Photon counting anomaly correction method and device

Abstract

The present invention discloses a method and device for correcting abnormal photon counting. The method uses temperature feedback and APC optical power feedback to ensure the stability and consistency of the light source, reduce errors, and improve the accuracy of PMT tube correction. At the same time, the light source is controlled at a constant temperature, which slows down the aging of the light source and increases the service life of the equipment. Circuit feedback is used to automatically correct the photon count, thereby improving the measurement accuracy of the device. At the same time, the PMT tube can be packaged together with the signal processing circuit, and the entire device can be used directly alone or in combination with other devices, greatly reducing the difficulty of using the PMT tube. The use of circuit automatic correction eliminates the need for additional personnel participation. At the same time, the PMT tube count is compensated by the circuit, and there is no need for separate calibration and disassembly of the PMT tube, which greatly reduces the number of repairs and the cost of replacing the PMT tube.

Description

Technical Field

[0001] The present invention relates to the field of photon counting technology, and in particular to a method and device for correcting photon counting anomalies, which can offset the influence of the use environment on the photon counting device to a certain extent during the correction process. Background Art

[0002] Photon counting is a technology for detecting weak light signals. It typically uses a photomultiplier tube as a receiver, detecting light signals in the form of photoelectrons. When a photon strikes a photodetector, electrons released from the photocathode of the tube are driven by the electric field within the tube to the anode, where a photoelectron pulse appears on the anode's load resistor. This pulse is then processed to digitally extract the light signal from the noise. Because weak radiation signals are temporally discrete photon streams, the detector outputs a naturally discrete electrical signal. Pulse amplification, pulse discrimination, and counting techniques can effectively improve the sensitivity of weak light detection.

[0003] Patent document No. 202210459484.0 describes a calibration method and device for a photon counting device. The patent describes a calibration method for a photon counting device, including the following steps: S1, a light source emits light at a predetermined power, and a photon-mass spectrometer (PMT) collects the irradiated light emitted by the light source to obtain a detection intensity value. If the detection intensity value is less than a reference intensity value, the difference between the detection intensity value and the reference intensity value is calculated as a percentage of the reference intensity value; S2, determining whether the percentage is less than a preset threshold. If the percentage is less than or equal to the preset threshold, the PMT does not need to be calibrated; if the percentage is greater than the preset threshold, the PMT is calibrated.

[0004] The above calibration method can obtain a relatively accurate result of the PMT tube status. However, in the actual use environment, the light source will generate a large amount of heat when working. This heat will affect the PMT tube and the photodiode for light source calibration, resulting in an erroneous judgment of the PMT tube status. At the same time, the above method only introduces the judgment of the PMT tube status. For PMT tubes that need to be calibrated, human intervention or replacement of the PMT tube is still required. This still does not solve the problem of avoiding damage to the closed darkroom during the disassembly, assembly and replacement of the photon counting device, which may cause secondary damage to the photon counting device. Summary of the Invention

[0005] In view of the above problems, the present invention provides a method and device for correcting photon counting anomalies to overcome or at least partially resolve these issues. During the correction process, circuit feedback can be used to automatically compensate for the photon counting device's results, offsetting the effects of the operating environment on the photon counting device to a certain extent.

[0006] The present invention provides the following solutions:

[0007] A method for correcting photon counting anomaly, comprising:

[0008] Get the actual temperature value of the light source;

[0009] generating a temperature adjustment strategy based on a relationship between the actual temperature value and a preset temperature range;

[0010] controlling a temperature adjustment unit to adjust the temperature of the light source according to the temperature adjustment strategy so as to adjust the actual temperature value to a target temperature value, wherein the target temperature value is within the preset temperature range;

[0011] Obtaining the actual optical power of the light source;

[0012] generating an optical power adjustment strategy according to a relationship between the actual optical power and the preset optical power range;

[0013] The optical power adjustment unit is controlled to adjust the optical power of the light source according to the optical power adjustment strategy, so as to adjust the actual optical power to the target optical power, and the target optical power is within the preset optical power range.

[0014] Preferably: obtaining the number of temperature adjustments and / or the number of optical power adjustments;

[0015] Whether the light source has a fault is determined according to a comparison result of the number of temperature adjustments and / or the number of optical power adjustments with a first number threshold.

[0016] Preferably, two temperature sensors arranged around the light source are used to obtain the actual temperature value, and the temperature adjustment unit includes a semiconductor refrigeration plate.

