period excluding a time period for acquiring a potential generated by the ion detection element.

According to the ion concentration measuring device according to the present invention, it is possible to suppress an effect of noise and heat generated from the memory on a measurement result while using an advantage of a measurement method using an ion-selective electrode. In addition, it is possible to use data stored in the memory by removing the cartridge.

In the following description, the first and second embodiments are embodiments of the present disclosure, and the other embodiments are embodiments of the invention.

<FIG> is an elevation view of a cartridge <NUM> included in an ion concentration measuring device <NUM> according to a first embodiment. The cartridge <NUM> includes an internal electrode <NUM>, a flow path <NUM>, and a communication line <NUM>. The internal electrode <NUM> is an electrode for outputting a potential generated by an ion-sensitive membrane <NUM> described later. The flow path <NUM> is a through-hole through which a liquid sample passes. The communication line <NUM> is connected to a semiconductor memory <NUM> described later. A reading-writing unit <NUM> described later accesses the semiconductor memory <NUM> via the communication line <NUM> and writes or reads data. The communication line <NUM> is also used to supply power to the semiconductor memory <NUM>.

<FIG> is a side view of the cartridge <NUM>. A chain line I-I is a section line of <FIG> described later. The cartridge <NUM> can be configured using, for example, resin such as polyvinyl chloride, polystyrene, polypropylene, or the like.

<FIG> is a cross-sectional view of the cartridge <NUM>, taken along the chain line I-I of <FIG>. A cutout for enabling the liquid sample to flow out is formed in a portion of the flow path <NUM>. The ion-sensitive membrane <NUM> is bonded to the flow path <NUM> to close the cutout. The ion-sensitive membrane <NUM> is configured so that electromotive force is generated depending on the type and concentration of ions within the sample. The ion-sensitive membrane <NUM> is constituted by resin such as polyvinyl chloride, polystyrene, polypropylene, or the like, a compound such as a ligand for supplementing ions, or the like. A plasticizer for plasticizing the ion-sensitive membrane <NUM>, a highly fat-soluble ionic compound for removing an effect on ions, or the like may be used.

As the ion-sensitive membrane <NUM>, a membrane of a type corresponding to an ion type to be measured is used. For example, when sodium is measured, a sensitive membrane that responds to a sodium ion is used. When potassium is measured, a sensitive membrane that responds to a potassium ion is used. The ion concentration measuring device for clinical inspection measures a sodium ion, a potassium ion, a chlorine ion, a calcium ion, a lithium ion, a phosphate ion, and the like in many cases. The first embodiment describes an example in which a sodium ion, a potassium ion, a chlorine ion are measured.

The cartridge <NUM> is filled with internal gel <NUM>. The internal electrode <NUM> is fixed so that the internal electrode <NUM> is in contact with the internal gel <NUM>. When the sample is introduced into the flow path <NUM>, the ion-sensitive membrane <NUM> contacts the sample and generates electromotive force depending on the concentration of ions within the sample. Since the ion-sensitive membrane <NUM> is electrically conductive with the internal electrode <NUM> via the internal gel <NUM>, a change in the electromotive force of the ion-sensitive membrane <NUM> can be measured by measuring a potential output by the internal electrode <NUM>. Therefore, the concentration of ions within the sample can be calculated.

The semiconductor memory <NUM> is arranged on a portion separated from the internal gel <NUM> within the cartridge <NUM>. The communication line <NUM> is connected to the semiconductor memory <NUM> and extends from the semiconductor memory <NUM> to the outside of the cartridge <NUM>.

