JPH059919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to an X-ray tube deterioration determination device that determines the deterioration of an X-ray tube.

(Technical Background of the Invention and its Problems) Conventionally, an X-ray generator that continuously irradiates X-rays has been used to measure the thickness of an object to be measured. Such an X-ray generator is required to generate highly stable X-rays, but these X-rays are very susceptible to fluctuations in the tube voltage and tube current of the X-ray tube.
That is, fluctuations in the tube voltage appear in the energy and amount of X-rays emitted, and fluctuations in the tube current appear as changes in the amount of X-rays. Therefore, when measuring the thickness, the influence of the variation directly appears as an error in the thickness indication, that is, the measurement. For this reason, an X-ray generator as shown in FIG. 1 has conventionally been used to stably generate X-rays. Note that FIG. 2 is a block diagram of the tube voltage control section and tube current control section of the same device. In this X-ray generator, the X-ray tube voltage VD is boosted by a high-voltage transformer T1, further rectified and boosted by a Kotscroft rectifier circuit 1, and sent to the X-ray tube XT. It is sent to the filament of the X-ray tube XT via T2 to generate X-rays. On the other hand, the tube voltage detection section 2 detects the X-ray tube voltage VD of the Kotscroft rectifier circuit 1, and sends the voltage obtained by dividing the voltage of the resistors to the tube voltage control section A as a tube voltage detection signal VT. Further, the tube current detection unit 3 detects the X-ray tube current FD of the filament transformer T2,
The tube current detection signal T is sent to the tube current control section B. These tube voltage and tube current control parts A and B are
The X-ray tube voltage VD and the X-ray tube current FD are separately controlled by the tube voltage detection signal VT and tube current detection signal T, respectively. That is, in the tube voltage control section A, the tube voltage detection signal VT is converted into a predetermined signal by the operational amplifier 11. Then, the tube voltage control signal of the difference between this signal and the set tube voltage of the X-ray tube XT set in the tube voltage setting device 12 is transmitted to the error amplifying section 13.
After amplifying the signal, the signal is sent to the tube voltage driver 14. This tube voltage drive unit 14 transmits the X-ray tube voltage VD from the X-ray tube power supply 15 to the high voltage transformer T1 in accordance with the tube voltage control signal.
Supply as. This controls the X-ray tube voltage VD. Further, the tube current control signal T is converted into a voltage signal by the current-voltage converter 16 and sent to the error amplification section 17. Hereinafter, similarly to the control of the X-ray tube voltage VD, a tube current control signal representing the difference between the signal from the current-voltage converter 16 and the set tube current from the tube current setting device 18 is sent from the error amplifying section 17 to the filament driving section 19. The filament drive unit 19 supplies the filament power source 20 as the X-ray tube voltage FD.
Supplied from. This controls the X-ray tube current FD.

By the way, if leakage (discharge) occurs in the X-ray tube voltage or X-ray tube current due to deterioration of insulation inside or outside the X-ray tube XT, energy decreases, so each control section A , B decreases, and to compensate for this, control is performed to increase the energy. Since the above-mentioned discharge generally occurs instantaneously, the control for its recovery is also performed by the control units A and B.
If the response speed is sufficient, a spike-like signal will be generated in response to fluctuations caused by discharge, and a spike-like pulse will appear in each tube voltage and tube current control signal.

As mentioned above, the X-ray tube voltage VD and the X-ray tube current
Even if the FD is controlled, the X-rays generated due to the deterioration of the X-ray tube XT itself will fluctuate rapidly in a spike-like or step-like manner. Fluctuations caused by deterioration cannot be fully controlled even in the tube voltage and current sensing control sections A and B, and are detected by the tube voltage and tube current detection sections 2 and 3. Furthermore, this variation increases as the degree of deterioration of the X-ray tube XT progresses. Therefore, when measuring the thickness, etc., not only is the measurement not accurate, but there is also a risk that the X-ray generator may malfunction.

Therefore, if the X-rays suddenly fluctuate, it is determined that the X-ray tube XT has deteriorated, and the X-ray tube XT is replaced with a new one.

