JPS5945949B2 - thermoluminescent dosimeter - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a thermoluminescence dosimeter (hereinafter referred to as a dosimeter) for measuring radiation exposure dose, and a thermoluminescence dosimeter element (hereinafter referred to as an element) that measures the radiation exposure dose by hand or the like.
When inserted into the dosimeter, it is automatically pulled into the dosimeter and measured.

It is an object of the present invention to provide a dosimeter in which the element is automatically ejected from the dosimeter when measurement is completed.

When an element exposed to radiation is heated, it emits thermoluminescence in proportion to the exposure dose.

The amount of radiation exposure can be determined by converting this thermoluminescence into a current using a photomultiplier tube and integrating it, and by measuring this integrated value or by counting the number of photons of thermoluminescence.

The present invention relates to a dosimeter that utilizes such a principle.

FIGS. 1 and 2 show elements used in a dosimeter according to an embodiment of the present invention.

In FIG. 1 and FIG. 2, 1 is a case body, and protrusions 2 and 3 are formed on this case body 1.
A cover plate 4 is fixed to the upper surface of 3 to form a case with one end open.

5 is a notch formed between the protrusions 2 and 3, and 6 is the protrusion 2.
A protrusion 7 formed at the end of the case body 1 is an information reading section formed integrally with the case body 1, and a large number of blind holes 8 are formed in this information reading section 7, and any blind hole 8 can be bored. As a result, personal codes etc. are recorded.

Reference numeral 9 denotes a card housed in the case, and a plurality of holes 10 are formed in the card 9, and a thermoluminescent material 11 is housed in the holes 10.

Reference numeral 12 indicates an engaging claw formed on the card 9, and reference numeral 13 indicates four parts formed on the card 9. When the card 9 is inserted into the case, the engaging claw 12 engages with the notch 5, and the card 9 is inserted into the case. 9 is held within the case.

FIG. 3 shows the external appearance of a measuring section of a dosimeter in one embodiment of the present invention.

In FIG. 3, 16 is a main housing, and this main housing 16 is equipped with a motor 19 to which a gear head 18 is attached via a stud 17, and a first pulse motor 20.
．． 12 pulse motors 21 and light guide support members 22
A case 23 containing a photomultiplier tube and a printed circuit board 24 are attached via.

A lamp 28 for heating the thermoluminescent material 11 and a printed circuit board 29 are attached to a sub-housing 26 fixed to the main housing 16 with screws 25 through a condenser tube 27.

30 is an opening formed in the main housing 16 and the sub housing 26, and the element 14 is inserted through this opening 30.
enters and exits the measuring section.

31 is a stud for fixing the measuring section to the substrate 32.

FIG. 4 is a top view of the main housing 16, with the subhousing 26 shown in constant phantom lines.

Reference numeral 33 denotes an element holding member. This element holding member 33 is composed of arm parts 34 and 35, a base part 36, and a connecting part 37, and a rank 38 is fixed to the connecting part 37.

Furthermore, a notch 39 is formed in the connecting portion 37 as shown in FIG. 5 so that the element 14 can freely enter and exit the measuring portion 15 through the opening 30.

40 is a gear fixed to the rotating shaft 41 of the first pulse motor 20, and this gear 40 meshes with the rank 38.

A roller 42 is rotatably supported by a shaft 43 fixed to the main housing 16 and comes into contact with the connecting portion 37 .

In FIG. 6, 44 is a shaft 45 fixed to the base 36.
The main housing 16 is rotatably supported by a roller.
The element holding member 33 is guided by a roller 44 and a groove 46, a gear 40 and a roller 42, and is movable in the M and N directions.

A sleeve 47 is fitted onto the shaft 48 of the gear head 18, and a roller 50 having a rubber lining is rotatably supported on the outer periphery of the sleeve 47.

49 is a collar of the sleeve 47.

51 is a screw for fixing the sleeve 47 and ring 52 to the shaft 48.

