CN101839991A - Oblique arrangement type high-energy ray detector of composite photosensor - Google Patents

Abstract

The embodiment of the present invention discloses a composite photosensitive device obliquely arranged high-energy ray detector, including: a scintillation crystal module, a composite photosensitive device array and a decoding module. Arranged along the width direction of the elongated scintillation crystal unit; the composite photosensitive device array is used to detect the scintillation light from the scintillation crystal module and output signals, including a first group of photosensitive devices and a second group of photosensitive devices, The size of the first group of photosensitive devices is larger than that of the second group of photosensitive devices, and the first group of photosensitive devices is arranged in a rhombus; the decoding module is used to obtain the spatial position and energy of high-energy rays according to the signal from the composite photosensitive device array. According to the high-energy ray detector provided by the present invention, a smaller detection dead zone can be obtained by flexibly selecting the size of the photosensitive device, and different spatial resolutions can be obtained in two directions.

Description

A Composite Photosensitive Device Oblique Arrangement Type High Energy Ray Detector

technical field

The invention relates to the field of radiation detection and imaging, in particular to a composite photosensitive device obliquely arranged high-energy ray detector.

Background technique

One of the commonly used detectors in high-energy ray detection technology is a scintillator detector. Scintillator detectors usually use a scintillation crystal that can effectively block and absorb electromagnetic radiation and produce luminescence with it as a detection material. When high-energy rays are incident into the scintillation crystal, according to the difference in ray energy, effective atomic coefficient and density of the scintillation crystal, different proportions of photoelectric effect, Compton scattering effect and electron pair effect will occur with the scintillation crystal, and the energy will be deposited in the scintillation crystal. , The excited scintillation crystal de-excites to emit weak scintillation light, and the de-excitation obeys the law of exponential decay. The scintillation crystals of different materials have different luminescence spectra, including different luminescence decay times, different peak values, etc. The flashing light located in the visible light region or the ultraviolet light region is photoelectrically converted and multiplied by a photosensitive device to form a pulse signal. The intensity of the pulse signal reflects the energy of the high-energy ray; the occurrence time of the pulse signal reflects the incident time of the high-energy ray; the intensity distribution of the pulse signal in multiple photosensitive devices reflects the incident position of the high-energy ray, etc. Scintillation detectors have the characteristics of high detection efficiency and short resolution time, and are widely used in the research of nuclear medicine, safety inspection, high-energy physics and cosmic ray detection, and are an indispensable and main means in the field of radiation detection technology today.

When traditional scintillation detectors perform imaging detection, they usually use long scintillation crystal units to form square scintillation crystal arrays to couple square arrays or hexagonal arrays of photosensitive devices for positioning analysis of high-energy rays. Except the side coupled with the photosensitive device, the other six sides of the scintillation crystal array are covered with reflective film. The long scintillation crystal units between the scintillation crystal arrays are pasted or sprayed with reflective materials of different lengths according to certain rules, and silicone oil is added between the long scintillation crystal units, and fixed with highly transparent optical glue. The scintillation crystal array and the photosensitive device array are directly coupled or light-conducting materials are added, such as organic plastics, glass, optical fibers, etc.

When the high-energy ray is incident on the scintillation crystal array and interacts with the long scintillation crystal unit, the energy is deposited on the long scintillation crystal unit, and the long scintillation crystal unit de-excites a large number of low-energy photons, such as visible light or ultraviolet light, The low-energy photons propagate in the elongated scintillation crystal unit, and after multiple reflections, are finally detected by the photosensitive device or escape or are absorbed by the elongated scintillation crystal unit. When low-energy photons encounter a surface without a reflective film, they will be transmitted to the adjacent elongated scintillation crystal unit and may be detected by other photosensitive devices. In the end, all photosensitive devices will get signals of different intensities. The intensity of the signal reflects the number of low-energy photons detected, and the sum of the signals on each photosensitive device can reflect the energy of incident high-energy rays. Through the distribution of low-energy photons in each photosensitive device, high-energy The incident position of the ray. Therefore, traditional detectors usually use the Anger center of gravity method for positioning.

As shown in FIG. 1 , it is a schematic diagram of a traditional scintillation detector using a scintillation crystal array coupled with a square photosensitive device array in the prior art. FIG. 2 is a schematic diagram of a traditional scintillation detector using a scintillation crystal array coupled with a PQS photosensitive device array. Fig. 3 shows the principle of a traditional scintillation detector using a scintillation crystal array coupled with a regular hexagonal photosensitive device array. Wherein, 1 is a photosensitive device, 2 is a scintillation crystal module, and 3 is a strip type scintillation crystal unit. In Figure 1, the array of photosensitive devices is arranged in a square shape. In Figure 3, the array of photosensitive devices is arranged in a regular hexagon.

