Diagnostic device for particle accelerator, diagnostic method for particle accelerator, and diagnostic program for particle accelerator

Abstract

Provided is a diagnostic technique for a particle accelerator that enables evaluation of the extraction efficiency of charged particles in a short period. A diagnostic device (10) for a particle accelerator includes a first reception unit (11) that receives a first detection signal (S1) output as a signal corresponding to a first current value generated due to movement of charged particles in a circular accelerator (20) from a first detector (28) that detects the first current value; a second reception unit (12) that receives a second detection signal (S2) output as a signal corresponding to a second current value generated due to movement of charged particles extracted from the circular accelerator (20) to a beam transport system (30) from a second detector (55) that detects the second current value; and a calculation unit (40) that calculates the extraction efficiency (Q) of the charged particles based on the first detection signal (S1) and the second detection signal (S2).

Description

Technical Field

[0001] Embodiments of the present invention relate to diagnostic techniques for particle accelerators that perform delayed extraction of charged particle beams. Background Technology

[0002] In recent years, research has been conducted on the application of charging particles (ions) in a wide range of fields, including engineering and medicine, to accelerate them into high-energy beams. Currently, widely used accelerator systems generally consist of an ion source and linear or circular accelerators, which accelerate the charged particles in stages. Then, when the charged particles rotating in the circular accelerator reach a predetermined energy, the ejection device activates, extracting the beam of charged particles after its direction of travel has changed from its rotating trajectory and delivering it to the beam delivery system.

[0003] The ejection equipment that extracts a beam of charged particles from a circular accelerator is classified into fast extraction and slow extraction. "Fast extraction" is a method that completely extracts the cluster (beam) of charged particles rotating in the circular accelerator within a week.

[0004] In contrast, "slow extraction" is a method of extracting charged particle beams while rotating the circular accelerator. Therefore, charged particle beams emitted by "slow extraction" can be extracted from the circular accelerator little by little over time, compared to charged particle beams emitted by "fast extraction".

[0005] Therefore, by accelerating the charged particle beam rotating in a circular accelerator in stages, the energy of the charged particle beam extracted to the beam delivery system can be varied in stages. Then, in one acceleration cycle of the circular accelerator, charged particle beams of different energies (e.g., several hundred levels) can be extracted to the beam delivery system.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 4873563 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, it is desirable to minimize the loss of the charged particle beam accelerated by the circular accelerator until it reaches the end device of the beam delivery system (e.g., the irradiation device in a treatment room). If the delivery loss of the charged particle beam is large, there is a risk that the predetermined energy pattern cannot be executed. Furthermore, if the delivery loss of the charged particle beam is large, there is also a risk of reduced beam utilization efficiency.

[0011] It is known that the extraction efficiency of such charged particle beams varies depending on their energy value and can be improved by adjusting the excitation current of the electromagnets constituting the circular accelerator. Furthermore, since the magnetic field of the electromagnets subtly changes with environmental variations within the circular accelerator (cooling water temperature, room temperature), meticulous adjustments are required to efficiently maintain the extraction of the charged particle beams.

[0012] Furthermore, it is assumed that the extraction efficiency of the charged particle beam is 10 -5 seconds to 10 -1 The beam extraction efficiency varies on the order of seconds. Therefore, in order to maintain the beam extraction efficiency efficiently, it is desirable to control the excitation current of the electromagnet while obtaining the beam extraction efficiency as close to real-time as possible.

[0013] The embodiments of the present invention were made with regard to the following circumstances, and the object is to provide a diagnostic technique for particle accelerators that can evaluate the extraction efficiency of charged particles in a short period of time. Attached Figure Description

[0014] Figure 1 This is a block diagram of a diagnostic device for a particle accelerator according to the first embodiment of the present invention.

[0015] Figure 2 This is a block diagram of a diagnostic device for a particle accelerator according to the second embodiment of the present invention.

[0016] Figure 3 (A), (B), (C), (D), and (E) are timing diagrams illustrating the operation of the diagnostic device for the particle accelerator in the embodiment.

[0017] Figure 4 This is a block diagram of a diagnostic device for a particle accelerator according to the third embodiment of the present invention.