53 and 54 are thrust washers, and 55 is the roller 50.
is pressed against the collar 49 via the thrust washer 53,
This is a spring that presses the thrust washer 54 against the ring 52, and frictional force is generated between the thrust washer 53 and the collar 49, and between the thrust washer 54 and the ring 52, and the roller 5
0 rotates with a predetermined torque relative to the sleeve 47, forming a kind of slip mechanism.

In FIG. 7, 56 is a rib for forming a recess 57 for guiding the element 14 in the M and N directions.

58 is a light emitting diode attached to the printed circuit board 29;
59 is a phototransistor attached to the printed circuit board 24, and 60 is a hole for regulating the diameter of the optical axis of light incident on the phototransistor 59.

Assuming that the optical axis constituted by the light emitting diode 58, phototransistor 59 and hole 60 is Ll, optical axes L2 to L8 having the same structure as Ll are arranged as shown in FIG.

In FIG. 8, reference numeral 61 indicates a hole corresponding to the blind hole 8 of the element 14, and guides the light from the lamp 62 attached to the printed circuit board 29 to the photosensitive portion 64 of the sensor 63 attached to the printed circuit board 24.

65 is a reflecting plate that reflects the light from the lamp 62.

In FIG. 4, 66 is a plate on which a protrusion 67 is formed for pushing the engagement pawl 12 through the notch 5 of the element 14 and disengaging it from the protrusion 6. is fixed.

In FIG. 4, 68 is a protrusion 69 that engages with the recess 13 of the card 9, and holes 70, 71, 72, 73° 74.7.
5 is a card drive plate on which a number 5 is formed.

A calibration light source 376 is fixed to the card drive plate 68 and is made of a luminescent material such as luminous paint.

The card 1 driving plate 68 is guided by a groove 78 formed by a lip 77 shown in FIG. 11, and is movable in the R2S direction in FIG. 4.

Further, the groove 79 is a groove for guiding the card 9 in the R and S directions.

In FIG. 10, a rack 80 is fixed to the card drive plate 68, and this rack 80 meshes with a gear 82 fixed to the rotating shaft 81 of the second pulse motor 210.

83 connects the second pulse motor 21 to the main housing 16
This is a board that is fixed to the

A roller 84 is rotatably supported by a shaft 85 fixed to the main housing 16, and this roller 84 comes into contact with the card drive plate 68 to prevent the card drive plate 68 from floating up.

In FIG. 9, 22 is a light guide support member that supports the light guide 86, and this light guide support member 2
2 is fixed to the main housing 16.

87 is a photomultiplier tube, and this photomultiplier tube 87 is housed in a case 23 fixed to the light side support member 22.

Reference numeral 88 denotes a filter that blocks visible light and transmits only infrared rays, and this filter 88 is fixed to the condenser tube 27 together with the lamp 28 having a reflecting mirror 89 by being pressed by an annular plate 91 via an O-ring 90. ing.

A through hole having a conical reflective surface 92 is formed in the condenser tube 27, and the reflective surface 92 more effectively converges the light from the lamp 28 that cannot be converged by the reflective mirror 89. The thermoluminescent material 11 that has come to the P portion of the optical axis connecting the light guide 86 and the light guide 86 is heated.

The screw 93 presses the annular plate 91 and fixes the condenser tube 27 to the sub-housing 26.

In FIG. 4, 94 is a pin for positioning the sub-housing 26 on the main housing 16, and 95 is a screw hole for the screw 25.

Reference numeral 96 denotes a microswitch fixed to the printed circuit board 24, which is activated by being pressed by the sub-housing 26 to detect whether or not the sub-housing 26 is fixed to the main housing 16, and only when the sub-housing 26 is fixed to the main housing 16, the photomultiplier tube 87 is activated. Supply high pressure.

Therefore, even when the sub housing 16 is carelessly separated from the main housing, it is possible to prevent external light from entering the highly sensitive photomultiplier tube 87 and damaging the photomultiplier tube 87 by cutting off the high voltage.

