JPS5941551B2 - Sensitivity information recording device for thermoluminescent dosimeter elements - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for recording sensitivity information on a thermoluminescent dosimeter element used in a thermoluminescent dosimeter for measuring radiation exposure dose.

A thermoluminescence dosimeter that measures the exposure dose of radiation consists of a main body of the measurement device and a thermoluminescence dosimeter element (hereinafter referred to as the element) carried by a radiation worker. The radiation exposure dose is measured by setting it in the main body of the measuring device and heating the element.

That is, when an element is heated, thermoluminescence corresponding to the radiation exposure dose is generated from the element, and by detecting this thermoluminescence, the radiation exposure dose can be measured.

In recent years, there has been an increasing demand for accurate measurement of very low-level radiation exposure, especially in order to accurately manage the radiation exposure dose of the human body, etc.

In this way, when measuring low-level radiation exposure (dose), variations in the sensitivity of individual elements become a problem.

In order to accurately measure the radiation exposure dose, it is necessary to know in advance the variations in sensitivity of each element, and to take the variations in sensitivity of the elements into consideration during measurement.

In view of the above points, the present invention provides a sensitivity information recording device that detects variations in sensitivity of each element and records the extent of this variation in sensitivity in each element.

FIGS. 1 and 2 show the structure of an element in one embodiment of the present invention.

In FIGS. 1 and 2, reference numeral 1 denotes a case body, and the case body 1 has protrusions 2 and 3 formed thereon.

4 is a protrusion formed with an IC at one end of the protrusion 2; 5 is the protrusion 2 and 3;
This is a notch formed in between.

Reference numeral 6 denotes an element information recording section formed on one side of the case body 1, and this element information recording section 6 has a large number of holes 7 formed therein.

As shown in FIG. 3, this hole 7 is a blind hole whose bottom is closed with a thin wall 8. By punching out the thin wall 8 of any hole 7 to form a through hole, the sensitivity of this element The degree of variation (rank), individual code, etc. are recorded.

A cover plate 9 is fixed to the upper surface of the protrusions 2 and 3 of the case body 1, forming a case having a flat gap.

Reference numeral 10 denotes a card stored in the case, and this card 10 has a plurality of holes 11a and 1 lb.

11c, 11d are formed, and these holes 11a, 11b
.

Thermoluminescent material 12a in 11c, 11d.

12b, 12c, and 12d are retained.

13 is a recess formed in the card 10, and 14 is an engaging claw formed in the card 10. When the card 10 is inserted into the case, the engaging claw 14 engages with the notch 5 of the case.
The card 10 is retained within the case.

The thermoluminescent materials 12a and 12b are, for example, Li2B4O□, which has a small energy dependence and can accurately measure the exposure dose of radiation over a wide range of energies, and the thermoluminescent material 12c.

12d is C a SO4 which has high sensitivity and can accurately measure very low level radiation, and material 12a.

12b and materials 12c and 12d are made from the same lot, so there is little variation in sensitivity, for example, ±2 factors. However, if the loft changes, even if the material is the same, the difference between the lofts may vary due to subtle changes in manufacturing conditions, etc. For example, the variation in sensitivity may be ±12% with respect to the reference value, and the overall sensitivity variation is ±14%.

The present invention relates to a device that measures the degree of variation in sensitivity of such materials in advance and records this degree of variation (rank) in the element information recording section 6 of the case body of the element. When measuring the radiation exposure dose using a measuring device, the measuring device detects the degree of variation in sensitivity, corrects the measured value, and enables accurate measurement.

For example, in the present invention, the sensitivity variation is
-8%, -4%, 0%, +4%, +8%, +12% 7
The device is divided into ranks and this rank is recorded for each element.

For example, if the sensitivity variation of a certain material is -9.5, the nearest 18% is recorded on the element, and at the time of measurement, the sensitivity variation recorded on this element -8 is read and measured. By dividing by the value (1-0,08), the measurement error can be reduced to a factor of 1.5.