However, the degree of deterioration of conventional X-ray tubes is determined by having a monitor judge monitor the drive voltage of the X-ray power source 15. However,
Even if fluctuations in the X-ray tube voltage are monitored, variations in the determination of deterioration occur due to differences in the criteria for determining deterioration and individual differences among the judges. Furthermore, since the drive voltage must be constantly monitored, there is a problem in that maintenance and organization of the monitored recording paper is time consuming and extremely complicated.

(Object of the Invention) The present invention has been made to solve the above problems, and is capable of automatically determining the degree of deterioration of an X-ray tube, eliminating the need to maintain and organize recording paper, and easily
An object of the present invention is to provide an X-ray tube deterioration determination device that can determine the degree of deterioration of a ray tube and generate stable X-rays.

(Summary of the Invention) The present invention provides deterioration determination of an X-ray tube in an X-ray generator that applies an X-ray tube voltage from a high-voltage transformer to the X-ray tube and also flows an X-ray tube current from a filament transformer to generate X-rays. The device is newly equipped with a tube voltage fluctuation detection means, a tube current fluctuation detection means, and a counting alarm means, and the tube voltage fluctuation detection means detects the difference between the tube voltage detection signal of the X-ray tube voltage and the set tube voltage of the X-ray tube voltage. The spike-like changes included in the signal flowing to the tube voltage control unit, which controls the X-ray tube voltage based on the The tube current fluctuation detection means outputs a pulse signal, and the tube current fluctuation detection means flows to a tube current control section that controls the X-ray tube current based on the difference between the tube current detection signal of the X-ray tube voltage and the set tube voltage of the X-ray tube current. The spike-like changes included in the signal are captured and converted into pulses, and when the voltage value of this pulse exceeds a preset voltage level, a tube current pulse signal is output, and the counting alarm means detects tube voltage fluctuations. Each pulse signal from the means and the tube current fluctuation detection means is counted, and when at least one of these counted values exceeds a preset value within a predetermined cycle time, an alarm or the like is issued. This is an X-ray tube deterioration determination device.

(Embodiment of the Invention) An embodiment of the present invention will be described below with reference to FIGS. 1 and 3. In addition, Figures 1 and 2
Components that are the same as those in the figures are given the same reference numerals and detailed explanations will be omitted. FIG. 3 is a block diagram of an X-ray tube deterioration determining apparatus according to the present invention. This deterioration determination device 30 includes a tube voltage control signal detection section 31 as a tube voltage fluctuation detection means and a tube current fluctuation detection section as a tube current fluctuation detection means for a tube voltage control section A and a tube current control section B shown in FIG. A control signal detection section 32, a preset counter 33 and an alarm lamp 34 constituting a counting alarm means are provided to control the X-ray tube voltage and X-ray tube current of the X-ray tube XT, and to check the degree of deterioration of the X-ray tube XT. It has a function to make judgments. The tube voltage control signal detection section 31 is composed of a differentiating circuit, and generates a tube voltage pulse by differentiating a spike-like change included in the tube voltage control signal from the error amplifier 13, and generates a tube voltage pulse. It has a function of outputting a tube voltage pulse signal when the voltage value of the tube exceeds a preset voltage level. Further, the tube current control signal detection section 32 is composed of a differentiating circuit, and the error amplifier 1
A tube current pulse is generated by differentiating the spike-like change included in the tube current control signal from 7, and when the voltage value of this tube current pulse exceeds a preset voltage level. It has a function of outputting a tube current pulse signal. Note that these tube voltage control signal detection section 31 and tube current control signal detection section 32 generate tube voltage pulses and tube current pulses, respectively, and compare them with each voltage level. Since this occurs in both positive and negative ways, it is provided, for example, on the first polarity side. Note that these voltage levels may be provided on both positive and negative polarity sides.

The preset counter 33 counts the tube voltage pulse signal and the tube current pulse signal individually and simultaneously,
An alarm signal is output when at least one of these count values exceeds a preset value within a predetermined cycle time.
The alarm lamp 34 is turned on in response to an alarm signal from the preset counter 33, and is used to warn of deterioration of the X-ray tube.

Next, the operation of the apparatus configured as described above will be explained. First, when the power is turned on, the X-ray generator applies the X-ray tube voltage VD to the X-ray tube XT through the Kotscroft type rectifier circuit 1 after boosting the X-ray tube voltage VD by the high-voltage transformer T1.
FD to X-ray tube via filament transformer T2
Stream to XT. This causes X-rays to be generated from the X-ray tube XT.