[0017] Preferably, the step of generating a temperature adjustment strategy based on the relationship between the actual temperature value and the preset temperature range includes:

[0018] When it is determined that the actual temperature value is lower than a lowest value of the preset temperature range, determining that the temperature adjustment strategy includes heating the light source by the temperature adjustment unit;

[0019] When it is determined that the actual temperature value is higher than the highest value of the preset temperature range, determining the temperature adjustment strategy includes cooling the light source by using the temperature adjustment unit.

[0020] Preferably, the magnitude and direction of the power supply current of the semiconductor refrigeration chip are controlled according to the temperature adjustment strategy, so that the semiconductor refrigeration chip can heat or cool the light source.

[0021] Preferably: a photodiode arranged around the light source is used to obtain the actual optical power of the light source; and the optical power adjustment unit includes an automatic power control optical power feedback circuit.

[0022] Preferably: obtaining the actual count value of the light source after temperature adjustment and light power adjustment are completed;

[0023] determining a baseline adjustment strategy based on a relationship between the actual count value and a preset count range;

[0024] The baseline is adjusted by the baseline adjustment unit according to the baseline adjustment strategy, so as to adjust the actual count value to a target count value, and the target count value is within the preset count range.

[0025] Preferably, counting is performed by a photomultiplier tube, an amplifier circuit is used to amplify the output signal of the photomultiplier tube, and the actual count value is obtained by comparing with a preset comparison baseline.

[0026] Preferably: obtaining the number of times the baseline adjustment is performed;

[0027] Whether the photomultiplier tube has a fault is determined according to a comparison result of the number of times the baseline is adjusted and the second number threshold.

[0028] A device for correcting photon counting anomalies, comprising:

[0029] A light source base plate, wherein the light source base plate is provided with a light source;

[0030] A temperature acquisition and adjustment unit, comprising a temperature adjustment circuit, two temperature sensors, and a semiconductor refrigeration chip, all connected to the light source base plate;

[0031] An optical power acquisition and adjustment unit, the optical power acquisition and adjustment unit comprising an automatic power control optical power feedback circuit and a photodiode both connected to the light source baseboard;

[0032] A counting acquisition and adjustment unit, comprising a photomultiplier control board connected to the light source baseboard, and an amplification and comparison circuit and a photomultiplier tube connected to the photomultiplier control board;

[0033] a processor, wherein the processor is communicatively connected to the temperature adjustment circuit, the temperature sensor, the semiconductor refrigeration plate, the automatic power control optical power feedback circuit, the photodiode, the photomultiplier control board, the amplification and comparison circuit, and the photomultiplier tube;

[0034] Wherein, the processor is used to execute the above-mentioned photon counting anomaly correction method.

[0035] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0036] The embodiment of the present application provides a method and device for correcting photon count anomalies, which uses temperature feedback and APC optical power feedback to ensure the stability and consistency of the light source, reduce errors, and improve the accuracy of PMT tube correction; at the same time, the light source is controlled at a constant temperature, which slows down the aging of the light source and increases the service life of the equipment. Circuit feedback is used to automatically correct the photon count, thereby improving the measurement accuracy of the device. At the same time, the PMT tube can be packaged together with the signal processing circuit, and the entire device can be used directly alone or in combination with other devices, which greatly reduces the difficulty of using the PMT tube. The use of circuit automatic correction does not require additional personnel participation. At the same time, the PMT tube count is compensated by the circuit, and there is no need for separate calibration and disassembly of the PMT tube, which greatly reduces the number of repairs and the cost of replacing the PMT tube.

[0037] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0039] Figure 1 This is a flow chart of a method for correcting photon counting anomalies provided by an embodiment of the present invention;

[0040] Figure 2 It is a structural schematic diagram of a photon counting anomaly correction device provided by an embodiment of the present invention.

[0041] In the figure: light source base plate 1, temperature adjustment circuit 2, temperature sensor 3, semiconductor refrigeration plate 4, automatic power control light power feedback circuit 5, photodiode 6, photomultiplier control board 7, amplification and comparison circuit 8, photomultiplier tube 9, processor 10, light source 11, output line 12. DETAILED DESCRIPTION

[0042] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0043] See also Figure 1 , is a method for correcting photon counting anomalies provided by an embodiment of the present invention, such as Figure 1 As shown, the method may include:

[0044] Get the actual temperature value of the light source;

[0045] generating a temperature adjustment strategy based on a relationship between the actual temperature value and a preset temperature range;

[0046] controlling a temperature adjustment unit to adjust the temperature of the light source according to the temperature adjustment strategy so as to adjust the actual temperature value to a target temperature value, wherein the target temperature value is within the preset temperature range;

[0047] Obtaining the actual optical power of the light source;

[0048] generating an optical power adjustment strategy according to a relationship between the actual optical power and the preset optical power range;

[0049] The optical power adjustment unit is controlled to adjust the optical power of the light source according to the optical power adjustment strategy, so as to adjust the actual optical power to the target optical power, and the target optical power is within the preset optical power range.