In addition, when dividing the sensitivity variation into seven ranks as described above, among the many holes 7 shown in FIGS. 1 and 2, material 1
There are three holes for each type, and six holes 7 may be used for two types of materials.

To further improve accuracy, it is sufficient to assign a rank to each material or to increase the number of divisions of ranks.

FIG. 4 shows an outline of the apparatus of the present invention, and FIG. 5 shows the main parts of the apparatus of the present invention.

In FIGS. 4 and 5, reference numeral 15 denotes a board, and guides 17 and 18 for guiding the magazine 16 are fixed to this board 15.

The magazine 16 stores a plurality of elements 19 that have been irradiated with a certain amount of radiation in advance.

As shown in FIG. 5, there are holes 2 in the bottom of the magazine 16.
0 is formed, and a rack 21 is formed on the side.

Reference numeral 22 denotes a fixed pulse motor on the substrate 151/7, and a gear 24 that meshes with the rack 21 of the magazine 16 is fixed to the rotating shaft 23 of the pulse motor 22.

When the pulse motor 22 rotates, the magazine 16 is transferred forward or backward.

25 is a pulse motor fixed to the substrate 15, and a gear 27 is fixed to the rotating shaft 26 of this pulse motor 25.

A sliding rod 28 is supported so as to be slidable up and down, and a rack 29 that meshes with the gear 27 is formed on the sliding rod 28.

30 is a push-up piece fixed to the upper end of the sliding rod 28, and when the pulse motor 25 rotates, the sliding rod 28 slides upward or downward.

When the slide rod 28 slides upward, the push-up piece 30 moves upward and enters the hole 20 in the bottom of the magazine 16, and the magazine 1
1901 elements stored in the magazine 16 are pushed upward and the element 19 is extracted from the magazine 16.

In FIGS. 4 and 5, reference numerals 31 and 32 indicate support legs for fixing the plate-shaped main housing 33 to the base plate 15. As shown in FIGS.

Positioning pins 34 and 35 are implanted in the housing 33, and a plate-shaped sub-housing 36 is attached to the positioning pins 34 and 35.
4.35, is superimposed on the main housing 33, and is fixed to the main housing 33 by screws 37.38.

Reference numeral 39 denotes a vertical groove formed in the joint surface between the main housing 33 and the sub-housing 36, and the element 19 extracted from the magazine 16 is inserted into the vertical groove 39 and transported upward.

40 is a horizontal groove formed between both housings 33 and 36, and the card 10 extracted from the element 190 case is transferred within this horizontal groove 40.

Reference numeral 41 denotes a horizontal groove formed between the two housings 33 and 36, through which the case of the element is transferred.

Note that the horizontal grooves 40 and 41 are formed at right angles to the vertical groove 39.

42 is a card driving plate slidably supported in the horizontal groove 40, and an element 19 is provided at one end of this card driving plate 42.
An engaging protrusion 43 that engages with the recess 13 of the card 10 is formed.

Reference numeral 44 denotes a calibration light source attached to the card driving plate 42, and is constructed by providing a self-luminous substance such as luminous paint.

45 is a small hole formed in the card drive plate 42.

Is 46 the main housing 33V? c is a fixed pulse motor, and a gear 48 is fixed to the rotating shaft 47 of this pulse motor 44 as shown in FIG.

This gear 48 meshes with a rack 49 attached to one side of the card drive plate 42.

50 is a shaft fixed to the main housing 33, and a roller 51 is rotatably supported on this shaft 50.

This roller 51 holds the card drive plate 42 together with the gear 48, and when the pulse motor 46 rotates, the card drive plate 42 slides and transfers the card 10 engaged with the engagement protrusion 43. .

Next, the thermoluminescent material 1 provided on the card 10
The structure of the measuring section for heating the material 2 and detecting thermoluminescence generated from the material 12 will be explained with reference to FIGS. 4, 5, and 7.

