JPS6093400A - Gamma-ray irradiator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention &J1 relates to a gamma ray irradiation device using radioactive isotopes, and relates to an irradiation device suitable for irradiation testing of large amounts of electric elements on bamboo.

[H scene of invention]

Irradiation devices using radioactive isotopes are widely used for research purposes, medical purposes, ivy drawings, and other purposes. In particular, for research purposes, irradiation equipment with a particularly high dose rate is desired in connection with atomic couplants, space development, etc. The objects to be tested are mainly 50/50 V-body elements, materials, optical elements, materials, sensor elements, and materials. These elements and materials must: (1) When used in artificial satellites, etc., be able to function properly for a long period of time even under the irradiation of spacesuits, which mainly contain mesons; In the case of robot elements and materials used for temple inspections, it is necessary that they can function correctly and reliably even under heavy neutron and gamma irradiation, so research into these irradiation-resistant elements and abrasive materials is required. For development, a gamma ray irradiation device that can accurately measure the characteristics under irradiation is an essential equipment. From this point of view, if we look at the conventional gamma station irradiation equipment, they can be classified into the following four types, and the patents and problems of each type will be explained.

(Linol storage type) This type sinks the radioactive isotope (hereinafter referred to as the radiation source) to the bottom of the pool and uses a crane or some other source to transport it.
A single structure is raised above the water surface to irradiate a sample placed near a pool.In Japan, representative examples include those at the Japan Atomic Energy Research Institute's Ninzaki Research Institute and the Japan IsothoflIJJ Society's Koka Research Institute. It is. FIG. 1 shows a typical configuration example of this type of gamma ray irradiation equipment.

In the example shown in Figure 1, the irradiation chamber 10 has a thick concrete wall l.
5. Contains pool 2.

The water in the pool is not used for shielding purposes, and the standard radiation source used in the Dai-iI irradiation device is tens of thousands to hundreds of thousands of Ci, so the depth of the pool must be about 10m. It is. The radiation source 3 is connected to a drive mechanism 4 from a storage container 12 submerged in water.
The radiation source is fixed on the radiation source fixing table. The sample 9 is placed on the sample stage 6 by opening the shutter 7 from outside the irradiation chamber 11. The sample 9 is irradiated by closing the shutter 7 and raising the υ radiation source 3 above the water surface using the drive mechanism 4.

The advantage of this type is that since the irradiation chamber 1o is large, the space for placing the sample 9 can be sufficiently large, but it has the following drawbacks.

(1) Since the crane 5 and the pool 2 are built in, the entire facility is large, which inevitably increases costs.

(11) Because the radiation source is stored in the pool, the stroke of the drive device 4 is 10 m or more, and it takes time to change between irradiation and non-irradiation states, so it only takes time to exchange the sample. This makes it difficult to analyze electrical signals during state transitions.

G1ft As equipment becomes larger, the cables used to extract electrical signals also become longer, and due to the capacity of the cables,
High frequency signal transmission becomes difficult, and in some cases it is unavoidable to use an amplifier (5<5) under irradiation.

(2) Underfloor storage Ml type This type places the radiation source storage container under the floor +LL, removes the top cover of the container with a crane, etc., and pushes the radiation source above the floor using the drive m (i#) inside the container. The one at the Tokyo Industrial Research Institute is representative.

FIG. 2 shows the basic configuration of this type.

Sample 9 can be loaded and unloaded in irradiation chamber 1, as in the pool storage type.
This is done by opening and closing shutter 7 of 0. When irradiating the sample 9, first open the irradiation chamber 10 using the monitoring window 13 made of lead glass or the like.
While monitoring the inside of the radiation source storage container 12, the crane 5
The lid 16 of the radiation source 3 is removed, and the motor 13 rotates the pulley wheel and screw 15, which raises the source table 17 and pushes the radiation source 3 above the floor.

Although this type requires smaller equipment than the pool storage type, the advantage of this type is that it allows for a wide range of alternative solutions, but it has the following drawbacks.

