JPS6035954B2 - Thermal fluorescent phosphors and thermal fluorescent dosimeter elements - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal crab photon and a thermal crab photo dosimeter element.

More specifically, the present invention relates to a cerium (Ce)-activated strontium oxalate thermal crab photon and a thermal photo dosimeter element using this photon. Thermophototropic crab photophores (hereinafter referred to as “TL”)
Thermal light dosimeter (hereinafter referred to as "the halo") mainly utilizes the proportional relationship between the relative heat light intensity and the irradiated radiation dose.
TLD).

Many conventional TL crab light bodies are known, but in reality TLD
There are only a few TL crab photons that can be used as elements, and the TL crab photons currently in practical use as TLD devices include lithium fluoride crab photons (LiF), calcium fluoride crab photons (CaF2), and thulium-activated calcium sulfate crab photons ( CaS04:Tm),
Terbium-activated magnesium silicate crab light body (Mgbui04
:Tb) etc. There are only a few types. Looking at the recent spread of TLDs, due to their high sensitivity, ease of handling, and high measurement accuracy, they are being used not only for personal exposure dose management but also for microdose management such as environmental radiation dose management. . Under these circumstances, there is a need for a TLD element that is more sensitive than the conventional TLD element, that is, a TL crab photon that is more sensitive than the conventional TL crab photon. The present invention has been made in view of this demand, and is based on Mg2Si, which is said to have the highest sensitivity among the conventional practical TL light materials.
04: The purpose is to provide a TL backlight with higher sensitivity than Tb.

Furthermore, the present invention provides a TL using the above Mg2Si04:Tb.
The purpose of this invention is to provide a TLD element with higher sensitivity than a D element. In order to achieve the above object, the present inventors conducted various studies on the selection of the matrix, the selection of the amount of activation for activating the matrix, the combination of the matrix and the activator, etc.

As a result, strontium oxide (S) and silicon oxide (Si
The present invention was based on the discovery that a composite oxide consisting of 02) is used as a base material and activated with Ce to exhibit thermal phosphor properties that are more sensitive than M&Si04:Tb. C of the present invention
The e-activated strontium silicate halo has a composition formula of S.
Hand 02: ace (where x and a are numbers satisfying the conditions of 0.5×S2.0 and 10-6SaSIO-3, respectively).

From the viewpoint of heat crab light intensity, the more preferable x and a value ranges of the above composition formula are each 0.6SxSI. 3 and 4×10
-6 myaS4×10-4. The TL crab optical material of the present invention represented by the above compositional formula is manufactured by the manufacturing method described below. First, the raw materials for the crab photoreceptor include IS, strontium compounds such as nitrates and carbonates which can be easily converted to S at high temperatures, Si02 or silicon compounds which can easily be converted to Si02 at high temperatures such as silicic acid.

and 3) Ce203 or cerium compounds that can be easily converted to Ce203 at high temperatures, such as nitrates and carbonates.

is used. The above three crab photomaterial raw materials are stoichiometrically S
No. Mix thoroughly.

From the viewpoint of hot light intensity, the more preferable ranges of the x and a values of the above mixed composition formula are each 0.6SxSI. 3 and 4
x10-6 Sa mi 4 x 10-1. Note that strontium silicate represented by the compositional formula S^].xSi02 (where x has the same definition as above) may be used instead of the above-mentioned crab photomaterial raw materials 1) and 2).

Additionally, in addition to the above-mentioned crab-photo material raw materials, if a fluxing agent such as NH4CI or N-Br, which is often used in the production of silicate halo materials, is used in combination, a crab-photo material with even better thermal crab light intensity may be obtained. . Next, the crab photo material raw material mixture is filled into a heat-resistant alumina container and fired in air.

