JPS6131432B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation (charged particle) detection device equipped with several independent semiconductor detectors.

The conventional method of this type of device is a telescope detection method in which several semiconductor detectors are arranged in the direction of particle incidence, and the output signals of each detector are combined in a circuit to measure multiple channels (see Figure 1). Another method was to use semiconductor detectors for the same number of measurement channels and measure charged particles using independent circuits (see Figure 4).

Figure 1 is a functional diagram of a telescope that uses three detectors with approximately the same area. Particles that pass through detector 7 are always sent to detector 8 or to an input circuit 15 that uses a scintillator and a photomultiplier tube. The structure is such that a particle that enters and passes through the detector 8 always enters the detector 9 or the input circuit 15 . Detector 7
.about.9 and the input circuit 15 are converted into voltages and processed by the amplifier 3, level discriminator 4, and logic 5. In this case, input circuit 1
By using the output from the detector 5 to cancel the outputs of the detectors 7 to 9, the incident particles are collimated. In addition, Fig. 2 shows a case in which the area of the detectors at the rear is larger, so that the detector 8,
9. FIG. 3 shows the radiation detection device shown in FIG. 1 or 2.
Incident energy of radiation 1 and detectors 7, 8 and 9
The relationship between the detection outputs 24, 25, and 26 is shown. As the incident energy increases from zero, the radiation penetrates the detector 7 at points 16 and the output of the detector 8 begins to increase. As the incident energy further increases, it passes through the detector 8 at point 17 and reaches the detector 9, and the output of the detector 9 also begins to increase. On the other hand, for incident energies above the point '17, the output of the detector 8 begins to decrease as shown.

Detection levels 13 and 14 are the discrimination levels (threshold levels) of the detector 8, and discrimination levels 11, 12, or 15 are the discrimination levels for the detector 7 or 9, which exhibits the same detection output characteristics as the detector 8. It shows. The incident energy level determined by the detection output of the detector 8 and the threshold levels 13 and 14 and the detection output of the detector 7 or 9
detection output and threshold level 11, 12
Alternatively, if you combine it with the incident energy level determined by 15, the incident energy level will be 18 ~
Uniquely determined within the range of 22. In this case, the number of incident energy levels (number of channels) that can be detected
is determined by the number of threshold levels.

Next, in the method shown in FIG. 4, a threshold level 23 is set for the input/output characteristics 27 to 30 of each independent detector according to the measurement energy range, and the level determination circuit 4 determines that this level or higher is "1". ", and the following are set to "0" to perform level discrimination and count the number of particles for each channel. In this method, the number of detectors and the number of channels are the same.

In the case of conventional methods like this, the former requires a scintillator and a photomultiplier tube or a large-area semiconductor detector for the antennae system, as mentioned above, in devices that require a large solid angle of incidence. Ta. Furthermore, a failure of one detector usually makes it impossible to acquire data for most channels. In addition, the latter has the disadvantage that when the number of measurement channels is large, the number of detectors and the number of processing times are increased, resulting in an increase in size, weight, and power consumption. These drawbacks are particularly important for space equipment such as satellites and rockets, which require 1) small size and light weight, 2) high reliability of the equipment (cannot be replaced or repaired once launched), and 3) low power consumption and low voltage. It was disadvantageous in terms of driving (high voltage causes discharge and dielectric breakdown in response to wide range of atmospheric pressure fluctuations), etc.

In order to eliminate these drawbacks as a charged particle detection device, the present invention acquires data of multiple channels using several independent semiconductor detectors, and later performs simple calculation of the data to obtain the required channels. It is located in the radiation detection device that allows the data to be obtained.

A detailed explanation will be given below with reference to the drawings.

FIG. 6 is a block diagram of a processing circuit according to an embodiment of the present invention, and FIG. 7 is a detection characteristic diagram thereof. 1
2 is a charged particle, 2 is a detector system, 3 is an amplifier system, 4 is a level discrimination circuit system, and 7 to 10 are each detector. In addition, in FIG. 7, the vertical axis is the amplifier output, the horizontal axis is the incident particle energy, and 41 to 44 are the detector 7.
Detection characteristics corresponding to 10, 45 to 48 are energy discrimination levels of the discrimination circuit 4 for detection characteristics 41 to 44, and 51 to 57 are charges measured by each detector 7 to 10 and each discrimination level 45 to 48. Shows channel range versus particle energy.
In FIG. 6, when a charged particle 1 enters a detector system 2 and its energy is generated as a charge in the detector system 2, it is converted into a voltage by an amplifier system 3, and the voltage is determined by a discrimination circuit 4. A determination is made as to whether it is large or small, and the signal is converted into a "1" or "0" signal. The detectors 7-10 can have different properties 41-44 by selecting their thickness and the thickness of the absorber placed in front of them.