(1) Since l4jt radiation requires two steps: removing the radiation source and pushing up the radiation source, it takes time for the state transition between irradiation and non-irradiation.

(11) Irradiation room 1 to set up a crane inside the irradiation room
0 is larger than necessary, the same as the pool storage type 4: tJ
It becomes difficult to transmit and measure the L signal of the +G frequency.

(During 110 irradiation, the radiation source drive mechanism 13+14+15+1
If something goes wrong with 7, #i! It becomes extremely difficult to store m3 in the container 12.

(3) Ceiling hanging type This type irradiates the sample by storing the radiation source in the ceiling and suspending it in the irradiation room downstairs.The one at the Faculty of Engineering, University of Tokyo is a typical example. be.

FIG. 3 shows the basic configuration of this type. In order to irradiate the sample 9, first slide the shutter 18 of the storage container 12 in the storage room 19 located on the upper floor of the irradiation chamber 10 sideways. The urine source 3 is suspended downstairs by a small movement mechanism using a motor 13, a gear 14, and a rack.

This type has the advantage of being able to take a wide range of (u vs. 10) and that the insertion and removal of the line λ can be done in a relatively short time, but the amount of glands dρ required to obtain a thick dose rate is large. Therefore, the water stone in the storage container 12 is large, and special measures are required for the dust-proof and load-bearing structure of the entire irradiation container, which makes the construction difficult and increases the cost.

(4) In-storage container irradiation method In this type, an irradiation pit is provided near the radiation source fixed in the container, and samples are taken in and out of this pit. FIG. 4 shows a typical configuration example of this type, in which the storage container 12
An irradiation box 25 with shields provided above and below is provided inside the irradiation box 25, and the irradiation box 25 is raised and lowered by a hydraulic lifting device comprising an oil tank 23, a pump 22, and a valve 24.

This type has the advantage that it is easy to take in and take out the sample 9, and the entire device is smaller than others, but the +iJM for storing the sample 9 is inevitably smaller, and - it is difficult to extract the gas signal. However, there are drawbacks such as the fact that special measures are required for the wiring, whereas conventional devices do not have such measures.

[Purpose of the invention]

The objects of the present invention are: - It is easy to take in and take out the blast irradiation sample, and the irradiation and non-J1 (J1 for single shot state) is short.
Moreover, it is an object of the present invention to provide an underfloor storage type gamma ray irradiation device that has a high rate of success and requires only short electrical signal wiring.

[Summary of the invention]

In order to achieve the above object, the gamma ray irradiation device of the present invention has a radiation source storage container with a radiation source fixed to the lower part of the lid placed below the irradiation bit surrounded by a strong body. It can be raised and lowered into the irradiation bit together with the lid by a radiation source driving device located above the outside of the bit, and a part of the shield is formed as a movable shutter so that the shutter can be moved outside the irradiation bit. It is characterized by Ll that it is configured to be moved by a U mechanism.

[Embodiments of the invention]

The overall basic configuration of the embodiment of the present invention is shown in FIG. 5. The gamma ray irradiation device of this embodiment includes a radiation source drive device consisting of a motor 13, a gear 14, a screw 15, etc., an iron shield 27, and a part thereof. With the eggplant shutter 28 and the streaming prevention cover 26! llll shielded irradiation bit 30, +
m consists of a radiation source storage container 16 having a fixed head 16;

The sample 9 is taken in and out of the irradiation bit 30 by opening the upper part of the irradiation bit 30 by moving the shutter 28 supported by wheels 29 mounted on a rail to the right in the figure. The sample 9 is irradiated by the above-mentioned radiation source drive mechanism located above the iron shield 27F) +WWB2 storage container lid 16
At the same time, the bit 30 is lifted upward and the inside of the bit 30 is irradiated.

The signal cable 32 travels through a maze duct formed inside the iron shield 27 and is connected to an external signal processing device 31! j, continued. The streaming prevention cover 26 is
This shields gamma rays leaking from areas that tend to be insufficiently shielded, such as the irradiation pipe 30.