Reference numeral 52 denotes a condenser tube fixed to the main housing 33 with screws 53 and 54, and a conical hole 55 is formed in the condenser tube 52.

56 is a reflecting mirror fixed to one end of the condenser tube 52, 57 is a lamp attached to the reflecting mirror 56, 58 is a filter that allows only infrared rays to pass, and 59 is an O-ring.

60 is a support member fixed to the sub-housing 36;
A tube 61 is attached to this support member 60, and a photomultiplier tube 62 is housed within this tube 61.

A light guide 63 is housed in a hole formed in the support member 60.

FIG. 7 shows a state in which the card drive plate 42 is interposed between the condenser tube 52 and the light glass 63, and this car 1 drive plate 42 moves to move the lamp 57 and the light guide. When the thermoluminescent material 12 of the card 10 of the element 19 is present on the optical axis L1 connecting the elements 63, the material 12 is heated by the infrared rays from the lamp 57 and generates thermoluminescence.

This thermoluminescence enters the photomultiplier tube 62 via the light guide 63, and its intensity is measured.

In FIG. 5, 64 is a small hole formed in the main housing 33. Next, an AA/cross section including this small hole 64 will be explained with reference to FIG. 8.

In FIG. 8, 65 is a hole formed in the main housing 33, and the small hole 64 is formed at the tip of this hole 65.

66 is a phototransistor supported by a printed circuit board 67 and inserted into the hole 65; 68 is a sub-housing 36;
The hole 69 formed in is supported by the printed circuit board 70,
This is a light emitting diode inserted into the hole 68, and this light emitting diode 69. Small hole 64. Phototransistor 66
The optical axis L2 with the required diameter is configured by the card driving plate 42.
Detect the end face of

That is, the pulse motor 46 is driven until the end surface of the card drive plate 42 reaches the optical axis L2, and the card drive plate 42
When the motor enters the standby state shown in FIG. 5, the pulse motor 46 is controlled to stop.

FIG. 9 shows the D-D' cross section in FIG. 5.

In FIG. 9, 71 is a lamp attached to a printed circuit board 72 and inserted into a hole 73 formed in the main housing 33, and 74 is a reflector.

Reference numeral 75 indicates a hole formed in the sub-housing 36, and reference numeral 76 indicates a sensor having a photosensitive portion 77. This sensor 76 is attached to a printed circuit board 78.

When the element 19 extracted from the magazine 16 rises within the vertical groove 39 and reaches the upper edge of the vertical groove 39, the hole 7 of the element information recording section 6 of the element 19 is located in front of the hole 75, and the hole 75 is located in front of the hole 75. The presence or absence of the opening 7 is detected by a sensor 76, and information recorded in the element information recording section 6 of the element 19 is read.

In FIG. 5, reference numeral 79 indicates a horizontal groove formed in the joint surface between the main housing 33 and the sub-housing 36;
A rack plate 80 is slidably supported at 9 .

As shown in FIG. 10, 81 is a case drive claw screwed to the rack plate 80.
1 includes a guide piece 82 for guiding the element 19 when the element 19 is transferred in the longitudinal groove 39, and a notch of the element shown in FIG. 2 when the element 19 reaches the upper edge of the longitudinal groove 39. A protruding piece 83 that is inserted into the portion 5 and presses the engaging claw 14 of the card 10 to disengage the card 10 from the case is formed.

84 is a pulse motor fixed to the main housing 33, and a gear 86 is attached to a rotating shaft 85 of the pulse motor 84, as shown in FIG.

87 is a shaft fixed to the main housing 33, and a roller 88 is rotatably supported on this shaft 87.

The rack plate 80 is held between the roller 88 and the gear 86, and when the pulse motor 84 rotates, the rack plate 80 slides within the horizontal groove 79.