[0050] The photon counting anomaly correction method provided in the embodiment of the present application can realize automatic correction of light source temperature and power, perform environmental correction on the correction process, and ensure that the correction process is consistent with the environmental conditions of the device factory inspection.

[0051] In order to enable the method to detect whether there is a fault in the light source during execution, the embodiment of the present application may further provide a method for obtaining the number of temperature adjustments and / or the number of optical power adjustments;

[0052] Whether the light source is faulty is determined based on a comparison result of the number of temperature adjustments and / or the number of optical power adjustments with a first number threshold value, which may be 10 times.

[0053] In practical applications, the actual temperature value of the light source can be obtained in a variety of ways. For example, in one implementation, an embodiment of the present application can provide two temperature sensors arranged around the light source to obtain the actual temperature value, and the temperature adjustment unit includes a semiconductor refrigeration plate.

[0054] The embodiment of the present application uses a semiconductor refrigeration chip to adjust the temperature of the light source. It does not require any refrigerant, can work continuously, has no pollution source, no rotating parts, will not produce a rotation effect, and has no sliding parts. It is a solid piece, has no vibration or noise during operation, has a long life, and is easy to install. The semiconductor refrigeration chip has two functions, which can both cool and heat. Therefore, a single piece can replace a separate heating system and a refrigeration system. The semiconductor refrigeration chip is a current transducer type piece. By controlling the input current, high-precision temperature control can be achieved. In addition to temperature detection and control means, it is easy to realize remote control, program control, and computer control, which is convenient for forming an automatic control system.

[0055] When performing temperature adjustment, the embodiment of the present application may provide a temperature adjustment strategy generated according to the relationship between the actual temperature value and the preset temperature range, including:

[0056] When it is determined that the actual temperature value is lower than a lowest value of the preset temperature range, determining that the temperature adjustment strategy includes heating the light source by the temperature adjustment unit;

[0057] When it is determined that the actual temperature value is higher than the highest value of the preset temperature range, determining the temperature adjustment strategy includes cooling the light source by using the temperature adjustment unit.

[0058] Specifically, the magnitude and direction of the power supply current of the semiconductor refrigeration chip are controlled according to the temperature adjustment strategy, so that the semiconductor refrigeration chip can heat or cool the light source.

[0059] The embodiment of the present application may also provide for obtaining the actual optical power of the light source by using a photodiode disposed around the light source; the optical power adjustment unit includes an automatic power control (APC) optical power feedback circuit. The specific acquisition method and adjustment process will be described in detail later.

[0060] It is understandable that the light source environment can be corrected by the above two methods. In order to correct the count value, the embodiment of the present application can also provide a method for obtaining the actual count value of the light source after the temperature adjustment and the light power adjustment are completed.

[0061] determining a baseline adjustment strategy based on a relationship between the actual count value and a preset count range;

[0062] The baseline is adjusted by the baseline adjustment unit according to the baseline adjustment strategy, so as to adjust the actual count value to a target count value, and the target count value is within the preset count range.

[0063] Specifically, counting is performed by a photomultiplier tube, an amplifier circuit is used to amplify the output signal of the photomultiplier tube, and the actual count value is obtained by comparing with a preset comparison baseline.

[0064] In order to detect whether a photomultiplier tube (PMT) is faulty, the embodiment of the present application may provide a number of times the baseline adjustment is obtained;

[0065] Whether the photomultiplier tube has a fault is determined according to a comparison result of the number of times the baseline is adjusted and the second number threshold.

[0066] The following describes in detail the implementation process of the method provided in the embodiment of the present application by taking a specific implementation method as an example.

[0067] In actual use, the method for automatically correcting photon count anomalies provided in the embodiments of the present application can be divided into two processes: an automatic correction process for light source temperature and power; and a PMT tube count correction process. Automatic correction of source temperature and power performs environmental correction during the correction process to ensure that the correction process is consistent with the environmental conditions of the device's factory inspection. The PMT tube count correction process calibrates the PMT tube count value. A constant-power light source with a known frequency provides the count value, which is then compared and adjusted with a preset range to automatically correct the PMT tube's output count.

[0068] After the device is powered on, the source temperature and power are automatically calibrated. During this process, only the light source is powered, and the PMT tube is disconnected. This ensures that the PMT tube exposure will not be damaged due to light source failure.