Furthermore, 1, 1: To explain in detail, Figure 6 shows the structure of the radiation source storage section, and in this example, the radiation source 3 is a commercially available double container made of SO8'316. Using the Kobatro 0 sealed wire pellets 34 stored in the container 33, they are stored side by side in the container 35, and the container 35 is fixed to the protrusion of the upper shell 16 with the bolt 36.

These steps 5 can be easily performed in a facility such as a hot lab that is sufficiently shielded and equipped with magic hands and the like, so there is no risk of being injured during the work.

(Figure 57 shows the structure of the storage containers and irradiation bits with a storage capacity of 11 under the floor of the concrete irradiation power l!io. In this practical example, the storage container 12 is a large one. It is a modified version of the standard shipping container, so it is extremely easy to install the radiation source, transport it, install it in irradiation equipment, replace the source, etc., and there is no risk of radiation exposure during these operations. A drain 38 is connected to the radiation source storage container 12, the irradiation bit 37 that houses it, and the irradiation bit 30 to prevent the surface of the υ device from being corroded by accumulated water, and to prevent the surface of the υ device from being corroded by accumulated water. It can be used for cleaning when the inside of the container becomes contaminated.

The upper iron shielding body 27 is made up of a large number of Chichichi blocks. For example, when using the I-Ryo (of the order of io, ooo-ci), the entire thickness is about 60 crn, and the external storage, [i (
The rate can be reduced to 1 mR/h [degrees] below the permissible value.

The wiring duct 39 through which the signal cable is passed is a labyrinth duct formed by appropriately cutting a notch in the iron block, and it is sufficient to bend the duct two or three times to prevent streaming. In this case, the length of the wiring connecting the inside and outside of the irradiation bit is only 3 m. Therefore, unless the quotient frequency 1d becomes a problem, there is no need to provide a preamplifier or the like in the irradiation bit 30, making electrical measurement extremely easy.

The shutter 28 is made of an iron block like the upper shield 27, and has a rack 4o fixed to its upper surface. When moving the shutter 28, the motor 13 rotates the gear 14 that meshes with the rack 40. 141 of this shutter drive motor 13. In order to prevent the source from entering the storage container 12 unless it is stored in the storage container 12, the radiation source drive unit K (described in detail later)) lfL#:j, Nyasota 28 They are mutually interlocked to prevent them from entering if they are left open. The device for the above/Yatta drive 11: (T) Like the line color drive device described below, it is installed outside the planting body 27, so deterioration due to irradiation can be avoided.

Figure 8 is a diagram illustrating the construction of the w source and the ringing device i'l (D#I'). The upper end is fixed to the support 42, but preferably it is semi-fixed to the support 42 so that it can move freely in the vertical direction.The reason for semi-fixing is that the radiation source 3 does not move due to an abnormality of 1 μJ etc. This is to prevent the device from being damaged by forcefully pushing down the rod 41.The support base 42 has holes on all sides, and two of the holes are female threaded. A screw 46 is engaged with this.The rotation of the motor 13 is controlled by a clutch 46.
, the transmission 44, the worm 45, and the worm gear to the screw 46, and depending on the direction of rotation of the screw 46, the support base 42, the line fit lowering rod 41, and the ferrule 3 move up or down. 431Ii connects when power is applied, and disconnects when power is not applied.
By turning on and off the current, the position of the radiation source can be changed to 19
It can be well controlled. In addition, if the radiation source cannot be stored due to an abnormality in the motor 13, clutch 43, etc. or a power outage, the worm 45 can be rotated by manually operating the handle 47 by engaging the connector 48 by operating the handle 47. The radiation source 3 can be stored in the storage container 12.

The entire weight of the gland 'm and the drive device, including the upper lid 16 of the radiation source container, is supported by a pedestal 49. The pedestal 49 is supported on the floor of the facility.