The operation of the present invention will be explained below.

The state shown in FIG. 4 is the timing state, and it is detected by the optical axis L3, the element holding member 33, and the optical axis L6 whether the card drive plate 68 is at the timing position.

As shown in FIG. 12, the element 14 is inserted from the outside in the R direction through the opening 30 and the notch 39.

At this time, since there is a gap K between the element 14 and the roller 50, the element 14 can be inserted freely.

When the optical axis L1 is blocked by the element 14, it is detected that the element 14 is inserted into the measuring section, and the roller 50 is moved by the motor 19.
is driven clockwise.

At the same time, the gear 40 is driven counterclockwise by the first pulse motor 20, the element holding member 33 is driven in the N direction, and the arm 34 presses the element 14 against the roller 50.

Therefore, the element 14 is driven by the roller 50 to
It is pulled into the position shown in the figure and ready for measurement.

Note that the feed amount of the element holding member 33 per step of the first pulse motor 20 is T, and the pulse for sending the element holding member 33 in the N direction from the state shown in FIG. 12 to press the element 14 against the roller 50 is Assuming that the required number of steps for the motor 20 is U, when driving the pulse motor with two-phase excitation, for example, if TU/T<2TU>K, the pulse motor 20 can press the element 14 against the roller 50 without stepping out. can do.

That is, the pressure contact force can be generated by exciting the phase in which the rotor of the pulse motor is further shifted in the forward direction within the range of O to 2 steps from the stop position under no load, that is, the advanced phase.

Further, when (TU - K) /T = 1, that is, when the phase advanced by one step is excited, the pressure contact force, that is, the torque generated by the pulse motor becomes maximum.

The driving method of the pulse motor is not limited to two-phase excitation, but other methods may be used, and it is sufficient to excite the phase advanced by a required step so as to obtain the required pressure contact force.

Furthermore, the frictional force between the roller 50 and the element 14 causes the arm portion 34 and the element 1 to
The contact surface of the arm portion 34 with the element 14 is coated with Teflon so that the frictional force is sufficiently greater than the friction force of 4.

When the element 14 reaches the measurement preparation position, the optical axis L2 opens, and it is detected that the element 14 has reached the measurement preparation position.At the same time, the motor 19 stops driving, and the second pulse motor 20 starts rotating clockwise. The element 14 is pushed by the arm 35 and transferred in the M direction until the element 14 reaches the position shown in FIG.

At this time, the pulse motor 20 is driven so that the arm portion 35 presses and firmly holds the element 14 against the stepped portion 97 of the main housing 16 shown in FIG. 8 in the same manner as described above.

When the element 14 is in the state shown in FIG. 14, the element 14 is in the information reading position.

When the element 14 reaches the information reading position, the protrusion 67 enters the notch 5 of the case body 1, pushes the engagement claw 12 to disengage the card 9 from the case body 1, and the protrusion 69 enters the recess 13 of the card. engage with.

Furthermore, by blocking the optical axis L4 with the arm portion 34, it is reliably detected that the element 14 has reached the number reading position.

In the state shown in FIG. 14, the lamp 62 shown in FIG. 8 is lit, the presence or absence of the blind hole 8 being opened is detected, and the information is read by the sensor 63.

Furthermore, the lamp 28 in FIG. 9 lights up, and the lamp 28
A part of the infrared rays emitted from the lamp 28 is guided through the hole 70 to the light guide 86, enters the photomultiplier tube 87, and is detected to determine whether the intensity of the infrared rays from the lamp 28 is within the specified intensity. is monitored.

Further, when the element 14 is in the state shown in FIG.
is removed from the aperture 30, and the aperture 30 is closed by the element holding member 330 base 36 to prevent further insertion of another element 14 into the measurement part, and to prevent external light from entering the measurement part from the aperture 30. Photomultiplier tube 87 with high light sensitivity
This prevents measurement errors caused by human error.

