CN202372648U

CN202372648U - Detector

Info

Publication number: CN202372648U
Application number: CN2011205448548U
Authority: CN
Inventors: 赵崑; 阮明
Original assignee: Nuctech Co Ltd
Current assignee: Nuctech Co Ltd
Priority date: 2011-12-22
Filing date: 2011-12-22
Publication date: 2012-08-08
Anticipated expiration: 2021-12-22

Abstract

The utility model discloses a detector which comprises a detector crystal, a multi-layer moderation body and a multi-layer conversion body, wherein the moderation body adopts the structure that neutrons entering into the moderation body are moderated; the conversion body adopts the structure that the moderated neutrons and the conversion body are subjected to neutron-capture reaction; the detector crystal is used for detecting the incident rays; and the moderation body and the conversion body are arranged outside the detector crystal in an overlapping manner.

Description

A kind of detector

Technical field

The utility model relates to a kind of radioactive matter monitoring, detector of detected neutron and gamma ray simultaneously of being used for.

Background technology

³The He proportional counter tube is one of the most frequently used neutron detector, in fields such as neutron spectrum measurement, special nuclear material monitoring, radioactive matter monitorings, because of characteristics such as its detection efficiency height, makes it become the first-selected neutron detector in these fields.

But ³He gas is a kind of scarce resource, and its acquisition is restricted, thereby causes ³The use of He proportional counter tube is restricted.For this reason, the utility model provides a kind of new neutron detection device and measuring method, according to the sniffer of the utility model needs not ³The He proportional counter tube.

The utility model content

According to an aspect of the utility model, it provides a kind of detector, and it comprises: detector crystal, multilayer slow body and multilayer conversion body; Said slow body is arranged to make the moderation of neutrons that gets into slow body; Said conversion body is arranged to make by the neutron of slowing down and conversion body generation neutron-capture reaction; Said detector crystal is arranged to the ray that gets into is surveyed; Wherein, said slow body and said conversion body overlap and are provided with, and it is outside that said slow body and said conversion body are arranged on said detector crystal.

Preferably, said slow body is made up of tygon.

Preferably, said conversion body is made up of iron or copper.

Preferably, said detector crystal is made up of sodium iodide.

Preferably, the thickness of every layer of said slow body is 1-2cm.

Preferably, the thickness of every layer of said conversion body is 1-4mm.

Preferably, said detector crystal is a rectangular parallelepiped, and the area of said detector crystal is identical with the area of said slow body and conversion body.

The above-mentioned not specific embodiment of the utility model has the advantage and the effect of following one or more aspect at least:

Compared with prior art, the constituent material of the detector of the utility model is easy to obtain, and cost reduces; And the detector of the utility model is applied widely, surveys sensitive higher.

Description of drawings

Fig. 1 is the cut-open view according to the front of the detector of a kind of embodiment of the utility model;

Fig. 2 is the side cross-sectional, view of detector shown in Figure 1.

Embodiment

Pass through embodiment below, and combine accompanying drawing 1-2, do further bright specifically the technical scheme of the utility model.In instructions, same or analogous drawing reference numeral is indicated same or analogous parts.Followingly the explanation of the utility model embodiment is intended to the overall utility model design of the utility model is made an explanation, and is not to be understood that and is a kind of restriction the utility model with reference to accompanying drawing.

According to the detector preferred embodiment of the utility model, as illustrated in fig. 1 and 2, it comprises: detector crystal 1, multilayer slow body 2 and multilayer conversion body 3; Slow body 2 is arranged to make the moderation of neutrons that gets into slow body 2; Conversion body 3 is arranged to make by the neutron of slowing down and conversion body generation neutron-capture reaction; Detector crystal 1 is arranged to the ray that gets into is surveyed; Wherein, slow body 2 overlaps with conversion body 3 and is provided with, and slow body 2 is arranged on detector crystal 1 outside with conversion body 3.As shown in Figure 1, slow body 2 surrounds detector crystal 1 with conversion body 3.

According to the utility model preferred embodiment, detector crystal is made up of sodium iodide, and detector crystal also can be made up of cesium iodide, lanthanum bromide, and Nal detector is the higher detector of energy resolution.In addition, because tygon is the ideal material that is used for degraded neutron, preferably, slow body 2 is made up of tygon.Iron or copper are thermal neutron capture reaction cross section (iron σ _γ=2.56 targets, copper σ _γ=3.78 targets) bigger element can react with thermal neutron and emit high-energy gamma ray, and preferably, conversion body 3 is made up of iron or copper.