The features of the present invention are characteristics 41 to 44 and level 4.
By devising the selection of 5 to 48, the detection ranges 51 to 57 in each detector are made continuous, and each channel 55 to 57 obtained from characteristic 41 and each channel 55 to 57 obtained from characteristics 42 to 44 are made continuous. 57
The goal is to completely overlap the two. In the example shown in FIG. 6, four detectors are used independently. In this case, the detector that detects the lowest energy is provided with four discrimination levels 45, and four channels of detection are performed. Data corresponding to the channel 54 can be obtained by counting only the outputs having the highest discrimination level or higher. or,
By counting only the outputs at levels between the first and second highest, a total count corresponding to channels 53 and 55 is obtained. Similarly, channels 52 and 56, 51
and a respective total count corresponding to 57 is obtained.

Next, by selecting the characteristics 42 to 44 of the detectors 8 to 10 and the discrimination level, the counts of channels corresponding to channel 55 in detector 8, channel 56 in detector 9, and channel 57 in detector 10 are obtained, respectively. .

The count number of the channel 54 can be obtained from the output of the detector 7 that is equal to or higher than the highest determination level 45. Channel 55, 56
and 57 counts are detected by detectors 8, 9 and 10.
The outputs are determined and counted at determination levels 46, 47, and 48, respectively. Furthermore, the counts of channels 51, 52, and 53 are calculated by subtracting the counts of detectors 8 to 10 from the counts of detector 7, since the charged particles 1 statistically enter the detectors 7 to 10 almost equally. Obtained by subtraction. That is, the detector 7
The count number of the channel 51 is obtained by subtracting the count number of the channel 57 measured by the detector 10 from the count number of the channel (51+7) measured by the channel (52+56) of the detector 7 and ( By subtracting the counts of channels 56 and 55 by detectors 9 and 8 from the counts of 53+55), the counts of channels 52 and 53 are obtained. In this way, the radiation spectrum in the predetermined energy measurement ranges 51 to 57 can be continuously measured.

As explained above, in the method according to the present invention, data is acquired using a simple system that only judges each detector output as "1" or "0" with respect to a certain reference level, and then simply calculates the difference between the count data. There is an advantage that the charged particle energies and counts of multiple channels can be obtained simply by performing a pull. In addition, large-area detector scintillators and photomultiplier tubes (and the high voltage required for these) are no longer necessary, and the range of influence of detector failures is narrowed, and the latter of the conventional methods is It has the advantage of being smaller and lighter than the conventional case.

The apparatus according to the present invention is particularly effective not only for the space requirements mentioned in Section 2 but also for the requirement that data processing on a satellite be simple.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional telescope type measuring device, Figure 2 is another configuration diagram of the detector section in Figure 1, Figure 3 is a detection characteristic diagram of Figure 1, and Figure 4 is a diagram of the conventional telescope type measuring device. FIG. 5 is an input/output characteristic diagram of FIG. 4, FIG. 6 is a block diagram of an embodiment of the present invention, and FIG. 7 is an input/output characteristic diagram of FIG. 6. In the figure, 1...Charged particles, 2...Detector system, 3...Amplifier system, 4...Level discrimination circuit, 5...Logic,
7-10...Detector, 11-15, 23, 45...
...Threshold level, 15...Input circuit,
16, 17...Output point, 24-30, 41-44
. . .Characteristic curve, 45 to 48 . . .Discrimination level.

Claims (1)

[Claims] 1. A collection of three energy measurement ranges including first and second detectors for detecting charged particles made of semiconductors, and including a detector penetration region of the first detector,
and two determination levels, high and low, for the output of the first detector so that one of the energy measurement ranges other than the energy measurement range including the penetration region and the energy measurement range of the second detector match, One determination level is set for each of the second detectors, and the thickness of each detector, the thickness of the front absorber, etc. are adjusted, and the count number of the energy measurement range including the penetration area is set to the first determination level. A count number in a measurement range in which the energy measurement ranges of the first and second detectors match is obtained from the output count number of the second detector. , the number of counts in the remaining energy measurement range is determined by the first
The radiation spectrum within a predetermined energy measurement range is obtained by subtracting the output count number of the second detector from the output count number between the high judgment level and the low judgment level of the detector. A radiation detection device characterized by continuous measurement.