Here, X from Kotscroft type rectifier circuit 1
The tube voltage is detected by the tube voltage detection section 2, and the X-ray tube current FD from the filament transformer T2 is detected by the tube current detection section 3. The tube voltage detection signal VT and tube current detection signal IT are then sent to tube voltage and tube current control sections A and B of the deterioration determining device 30 shown in FIG. 3, respectively.

Here, the deterioration determination device 30 controls the X-ray tube voltage VT and the X-ray tube current FD, and simultaneously determines the deterioration of the X-ray tube XT. Currently, the deterioration of the X-ray tube XT is causing
When this occurs inside or on the surface of the X-ray tube XT, a sudden drop in the X-ray tube voltage VD applied to the X-ray tube XT is detected by the tube voltage detection section 2. This tube voltage detection section 2 sends the tube voltage detection signal VT to the tube voltage control section A.
The signal is sent to the operational amplification section 11. This tube voltage detection signal
VT is converted into a predetermined signal by the operational amplifier section 11 and sent to the error amplifier 13. This error amplification section 1
3 determines the difference between the set tube voltage of the X-ray tube XT set in the tube voltage setting device 12 and the signal from the operational amplifier section 11, and outputs a tube voltage control signal. By the way, this tube voltage control signal includes rapid fluctuations, that is, spike-like changes, in the X-ray tube voltage VD. Here, the larger the spike-like change, the higher the X-ray tube voltage.
The fluctuations in VD are large. Therefore, the tube voltage control signal detection section 31 differentiates the spike-like changes included in the tube voltage control signal using a differentiating circuit and converts them into tube voltage pulses having a voltage value corresponding to the amount of variation, that is, the magnitude of the spike-like signal. , and when the voltage value of this tube voltage pulse exceeds a preset voltage level, a tube voltage pulse signal is output to the preset counter 33. This preset counter 33 counts the tube voltage pulse signals sent thereto, and when this counted value exceeds a preset value within a predetermined cycle time, it sends out an alarm signal to the alarm lamp 34. As a result, the alarm lamp 34 lights up, giving an alarm that the X-ray tube has deteriorated, that is, it is time to replace the X-ray tube XT.

On the other hand, fluctuations due to deterioration of the X-ray tube XT are also included in the tube current control signal from the error amplification section 17 as spike-like changes. Therefore, like the tube voltage control signal detection section 31, the tube current control signal detection section 32 detects only spike-like changes included in the tube current control signal that are equal to or higher than a predetermined voltage level. A preset counter 33 counts the number of times. When this count value exceeds a preset value within a predetermined cycle period, the alarm lamp 3
Sends an alarm signal to 4. As a result, the alarm lamp 34 lights up, indicating that the X-ray tube has deteriorated or
An alarm will be issued to notify you that it is time to replace the XT.

Therefore, according to the present device, when the tube voltage and tube current control signals fluctuate due to deterioration of the X-ray tube XT, the tube voltage and tube current control signal detection units 31 and 32 output the tube voltage pulse signal and the tube current pulse signal, respectively. The preset counter 33 counts the tube voltage pulse signal and the tube current pulse signal, and issues an alarm when at least one of these counts exceeds the preset value within a predetermined cycle time. Therefore, it is possible to automatically determine the deterioration of the X-ray tube XT without having to monitor the monitor and determine the deterioration of the X-ray tube XT, which is the case in the past. It is possible to determine whether the time is right. Furthermore, there is no need to maintain or organize the recording paper recording the X-ray tube voltage VD, and by monitoring the count value of the preset counter 33, the degree of deterioration of the X-ray tube XT can be ascertained. This allows the X-ray tube XT to be replaced with a new one before the deterioration of the X-ray tube XT progresses.

Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, the tube voltage and tube current control signal detection units 31 and 32 detect the tube voltage and tube current control signals from the error amplification units 13 and 17, but the operational amplification unit 1
1 and the current-voltage converter 16, or the output signals from the tube voltage drive unit 14 and the filament drive unit 19 may be detected. In this case, as in the above embodiment, these output signals include fluctuations due to deterioration of the X-ray tube XT. Therefore, the tube voltage and tube current control signal detection units 31, 3
2 converts the spike-like changes contained in these output signals into pulses by differentiating them, and when the voltage value of these pulses exceeds a preset voltage level, it generates a tube voltage pulse signal and a tube current pulse signal. Output. And the preset counter 33
counts the tube voltage pulse signal and the tube current pulse signal, respectively, and outputs an alarm signal when at least one of these counts exceeds a preset value within a predetermined cycle time. As a result, the alarm lamp 34 lights up and an alarm is issued.