As shown in Figure 1, preferably, detector crystal 1 is a rectangular parallelepiped, and the area of the area of detector crystal 1 and slow body 2 and conversion body 3 is identical, and slow body 2 every layer thickness are 1-2cm.Conversion body 3 every layer thickness are 1-4mm.Can detector crystal 1, slow body 2 and conversion body 3 be fixed together through shell, slow body and conversion body are arranged alternately the probability that capture reaction can be provided.

The principle of work of the utility model is that the neutron of entering slow body 2 at first by slowing down, becomes the lower neutron of energy; Subsequently, have the part low energy neutron can get into conversion body 3, with conversion body 3 with certain probability generation capture reaction, emit gamma ray (energy is less than 8MeV); These gamma rays are detected by detector, and signal is through the processing and the examination of subsequent conditioning circuit, if energy between 3～8MeV, then is registered as neutron counting.Otherwise for the gamma ray that gets into detector, its signal is through the processing and the examination of subsequent conditioning circuit, if energy then is registered as gamma ray count less than 3MeV (gamma energy that the gamma radioactive source sends is usually all less than 3MeV).

Another one aspect according to the utility model; The utility model also provides the method for a kind of while detected neutron and gamma ray; Utilize the detector of the utility model; Gamma ray is surveyed by said detector, and detector output signal is handled, and analyzes the size of the energy of said gamma ray and carries out neutron counting or gamma ray count.

Preferably,, then be registered as neutron counting, if said energy less than 3MeV, then is registered as gamma ray count if said energy is in 3MeV-8MeV.

For common gamma ray, energy is usually less than 3MeV.The output signal of detector is divided into two intervals, and one is called the gamma district less than 3MeV, and the gamma ray background counting rate in this district is very high; One is called middle subarea between 3～8MeV, the gamma ray background counting rate in this district is very low.For the capture reaction gamma ray of energy less than 3MeV, though can be counted the gamma district, therefore its relative populations can not cause the false alarm in gamma district basically than the gamma background much less in this district; And for the capture reaction gamma ray of energy greater than 3MeV, the gamma background in its relative populations is then distinguished with this is suitable, the warning in subarea in can causing; For the non-capture reaction gamma ray of energy, can be counted the gamma district less than 3MeV; And for the non-capture reaction gamma ray of energy greater than 3MeV, though can be counted middle subarea, its quantity is few, the false alarm in subarea in therefore can not causing basically.

If the activity of neutron source is very big, the energy that sends of capture reaction also can be a lot of less than the gamma ray quantity of 3MeV so, so just might cause the false alarm in gamma district.The way that addresses this problem is that the power spectrum in gamma district is analyzed.Because the energy of the gamma ray that the neutron-capture reaction of iron or copper is sent comparatively disperses, therefore be difficult on the power spectrum in the gamma district form characteristic peak, even formed characteristic peak, also can judge whether from neutron-capture reaction according to its peak position.When the gamma district takes place to report to the police,, explain that then this warning is that big activity neutron source causes if can not find characteristic peak in the power spectrum in gamma district; If there is characteristic peak to exist in the power spectrum in gamma district, and this characteristic peak belongs to the gamma radioactive source, explains that then this warning is that the gamma radioactive source causes really.

Though some embodiment of this overall utility model design are shown and explain; Those skilled in the art will appreciate that; Under the situation of principle that does not deviate from this overall utility model design and spirit; Can make a change these embodiment, the scope of the utility model limits with claim and their equivalent.

Claims

1. detector, it comprises:

Detector crystal, multilayer slow body and multilayer conversion body;

Said slow body is arranged to make the moderation of neutrons that gets into slow body;

Said conversion body is arranged to make by the neutron of slowing down and conversion body generation neutron-capture reaction;

Said detector crystal is arranged to the ray that gets into is surveyed;

Wherein, said slow body and said conversion body overlap and are provided with, and it is outside that said slow body and said conversion body are arranged on said detector crystal.

2. detector according to claim 1, wherein,

Said slow body is made up of tygon.

3. detector according to claim 1, wherein,

Said conversion body is made up of iron or copper.

4. detector according to claim 1, wherein,

Said detector crystal is made up of sodium iodide.

5. detector according to claim 1, wherein,

The thickness that said slow body is every layer is 1-2cm.

6. detector according to claim 1, wherein,

The thickness that said conversion body is every layer is 1-4mm.

7. detector according to claim 1, wherein,

Said detector crystal is a rectangular parallelepiped, and the area of said detector crystal is identical with the area of said slow body and conversion body.