[0018] Figure 5 This is a block diagram of a diagnostic device for a particle accelerator according to the fourth embodiment of the present invention.

[0019] Figure 6 This is a flowchart illustrating the diagnostic methods and procedures for particle accelerators in various embodiments. Detailed Implementation

[0020] (First Embodiment)

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1This is a block diagram of a diagnostic device 10A for a particle accelerator according to a first embodiment of the present invention. The diagnostic device 10A (10) for the particle accelerator includes: a first receiving unit 11 that receives a first detection signal S1 output as a signal corresponding to a first current value from a first detector 28 that detects a first current value generated by the movement of charged particles within the circular accelerator 20; a second receiving unit 12 that receives a second detection signal S2 output as a signal corresponding to a second current value from a second detector 55 that detects a second current value generated by the movement of charged particles extracted from the circular accelerator 20 to the beam delivery system 30; and a calculation unit 40 that calculates the extraction efficiency Q of charged particles extracted from the circular accelerator 20 to the beam delivery system 30 based on the first detection signal S1 and the second detection signal S2.

[0022] Furthermore, the calculation unit 40 has a processing unit 16, which performs a differential processing on the first detection signal S1 to obtain a first processing signal D, and calculates the extraction efficiency Q of the extracted charged particles based on the first processing signal D and the second detection signal S2 (at least the ratio of the first processing signal D to the second detection signal S2 is calculated).

[0023] The particle accelerator system consists of an ion source 21, a linear accelerator 22, and a circular accelerator 20, which sequentially accelerate charged particles in stages. Then, when the charged particles rotating in the circular accelerator 20 reach a predetermined energy, the ejection device 29 is activated while maintaining that energy to extract the charged particle beam, which has changed direction from its rotating trajectory, into the beam delivery system 30. Furthermore, in this description, "energy" refers to "the kinetic energy of each nucleon." Here, the particle accelerator to be diagnosed by the diagnostic device 10A of the particle accelerator of this embodiment is a device configured to include at least the aforementioned linear accelerator 22, circular accelerator 20, and beam delivery system 30.

[0024] In addition to high-frequency (including microwave) irradiation types such as ECR (Electron Cyclotron Resonance) ion sources and PIG (Penning Ionization Gauge) ion sources, laser irradiation type ion sources can also be cited as examples, but they are not limited to these.

[0025] The linear accelerator 22 arranges multiple accelerating electric fields with opposite electric field components in a straight line, causing the electric field direction to repeatedly reverse at a high frequency, so that charged particles passing through the accelerating electric field are always accelerated in only one direction. Then, after accelerating the ions incident from the ion source 21 to a predetermined energy, the linear accelerator 22 ejects them into the circular accelerator 20.

[0026] The circular accelerator 20 comprises the following components: a high-frequency accelerating cavity 25, which accelerates charged particles incident from the linear accelerator 22 using high-frequency electricity; multiple deflecting electromagnets 26, which generate magnetic fields that bend the rotating charged particles; multiple quadrupole electromagnets 27, which generate magnetic fields that cause the rotating charged particles to diverge or converge and remain within the rotating orbit; a current detector (first detector) 28, which detects the current value of the beam of rotating charged particles; and an ejection device 29, which ejects the beam of rotating charged particles in the circular accelerator 20 bit by bit into the beam delivery system 30.

[0027] The circular accelerator 20 configured in this way can accelerate a beam of charged particles incident from the linear accelerator 22 at low energy to an upper limit energy of 70-80% of the speed of light while rotating. Then, the circular accelerator 20 can maintain the energy of the rotating beam of charged particles at any energy lower than this upper limit energy. The control unit 23 then controls the ion source 21, the linear accelerator 22, and the circular accelerator 20 in a coordinated manner to accurately accelerate the aforementioned beam of charged particles.

[0028] Additionally, the beam delivery system 30 is equipped with a quadrupole electromagnet 27 for holding the linearly advancing charged particles within their orbit, and a deflecting electromagnet 26 for bending the orbit of the charged particles. Then, an irradiation device 50 for treating the tumor of the patient 52 by irradiating the charged particle beam 51 is connected to the front end of the beam delivery system 30. Furthermore, this irradiation device 50 is an example, and the facility connected to the front end of the beam delivery system 30 is not particularly limited.

