JPS5814073A - Self-output type radiation detector - Google Patents

Abstract

PURPOSE:To reduce the trouble of cut wire during manufacture without reducing radiation detection performance by gradually reducing the outer diameter of the end of the lead wire connected to an emitter to the diamter that is same as that of the emitter. CONSTITUTION:An emitter 2 is inserted coaxially in a collector 1. A lead wire 3 is connected to one end of the emitter 2, and it is tapered to become larger from its joint with the emitter. At the joint the outer diameters of the emitter and the wire are the same. Accordingly there is no difference in substance regarding the radiation detection performance between this case and conventional detectors, but the former has larger resistance to tensile force applied in the process of reducing size of the wire. Therefore, the trouble of cut wire can be made less likely to occur in the manufacturing process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a self-powering radiation detector that detects neutrons and gamma rays.

FIG. 1 is a sectional view showing the configuration of a conventional self-output type radiation detector. In FIG. 1, 1 is a cylindrical sheath-like collector, and 2 is a cylindrical emitter disposed coaxially inside the collector 1. In FIG. A lead wire 8 is electrically connected to one end of the emitter 2. This lead wire 8 is disposed coaxially inside the collector 1 and is used for extracting signals.

The gap between the collector l and the emitter 20 is filled with an insulator 4. Due to this insulator 4, collector 1 and emitter are electrically isolated from lead wire 8.

As the insulator 4, A1*Os or MgO is usually used.

In a neutron detection tube, the emitter is made of a material with a large neutron absorption cross section, such as rhodium or vanadium, and when a neutron is incident, the emitter absorbs the neutron, becomes radioactive, and undergoes β decay.

At this time, a part of the emitted β rays penetrates the insulator 4 and reaches the collector l. Collector 1 is also radioactive,
β-rays are emitted, but since a material with a small neutron absorption cross section is selected for the collector l, the net flow of β-rays is directed from the emitter 2 to the collector 1.

The flow of β-rays is proportional to the surrounding neutron flux, so if the current flowing between the emitter and collector is measured, a signal proportional to the neutron flux can be obtained.

In addition, in the gamma ray detector, a material with a large beta ray absorption cross section is used for the emitter 2, and a material with a small beta ray absorption cross section is used for the collector l. The net flow of electrons is from the emitter 2 to the collector 1, and since the magnitude of this current is proportional to the β-ray flux, measuring this current yields a signal proportional to the T-ray flux.

Now, the typical manufacturing method for a self-output type detector is to use a collector pipe with an outer diameter much larger than the finished outer diameter, an emitter rod, a lead wire, and a bead-shaped insulator, and assemble it as shown in Figure 2. I do.

In FIG. 2, the same parts as in FIG. 1 are given the same reference numerals, and 4a to 41 indicate bead-shaped insulators, respectively.

Drawing or swaging is applied nine times to the assembly assembled as shown in FIG. 2, thereby increasing the filling rate of the bead-shaped insulators and reducing them to a predetermined finished size.

However, in the conventional self-output type radiation detector, the rod-shaped emitter 2 and the lead wire 8 with a smaller diameter are joined together by welding or other methods with different outer diameters. In addition, a large force was applied to this joint, which often caused the wire to break during manufacturing.

This invention was made to eliminate the above-mentioned conventional drawbacks, and the emitter and lead wire are connected by either gently changing the outer diameter of one or both, or by interposing a truncated cone-shaped metal piece between the two. It is an object of the present invention to provide a self-output type radiation detector that can make the outer diameters of the emitter and lead wire equal at their joint surfaces and reduce the occurrence of wire breakage during the reduction process during manufacturing.

Embodiments of the self-output type radiation detector of the present invention will be described below with reference to the drawings. FIG. 8 is a sectional view showing the configuration of one embodiment. In FIG. 8, the same parts as in FIGS. 1 and 2 will be described with the same reference numerals.

Emitter 2 is coaxially inserted into collector l,
A lead wire 8 is connected to one end of the emitter 2, and the end where it connects to the emitter 2 is tapered and thick.
At the joint surface, the emitter 2 and the lead wire 8 have the same outer diameter.

In this case, there is no substantial change in radiation detection performance compared to conventional self-powering radiation detectors, but it shows strong resistance to the tensile force applied during the manufacturing process and It is possible to reduce the problem of wire breakage during manufacturing, which was a drawback.

It is clear that the same effect can also be obtained by tapering the outer diameter of the emitter at its ends.

FIG. 4 is a sectional view showing the structure of another embodiment of the self-output type radiation detector of the present invention. In FIG. 4, instead of changing the outer diameter of the lead wire 8 or the emitter 2 at the joint end portion, a truncated cone-shaped metal piece 5 is interposed to change the outer diameter of the lead wire 8 or the emitter 2 on both sides of the two joint surfaces. The outer diameters are the same.

Further, the outer diameter of the truncated conical metal piece 5 between the joint surfaces of the two joint end portions changes gradually. This allows the eighth
As in the case shown in the figure, disconnection troubles during the manufacturing process can be reduced.

Note that 4 in FIGS. 8 and 4 is an insulator similar to the conventional one.

As described above, according to the self-output type radiation detector of the present invention, the end of the lead wire connected to the emitter is made to have the same outer diameter as the emitter and gradually decreases, or a cone is formed between the emitter and the lead wire. A truncated metal piece is interposed, and the emitter side of this truncated conical metal piece has the same dimensions as the emitter's outer diameter and gradually decreases toward the lead wire, so it can be manufactured easily without degrading radiation detection performance. It is possible to reduce disconnection troubles at times.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional self-output type radiation detector;
The figure is a cross-sectional view of the initial assembly stage of a conventional self-output type radiation detector, FIG. 8 is a cross-sectional view showing the configuration of an embodiment of the self-output type radiation detector of the present invention, and FIG. 7 is a cross-sectional view showing the configuration of another example of the output type radiation detector. 1... Collector, 2... Emitter, 8
...Lead wire, 4...Insulator, 5...
A truncated cone-shaped metal piece. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 1/2

Claims (2)

[Claims] (1) A cylindrical sheath-like collector, a columnar emitter electrically insulated and concentrically arranged within this collector, electrically connected to one end of this emitter to output signals, and A self-output type radiation detector comprising a lead wire having the same outer diameter as the emitter at the joint end portion thereof and whose outer diameter gradually decreases in the direction opposite to the emitter. (2) The lead wire is joined to the emitter with a truncated cone-shaped metal piece interposed at the end where it connects to the emitter, and the outer diameter of the joined end of this metal piece on the emitter side is the same size as the emitter. 2. The radiation detector according to claim 1, wherein the radiation detector gradually decreases toward the sides.