JPS6395375A - Phototimer head - Google Patents

Abstract

PURPOSE:To enable the formation of a number of dose detecting sections along with varied light fields, by covering an electromagnetic wave acceptor layer provided on the surface of a support substrate with a phosphor layer to eliminate interference between fluorescences. CONSTITUTION:For example, a slurry comprising 80pts.wt. of CaWO4 phosphor with the average particle size of 3mum and 20pts.wt. of nitrocellulose is applied on a polyethylene terephthalate sheet 400mm long and wide and 25mum thick at a coat density of 15mg/cm<2>. Then, an a(amorphous)-Si film with the thickness of 1mum is formed at two points of an identical sheet by evaporation and an aluminum lead is extended therefrom. Then, these sheets adhere to each other through a double-side adhesive tape with the polyethylene terephthalate sheet as base material and fixed on an acrylic resin plate with the thickness of 2.5mm. Then, the work is cut by 354mm square and covered entirely with a carbon- kneaded polyester film 75mum thick for shielding light to complete a head.

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention is an X-ray section! The present invention relates to a phototimer head for cedar trees, and more specifically, to a phototimer head with a novel structure that allows imaging without interference between patterns and allows wildflowers to be captured in a lot of light.

(Prior Art) In direct X-ray imaging, a phototimer head is set in front of a cassette containing a combination of xi film and an intensifying screen. This is to time-control the amount of X-rays incident on the cassette in order to optimize the photographic density.

As such a phototimer head, one having a structure as shown in FIG. 3 is first known. In FIG. 3, reference numeral 21 denotes an optical guide path, which is usually made of an acrylic resin plate with a thickness of about 2 mm. A reflecting plate 2 such as an aluminum plate is provided on the back side of this leading path 21 as a light reflecting member.
2 are arranged in close contact with each other. Furthermore, a phosphor layer 23 that emits light by irradiated X-rays is disposed over the entire surface of the front surface of the optical guide path 21 .

The transmitted X-rays that have passed through the human body etc. are incident on the phosphor layer 23, and the phosphor layer 23 emits light according to the incident dose. The emitted fluorescence is optically coupled in a lattice shape that corresponds to the diagnostic target area provided on the optical guide! 26 and enters the light guide path through the reflecting plate 22
The emitted fluorescent light is reflected repeatedly between the light guide 21 and the light guide 21, reaches the photomultiplier tube 25 in the lead box 24, for example, and is converted into an electrical signal. This electrical signal, which is a function of the amount of x-ray vj, is communicated to a predetermined control system to drive the on-off operation of the Xfi source.

Further, recently, a phototimer RAD as shown in FIGS. 4 and 5 has been developed. 4 shows a side view, and FIG. 5 shows a front view. In the figures, 31 is a support substrate made of, for example, an acrylic resin plate, and 32 is a support substrate 31.
This is a single-crystal silicon photodiode embedded in the required locations.

In the case of this phototimer head, the transmitted light xVj is incident on the silicon photodiode 32. The X-rays at this time are converted into electrical signals corresponding to the dose of the X-rays in the silicon photodiode 32.The electrical signals are routed from the diode 32 over the surface of the support substrate 31, and are sent to the control system via the lead 33. and from there proceed with the turn-off operation of the xa source.

(Problems to be Solved by the Invention) These phototimer heads described above have the following problems. That is, first of all, in the system shown in Fig. 3, when increasing the performance of the phototimer head by providing multiple dose detection units, it is difficult to prevent interference between the fluorescence emitted from each detection unit. In order to independently detect the fluorescence of each detection section, it is necessary to install a plurality of photomultiplier tubes, but such installation is extremely difficult. In other words, in the case of the phototimer head shown in FIG. 3, it is extremely difficult to grow wildflowers with a lot of sunlight.

In the case of the devices shown in FIGS. 4 and 5, it is only necessary to embed the silicon photodiode 32 in the dose detection part of the support substrate 31, so it is extremely superior in terms of receiving wildflowers with a lot of sunlight.

However, the thickness of the silicon diode used must be at least 200 μm. For this reason, the support substrate 31
Due to the difference in the X-ray absorption coefficients of the silicon photodiode 32 and the silicon photodiode 32, the boundary between the two is photographed, and single-crystal silicon photodiodes are expensive, which is an economic disadvantage.

An object of the present invention is to provide a phototimer head with a novel structure that eliminates all of the problems with the phototimer head described above.

[Constitution of the Invention (Means for Solving Problems) The phototimer head of the present invention comprises: a supporting substrate; an electromagnetic phosphor layer disposed on the surface of the supporting substrate; and an electromagnetic wave phosphor layer extending from the phosphor layer. A phosphor layer is provided to cover the phosphor layer; and a light-shielding film covers all of these.

A more detailed explanation will be given below with reference to the drawings. FIG. 1 is a side view, and FIG. 2 is a front view thereof.