[0029] The ejection device 29 used in this embodiment is designed for "slow extraction," gradually removing the cluster (beam) of charged particles rotating within the circular accelerator 20. The ejection device 29 excites the ejection electrodes (not shown) based on a control signal G input from the control unit 23, thereby extracting the beam that has shifted to an unstable region from the circular accelerator 20 to the beam delivery system 30. Furthermore, a second detector 55 is provided in the beam delivery system 30 to detect and monitor the current value (second current value) generated due to the movement of the passing charged particles.

[0030] The first detection signal S1 received by the first receiving unit 11 is a signal output from the first detector 28 installed in the circular accelerator 20, and is a signal corresponding to the current value (first current value) generated due to the movement of the rotating charged particles. The first detector 28 measures the current value using Ampere's law, detecting the magnetic field formed in concentric circles around the current. Then, the first detector 28 outputs the first detection signal S1, which is proportional to the first current value generated by the movement of the rotating charged particles.

[0031] The processing unit 16 outputs a first processed signal D obtained by processing the first detection signal S1 by at least including a time derivative. Here, the first processed signal D, when extracted from the circular accelerator 20 to the beam delivery system 30 without loss, is equivalent to the ideal value of the second detection signal S2 detected by the second detector 55.

[0032] Here, the first detection signal S1, representing the value of the cyclotron current in the circular accelerator 20, is proportional to the cyclotron frequency f of the charged particles, which is proportional to the velocity of the charged particles. Furthermore, the decrease A per unit time of the charged particles rotating in the circular accelerator 20 is represented by equation (1), corresponding to the first processing signal D. Here, the coefficient k is a coefficient that converts the charge quantity into the particle number, a quantity determined by the nucleus species of the charged particles. ΔS1 is the change in the first detection signal S1 during the period Δt.

[0033] The decrease in charge per unit time of a rotating charged particle is A = D × K1 ……(1)

[0034] [D = ΔS1 / Δt, K1 = k / f]

[0035] Furthermore, although not shown in the figure, a noise filter (not shown) is provided before the processing unit 16 performs time differentiation on the first detection signal S1 to remove the noise components contained in the first detection signal S1. In addition, an amplifier (not shown) is provided to amplify the analog signal, i.e., the first detection signal S1, before it is input to the noise filter. Sometimes, the amplified first detection signal S1 remains an analog signal and is processed by the noise filter and processing unit 16, but sometimes it is converted to a digital signal and then processed by the noise filter and processing unit 16.

[0036] The second detection signal S2 received by the second receiving unit 12 is a signal output from the second detector 55 installed in the beam delivery system 30, and corresponds to the current value (second current value) generated due to the movement of the linearly advancing charged particles. The principle of the second detector 55 in measuring the current value is to count the pulse signal generated by the ionization of electrons when the charged particle beam passes through the gas. The count of this pulse signal per unit time corresponds to the current value generated accompanying the movement of the charged particles through the beam delivery system 30.

[0037] The second detector 55 generates a pulse signal with a frequency proportional to the current value of the passing charged particles, and outputs the cumulative count of the pulse signals generated per unit time as the second detection signal S2. Then, the number B of charged particles passing through the beam delivery system 30 in a straight line per unit time is as shown in Equation (2), and is obtained by multiplying the second coefficient K2, which represents the number of charged particles per pulse, by the second detection signal S2.

[0038] The number of times a charged particle traveling in a straight line passes per unit time is B = S² × K² ……(2)

[0039] The calculation unit 40 calculates the extraction efficiency Q of the charged particle as shown in equation (3). Thus, the extraction efficiency Q takes the ratio (S2 / D) of the second detection signal S2 to the first processing signal D as a factor. Furthermore, the extraction efficiency Q under the condition of charged particle energy variation is obtained by multiplying the ratio (S2 / D) of the second detection signal S2 to the first processing signal D by the gyration frequency f and a constant (K2 / k).

[0040] Extraction efficiency Q = B / A = K³ × S² / D ……(3)

[0041] [K3 = K2 / K1 = f·K2 / k]

[0042] The beam extraction efficiency Q varies for various reasons, but it can be restored by adjusting the magnetic field based on the current value of the electromagnets constituting the circular accelerator 20 and the beam delivery system 30. In particular, it can be improved by adjusting the current pattern of the quadrupole electromagnet 27 that converges the charged particle beam rotating in the circular accelerator 20.

