JPS5935213A - Stabilized power source device for detector - Google Patents

Abstract

PURPOSE:To supply a stable direct current to a detector for a CT device without reference to a DC power source in use by composing a stabilized power source device of a switch and a capacitor. CONSTITUTION:When the detectr 20 for the CT device is not irradiated with X rays, the switch A is on and the capacitor B is charged with constant charge by the detector power source 10. Then when the detector 20 is irraidated with X rays and obtains data from a sample, the switch A is on and the charge of the capacitor B is applied to the detector 20. Therefore, even if the detector power source 10 includes an AC component, the output (d) of the stabilized power source device 30 contains no AC component. Further, the switch A is turned on and off synchronously with the control signal of the data processing control 32 of the detector 20. Thus, even when any DC power source is used, a stable direct current is supplied to the detector.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device for a detector used in a computed tomography apparatus (CT apparatus).

An extremely stable DC power source is required for the ionization chamber type detector used in CT equipment. This is because when an alternating current component is applied to the power supply, the alternating current component passes through the detector and enters the signal circuit system, corrupting the data.

An object of the present invention is to provide a stabilized power supply device for a detector that can supply extremely stable direct current to the detector using any direct current power source, thereby ensuring data reliability. The purpose of this is to be installed between the detector power supply and the ionization chamber type detector.It consists of a switch and a charge storage capacitor, which is constantly connected to the detector on one side, but on the other side. When X-rays are not incident on the detector, that is, when the detector is not collecting data, it is connected to the detector power supply and charged up by the capacitor, and when the detector is collecting data, the detector power supply This is achieved by disconnecting the wire between the capacitor and the capacitor and using only the charge held in the capacitor as the high-voltage power source for the detector.

Next, the gist of the present invention will be explained with reference to the drawings.

FIG. 1 shows a conventional usage example in which a detector power supply 10 and a detector 20 are directly connected. In this case, as shown in the upper part of Figure 2,
When the AC component (■) is superimposed on the DC voltage waveform (■), as shown in the lower part of Figure 2, the detector output (■) is also affected by the AC component (■) even if the amount of incident X-rays is constant.

FIG. 3 is a diagram showing one embodiment of the present invention, and a stabilized power supply device 30 according to the present invention mainly consists of a switch and a charge storage capacitor (2). According to the invention, in order to control the operation of the switch
DAS control) 32 is used. This divides the operation into two parts, which will be explained with reference to FIGS. 4 and 5.

FIG. 4 shows an embodiment in which the switch is turned on when no X-rays are irradiated, and a constant charge is accumulated in the capacitor (2) due to the change in the on state. Note that it is always connected to the detector 20.

FIG. 5 shows an embodiment in which the switch is turned off when X-rays are irradiated and the detector 20 takes data from the subject. In this case, even if the DC voltage waveform has an AC component ■, the output ■ of the stabilized power supply 30 (as shown in the upper part of Figure 6) has no AC component, as shown in the middle part of Figure 6. As shown in the lower part of the figure, the detector output (2) can also be a signal that is not affected by alternating current components due to the detector voltage.

As mentioned above, the data processing control 32 of the detector 20 operates the switch 1 in synchronization with this control signal.
Turn on and off.

In the embodiment described above, when the switch (2) is irradiated with X-rays, it is turned off;
On the other hand, so that it is turned on when X-rays are not being irradiated,
It is controlled by the DAS control 32, but according to another embodiment, it is turned off for a certain period of time even when it is not irradiating, and during that time the dark current of the detector 20 is taken without being affected by the alternating current component. . Therefore, the DAS control 32 requires a circuit design such as connecting it to the switch (2) via a delay circuit or the like.

Conventionally, when a detector power supply with inferior performance is used as a power supply for an ionization phase detector, the detector is strongly influenced by noise such as AC components generated by the power supply, and the output accuracy of the detector is significantly reduced. On the other hand, when using the stabilized power supply device according to the present invention, even if a detector power supply device with inferior performance is used,
The direct current voltage supplied to the detector is not affected by alternating current components, and the output accuracy of the detector does not deteriorate. Therefore, since a power supply device with inferior performance can be used, there is no need to use an expensive, high-precision power supply device, and costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a circuit block diagram of a conventional example, Fig. 2 is an output waveform diagram in that case, Fig. 3 is a circuit block diagram showing an embodiment of the present invention, and Fig. 4 is a circuit block diagram of a conventional example. FIG. 5 is a circuit block diagram when the switch is open, and FIG. 6 is a circuit block diagram when the switch is opened.
, ■, 0 point waveform diagram 0 10 is the detector power supply, 20 is the detector, 30 is the stabilizing power supply, 32 is the data processing controller of the detector 20, ■ is the switch, and ■ is the charge storage capacitor. Some 0

Claims (1)

[Claims] It consists of a switch and a charge storage capacitor, on one side permanently connected to the detector via both terminals of the capacitor, and on the other side the switch operates synchronously with the data processing control of the detector, thereby A stabilized power supply device for a detector, characterized in that it is connected to a detector power supply in a disconnectable manner.