A suitable firing temperature is 800° C. to 1600 am. More preferably, it is 1000qo to 1500oo. The firing time varies depending on the filling amount, firing temperature, etc., but within the above firing temperature range, 0.5 to 5 hours is appropriate. In addition, once the TL halo material mixture has been fired under the above firing conditions, the thermal crab light intensity can be further improved by re-firing it once or twice or more under the same conditions as the above firing conditions. A good TL crab light body can be obtained. After firing, if necessary, operations such as washing, drying, sieving, etc. that are currently employed in the production of crab phosphors may be carried out. In this way, the Ce-attached activated strontium silicate TL nectar of the present invention represented by the above-mentioned compositional formula can be obtained. FIG. 1 illustrates the thermal light curve of the TL light material of the present invention in comparison with that of the conventional Mg exchange i04:Th. The crab light curve, curve b is the thermal footlight curve of Mg2Sj04:0.00 level b.

The thermal crab light intensity of the TL crab light body (curve a) of the present invention is 1/
This is a drawing scaled down to 5. As is clear from FIG. 1, the TL crab light body of the present invention is different from the conventional
The thermal crab light intensity is significantly stronger (i.e., it is highly sensitive) compared to .

Furthermore, as is clear from FIG. 1, the TL crab photoreceptor of the present invention has a thermal crab photo main peak at 340 to 3460, and this thermal crab photo main peak is on the higher temperature side than that of M&Si04:Th. This means that the thermal light properties of the TL light body of the present invention are more stable than those of M&Sj04:Tb, and fading is less likely to occur.
Figure 2 shows the x value of S of the present invention at 0.000 and e (number of moles of Si02 relative to 1 mole of Sr02).
It is a graph which shows the relationship between and heat crab light intensity.

The thermal crab light intensity on the vertical axis is the main peak intensity, and the conventional Mg2
It is shown as a relative value with the main peak intensity of Sj04:0.009b as 100.

As is clear from FIG. 2, the TL crab photoreceptor of the present invention exhibits a stronger thermal light intensity than Mg2Si04:Tb in the x value range of 0.5 m x S2.0, and especially in the range of 0.6 m x SI. In the range of 3, it shows extremely strong thermal light intensity (5 times or more than Mg2Si04:Tb).

Note that Fig. 2 is a graph showing the relationship between the x value and the heat crab light intensity for Sr○ x Si02: 0.000 length e.
It was confirmed that even if the Ce activation amount (a value) changed, the relationship between the x value and the thermal crab light intensity had the same tendency as shown in FIG. 2. FIG. 3 is a graph showing the relationship between the a value (the number of gram atoms of Ce per mole of Sr0) and the thermal crab light intensity in Sr○.Si02:ace of the present invention.

As in FIG. 1, the thermal crab light intensity on the vertical axis is the main peak intensity, and is shown as a relative value with the main peak intensity of the conventional Mg2Si04:0.00 rainbow b as 100. As is clear from FIG. 3, the TL crab photoreceptor of the present invention has an a value of 10-6SaS
In the range of I0-3, it shows a stronger thermal crab light intensity than that of Mg2Si04:Tb, and especially in the range of 4xlo-6SaS4x104, it shows a significantly stronger thermal crab light intensity (5
2 times or more).

In addition, Fig. 3 is a graph showing the relationship between the a value and the heat crab light intensity in S/Si02:ace, but the amount of Si02 (
It was confirmed that even if the x value) changed, the relationship between the a value and the heat crab light intensity was similar to that shown in FIG. 3. As described above, the TL crab light body of the present invention is similar to the conventional M&Si04:T
It has significantly higher sensitivity than that of B.b, and its thermal light properties are stable, making it excellent as a light material for TLD elements. A TLD element using the TL backlight of the present invention will be described below. By using the TL light body of the present invention as a TL light body of a TLD element, a highly sensitive TLD element can be obtained. As is clear from FIGS. 1 to 3, the TLD element using the Ce-activated strontium silicate light body of the present invention is different from the conventional TL using Mg2Sj04:Tb.
It has a sensitivity approximately 1 to 15 times that of the D element. As described above, since the TLD element of the present invention has higher sensitivity than the conventional TLD element, by using the TLD element of the present invention,
The side light mechanism of the LDIJder can be simplified, the dose detection limit can be lowered, and the measurement accuracy of iso-low doses can be improved. The structure of the TLD element of the present invention is completely the same as that of the conventional TLD element except that the Ce-attached activated strontium silicate light body of the present invention is used as the TL light body.