[0043] (Second Implementation)

[0044] Next, refer to Figure 2 The second embodiment of the present invention will be described. Figure 2 This is a block diagram of the diagnostic device 10B for a particle accelerator according to the second embodiment of the present invention. Additionally, regarding... Figure 2 It has with Figure 1 Common components or functions are marked with the same symbol and repeated descriptions are omitted.

[0045] The calculation unit 40 of the diagnostic device 10B(10) for the particle accelerator in the second embodiment includes: a first conversion unit 41, which multiplies the first processed signal D by a first coefficient K1 to convert it into a first conversion value A representing the decrease in the number of charged particles rotating in the circular accelerator 20 per unit time; and a second conversion unit 42, which multiplies the second detection signal S2 by a second coefficient K2 to convert it into a second conversion value B representing the number of charged particles passing through the beam delivery system 30 in a straight line per unit time. Furthermore, a division unit 45 divides the second conversion value B by the first conversion value A to calculate the extraction efficiency Q.

[0046] The first conversion value A output from the first conversion unit 41 is obtained by multiplying the first processing signal D input from the processing unit 16 by the first coefficient K1, as shown in equation (1) above. In addition, the first coefficient K1 is configured to include the rotation frequency f of the circular accelerator 20, so the first coefficient K1 changes accordingly when the energy of the rotating charged particles changes.

[0047] The second conversion value B output from the second conversion unit 42, as shown in equation (2) above, is obtained by multiplying the second detection signal S2 by the second coefficient K2. This second conversion value B represents the number of charged particles passing through the beam delivery system 30 in a straight line per unit time, while the first conversion value A represents the number of charged particles decreasing per unit time while rotating in the circular accelerator 20. Therefore, even when the energy of the charged particles rotating in the circular accelerator 20 changes in stages, the ratio of the second conversion value B to the first conversion value A (B / A) represents the extraction efficiency Q.

[0048] Figure 3 (A), (B), (C), (D), and (E) are timing diagrams illustrating the operation of the diagnostic device for the particle accelerator in the embodiment. Figure 3 The timing shown in (A) is from the control unit 23 ( Figure 1 A command signal is sent to ion source 21. Then, charged particles are output from ion source 21, and after being accelerated by linear accelerator 22, the beam of charged particles is supplied to circular accelerator 20.

[0049] Figure 3 (B) indicates from control unit 23 ( Figure 1 The graph shows the excitation current supplied to the deflecting electromagnet 26. The excitation current of the deflecting electromagnet 26 is uniquely determined by the energy of the rotating charged particle; therefore, it can also be considered... Figure 3 (B) represents a graph of the energy of a charged particle rotating in the circular accelerator 20.

[0050] The circular accelerator 20 sends a command signal ( Figure 3 Before (A), the initial state is set to correspond to the rotation of charged particles with incident energy E0 supplied from the linear accelerator 22. Then, after the beam of incident charged particles, the circular accelerator 20 changes the set state in the direction of increasing charged particle energy and maintains the set state when it stabilizes at a predetermined energy E1.

[0051] Figure 3 (C) indicates that when the circular accelerator 20 is set to energy E1 (or E2, E3), the control unit 23 ( Figure 1During the period Δt during which the control signal G is sent to the emission device 29, the beam of charged particles rotating in the circular accelerator 20 is gradually extracted into the beam delivery system 30.

[0052] Figure 3 (D) indicates that at the first detector 28 ( Figure 1 The first detection signal S1 is plotted in the graph of the current value of the beam of charged particles rotating in the circular accelerator 20. The processing unit 16 performs time differentiation of the change ΔS1 of the first detection signal S1 during the output period Δt, and outputs the first processing signal D.