Therefore, the operational amplifier section 11 and the current-voltage converter 1
Deterioration of the X-ray tube XT can also be determined by detecting spike-like changes included in the output signals from the X-ray tube XT 6 or the output signals from the tube voltage drive unit 14 and the filament drive unit 19 in the same manner as in the above embodiment.

In addition, an alarm signal is output when at least one of the counted values of the tube voltage pulse signal and the tube current pulse signal exceeds a preset value. current
Detection is performed for the FD, and if either one changes suddenly, it can be determined that the X-ray tube XT has deteriorated.

Further, the preset counter 33 can be replaced with an electronic computer, such as a microcomputer, and the tube voltage and tube current control signal detectors 31, 3
2 was also replaced with a microcomputer with an analog input section, which allows monitoring and determining the deterioration of the X-ray tube XT.

Furthermore, the tube voltage and tube current control signal detection section 3
1 and 32 may generate tube voltage and tube current pulse signals by combining a differentiating circuit with a mono-multivibrator or the like.

(Effects of the Invention) As detailed above, according to the present invention, it is possible to automatically determine the degree of deterioration of the X-ray tube, and furthermore, it is possible to easily detect the deterioration of the X-ray tube by eliminating the need for maintenance and organization of recording paper. It is possible to provide an X-ray tube deterioration determination device that can determine the degree of deterioration and generate stable X-rays.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an X-ray generator, FIG. 2 is a block diagram of a control section of a conventional X-ray generator, and FIG. 3 is an embodiment of an X-ray tube deterioration determination device according to the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Kotscroft type rectifier circuit, 2... Tube voltage detection section, 3... Tube current detection section, 11... Operational amplifier section, 12... Tube voltage setting device, 13, 17... Error amplification section, 14... ...Tube voltage drive unit, 15...X-ray power supply, 16...Current voltage converter, 18...Tube current setting device, 19...Filament drive unit, 20...
Filament power supply, 30...Deterioration determination device, 31
...Tube voltage control signal detection section, 32...Tube current control signal detection section, 33...Preset counter, 34
...Alarm lamp, T1...High voltage transformer, T2...
...Filament transformer, XT...X-ray tube, A...
...Tube voltage control section, B...Tube current control section.

Claims (1)

[Claims] 1. In an X-ray tube deterioration determination device for determining whether an X-ray tube is deteriorated during X-ray irradiation, a tube voltage detection means for detecting an X-ray tube voltage supplied to the X-ray tube and outputting a tube voltage detection signal; , tube current detection means for detecting the X-ray tube current of the X-ray tube and outputting a tube current detection signal;
A tube voltage control signal of the difference between the line tube voltage and the set tube voltage is obtained, and the above-mentioned
A tube voltage control unit that controls the X-ray tube voltage supplied to the X-ray tube, and a tube current control unit that determines a tube current control signal representing the difference between the tube current detection signal and a preset tube current of the X-ray tube current; A tube current control unit that controls the X-ray tube current according to the voltage value of the current control signal, and a tube voltage control unit that captures spike-like changes included in the signal flowing to the tube voltage control unit and converts it into a pulse, and the voltage value of this pulse is set in advance. tube voltage fluctuation detection means that outputs a tube voltage pulse signal when the voltage exceeds a set voltage level; and a tube voltage fluctuation detection means that captures a spike-like change included in the signal flowing to the tube current control section and converts it into a pulse, and the voltage value of this pulse. tube current fluctuation detection means that outputs a tube current pulse signal when the voltage exceeds a preset voltage level, and tube voltage pulse signals and tube current pulse signals from these tube voltage fluctuation detection means and tube current fluctuation detection means. An X-ray tube characterized in that the X-ray tube is equipped with a counting alarm means that counts each of the counted values and issues an alarm when at least one of these counted values exceeds a preset value within a predetermined cycle time. deterioration determination device.