[0069] The light source starts working when it is powered on. The temperature around the light source is collected through two temperature sensors close to the light source beads to monitor whether the temperature of the light source reaches the temperature limit. When the temperature of the light source is lower than the temperature limit, the power supply provides forward current to the semiconductor refrigeration chip fixed behind the light source. The current size is controlled according to the PID algorithm of the program, and the semiconductor refrigeration chip heats the light source; when the temperature of the light source is higher than the temperature limit, the power supply provides reverse current to the semiconductor refrigeration chip fixed behind the light source. The current size is controlled according to the PID algorithm of the program, and the semiconductor refrigeration chip cools the light source.

[0070] After the light source temperature stabilizes, the light source's optical power is collected through a photodiode fixed on the side of the light source. The collected data is compared with the preset power value, and the APC optical power feedback circuit is used to automatically adjust the light source's supply voltage and current to ensure the stability of the light source's optical power.

[0071] If the temperature and optical power adjustments are completed within 10 times, the light source is normal. If the light source fails to reach a stable state after 10 times, it indicates that the light source is faulty.

[0072] The calibrated light source flashes at a set frequency and is counted by the PMT tube. The amplifier circuit amplifies the PMT output signal and compares it with the preset comparison baseline to obtain the count value.

[0073] The obtained PMT tube count value is compared with the pre-stored count range. When the count value is less than the lower limit of the range, the baseline is lowered by reducing the output of the DAC, and the counting pass rate is increased to achieve the purpose of increasing the count value; when the count value is greater than the lower limit of the range, the baseline is raised by increasing the output of the DAC, and the counting pass rate is reduced to achieve the purpose of lowering the count value.

[0074] The PMT tube count value is corrected to the normal range by automatically adjusting the threshold baseline. If the threshold baseline is adjusted more than 10 times, the device will prompt a PMT failure.

[0075] In summary, the photon counting anomaly correction method provided by this application uses temperature feedback and APC optical power feedback to ensure the stability and consistency of the light source, reduce errors, and improve the accuracy of PMT tube correction; at the same time, the light source is controlled at a constant temperature, which slows down the aging of the light source and increases the service life of the equipment. Circuit feedback is used to automatically correct the photon count, thereby improving the measurement accuracy of the device. At the same time, the PMT tube can be packaged together with the signal processing circuit, and the entire device can be used directly alone or in combination with other devices, greatly reducing the difficulty of using the PMT tube. The use of circuit automatic correction does not require additional personnel participation. At the same time, the PMT tube count is compensated by the circuit, and there is no need for separate calibration and disassembly of the PMT tube, which greatly reduces the number of repairs to the PMT tube and the cost of replacing the PMT tube.

[0076] See also Figure 2 , the embodiment of the present application can also provide a device for correcting photon counting anomalies, such as Figure 2 As shown, the device may include:

[0077] A light source base plate 1, wherein the light source base plate 1 is provided with a light source 11;

[0078] A temperature acquisition and adjustment unit, comprising a temperature adjustment circuit 2, two temperature sensors 3, and a semiconductor refrigeration chip 4, all connected to the light source base plate 1;

[0079] An optical power acquisition and adjustment unit, the optical power acquisition and adjustment unit comprising an automatic power control optical power feedback circuit 5 and a photodiode 6 both connected to the light source baseboard 1;

[0080] A counting acquisition and adjustment unit, comprising a photomultiplier control board 7 connected to the light source baseboard 1 and an amplifying and comparing circuit 8 and a photomultiplier tube 9 connected to the photomultiplier control board 7;

[0081] a processor 10, wherein the processor 10 is communicatively connected to the temperature adjustment circuit 2, the temperature sensor 3, the semiconductor refrigeration plate 4, the automatic power control optical power feedback circuit 5, the photodiode 6, the photomultiplier control board 7, the amplification and comparison circuit 8, and the photomultiplier tube 9;

[0082] The processor 10 is used to execute the above-mentioned photon counting anomaly correction method.

[0083] The photon counting anomaly correction device provided in the present application comprises a constant-power light source with temperature compensation, a PMT tube, a front-end amplifier circuit module, and a microprocessor. Temperature compensation measures such as semiconductor cooling are used to control the light source temperature within a constant range, thereby preventing the light source from affecting the ambient temperature.

[0084] At the same time, the light source control circuit adopts APC (automatic power control) circuit and uses photodiode to form a feedback circuit to ensure constant output light power. The PMT tube collects light signals and converts them into corresponding current signals. After processing by the front-end amplifier circuit, it is transmitted to the microprocessor for comparison with the pre-stored data to determine the status of the PMT tube. If the real-time data is less than the lower limit threshold, the microprocessor lowers the baseline of the front-end amplifier circuit through the DAC output to increase the real-time data value to the range of the pre-stored data; otherwise, the baseline of the front-end amplifier circuit is raised to reduce the real-time data value to the upper limit threshold range.