Generally, the TL light substance is a powder, and its constant value can be used as a TLD element as it is. However, it is difficult to handle it as a powder, so for example, it is sealed in a glass tube with an inert gas, compressed into tablets with a small amount of a molding agent such as potassium bromide, or made with a material such as fluororesin or silicone resin. It is solidified, that is, made into an element, by a suitable means such as injecting it into a heat-resistant resin. In making the T-ray trunk light body of the present invention into a device, the conventional method is directly adopted. FIG. 4 illustrates the TLD element of the present invention, and shows the ta
) and [b} are glass-sealed elements with handles, [c} are rod-like elements, 'd} are sheet-like elements, and 'e} are disk-like elements. As explained above, the TL phosphor of the present invention has excellent thermal properties, and is suitable for TLD devices.
It can be used as an L crab light body.

As described above, the industrial utility value of the present invention is extremely large. Next, the present invention will be explained by examples.

Example 1 Strontium carbonate SrC03 29-5
Silicon oxide Si02 84 Sodium oxide Ce203 0.0033 The above raw materials were thoroughly mixed using a ball mill.

The resulting mixture was packed into an alumina tube and heated in air for 1 hour.
It was baked at a temperature of 300 oo for 1 hour. After firing, the fired product was cooled and knotted. In this way, Sr○・0. Oj
02: Obtained 0.0000$e. After irradiating this TL crab light body with 10R of X-rays with a tube voltage of 120 KVp, the thermal crab light intensity was measured.
2 Sio thousand: o. It was about 1 river sound of oo shore b. Example 2 Strontium carbonate Sr003 29.5
Silicon oxide Si02 84 Cerium oxide -Ce203 0.020 The above raw materials were thoroughly mixed using a ball mill.

The resulting mixture was packed into an aluminous tube and fired in air at a temperature of 130,000°C for 2 hours. After firing, the fired product was cooled and knotted. In this way, Sro・0. i02: I got 0.000$e. When the stimulating light intensity of this TL cage light body was measured in the same manner as in Example 1, it was found that M&S
The ratio was approximately i5 times the ratio of j04:0.00. Example 3 Strontium carbonate SrC03 29.5
Silicon oxide Si02 12.0
Sodium oxide Ce203 0.0066
? The above raw materials were thoroughly mixed using a ball mill.

The resulting mixture was packed into an alumina tube and heated in air for 1 hour.
It was baked at a temperature of 200 qo for 2 hours. After firing, the fired product was cooled and streaked. In this way, S.Si02:
0.0001Ce was obtained. This T
When the thermal crab light intensity of the L crab light body was measured, it was found that M&Si04
:0.00 It was about 8 times the illusion ratio.

[Brief explanation of the drawing]

FIG. 1 shows the thermal coupling light curve of the Ce-activated strontium silicate crab light of the present invention in comparison with that of the conventional M-axis Si04:Th. Body heat crab light curve, curve b is M&Si04:
This is the thermal crab light curve of Th. Note that the heat crab light intensity of curve a is drawn reduced to ]/5. FIG. 2 is a graph showing the relationship between the x value (the number of moles of Si02 per mole of Sr01) and the thermal scale light intensity in the Ce-attached strontium silicate light body of the present invention. FIG.
It is a graph showing the relationship between the value (the number of gram atoms of Ce per mole of Sr0) and the thermal crab light intensity. FIG. 4 illustrates the TLD device of the present invention. Figure 1 Figure 2 Figure 4 Figure 3

Claims (1)

[Claims] 1 SrO x SiO_2: aCe (where x and a are numbers satisfying the conditions of 0.5≦x≦2.0 and 10^-^6≦a≦10^-^3, respectively) A cerium-activated strontium silicate thermal fluorescent phosphor. 2 x and a in the above compositional formula are each 0.6≦x≦1
．． 3 and 4×10^-^6≦a≦4×10^-^4. 3 The compositional formula is represented by SrO・xSiO_2:aCe (where x and a are numbers that satisfy the conditions of 0.5≦x≦2.0 and 10^-^6≦a≦10^-^3, respectively) Cerium-activated strontium silicate thermal fluorescent phosphor. 4 x and a in the above composition formula are each 0.6≦x≦1
．． 3 and 4×10^-^6≦a≦4×10^-^4.