[0053] Figure 3 (E) shows the second detector 55 ( Figure 1 The graph shows the count of the cumulative pulse signal generated by the second detection signal S2 during the period Δt of the charged particle moving in a straight line in the beam delivery system 30. Then, at the timing of obtaining the first processing signal D and the second detection signal S2, the extraction efficiency Q is calculated by the above equation (3). Then, under the state in which the set state of the energy E of the circular accelerator 20 changes in stages from E1 to E2 and E3, the first processing signal D and the second detection signal S2 are obtained, and the extraction efficiency Q is calculated by substituting the above equation (3) with the gyration frequency f corresponding to the energy E.

[0054] In addition, Figure 3 In order to simplify the explanation, the period of differentiation and accumulation is made to be consistent with the beam extraction period Δt of the beam delivery system 30, but it can also be set to a smaller period Δt within the beam extraction period (e.g., 100ms, 10ms, 1ms, etc.).

[0055] Control signal G is sent to emission device 29. As time passes, the beam of charged particles rotating in circular accelerator 20 decreases or disappears. Therefore, the set state of circular accelerator 20 is returned (decelerated) from energy E1, E2, E3 to the initial set state, i.e., incident energy E0, and command signal is sent to ion source 21 again. Figure 3 (A)) can be used to recalculate the extraction efficiency Q.

[0056] (Third Implementation)

[0057] Next, refer to Figure 4 The third embodiment of the present invention will be described. Figure 4 This is a block diagram of the diagnostic device 10C for a particle accelerator according to the third embodiment of the present invention. Additionally, regarding... Figure 4 It has with Figure 1 Common components or functions are marked with the same symbol and repeated descriptions are omitted.

[0058] The diagnostic device 10C (10) of the particle accelerator in the third embodiment includes a selection unit 15, which selects one of a plurality of second detection signals S2 (S2a, S2b) received from a plurality of second detectors 55 (55a, 55b) provided in the beam delivery system 30. The second detection signal S2 selected by the selection unit 15 is then received by the second receiving unit 12. Furthermore, the operation of the components of the third embodiment, except for the selection unit 15, is the same as that of the components of the first and second embodiments.

[0059] Here, the extraction efficiency Q, calculated based on the second detection signal S2a output from the second detector 55a located upstream of the beam delivery system 30, reflects the beam loss immediately following extraction from the circular accelerator 20 to the beam delivery system 30. Conversely, the extraction efficiency Q, calculated based on the second detection signal S2b output from the second detector 55b located downstream of the beam delivery system 30, also reflects the beam loss during its passage through the beam delivery system 30.

[0060] One reason for the deterioration of the extraction efficiency Q is the subtle change in the electromagnet's magnetic field caused by environmental variations such as the cooling water temperature and indoor temperature of the accelerator building. When the extraction efficiency Q calculated based on the second detection signal S2a deteriorates, adjustments are made to the peripheral equipment and control parameters of the circular accelerator 20. Furthermore, when the extraction efficiency Q calculated based on the second detection signal S2b deteriorates, adjustments are made to the peripheral equipment and control parameters of the beam delivery system 30. Thus, by calculating multiple extraction efficiencies Q based on the second detection signals S2 output from multiple second detectors 55 located at different positions in the beam delivery system 30, the causes of beam loss can be identified.

[0061] Furthermore, while the embodiment shows a single beam delivery system 30, there are also cases where the beam delivery system 30 is branched. In this case, by configuring multiple second detectors 55, it is easy to determine which branch of the beam delivery system 30 is causing the beam loss.

[0062] (Fourth implementation)

[0063] Next, refer to Figure 5 The fourth embodiment of the present invention will be described. Figure 5 This is a block diagram of the diagnostic device 10D for a particle accelerator according to the fourth embodiment of the present invention. Additionally, regarding... Figure 5 It has with Figure 1 Common components or functions are marked with the same symbol and repeated descriptions are omitted.

[0064] The diagnostic device 10D(10) for the particle accelerator in the fourth embodiment further includes a determination unit 17, which determines, based on the extraction efficiency Q, whether to output an abnormality alert signal R from the output unit 18 to the control units 23 and 24 of at least one of the circular accelerator 20 and the beam delivery system 30. This alert signal R is input to the control unit 23, causing the circular accelerator 20 and the beam delivery system 30 to perform predetermined operations. Furthermore, the operation of the components of the fourth embodiment, except for the determination unit 17 and the output unit 18, is the same as that of the components of the first and second embodiments.