<FIG> is a schematic configuration diagram of the ion concentration measuring device <NUM>. A dilution tank <NUM> is provided to dilute the sample. A sample cup <NUM> holds the sample. A sample dispensing mechanism <NUM> dispenses the sample into the dilution tank <NUM>. A dilution solution nozzle <NUM> discharges a dilution solution into the dilution tank <NUM>. An internal reference solution nozzle <NUM> discharges an internal reference solution into the dilution tank <NUM>. A sipper nozzle <NUM> sends the diluted sample and the internal reference solution from the dilution tank <NUM> to the flow path <NUM>. An electrode installation unit <NUM> includes one or more cartridges that are the same as or similar to the cartridge <NUM>. As described above, an example in which a Na detection cartridge <NUM>, a K detection cartridge <NUM>, and a Cl detection cartridge <NUM> are provided is described. A reference potential cartridge <NUM> also has the same configuration and outputs a reference potential to be used to measure a potential difference. A potential measurer <NUM> measures differences between potentials output by the internal electrodes <NUM> of the cartridges and a reference potential output by the internal electrode <NUM> of the reference potential cartridge <NUM>. A controller <NUM> controls units of the ion concentration measuring device <NUM> and uses results of measurement by the potential measurer <NUM> to calculate the concentration of ions within the sample. A storage unit <NUM> stores the results of the calculation. An output unit <NUM> outputs data stored in the storage unit <NUM>. A reading-writing unit <NUM> writes data such as the calculation results received from the controller <NUM> to the semiconductor memories of the cartridges or reads data from the semiconductor memories <NUM>.

To measure the concentration of ions within the sample, the internal electrodes <NUM> of the cartridges are connected to the potential measurer <NUM>, and the communication lines <NUM> are connected to the reading-writing unit <NUM>. The flow paths <NUM> are connected to the sipper nozzle <NUM>. The sample aspirated from the sipper nozzle <NUM> is sent to the flow paths <NUM> of the cartridges. The cartridges are electrically conductive with each other via the sample. The potential measurer <NUM> measures potentials output by the internal electrodes <NUM> of the cartridges using the potential output by the reference potential cartridge <NUM> as a standard.

The controller <NUM> supplies power to the semiconductor memories <NUM> in a time period excluding a time when the controller <NUM> acquires, from the potential measurer <NUM>, the potentials output by the internal electrodes <NUM> of the cartridges. It is, therefore, possible to suppress effects of electrical noise generated from the semiconductor memories <NUM> and heat generated from the semiconductor memories <NUM> on results of the measurement based on the ion-sensitive membranes <NUM>. A specific operational procedure is described using <FIG> described below.

<FIG> is a flowchart describing a procedure for measuring the concentration of ions within the sample by the ion concentration measuring device <NUM>. Steps of <FIG> are described below.

The sample dispensing mechanism <NUM> dispenses the sample within the sample cup <NUM> and discharges the sample into the dilution tank <NUM> (S501). The dilution solution nozzle <NUM> discharges the dilution solution into the dilution tank <NUM> to dilute the sample with the dilution solution (S502).

The sipper nozzle <NUM> aspirates the sample solution within the dilution tank <NUM> and sends the sample to the flow paths <NUM>. Therefore, the flow paths <NUM> of the cartridges are filled with the sample, and an electric circuit that connects the cartridges to the potential measurer <NUM> via the sample solution is formed.

The potential measurer <NUM> uses the potential output by the reference potential cartridge <NUM> as a standard and measures potentials output by the internal electrodes <NUM> of the Na detection cartridge <NUM>, the K detection cartridge <NUM>, and the Cl detection cartridge <NUM>. The controller <NUM> acquires the measurement results from the potential measurer <NUM> and uses the measurement results to calculate the concentration of ions within the sample. The controller <NUM> causes the calculation results to be stored in the storage unit <NUM>.

The controller <NUM> turns on power sources of the semiconductor memories <NUM> within the cartridges (or starts supplying power) (S505). The reading-writing unit <NUM> acquires the results of calculating the concentration of ions from the storage unit <NUM> and writes the results to the semiconductor memories of the cartridges (S506). The controller <NUM> turns off the power sources of the semiconductor memories <NUM> of the cartridges (or terminates the supply of power) (S507).

