JPH02162287A - Radiation image receiving apparatus - Google Patents

Abstract

PURPOSE:To perform the self-diagnosis of the abnormality of a sensor and a circuit in a radiation non-emitting state by mounting a sensor means, an amplifying means, a peak discrimination and comparison means, a counting means, a bias means and a voltage control means. CONSTITUTION:A voltage control circuit 21 converts the data from a CPU 7 to analogue data by a D/A converter to supply the same to a bias power supply 20 and a sensor array 1 is composed of a semiconductor detector or a scintillator composed of Si or CdTe enchanced in impedance. When a change is generated in the bias power supply 20, the almost same signal is detected in an amplifier 2. The sensor array 1 acts as a condenser because of high impedance and, therefore, a signal is taken in the CPU 7 through a comparator 3, a counter 4 and a latch circuit 5. As a result, when abnormality is present in the sensor or the circuit system, this abnormality can be discovered by the CPU 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a radiation image receiving apparatus used in radiological diagnostic equipment, non-destructive testing radiation testing equipment, etc. in the medical and industrial fields.

2. Description of the Related Art One type of conventional radiation image receiving apparatus is one in which elements sensitive to radiation are arranged in an array and a two-dimensional image is obtained by scanning the array. As such a system, there is one described, for example, in Japanese Patent Application Laid-open No. 80746/1983. This had multiple pulse counters and counted the pulse heights by classifying them into multiple arbitrary groups.

FIG. 5 is a block diagram of a conventional radiation image receiving apparatus. In FIG. 5, 1 is a sensor array, 2 is an amplifier, 31 to
3n is a comparator, and there are n comparators. 41
4n is a counter, 51 to 5n are latch circuits, 6 is a select circuit, 7 is a CPU, 8 is a data signal, 9 is a select circuit, 10 is a bias power supply, and 11 is a comparison level setting circuit.

The operation of the above configuration will be explained below.

Radiation is incident on the sensor array 1, and the generated charges are collected in one direction by the electric field of the bias power supply 10. As a result, the incident radiation is detected as a minute pulse, and the amplifier 2
After amplification, the signals are input to comparators 31 to 3n. Comparator 31
~3n, it is compared with the output of the comparison level setting circuit 11,
When the input conditions are satisfied, the pulses are output as binary pulses and counted by counters 41 to 4n. After that, it is counted for a certain period of time and then temporarily stored in the latch circuits 51 to 5n. In addition, in order to perform wave height discrimination, comparator 3
There are n outputs of the comparison level setting circuit 11 supplied to the comparators 1 to 3n, which are different for each of the comparators 31 to 3n.

The value thus obtained is selected by the select circuit 6 by the CPU 7 and taken in as the data signal 8.

Problems to be Solved by the Invention However, in such a radiation image receiving apparatus, sensors are arranged in an array, and an amplifier or a comparator is attached to each or several sensors. Therefore, a self-diagnosis function is required to check the operation of these many sensors and circuits.

In other words, if there is no self-diagnosis function and an abnormality is discovered after image capture, there is a drawback that time is wasted in retaking images and exposure increases. Furthermore, when checking by actually performing radiation irradiation, it is difficult to perform an accurate check because the data fluctuates somewhat depending on the condition of the radiation source. On the other hand, there are methods that use radioactive isotopes that do not have energy fluctuations, but they are difficult to handle and manage, the number of output photons per unit time is small, and it is almost impossible to make photons evenly enter all sensors. .

The present invention has been made in view of these points, and it is an object of the present invention to provide a radiation image receiving apparatus having a simple configuration and a highly accurate self-diagnosis function.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention includes a sensor means sensitive to radiation, an amplification means for amplifying the output of the sensor means, and a comparison means for discriminating the wave height of the output of the amplification means. The apparatus includes a counting means for counting the output of the comparing means, a bias means for applying voltage to the sensor means, and a voltage control means for controlling the output voltage of the bias means.

Effects of the present invention With the above-described configuration, when the output voltage of the bias means is varied, a signal is output from the sensor and amplified in the amplifier. A signal almost equivalent to that of incident radiation photons is obtained, and a signal is obtained for comparison in the subsequent stage. You can check for data abnormalities, including devices and counters.