[0065] If the extraction efficiency Q deteriorates beyond the allowable value, it is presumed that some kind of anomaly has occurred in the circular accelerator 20 or the beam delivery system 30. When a warning signal R is output during the patient treatment process in the irradiation device 50, it may sometimes notify the operator or cause an emergency stop of the operation of the circular accelerator 20 and the beam delivery system 30.

[0066] Alternatively, when an alert signal R is output, the control unit 23 inputs multiple correction current patterns into the electromagnet 27, and calculates multiple extraction efficiencies Q based on each correction current pattern. Thus, by employing the correction current pattern with the optimal extraction efficiency Q, the charged particle beam can be effectively irradiated.

[0067] based on Figure 6 The flowchart illustrates the diagnostic methods and procedures for particle accelerators in each embodiment (refer to the flowchart as appropriate). Figure 1 First, the charged particle beam rotating in the circular accelerator 20 is stabilized at a predetermined energy E (S11). Next, the charged particle beam is extracted from the circular accelerator 20 and propelled in a straight line in the beam delivery system 30 (S12). Then, a first detection signal S1 corresponding to a first current value generated due to the movement of the charged particles rotating in the circular accelerator 20 is received (S13), the first detection signal S1 is differentiated in time, and a first processing signal D is output (S14).

[0068] On the other hand, a second detection signal S2 (S15) corresponding to a second current value generated by the movement of charged particles extracted from the circular accelerator 20 and moving linearly in the beam delivery system 30 is received. Then, the ratio of the first processing signal D to the second detection signal S2 is calculated, and the extraction efficiency Q of the charged particles is calculated (S16).

[0069] If the extraction efficiency Q does not exceed a predetermined threshold (S17 "No"), an alert signal is output (S18 "End"). When the alert signal is output, the excitation current input to the electromagnet constituting the circular accelerator 20 or the beam delivery system 30 is adjusted according to the operator's judgment.

[0070] If the extraction efficiency Q is greater than the threshold (S17 "Yes"), update the energy E of the charged particle beam rotating in the circular accelerator 20 (S19 "No"), and repeat the process from (S11) to (S17). Then, when it is confirmed that the extraction efficiency Q is greater than the threshold for all the set energies E, the process ends (S19 "Yes", "End").

[0071] According to the diagnostic device for a particle accelerator according to at least one embodiment described above, by calculating the ratio of the time derivative of the beam current value of the circular accelerator to the beam current value of the beam delivery system, the extraction efficiency of the charged particle beam can be evaluated within a short period.

[0072] Furthermore, in each embodiment, it is sufficient to compare the decrease in the number of charged particles rotating in the circular accelerator with the number of charged particles emitted to the beam delivery system. For example, a differential operation on the first detection signal is described, but if the beam emission efficiency is calculated based on the change in the first detection signal caused by the emission of the beam (i.e., the decrease in charged particles in the circular accelerator) and the second detection signal corresponding to the timing of the beam emission, i.e., the timing of the emitted beam arriving at the second detector 55, then the differential operation is not a necessary computational process.

[0073] Several embodiments of the present invention have been described, but these embodiments are merely illustrative and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the invention described in the technical solution and its equivalents.

[0074] The diagnostic device for the particle accelerator described above is equipped with a control device that integrates a dedicated chip, a processor such as an FPGA (Field Programmable Gate Array), a GPU (Graphics Processing Unit), or a CPU (Central Processing Unit), a storage device such as ROM (Read Only Memory) or RAM (Random Access Memory), an external storage device such as an HDD (Hard Disk Drive) or SSD (Solid State Drive), a display device such as a monitor, an input device such as a mouse or keyboard, and a communication I / F, and can be implemented using conventional computer hardware.

[0075] In addition, programs executed by the particle accelerator's diagnostic device are pre-installed in ROM or the like. Alternatively, the program may be provided as an installable or executable file stored on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD, or floppy disk (FD).

[0076] Furthermore, the program executed by the diagnostic device of the particle accelerator in this embodiment can also be stored on a computer connected to a network such as the Internet and provided via network download. In addition, the diagnostic device can also be constructed by interconnecting and combining different modules that independently perform the functions of the constituent elements through a network or dedicated lines.