Next, the second pulse motor 21 is driven, and the card drive plate 68 pulls the card 9 with the protrusion 69, pulls the card 9 out of the case body 1, and is driven in the R direction by the required number of steps to the state shown in FIG. .

At this time, the optical axis L7 and the hole 71 are aligned, and it is detected that the card drive plate 68 has been reliably fed.

The calibration light source 76 is also moved onto the optical axis L9, and the intensity of the light from the calibration light source 76 is monitored by a photomultiplier tube 87, and the sensitivity of the photomultiplier tube 87, the loss of light in the light guide 86, etc. are checked. be done.

Further, when the card 9 moves to the state shown in FIG. 15, the thermoluminescent material 11a crosses the optical axis L5.

At this time, if the thermoluminescent material 11a is damaged and there is a hole, the optical axis L5 will be shifted to the thermoluminescent material 11a.
If there is any damage, it will be detected.

Next, the card driving plate 68 is further driven in the direction of the required number of steps R, so that the hole 72 reaches the position of the optical axis L7, and the thermoluminescent material 11a reaches the position along the optical axis.

Here, the thermoluminescent material 11a is heated by lighting the lamp 28, and the intensity of thermoluminescence is measured by the photomultiplier tube 87.

Furthermore, breakage of the thermoluminescent materials 11b and 11c is detected during the movement of the card 9 in the R direction.

Thereafter, the cards 9 are sent one after another in the R direction, and the cards 9 are sent to the holes 73 and 74.
．． 75 has reached the optical axis L7.

That is, after it is confirmed whether the card 9 has been sent normally, the thermoluminescent materials 11b and 11c11d are sequentially measured, and the presence or absence of damage to the thermoluminescent material 11d during movement is detected.

When all of the thermoluminescent material 11 has been measured, the card drive plate 68 is moved in the S direction by the second pulse motor 21 to the state shown in FIG.

At this time, the optical axis L5 monitors whether the thermoluminescent material 11 is damaged by heating during measurement.

Next, the element holding member 33 is moved by the first pulse motor 20 to transport the element 14 to the state shown in FIG.
is driven counterclockwise by the motor 19, and the element 14
At the same time as is pressed by the roller 50, the element 14 is driven in the S direction and is discharged to the outside through the opening 30.

When the element 14 is ejected, the element 14 opens the optical axis L1 (and the motor 19 stops, and the element holding member 33 is driven by the first pulse motor 20 and returns to the state shown in FIG. 12, completing the operation. Then, it waits for the next element 14 to be inserted.

In order to simplify the drawing, the element holding member 33 is shown in FIG.
Although the structure is similar to that shown in FIG. 8, in reality, in order to prevent the element 14 from floating upward in FIG. 8, a projecting portion 98 is provided on the arm portion 34 as shown in FIG. 16.

The present invention has the above configuration, and according to the present invention, the following effects can be obtained.

(1) Just by slightly inserting the element into the opening of the measurement section, it will automatically be pulled inside and measured, and when the measurement is completed, it will be ejected from the opening again, so it can be installed at the entrance to the radiation control area to protect workers. (When performing control, the operator can perform measurements very easily and reliably without requiring any special operations or precautions for measurement.)

Furthermore, since the measurement is carried out by drawing the element inside, the operator can perform stable measurements without touching the element.

(2) By making the retraction direction of the element and the transport direction of the pulled-in element perpendicular, and the transport direction of the element and the card transport direction perpendicular, the element can be connected to the retraction means and engaged only by the element transport operation. Since it can be attached to and detached from the release means and the card transfer means, the construction and operation are very simple, it is easy to downsize, and it is highly reliable.

(3) Since the opening into which the element is inserted can be closed by the operation of the element transfer means, it is possible to prevent external light from entering the m++ constant part during measurement and to prevent other elements from being inserted. It can be prevented.

Further, the opening can be closed simply by transferring the element holding member, and no special closing means is required.

(4) The element can be pressed against the roller simply by exciting the phase of the pulse motor whose rotor is advanced by a required step from the no-load stop position, and no other pressing means is required.