Embodiment FIG. 1 is a block diagram of an embodiment of the radiation image receiving apparatus of the present invention, and FIG. 2 is a diagram showing changes in the output voltage of the bias power supply. In FIG. 1, components that are the same as those in FIG. 5 are given the same reference numerals °, and explanations thereof will be omitted. 20 is a bias power supply, and 21 is a voltage control circuit. The voltage control circuit 20 performs D/A conversion on data from the CPU 7 and supplies the data to the bias power supply 20 . The bias power supply 20 is commercially available and can be controlled remotely.
The desired voltage is achieved by connecting signals from converters, etc. The sensor array 1 is composed of high impedance semiconductor detectors such as SL and CdTe, scintillators, and the like.

41 in Fig. 2 (a), the voltage is a signal that fluctuates between vl and v1 + ΔV, and in Fig. 2 (b), the voltage from 0 to Vl is Δ■
This is a signal that gradually increases. If there are changes in the bias power supply 20 as shown in FIGS. 2(a) and 2(b), the first
Almost the same signal is detected in amplifier 2 in the figure. In other words, since the sensor array 1 has a high impedance, it can be considered as a capacitor. Therefore, these signals are taken into the CPU 7 through the comparator 3, counter 4, and latch circuit 5. As a result, if there is an abnormality in the sensor or circuit system described above, the CPU 7 can discover it.

3(a) and 3(b) show an embodiment of the bias power supply 20. In FIG. 3(a), a high voltage power supply 22 is supplied to the sensor array 1 through a resistor R. When the relay 23 is turned on by a command from the CPU 7, the capacitor C
is charged. In the OFF state, a signal proportional to the output of the voltage control circuit 21 is applied to the sensor array 1 without being influenced by the capacitor C. That is, when the relay 23 is OFF, the signal shown in FIG. 2 is applied to the sensor array 1. ΔV is determined and checked by the outputs L1 and L2 of the comparison level setting circuit 11 shown in FIG. 5 within the range where the amplifier 2 is not saturated. Also, the time constants of R and C and the frequency of the check signal shown in FIG. (FIG. 2), the relay 23 may be omitted; however, the relay 23 can be replaced with a switching element such as a transistor or a thyristor.

In FIG. 3(b), a signal from the voltage control circuit 30 is connected to point A via a relay 31. relay 23
When the relay 31 is turned ON in the OFF state, a check signal from the voltage control circuit 30 is input to the sensor array 1. From then on.

It is checked as described above. Further, the relay 23 may be inserted between the point A and the resistor R and the capacitor C after being connected.

FIG. 4 is a block diagram of one embodiment of the voltage control circuit 21. In FIG. 4(a), data from the CPU 7 is converted by the D/A converter 24 and supplied to the bias power supply 20. Therefore, the frequency is determined by the command speed of the CPU 7. In FIG. 2B, the output signal of the oscillation circuit 26 is input to the select circuit 27 and added to the adder circuit 25.

The adder circuit 25 adds the output of the D/A converter 24 and supplies the resultant signal to the bias power supply 20 . Therefore, the signal frequency is determined by the oscillation circuit 26.

Also, when no check is performed, the select circuit 27 is
The adder circuit 25 selects ND (OV) and does not affect the adder circuit 25. The adder circuit 25 is composed of an OP amplifier or the like, and the select circuit 27 is composed of an analog switch or the like.

Note that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the gist thereof.

Effects of the Invention As described above, according to the present invention, it is possible to obtain a self-diagnosis function that determines abnormalities in sensors and circuits with an extremely simple configuration and in a state where no radiation has been irradiated. , the maintenance reliability of the radiation image receiving apparatus can be improved, and it is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1 shows a radiation image receiving device according to an embodiment of the present invention.
Block diagram, Figures 2 (a) and (b) are diagrams showing changes in the output voltage of the bias power supply, Figure 3 II Figure 1...Sensor array, 2...Amplifier,
7...CPU, 21...Bias power supply, 21...Voltage control circuit, 24...D
/A converter, 25...Addition circuit, 26...
...Oscillation circuit, 27...Select circuit, 3
0... Voltage control circuit. Name of agent: Patent attorney Awano Train: 1 person Figure 2 (a) (b) Time Time diagram c~ 2 Otsu diagram

Claims (1)

[Claims] a sensor means sensitive to radiation; an amplification means for amplifying the output of the sensor means; a comparison means for discriminating the wave height of the output of the amplification means; a counting means for counting the output of the comparison means; A radiation image receiving apparatus comprising a bias means and a voltage control means for controlling an output voltage of the bias means.