In FIG. 5, reference numeral 89 indicates a hole formed in the main housing 33. Similar to FIG.
Detecting means for detecting the end face of 0 is constructed, and the pulse motor 46 is controlled by this detecting means so that the rack plate 80 is in the timing state shown in FIG.

In FIG. 5, when the rack plate 80 moves to the right, the case body 1 engaged with the protrusion 83 of the rack plate 80 is transferred to the right in the lateral groove 41.

In FIG. 5, at 90, the rack plate 80 moves to the right,
This is a cover that protects a portion protruding from the main housing 33.

Next, a mechanism for recording the sensitivity variation rank of an element in the element information recording section 6 of the element will be explained with reference to FIGS. 5 and 12.

5 and 12, 91 is a support board fixed to the main housing 33, and an abbreviated punch lever 92.92' is rotatably supported on this support board 91 by a pin 93.93'. has been done.

94, 94' are punch pins formed at one end of the punch levers 92, 92'.

95 is a support column screwed to the support substrate 91;
A support member 96 is fixed to one end of this column 95.

97.97' is an air cylinder rotatably supported by the support member 96 with a pin 98°98', and the tip of the piston rod 99.99' of this air cylinder 97.97' is connected to the punch lever 92°. Pin 100, 10 to 92'
They are connected by 0'.

101.101', 102, and 102' are ports that supply air to the air cylinder 97.97', respectively. When air is supplied from the ports 101 and 101', the piston rod 99.99' moves to the left, and the port 102 ,
When air is supplied from 102', the piston rod 99.9
9' is for moving to the right.

Reference numeral 103 denotes a plate fixed to the main housing 33, and small holes 104° and 104' are formed in this plate 103.

105 is a hole formed in the sub-housing 36, and 106 is a box attached to the sub-housing 36.

When the element 19 is transported by the rack plate 80 and reaches the position shown in FIG. 12, the air cylinders 97 and 97' are operated according to the measurement result of the sensitivity variation of the thermoluminescent material, and according to the rank of the sensitivity variation, punch lever 9
2.92' is rotated, the punch pins 94, 94' are inserted into the hole 7 of the case body 1 of the element, and the thin wall 8 at the bottom of the hole 7 is punched out.

The punched thin wall 8 has small holes 104, 104'. Hole 105
are collected into the box 106 via the

In FIG. 5, 107 is an air cylinder fixed to the main housing 33, and the piston rod 108 of this air cylinder 107 extends into the longitudinal groove 39 of the main housing 33 to lower the element 19 into the magazine 16. It is something to return.

Ports 109° and 109' are for supplying air to the air cylinder 107.

Next, the operation of the above embodiment will be explained as shown in FIGS. 5 and 13 to 16.
This will be explained with figures.

FIG. 5 shows the timing state, and when the pulse motor 25 is started in this state, the sliding rod 28 rises and the push-up piece 30
enters the hole 20 in the bottom of the magazine 16, extracts the element 19 upward from the magazine 16, and moves it upward in the vertical groove 39.

As shown in FIG. 13, when the element 19 reaches the upper edge of the vertical groove 39, the engaging protrusion 43 of the card drive plate 42
At the same time, the projecting piece 83 of the case drive claw 81 enters the notch 5 of the case body 1, and the engagement claw 14
and the case body 1.

In this state, the lamp 57 is lit, and the infrared rays from this lamp 57 enter the photomultiplier tube 62 through the small hole 45 of the card drive plate 42 and the light guide 63, and the intensity of the infrared rays reaches a specified value. It is checked whether it is.

Next, the pulse motor 46 is activated and the card drive plate 42 is transferred to the position shown in FIG.

Note that with the transfer of the card driving plate 42, the card 10
will also be transferred.

In the state shown in FIG. 14, the calibration light source 44 reaches the optical axis, and the light from this calibration light source 44 enters the photomultiplier tube 62 via the light guide 63.
2, the light loss of the light guide 63, etc. are checked.