When a next specimen is waiting to be measured, the procedure returns to step S501 to measure the configuration of ions in the same procedure. When a specimen that is waiting to be measured does not exist, the flowchart is terminated.

The ion concentration measuring device <NUM> according to the first embodiment turns on the power sources of the semiconductor memories <NUM> in a time period excluding a time when the controller <NUM> acquires changes in the potentials generated by the ion-sensitive membranes <NUM>. It is, therefore, possible to suppress effects of electric noise generated from the semiconductor memories <NUM> and heat generated from the semiconductor memories <NUM> on results of measuring the potentials. This can improve the accuracy of the measurement while an advantage of each of the ion-selective electrodes is used.

The service life of the ion-sensitive membranes <NUM> is limited. Thus, after the ion-sensitive membranes <NUM> are used a certain number of times, the ion-sensitive membranes <NUM> need to be replaced. Since the cartridges <NUM> are attachable to and detachable from the ion concentration measuring device <NUM>, the entire cartridges <NUM> can be replaced and thus are convenient. In addition, when the cartridges <NUM> are replaced, the semiconductor memories <NUM> included in the cartridges <NUM> can be recovered. A configuration in which the semiconductor memories <NUM> are installed in the cartridges <NUM> is useful from that point of view. On the other hand, conventionally, since an ion-sensitive membrane <NUM> is arranged in the vicinity of a semiconductor memory <NUM>, an effect of electric noise or the like on a measurement result has been large. According to the first embodiment, it is possible to improve the accuracy of the measurement, while using the advantage that the semiconductor memories <NUM> are installed in the cartridges <NUM>.

<FIG> is a cross-sectional view of a cartridge <NUM> included in an ion concentration measuring device <NUM> according to a second embodiment. In the second embodiment, each of the cartridges <NUM> includes a temperature sensor <NUM> and a temperature control device <NUM>, as well as the configurations described in the first embodiment. Since other configurations are the same as or similar to those described in the first embodiment, different features related to these devices are mainly described below.

The temperature sensor <NUM> is a sensor for measuring the temperature of the ion-sensitive membrane <NUM>. It is desirable that the temperature sensor <NUM> measure the temperature, for example, with accuracy of ±<NUM> in a range of <NUM> to <NUM>. The temperature sensor <NUM> does not necessarily need to be in contact with the ion-sensitive membrane <NUM>. It is, however, desirable that the temperature sensor <NUM> be located in the vicinity of the ion-sensitive membrane <NUM> so that the temperature sensor <NUM> can measure at least a peripheral temperature around the ion-sensitive membrane <NUM>.

The temperature control device <NUM> is a device that cools the ion-sensitive membrane <NUM> heated with heat generated from the semiconductor memory <NUM> to a temperature at which the concentration of ions can be accurately measured. Since it is sufficient if the temperature control device <NUM> cools at least a peripheral region that is in thermal contact with the ion-sensitive membrane <NUM>, the temperature control device <NUM> does not necessarily need to be in direct contact with the ion-sensitive membrane <NUM>. For example, the temperature control device <NUM> can be configured so that a flow path for a cooling medium is installed in the temperature control device <NUM> in the cartridge <NUM> and the cooling medium (for example, water, oil, or the like) is supplied from the outside of the cartridge <NUM>. Furthermore, since the ion-sensitive membrane <NUM> is heated to an appropriate temperature, a thermoelectric element such as a Peltier element can be used. A cooling device and a heating device may be used.

The controller <NUM> receives measurement results from the temperature sensors <NUM> via the communication lines <NUM> and turns on and off the supply of power to the temperature sensors <NUM> and the temperature control devices <NUM>. Since electric and thermal noise is generated due to operations of the temperature sensors <NUM> and the temperature control devices <NUM> in a similar manner to the semiconductor memories <NUM>, the controller <NUM> supplies power to the temperatures <NUM> and the temperature control devices <NUM> in a time period excluding a time when the controller <NUM> receives the results of the measurement based on the ion-sensitive membranes <NUM>.