Furthermore, the element can be similarly easily fixed at one information reading position.

(5) When a means for detecting that the element has been inserted to the retractable position and a means for detecting that the element has been retracted to the measurement preparation position are provided, only these two detecting means are required to detect the retracting means and the The drive of the element transfer means can be easily and reliably controlled, and operations that require special attention from the operator are not required.

(6) By driving the roller that retracts the element via a slip mechanism, the element is stopped, for example, artificially, in the middle of the retracting or ejecting operation. and will not damage the device.

(7) By adopting a structure in which the element is pressed against the roller by the movement of the element holding member, compared to a method in which the element is constantly pressed against the roller by an elastic body, there is no transparency between the roller and the element holding member in the standby state. Since there is a gap, elements can be inserted without any resistance, and the configuration is simple.

In the latter case, since there is a load when inserting the element, it is difficult to completely insert the element (there is a high possibility that an operation error will occur).

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an element used in the thermoluminescent dosimeter of the present invention, FIG. 2 is an exploded perspective view of the same, FIG. 3 is a front view of the thermoluminescent dosimeter according to an embodiment of the present invention, and FIG. A top view of the main housing of the same thermoluminescence dosimeter, FIG. 5 is a cross-sectional view taken along line A and -A' in FIG. 4, FIG. C-Cj sectional view,
Figure 8 is a sectional view of D-Er in Figure 4, and Figure 9 is a cross-sectional view of E in Figure 4.
-Br sectional view, Fig. 10 is a FF' sectional view in Fig. 4, Fig. 11 is a GG sectional view in Fig. 4, and Figs. 12 to 15 are explanations of the operation of the thermoluminescence dosimeter. 16 are sectional views of essential parts of another embodiment of the present invention. 1...Case body, 4...Storage board, 5.
...Notch, 8...Blind hole, 9...
・Card, 11...Thermoluminescent material, 1
2... Engaging claw, 13... Recessed portion, 14...
...Element, 16...Main housing,
18... Gear head, 19... Motor, 20, 21... Pulse motor, 26...
...Subhousing, 27...Concentrator tube, 28.
... Lamp, 30 ... Opening, 33 ...
...Element holding member, 34, 35...Arm part, 36
...Base, 27...Connection part, 38...
... Rack, 39 ... Notch, 47 ...
... Sleeve, 50 ... Roller, 67 ...
... Projection piece, 68 ... Card drive plate, 69 ...
...Protrusion, 86...Light guide, 8T...
...Photomultiplier tube.

Claims (1)

[Scope of Claims] 1. A housing having an opening into which a thermoluminescent dosimeter element holding a card holding a thermoluminescent material is inserted into the case body, and a housing that rotates by receiving power from a power source. , a roller that drives the thermoluminescent dosimeter element inserted into the opening and draws the thermoluminescent dosimeter element into the housing; an element transfer means for transferring the element in a direction perpendicular to the retraction direction by the roller; an engagement release means for disengaging the card from the case body; and a card that engages with the card and pulls the card out of the case body. A thermoluminescent dosimeter comprising a transfer means and a measuring means for heating the thermoluminescent material held on the card and detecting thermoluminescence generated. 2. The thermoluminescent dosimeter according to claim 1, wherein the sliding member has a notch into which the thermoluminescent dosimeter element is inserted, an arm that pushes the thermoluminescent dosimeter element, and a base that closes the opening of the housing. A thermoluminescence dosimeter comprising an element moving means comprised of a flexible element holding member and a drive source for driving the element holding member. 3. The thermoluminescence dosimeter according to claim 1, in which a roller is coupled to the rotating shaft of the power source via a slip mechanism. 4. In the thermoluminescence dosimeter according to claim 2, the drive source of the element holding member is constituted by a pulse motor, and the pulse motor advances the required steps within a range that does not step out at the end of the stroke of the element holding member. A thermoluminescence dosimeter that excites the phases of a pulse motor to generate a pressing force against an element holding member.