Further, the pulse motor 46 moves, and the card 10 is transferred to the left as the card drive plate 42 moves.
The thermoluminescent material 12a held at 0 is aligned with the optical axis L1.
i/C matched.

Here, the lamp 57 is turned on, and the material 12a is irradiated with infrared rays from the lamp 57, and the material 12a is heated and generates thermoluminescence.

This thermoluminescence is transmitted through a light guide 63 to a photomultiplier tube 62v? C is incident, and the intensity of thermoluminescence is measured.

Likewise another thermoluminescent material 12b. 12c, 12
d are also sequentially transferred to the optical axis L1, the intensity of each thermoluminescence is measured, and the radiation dose is measured.

As described above, the thermoluminescent material is irradiated with a certain amount of radiation in advance, and the exposure dose X is known.

Therefore, the measured value must be X, but as mentioned above, there are variations in the sensitivity of thermoluminescent materials, and the measured values should be Xl, X2. X3. It becomes X4.

According to the difference between the measured values X1, X2, X3, and X4 and the known exposure dose X, a logic circuit ranks the sensitivity variations, and the ranks of each thermoluminescence are stored in the storage device.

While the measurements of the thermoluminescent material are being carried out,
The element 190 case body 1 is in the position shown in FIG.
External light is prevented from entering the horizontal groove 40 through the vertical groove 39 and further entering the photomultiplier tube 62, causing measurement errors.

When the measurement of the thermoluminescent material 12d is completed, the card 10 stops at the position shown in FIG.

Next, the pulse motor 84 is started, and the rack plate 80 is transferred to the right, and this rack plate 80V? The C-engaged case body 1 is transferred to the position shown in FIG. 16.

Here, the case body 1 is connected to the pulse motor 8 at each pitch of the hole 7.
Air cylinder 97.97 is driven by the rank signal stored in the storage device while being sent to the right by 4.
By the operation of
is punched out, and the rank is recorded in the element information recording section 6 of the case body 1.

Note that at this stage, information such as the type of thermoluminescent material, personal code, parity check, etc. may be recorded at the same time.

When all the recording in the element information recording section 6 of the case body 1 is completed, the pulse motor 84 is reversed and the case body 1 is transferred to the left to the position shown in FIG.

Next, the pulse motor 46 rotates to send the card 10 to the right and store the card 10 in the case body 1.

Here, the lamp 71 shown in FIG. 9 lights up, and the sensor 76
The information in the hole 7 is read and checked for any recording errors.

Next, the pulse motor 25 rotates and the sliding rod 28 descends,
The element 19 is lowered to the state shown in FIG.

Next, the air cylinder 107 operates, and the piston rod 10
8 is lowered to ensure that the element 19 is housed in the magazine 16.

Next, the pulse motor 22 rotates one pitch, and the magazine 16
is transferred, and the next element 19 is positioned at the bottom of the vertical groove 39,
The following operations are performed in the same manner.

As described above, by using an element with a recorded sensitivity variation rank, it is possible to greatly reduce measurement errors by reading the rank and correcting the thermoluminescence measurement value when measuring the exposure dose. .

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

(1) Since thermoluminescence measurement and sensitivity correction information can be recorded within the same housing, the case body and the card will not be mistakenly combined.

(2) Since the card is engaged and held in the case body, the card will not be pulled out from the case body even if the element is dropped, and the card will not be combined with another case body.

(3) If the element is inserted into the housing without providing a separate engagement release means, the engagement between the card and the case body is automatically disengaged, and the engagement between the card and the card transfer means and the case body are automatically disengaged. Engagement with case transport means can be effected.