<FIG> is a flowchart describing a procedure for measuring the concentration of ions within the sample by the ion concentration measuring device <NUM> according to the second embodiment. The ion concentration measuring device <NUM> performs steps S701 to S704 in parallel with steps S501 to S503 described with reference to <FIG>. Since other steps are the same as or similar to <FIG>, steps S701 to S704 are described below.

The controller <NUM> starts supplying power to the temperature sensors <NUM>.

The temperature sensors <NUM> start measuring peripheral temperatures around the ion-sensitive membranes <NUM>. The controller <NUM> acquires the measurement results. When the measured temperatures are in a predetermined range (or a range in which the ion-sensitive membranes <NUM> can output accurate measurement results), the procedure proceeds to step S704. Otherwise, the procedure proceeds to step S703. The temperature range in this step is determined based on necessary measurement accuracy. For example, it is desirable that the range is a range of ± <NUM> of a reference measurement temperature.

The controller <NUM> supplies power to the temperature control devices <NUM> to cause the temperature control devices <NUM> to operate and adjust the peripheral temperatures around the ion-sensitive membranes <NUM> to a range (same range as that in step S702) suitable for the measurement. After this step, the procedure returns to step S702 to repeat the same processes.

The controller <NUM> stops supplying power to the temperature sensors <NUM> (and the temperature control devices <NUM> when step S703 has been performed).

The ion concentration measuring device <NUM> according to the second embodiment causes the temperature control devices <NUM> to adjust the peripheral temperatures around the ion-sensitive membranes <NUM> to a temperature suitable for the measurement. Therefore, for example, when amounts of heat generated from the semiconductor memories <NUM> are large and heat generated in the measurement of an initial specimen affects the measurement of a next specimen, or when heat generated from the semiconductor memories <NUM> is accumulated and the temperatures change during the time when a plurality of specimens are continuously measured, or the like, it is possible to reduce an effect on the measurement results.

The second embodiment describes the case where the temperature control devices <NUM> adjust the peripheral temperatures around the ion-sensitive membranes <NUM> in accordance with the measurement results of the temperature sensors <NUM>. The measurement results of the temperature sensors <NUM> can be used for other purposes. A third embodiment describes a specific example thereof.

The ion-sensitive membrane <NUM> generally has a property varying depending on a temperature. For example, it is considered that characteristic data describing an association relationship between a potential generated by the ion-sensitive membrane <NUM> and the temperature of the ion-sensitive membrane <NUM> is stored in the storage unit <NUM> in advance and the controller <NUM> references the characteristic data and converts a potential output by the internal electrode <NUM> to the concentration of ions. For example, when a slope value changes depending on the temperature of the ion-sensitive membrane <NUM>, the temperature property is stored as the characteristic data in advance, the concentration of ions can be calculated by referencing the characteristic data using the difference between the reference potential and the measured potential and the result of the measurement by the temperature sensor <NUM>.

When the peripheral temperature around the ion-sensitive membrane <NUM> is high and is not suitable for the measurement, and the semiconductor memory <NUM> is further heated, the peripheral temperature further deviates from the temperature suitable for the measurement. Therefore, it is considered that, in the case where the measurement result of the temperature sensor <NUM> exceeds the temperature suitable for the measurement of the ion-sensitive membrane <NUM>, as the temperature is higher, the rate of writing to the semiconductor memory <NUM> is reduced. This is due to the fact that, when the writing rate is reduced, it is possible to suppress the generation of heat from the semiconductor memory <NUM>.

When the writing rate is reduced, there is a possibility that the writing is not completed in a time period up to the time when step S504 is performed next. In this case, remaining data that has not been completely written may be temporarily stored in the storage unit <NUM> and written again when step S506 is performed next.

