JP2996555B2 - Multi-sample radiation measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous counting type multi-sample radiation measuring apparatus for individually measuring radiation of a plurality of samples.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show a main part of a conventional multi-sample radiation measuring apparatus. In the conventional example shown in FIG. 3, a sample 12 containing a radioactive element is placed in a sample container 10 one-dimensionally or two-dimensionally at a predetermined interval. A solid scintillator 14 is arranged below each sample 12 of the sample container 10. Further, a pair of photomultiplier tubes 16a and 16b are provided for each sample via each sample 12.

In the conventional example shown in FIG. 4, a sample is mixed in a liquid scintillator 17 unlike the above conventional example. However, the basic configuration of the device is the same, and each liquid scintillator 17 into which a sample is mixed is provided with a pair of photomultiplier tubes 16a and 16b, respectively.

FIG. 5 is a block diagram showing the entire configuration of the apparatus shown in FIGS. 3 and 4. Outputs of the pair of photomultiplier tubes 16a and 16b are output from a pair of amplifiers 18a and 18a.
b and the discrimination circuits 20a and 20b. Here, the amplifiers 18a and 18b
Is for amplifying the detection pulse from the photomultiplier tube, and the discrimination circuits 20a and 20b are for eliminating background noise. A coincidence circuit 22 provided for each pair of photomultiplier tubes 16, in other words, provided for each sample, includes a detection pulse of one photomultiplier tube 16a and a detection pulse of the other photomultiplier tube 16b. Is counted only when are input simultaneously. That is, the coincidence circuit 22 performs AND
It includes a circuit and a counter.

The reason for performing the coincidence counting in this way is to eliminate random pulse noise generated by the photomultiplier tube itself.

Accordingly, with the above configuration, the radiation of the sample 12 is converted into photons by the solid scintillator 14 or the liquid scintillator 17, and the photons are simultaneously detected by the pair of photomultiplier tubes 16. The detection pulses output from the pair of photomultiplier tubes 16 are amplified by the amplifier 18, subjected to wave height discrimination by the discriminator 20, and further counted by the coincidence circuit 22. become. Therefore, the pulse noise generated by the photomultiplier tube itself is eliminated, and relatively accurate measurement of radioactivity can be performed.

[0007]

However, in the above-mentioned conventional multi-sample radiation measuring apparatus, two photomultiplier tubes are required for one sample in principle. There has been a problem that it becomes complicated and large, leading to an increase in cost. That is, a circuit such as a high voltage circuit and an amplifier is required for each photomultiplier tube, and the mechanism of the apparatus has been further complicated. In particular, the problem was becoming more serious in an apparatus targeting a larger number of samples.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to share a photomultiplier so that the mechanism of the apparatus can be simplified and the cost can be reduced. An object of the present invention is to provide a counting type multi-sample radiation measuring device.

[0009]

In order to achieve the above object, according to the present invention, of a pair of photomultiplier tubes provided for each sample, one photomultiplier tube is individually arranged as it is, and Is characterized in that the photomultiplier tube is shared by a plurality of samples.

Here, the shared photomultiplier tube is provided one for all samples or one for each sample group consisting of a plurality of samples.

[0011]

According to the above construction, the other photomultiplier tube is shared, but in principle, it is considered that a pair of photomultiplier tubes are arranged for each sample. The radiation of each sample can be individually counted by the coincidence counting circuit.

Therefore, radiation measurement by the coincidence method can be realized while reducing the number of photomultiplier tubes.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a main configuration of a multi-sample radiation measuring apparatus according to the present invention. In this embodiment, an individual photomultiplier tube 30 as one photomultiplier tube is arranged for each sample 12. On the other side of the individual photomultiplier tubes 30, a shared photomultiplier tube 32 is provided in the present embodiment as the other photomultiplier tube for detecting radiation of all samples. In the present embodiment, a plurality of samples 12 are two-dimensionally aligned and the scintillator 1 in the sample container 10 is arranged.
4 on top.

Sample container 10 and shared photomultiplier tube 32
A light guide 34 for guiding the light from the solid scintillator 14 is disposed between the solid-state scintillator 14 and the solid-state scintillator 14. In this embodiment, one common photomultiplier tube 32 is provided for all samples. However, all samples may be divided into a plurality of groups, and a common photomultiplier tube may be provided for each sample group. Good. In this embodiment, since one shared photomultiplier tube is provided, the number of photomultiplier tubes can be reduced by (number of samples-1) as compared with the conventional case.

In this embodiment, a large-area photomultiplier having a large light-receiving surface is provided as the shared photomultiplier 32. Of course, the same photomultiplier tube as the individual photomultiplier tube 30 can be used.

FIG. 2 is a block diagram showing the overall configuration of the multi-sample radiation measuring apparatus according to the present invention. The individual photomultiplier tubes 30 are indicated by 100 in the figure. The detection pulse from each individual photomultiplier tube 30 is input to one input terminal of the coincidence circuit 22 via the amplifier 18 and the discriminator 20 as in the conventional example.

The detection pulses output from the shared photomultiplier tube 32 are input to the other input terminals of all the coincidence circuits 22 via the amplifier 18 and the discriminator 20.

Therefore, according to the configuration shown in FIG. 2, the same operation as the configuration shown in FIG. 5 described in the conventional example can be obtained, and radiation can be individually counted for each sample. Can be.

The multi-sample radiation measuring apparatus of the present embodiment
Effective for measuring low-radiation radiation, and when detecting high-radiation radiation, that is, large amounts of radiation, as described above, the sample 12 is divided into a plurality of groups and shared by each group. It is preferable to dispose a photomultiplier tube. This is to prevent erroneous detection by eliminating contributions from other samples in the coincidence circuit 22. In any case, by arranging one shared photomultiplier tube 32 for a plurality of samples. Thus, the number of photomultiplier tubes can be surely reduced. In addition, as in this embodiment,
If a large area photomultiplier is used, a light guide is not necessarily required. Further, the multi-sample radiation measuring apparatus of this embodiment is particularly suitable for detecting low-energy β-rays.

[0021]

As described above, according to the present invention,
While maintaining the coincidence method, the number of photomultiplier tubes can be reduced, the device can be simplified, and the cost can be reduced.

Therefore, the present invention is more effective especially when measuring radiation of a larger number of samples.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a main part of a multi-sample radiation measuring apparatus according to the present invention.

FIG. 2 is a block diagram showing an overall configuration of a multi-sample radiation measuring apparatus according to the present invention.

FIG. 3 is an explanatory diagram showing a first conventional example.

FIG. 4 is an explanatory diagram showing a second conventional example.

FIG. 5 is a block diagram showing the entire configuration of a conventional device.

[Explanation of symbols]

 12 samples 22 coincidence circuit 30 individual photomultiplier tube 32 shared photomultiplier tube

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01T 1/172

Claims (1)

(57) [Claims] 1. A multi-sample radiation measuring apparatus for individually measuring radiation of a plurality of samples, comprising: an individual photomultiplier tube provided for each of the samples for detecting radiation of the samples; A shared photomultiplier tube that is provided one or one for each group of samples and collectively detects radiation of a plurality of samples; and a detection pulse from the individual photomultiplier tube provided for each of the samples. And a coincidence circuit that counts only when a detection pulse from the shared photomultiplier is simultaneously input, and a multi-sample radiation measurement apparatus.