In the figure, 11 is a support (a plate, support),
(The plate 11 does not need to be transparent and may be made of any material as long as it has an appropriate strength. However, it is preferably made of a material with as low an X-ray absorption coefficient as possible. For example, an acrylic resin plate, polyethylene terephthalate, etc.) A resin plate is suitable.

12a and 12b are electromagnetic phosphor layers disposed on the surface of the support substrate 11. The materials constituting the phosphor layer are:
Any material may be used as long as it can convert electromagnetic waves into electric signals when electromagnetic waves such as light and xi are incident thereon.
Amorphous silicon (a-5i) is the most suitable material because it has the above functions.

The phosphor layer may be disposed on the entire surface of the support substrate 11, but it may also be disposed only on the required dose detection section (two locations in the figure); however, the thickness of the phosphor layer may not be too thick. There is no point in using it, and it is usually preferable that the amount is about 0.1 to 10 μm.

For the arrangement, a known film-forming method, such as an a-Si weeding method or a sputtering method, may be applied.

Leads 13a and 13b extend from each phosphor layer and are used to transmit electrical signals obtained from the phosphor layer to the control system.

Reference numeral 14 denotes a phosphor layer disposed on the phosphor layers 12a, 12b and the surface of the support substrate 11. This phosphor layer 14 may be provided only on the surface of the phosphor layer. When disposing, for example, a predetermined fluorescent paint may be applied to the surface of the phosphor layer, or the entire surface of a transparent plastic sheet such as a polyethylene terephthalate sheet or a portion corresponding to the phosphor layer on the support substrate may be coated. It can also be provided by applying a fluorescent paint and overlapping it with a support substrate.

In the phosphor layer, the coating density is 1 to 30 mg/c1
12. It is preferable that the thickness is 0.2 to 3-3.

The phosphor to be used may be anything as long as it can cover the visible light region, but examples include calcium tungstate (CaWOa)*terbium-activated gadolinium oxysulfide (Gd202S:T)l),
Europium activated salt barium fluoride (BaFC text: Eu)
, silver-activated zinc sulfide (ZnS:Ag), copper-activated zinc sulfide (
Examples include ZnS:Cu).

(Embodiment of the Invention) A slurry consisting of 80 parts by weight of CaWOa phosphor with an average particle size of 3 tiles and 20 parts by weight of nitrocellulose was applied onto a polyethylene terephthalate sheet having a length of 400 x width of 400 mm and a thickness of 25 μm at a coating density of 15 mg/ It was applied in cm2.

A-S with a thickness of Ig was deposited on two parts of a similar sheet using a vapor deposition method.
iffQ was formed into a film, and aluminum leads were also extended from them.

These sheets were adhered via a double-sided adhesive tape having a polyethylene terephthalate sheet as a base material, and this was fixed to an acrylic resin plate having a thickness of 2.5+s+*. Then 3
The phototimer head of the present invention was obtained by cutting it to a length of 54 m and covering the whole with a 75 mm carbon-studded polyester film for light shielding.

For comparison, two patterns were formed and the optical guide had a thickness of 2.
．． A phototimer head of a conventional structure (Fig. 3) made of a 5-inch acrylic resin plate was prepared. This is referred to as Comparative Example 1.

In addition, a phototimer head was prepared in which two monocrystalline silicon diodes having the same planar shape as in the example and having a thickness of 0.4 mm were embedded in an acrylic resin plate having a thickness of 2.5 mm in the same pattern as in the example. This is referred to as Comparative Example 2.

X-ray photography was performed using the three types of phototimer heads mentioned above, and the performance of each was investigated.

Although interference between patterns was observed in Comparative Example 1,
However, it was not observed in Examples and Comparative Example 2. In addition, in Comparative Example 2, the boundary between the pattern and the acrylic resin plate was photographed, but in Comparative Example 1,
No such boundary was shown in the image.

[Effects of the Invention] As is clear from the above description, the phototimer head of the present invention does not cause interference even when a large number of dose detection units are provided on the support substrate, and is capable of detecting a large number of doses. can form a section.

In other words, it becomes possible to produce wildflowers that receive a lot of sunlight. At the same time, the boundary between the phosphor layer and the substrate is not visible in the photograph taken, and since the phosphor layer is extremely thin, the overall price is low.

Therefore, its industrial value is great.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams illustrating a side view and a front view, respectively, of the phototimer head of the present invention. FIG. 3A is a side view of a conventional phototimer head, and FIG. 3A is a front view. Figures 4 and 5 are side views of other conventional examples, respectively.
It is a figure which illustrates a front view. 11-Support substrate 12a, 12b-Electromagnetic wave phosphor layer 13-Lead 14-phosphor layer 1 Fig. 2 Fig. 3 b

Claims (3)

[Claims] (1) supporting substrate; an electromagnetic wave receptor layer disposed on the surface of the supporting substrate; leads extending from the phosphor layer; a phosphor layer disposed covering the phosphor layer; A phototimer head characterized by: (2) The phototimer head according to claim 1, wherein the phosphor layer is an amorphous silicon layer. (3) The thickness of the amorphous silicon layer is 1 to 10 μm
A phototimer head according to claim 2.