The first to third embodiments describe the example in which, in a time period excluding a time when the controller <NUM> acquires changes in the potentials generated by the ion-sensitive membranes <NUM>, the controller <NUM> turns on the power sources of the semiconductor memories <NUM>, and when the controller <NUM> acquires the changes in the potentials generated by the ion-sensitive membranes <NUM>, the controller <NUM> turns off the power sources of the semiconductor memories <NUM>. When noise levels of the potentials can be suppressed to a level equal to or lower than a level that may cause a problem, the controller <NUM> does not necessarily need to turn off the power sources of the semiconductor memories <NUM> when the controller <NUM> acquires the changes in the potentials. For example, each of the semiconductor memories <NUM> and the controller <NUM> can have a normal mode and a standby mode.

The normal mode is a mode in which power to be supplied to the semiconductor memories <NUM> is normal. Specifically, rated values are used as a supply voltage and an operation frequency, and high throughput can be obtained by using the functions of the semiconductor memories <NUM> and the functions of the controller <NUM> without a restriction. The standby mode is a mode in which power to be supplied to the semiconductor memories <NUM> is suppressed. Specifically, it is possible to suppress power consumption and reduce the occurrence of noise by any or a combination of methods that are a reduction in the supply voltage, a reduction in the operation frequency, the stop of an operation of a circuit block having a function other than a minimally necessary function (for example, a function necessary for hot start described later), and the like. The standby mode is referred to as sleep mode, power saving mode, idling mode, low-speed mode, low-voltage mode, temporal stop mode, or the like in some cases.

In the case where the mode is returned from the standby mode to the normal mode (this is referred to as hot start, warm start, or the like), the normal mode can be quickly activated, compared to the case where the normal mode is activated from a state in which the power sources are completely turned off (this is referred to as cold start or the like). This is due to the fact that, in the standby mode, a part of an initialization process or the entire initialization process can be omitted by holding at least a part of (or all of) information realizing a state in which the normal mode is activated in a static memory, a register, or the like. There is an effect of suppressing electric noise and heat generated from the semiconductor memories <NUM>, the communication lines <NUM>, and the reading-writing unit <NUM> and suppressing an effect on results of measuring the potentials by appropriately selecting the supply voltage, the operation frequency, a range of circuit blocks to function, and the like in the standby mode and using the standby mode when the controller <NUM> acquires the changes in the potentials.

Compared to the case where the power sources of the semiconductor memories <NUM> are completely turned off when the controller <NUM> acquires the changes in the potentials, there are effects in which the activation is quickly completed and a time efficiency is high, since the standby mode is used and the high-speed hot start process (instead of the cold start that takes time) is used for the reading-writing unit <NUM> to perform the writing (S506) of results of calculating the concentration of ions to the semiconductor memories. Of course, when the standby mode is used concurrently, there is an effect in which power consumption is low, compared to the case where the operation is performed in the normal mode through all the processes.

Combining the method, described in the first to third embodiments, of turning off the power sources of the semiconductor memories <NUM> when the controller <NUM> acquires the changes in the potentials with the standby mode described in the fourth embodiment can be regarded as the standby mode in a broad sense. In this case, the method of turning off the power sources can be considered as an extreme example of one of standby modes in a broad sense. This is due to the fact that turning off the power sources maximally suppresses power to be supplied to the semiconductor memories <NUM> and, in other words, reduces power to be supplied to zero.

The invention is not limited to the foregoing embodiments of the invention and includes various modification examples. For example, the foregoing embodiments of the invention are described in detail to clearly explain the invention and are not necessarily limited to all the configurations described. In addition, some of configurations described in a certain embodiment of the invention can be replaced with configurations described in another embodiment of the invention. Furthermore, a configuration described in a certain embodiment of the invention can be added to a configuration described in another embodiment of the invention. Furthermore, a configuration can be added to, removed from, or replaced with a part of the configurations of each of the embodiments of the invention.