The time required to raise and lower the radiation source 3 is the actual MM.
In the example, they are about 2 minutes and about 1 minute and 30 seconds, respectively. Further, the time required to open and close the shutter 28 described above is less than 30 seconds. Therefore, in the fastest case, the irradiation pit 30
It takes about 3 minutes to set the sample inside the chamber and bring it into the irradiation state.

h is the source drive device and shutter 1 drive! The entire I-gong device is not irradiated because there is one valley outside the body.
There is no deterioration due to irradiation, and even if abnormality occurs during irradiation, '? 'j - This can be easily repaired without explosion.

[Effect of departure]

As described above, the gamma ray irradiation apparatus of the present invention takes approximately 3 minutes to take in and take out the irradiated sample I) i'IM time 11j, and the time required for close proximity between the irradiation and non-irradiation states is 2 minutes or less1.
The radiation intensity can be shortened, and the cable that transmits the 8-air beam can be shortened, making it possible to irradiate a large amount of phosphorus, which speeds up the irradiation work. It is possible to facilitate or eliminate the need for analysis during the state evacuation of Ki-ki No. 16, and to eliminate the need to install a preamplifier under irradiation.
There are effects such as being able to perform measurements stably over a long period of time. Furthermore, force (main source drive mechanism and shack drive machine 1
Since the st is located outside the shield, there is no deterioration of them due to irradiation, maintenance is easy, and the entire irradiation device can be made relatively compact.

[Brief explanation of the drawing]

FIG. 1 shows a pool storage type gamma++-irradiation device u. The basic configuration diagram of fE's next example, Figure 2 is the basics of the conventional example of the gamma ray irradiation device for under-floor storage Jk+'-d (14' diagram, and Figure 3 is the basics of the conventional example of the gamma ray irradiation device of the ceiling 11 hanging type) FIG. 4 is a basic configuration diagram of a conventional example of a gamma ray irradiation device using the storage container irradiation method, FIG. 51 is a basic configuration diagram of an embodiment of the present invention, and FIG. 47
FIG. 7 is an elevational sectional view showing the storage container and irradiation bit of the embodiment of the present invention after being stored in the irradiation equipment; FIG.
The figure shows the line W drive of the embodiment of the present invention! 11b is an elevational view of the device. 1...Concrete wall of irradiation room, 2...Pool 3...Radial music isotope (Katsu υ1 le)
4... Kuragen mobile stand, 5... Crane, 6...
Sample stage 7...Shutter, 8...Monitor camera, 9...Sample, 10...Irradiation monitor, 11...Monitor room, 12...Radiation source storage 8, 13...Motor , 14...1 head ton, 15...
Screw, 16... Lid of radiation source storage container, 17...
- Source support stand, 18... moving shield, 19... 1
Lili! Source storage room, 20... same commercial letter! τ Hara, 2
1... Irradiation hole, 22... Bomb 0, 23... Oil tank, 24... Pulp, 25... Irradiation box, 26
... streaming prevention cover, 27... shielding body,
28...Sha, Ri, 29...Wheel, 30...
Irradiation bit, 31...I E1 processing device 1ffts
32...Signal cable, 33...Stainless steel 2-claw valley device 1 34...Cobalt 60iA' coated, 35...
Radiation source container, 36... Source fixing bolt, 37... Reservoir trough storage bit, 38... Drain hole, 39... Wiring tact, 40... Plate gear, 41... Radiation source hanging rod, 42...Radiation source support stand, 43...Clutch,
44...Transmission, 45...Worm, 46...
Screw, 47... Handle, 48... Connector, 49... Frame. Figure 1 Figure 2 1/14 Figure 4

Claims (1)

[Claims] A radiation source storage container with a radiation source fixed to the lower part of the lid, an irradiation bit installed above the radiation source storage container and surrounded by a shield, and an irradiation bit installed above the outside of the irradiation bit to connect the radiation source to the fl that is raised and lowered into the irradiation bit together with the lid of
A gamma ray irradiation device comprising: a Mil:λ drive mechanism, a movable shutter forming a part of the shield, and a movement mechanism for the shutter provided outside the irradiation bit.