[0085] After the factory settings are completed, the entire photon counting abnormality correction process is automatically carried out through circuit feedback, without the need for human intervention. Within the allowable abnormality range, there is no need to disassemble or assemble the closed darkroom for correction, thus avoiding damage to the photon counting device caused by disassembly or assembly.

[0086] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0087] Through the description of the above embodiments, it can be seen that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or certain parts of the embodiments of the present application.

[0088] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for correcting photon counting anomalies, characterized in that: include: Get the actual temperature value of the light source; generating a temperature adjustment strategy based on a relationship between the actual temperature value and a preset temperature range; controlling a temperature adjustment unit to adjust the temperature of the light source according to the temperature adjustment strategy so as to adjust the actual temperature value to a target temperature value, wherein the target temperature value is within the preset temperature range; Obtaining the actual optical power of the light source; generating an optical power adjustment strategy according to a relationship between the actual optical power and the preset optical power range; Controlling the optical power adjustment unit to adjust the optical power of the light source according to the optical power adjustment strategy so as to adjust the actual optical power to a target optical power, wherein the target optical power is within the preset optical power range; Obtaining the number of temperature adjustments and / or the number of optical power adjustments; Whether the light source has a fault is determined according to a comparison result of the number of temperature adjustments and / or the number of optical power adjustments with a first number threshold.

2. The photon counting anomaly correction method according to claim 1, characterized in that: The actual temperature value is acquired by using two temperature sensors arranged around the light source, and the temperature adjustment unit includes a semiconductor refrigeration plate.

3. The photon counting anomaly correction method according to claim 2, characterized in that: Generating a temperature adjustment strategy according to the relationship between the actual temperature value and the preset temperature range includes: When it is determined that the actual temperature value is lower than a lowest value of the preset temperature range, determining that the temperature adjustment strategy includes heating the light source by the temperature adjustment unit; When it is determined that the actual temperature value is higher than the highest value of the preset temperature range, determining the temperature adjustment strategy includes cooling the light source by using the temperature adjustment unit.

4. The photon counting anomaly correction method according to claim 3, characterized in that: The magnitude and direction of the power supply current of the semiconductor refrigeration chip are controlled according to the temperature adjustment strategy, so that the semiconductor refrigeration chip can heat or cool the light source.

5. The photon counting anomaly correction method according to claim 1, wherein: The actual optical power of the light source is obtained by using a photodiode arranged around the light source; the optical power adjustment unit includes an automatic power control optical power feedback circuit.

6. The photon counting anomaly correction method according to claim 1, wherein: Obtaining an actual count value of the light source after temperature adjustment and optical power adjustment are completed; determining a baseline adjustment strategy based on a relationship between the actual count value and a preset count range; The baseline is adjusted by the baseline adjustment unit according to the baseline adjustment strategy, so as to adjust the actual count value to a target count value, and the target count value is within the preset count range.

7. The photon counting anomaly correction method according to claim 6, characterized in that: The counting is performed by a photomultiplier tube, and an amplifier circuit is used to amplify the output signal of the photomultiplier tube, and the actual counting value is obtained by comparing with a preset comparison baseline.

8. The photon counting anomaly correction method according to claim 7, characterized in that: obtaining the number of times the baseline adjustment is performed; Whether the photomultiplier tube has a fault is determined according to a comparison result of the number of times the baseline is adjusted and the second number threshold.

9. A device for correcting abnormal photon counting, characterized in that: include: A light source base plate, wherein the light source base plate is provided with a light source; A temperature acquisition and adjustment unit, comprising a temperature adjustment circuit, two temperature sensors, and a semiconductor refrigeration chip, all connected to the light source base plate; An optical power acquisition and adjustment unit, the optical power acquisition and adjustment unit comprising an automatic power control optical power feedback circuit and a photodiode both connected to the light source baseboard; A counting acquisition and adjustment unit, comprising a photomultiplier control board connected to the light source baseboard, and an amplification and comparison circuit and a photomultiplier tube connected to the photomultiplier control board; a processor, wherein the processor is communicatively connected to the temperature adjustment circuit, the temperature sensor, the semiconductor refrigeration plate, the automatic power control optical power feedback circuit, the photodiode, the photomultiplier control board, the amplification and comparison circuit, and the photomultiplier tube; Wherein, the processor is used to execute the photon counting anomaly correction method described in any one of claims 1 to 8.

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