(4) Since the case body is equipped with a reading means for reading the sensitivity information recorded, it is possible to check whether the sensitivity information has been recorded correctly.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a thermoluminescence dosimeter element used in a sensitivity information recording device according to an embodiment of the present invention, Fig. 2 is an exploded perspective view of the same, and Fig. 3 is an enlarged cross-section of the same essential parts. 4 is a perspective view schematically showing a sensitivity information recording device according to an embodiment of the present invention, FIG. 5 is a front view of the main housing of the device, and FIG.
The figure is a sectional view taken along line BB' in Figure 5, and Figure 7 is a sectional view taken along line c-c in Figure 5.
'Cross-sectional view, Figure 8 is a cross-sectional view taken along the line AA' in Figure 5, Figure 9 is a cross-sectional view taken along line D-D' in Figure 5, and Figure 10 is a cross-sectional view taken along line E-E' in Figure 5.
11 is a sectional view taken along line FF' in FIG. 5, FIG. 12 is a sectional view taken along line GG' in FIG. be.

1.Pa...Case body, 5...Notch, 6
...Element information recording section, 7...hole, 8.
... Thin wall, 10 ... Card, 12 ...
... thermoluminescent material, 13 ... recess,
14... Engaging claw, 16... Magazine,
19...Element, 33...Main housing, 36...Sub-housing, 39...Vertical groove, 40, 41...Horizontal groove, 42...Card drive plate, 43...Engaging protrusion, 57...
... Lamp, 62 ... Photomultiplier tube, 79 ...
...Horizontal groove, 80...Rack plate, 81...
...Case drive claw, 83...Protrusion piece, 92,9
2'...Punch lever, 94.94'...
...Punch pin, 97,97'...Air cylinder, 99,99'...Piston rod.

Claims (1)

[Scope of Claims] 1. A thermoluminescent dosimeter element formed by engaging and holding a card holding a thermoluminescent material in a case body, in which a rank of sensitivity variation of the thermoluminescent material is recorded in an element information recording section of the case body. The sensitivity correction information recording device for a thermoluminescent dosimeter element for recording includes an element transfer means for inserting the thermoluminescent dosimeter element into a groove in the housing, and a case body of the thermoluminescent dosimeter element inserted in the housing. a card transfer means for extracting the card from the case body; a measuring means for heating the thermoluminescent material of the card extracted from the case body and measuring the intensity of thermoluminescence emitted from the thermoluminescent material; and the case body and the card. a case transport means for disengaging the case body and transporting the case body; a sensitivity information recording means for recording sensitivity information of the thermoluminescent material in an element information recording section of the case body based on the measurement results of the measuring device; A sensitivity information recording device for a thermoluminescence dosimeter element, comprising a reading means for reading recorded sensitivity information. 2. In the sensitivity information recording device for a thermoluminescence dosimeter element according to claim 1, the sensitivity is determined by punching means for punching out a blind hole formed in the element information recording portion of the case body to form a through hole. A sensitivity information recording device for a thermoluminescence dosimeter element comprising information recording means. 3. In the sensitivity information recording device for a thermoluminescent dosimeter element as set forth in claim 1, the thermoluminescent dosimeter comprises a case transfer means that engages an engaging pawl formed on a card with a notch in the case body. a case transfer means having a protrusion that is inserted into a notch in the case body of the element, disengages the engagement claw from the case body, and engages in the notch in the case body; and driving the case transfer member. and means for driving the card transporting member, the card transporting means comprising a card transporting member having an engaging protrusion that engages with a recess formed in the card, and means for driving the card transporting member. Sensitivity information recording device for metering elements. 4. In the sensitivity information recording device for a thermoluminescent dosimeter element according to claim 3, the engaging protrusion of the card transfer member and the case are arranged in the groove in which the thermoluminescent dosimeter element is inserted into the housing. A sensitivity information recording device for a thermoluminescent dosimeter element, in which a protruding piece of a transfer member can protrude into the groove. 5. In the sensitivity information recording device for a thermoluminescence dosimeter element as set forth in claim 1, a card transport direction by the card transport means and a case transport direction by the case transport means are arranged relative to the element transport direction by the element transport means. Sensitivity information recording device for thermoluminescence dosimeter elements with orthogonal to each other.