Claims

1. A diagnostic device for a particle accelerator, comprising: The first receiving unit receives a first detection signal, which is a signal corresponding to the first current value, from a first detector that detects the first current value generated by the movement of the first charged particle rotating inside the circular accelerator. The second receiving unit receives a second detection signal, which is a signal corresponding to the second current value, from a second detector that detects the movement of a second charged particle that has been extracted from the first charged particle rotating in the circular accelerator and is moving linearly in the beam delivery system; and the second detector receives a second detection signal that is a signal corresponding to the second current value. The computing unit processes the first detection signal, including differential processing, to obtain a first processed signal. Based on the ratio of the first processed signal to the second detection signal, it calculates the extraction efficiency of the second charged particle extracted from the first charged particle rotating in the circular accelerator and delivered to the beam delivery system.

2. The diagnostic device for a particle accelerator according to claim 1, wherein, The aforementioned computing unit has: The first conversion unit multiplies the first processed signal by a first coefficient to convert it into a first converted value representing the decrease in the number of charged particles rotating in the circular accelerator per unit time; and The second conversion unit multiplies the second detection signal by a second coefficient to convert it into a second converted value representing the number of charged particles passing through per unit time in the beam delivery system. The extraction efficiency is calculated by dividing the second conversion value by the first conversion value.

3. The diagnostic device for a particle accelerator according to claim 1 or 2, wherein, The aforementioned calculation unit calculates the extraction efficiency whenever the energy of the charged particles rotating in the aforementioned circular accelerator changes in stages.

4. The diagnostic apparatus for a particle accelerator according to any one of claims 1 to 3, wherein, The diagnostic device for the aforementioned particle accelerator includes a selection unit that selects any one of the plurality of second detection signals received from the plurality of second detectors provided in the aforementioned beam delivery system.

5. The diagnostic apparatus for a particle accelerator according to any one of claims 1 to 3, wherein, The diagnostic device for the aforementioned particle accelerator includes a determination unit that, based on the aforementioned extraction efficiency, determines whether to output an alert signal indicating an abnormality to the control unit of at least one of the aforementioned circular accelerator and the aforementioned beam delivery system.

6. The diagnostic device for a particle accelerator according to claim 5, wherein, When the above-mentioned reminder signal is output, the control unit inputs multiple correction current patterns into the electromagnet and calculates multiple extraction efficiencies based on each of the above-mentioned correction current patterns.

7. A diagnostic method for a particle accelerator, comprising: The step of receiving a first detection signal as a signal corresponding to the first current value from a first detector that detects the first current value generated by the movement of the first charged particle rotating inside the circular accelerator; The steps include: receiving a second detection signal, which is a signal corresponding to the second current value, from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; and receiving a second detection signal ... that is a signal corresponding to the second current value; and receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal that is a signal corresponding to the second current value; receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal from a second detector that is a signal corresponding to the second current value; receiving a second detection signal from a second detector that is a signal corresponding The steps involve processing the first detection signal, including differential processing, to obtain a first processed signal, and calculating the extraction efficiency of the second charged particle from the first charged particle rotating in the circular accelerator to the beam delivery system based on the ratio of the first processed signal to the second detection signal.

8. A diagnostic program product for a particle accelerator, wherein, Have the computer perform the following steps: The step of receiving a first detection signal as a signal corresponding to the first current value from a first detector that detects the first current value generated by the movement of the first charged particle rotating inside the circular accelerator; The steps include: receiving a second detection signal, which is a signal corresponding to the second current value, from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; and receiving a second detection signal ... that is a signal corresponding to the second current value; and receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal that is a signal corresponding to the second current value; receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal from a second detector that detects the movement of a second charged particle that is extracted from the first charged particle rotating in the aforementioned circular accelerator and is moving linearly in the beam delivery system; receiving a second detection signal from a second detector that is a signal corresponding to the second current value; receiving a second detection signal from a second detector that is a signal corresponding The steps involve processing the first detection signal, including differential processing, to obtain a first processed signal, and calculating the extraction efficiency of the second charged particle from the first charged particle rotating in the circular accelerator to the beam delivery system based on the ratio of the first processed signal to the second detection signal.

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