The foregoing embodiments describe the example in which the ion-sensitive membranes <NUM> are electrically connected to the internal electrodes <NUM> via the internal gel <NUM>. Instead of this, a technique that does not use the internal gel <NUM> and is referred to as solid electrode may be used. In this case, instead of the internal gel <NUM>, a carbon fiber, metal such as silver, platinum, gold, or iron, or a conductive material such as an ion liquid is used to electrically conduct the ion-sensitive membranes <NUM> and the internal electrodes <NUM>.

The foregoing embodiments describe the example in which power is supplied to the semiconductor memories <NUM> and data is written every time a specimen is measured. These operations may be performed in another time period excluding a time when step S504 is performed. For example, when the ion concentration measuring device <NUM> is activated or terminated, data held in the storage unit <NUM> may be collectively written.

The second embodiment describes the example in which the temperature sensor <NUM> and the temperature control device <NUM> are installed in each of the cartridges <NUM>. This is due to the fact that it is desirable that these devices be arranged in the vicinity of the ion-sensitive membrane <NUM> to control the temperature. As long as equivalent functions can be realized, the temperature sensor <NUM> and the temperature control device <NUM> may be arranged outside each of the cartridges <NUM> as constituent elements of the ion concentration measuring device <NUM>.

As the data to be written to the semiconductor memories <NUM>, not only the results of calculating the concentration of ions but also data useful for analysis after the cartridges <NUM> are recovered can be written. For example, the following items can be considered: (a) a time and date when the controller <NUM> calculates the concentration of ions or a time and date when the results of the calculation are written; (b) identifiers (manufacturing IDs or the like) of the ion-sensitive membranes <NUM> or the cartridges <NUM>; (c) a manufacturing date of the ion-sensitive membranes <NUM> or the cartridges <NUM>; (d) an expiration date of the ion-sensitive membranes <NUM> or the cartridges <NUM>; (e) the results of calculating the concentration of ions by the controller <NUM> in a process of calibrating the cartridges <NUM>; and (f) an alarm history (including an alarm occurrence time and date and the like) indicating that ion concentration calculated by the controller <NUM> is not in a reference range.

The controller <NUM> and the reading-writing unit <NUM> can be configured using hardware such as a circuit device having the functions of these units or can be configured by causing an arithmetic device to execute software having the functions of these units. The storage unit <NUM> can be constituted by, for example, a storage device such as a hard disk device.

Claim 1:
An ion concentration measuring device that measures the concentration of ions contained in a solution, comprising:
an ion detection element (<NUM>) for generating a first potential based on the concentration;
a first electrode (<NUM>) for outputting the first potential;
a memory (<NUM>) for storing data;
a reader-writer (<NUM>) for writing data to the memory or reading data from the memory; and
a controller (<NUM>) adapted to use the first potential to calculate the concentration, wherein
the ion detection element (<NUM>) and the memory (<NUM>) are installed in a first cartridge (<NUM>),
the memory (<NUM>) has a normal mode in which normal power is supplied and a standby mode in which the supply of power is suppressed,
the controller (<NUM>) is adapted to set the memory (<NUM>) to the normal mode in a memory access period which excludes a potential measurement period for which the controller acquires a potential value corresponding to the first potential output by the first electrode (<NUM>), and
the controller (<NUM>) is adapted to set the memory (<NUM>) to the standby mode when the memory access period is complete,
characterised in that the ion concentration measuring device further comprises:
a temperature sensor (<NUM>) for measuring a peripheral temperature around the ion detection element (<NUM>); and
a temperature control device (<NUM>) adapted to adjust the peripheral temperature around the ion detection element (<NUM>) in accordance with the result of the detection by the temperature sensor, wherein
the controller (<NUM>) is adapted to reduce the rate of the writing to the memory (<NUM>) as the peripheral temperature around the ion detection element (<NUM>) detected by the temperature sensor (<NUM>) exceeds a temperature suitable for measurement by the ion detection element (<NUM>), to suppress the amount of heat generated from the memory in the writing of the data to the memory.