Taking the square array of photosensitive devices as an example, as shown in Figure 1, the light output signals of the four photosensitive devices are V _A , V _B , V _C , and V _D , then the spatial positions X, Y and energy E of high-energy rays are determined by the following The formula determines:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}\\ \mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}}{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}}{\mathrm{<span\; class="notranslate">\; E.</span>}}\end{array}\right.$

If a flood source is used to irradiate the detector to collect a sufficient number of high-energy ray particles, the position of each high-energy ray particle is calculated according to the above-mentioned center of gravity method, and drawn in a two-dimensional histogram to obtain a flood histogram or two-dimensional position graphic. The randomness of the process from the interaction between the high-energy ray particles and the crystal to the detection of the photosensitive device to generate the electric pulse signal leads to the uncertainty of the output signal. Several high-energy ray particles incident on the same elongated crystal unit will output different The X and Y signals are reflected in the pan-field histogram, that is, each crystal block presents a white mass. According to the distribution of the white clusters on the pan-field histogram, determine their boundary lines and record them in the lookup table. During data collection, according to the X and Y signals generated by each incident event and the look-up table, it can be judged which elongated crystal unit the incident particle entered, so as to obtain the position code of the corresponding crystal block in the detector module. Another method is to use the full-field histogram to use the maximum likelihood estimation method to judge which elongated crystal unit it occurs in from the X and Y values of the incident particle.

The disadvantage of the prior art is that the spatial resolution obtained by traditional detectors in the X and Y directions is the same, and if the scintillation detectors in Fig. 1, Fig. 2 and Fig. 3 are used, there is a large gap between photosensitive devices. Detect dead zone.

Contents of the invention

The purpose of the present invention is to at least solve one of the above-mentioned problems, and specifically proposes a composite photosensitive device obliquely arranged high-energy ray detector with the characteristics of flexible photosensitive device size selection, different spatial resolutions, small detection dead zone, and expandability. .

An embodiment of the present invention discloses a composite photosensitive device obliquely arranged high-energy ray detector, including: the high-energy ray detector includes: a scintillation crystal module, a composite photosensitive device array and a decoding module,

The scintillation crystal module is used to generate scintillation light, and the scintillation crystal module is composed of strip-shaped scintillation crystal units arranged along the width direction of the strip-shaped scintillation crystal units;

The composite photosensitive device array is used to detect the scintillation light from the scintillation crystal module and output signals, the composite photosensitive device array includes a first group of photosensitive devices and a second group of photosensitive devices, and the first group of photosensitive devices The size is larger than the size of the second group of photosensitive devices, the first group of photosensitive devices includes four photosensitive devices arranged in a rhombus, the second group of photosensitive devices includes one photosensitive device, placed in the center of the rhombus, the The second group of photosensitive devices is closely adjacent to some of the photosensitive devices in the first group of photosensitive devices;

The decoding module is used to obtain the spatial position and energy of the high-energy ray according to the signal from the composite photosensitive device array.

The high-energy ray detector provided according to the embodiment of the present invention has the following characteristics and advantages:

1. The size of the photosensitive device can be flexibly selected: the rhombus angle formed by the large-sized photosensitive device can be determined according to the size of the small-sized photosensitive device, and the inclination angle of the arrangement can be changed arbitrarily, so photosensitive devices of various sizes can be used.

2. Different types of photosensitive devices can be combined, which can be composed of circular photosensitive devices such as photomultiplier tubes and rectangular photosensitive devices such as avalanche diodes.

3. Different spatial resolutions in X and Y directions can be obtained: According to the arrangement characteristics of photosensitive devices, it can be concluded that the resolution in the Y direction is better than that in the X direction.

4. More efficient detection of high-energy rays: The gap area between the obliquely arranged composite photosensitive devices is smaller than that of the traditional square-arranged photosensitive device array, so the obliquely arranged composite photosensitive devices have a smaller blind area for detection by high-energy ray detectors.

5. Expandable: The detector modules can be spliced and expanded into large flat-panel detectors, arc or ring detectors.

The high-energy ray detector provided by the invention can obtain a smaller detection dead zone and different spatial resolutions in two directions by flexibly selecting the size of the photosensitive device.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

1 is a schematic diagram of the principle of a traditional scintillation detector using a scintillation crystal array coupled to a square photosensitive device array;

Fig. 2 is the schematic diagram of the principle of a traditional scintillation detector using a photosensitive device array coupled with a scintillation crystal array in a PQS mode;

3 is a schematic diagram of the principle of a traditional scintillation detector using a scintillation crystal array coupled to a regular hexagonal photosensitive device array;

Fig. 4 is a schematic diagram of the principle of an obliquely arranged high-energy ray detector using a square scintillation crystal array coupled with a composite photosensitive device according to an embodiment of the present invention;

FIG. 5 is a two-dimensional flood histogram obtained by a high-energy ray detector according to an embodiment of the present invention;

Fig. 6 is a schematic diagram of the principle of a diagonally arranged high-energy ray detector composed of a first group of circular photosensitive devices and a second group of rectangular photosensitive devices according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of the principle of expanding the obliquely arranged high-energy ray detector of photosensitive devices into a planar detector in FIG. 4 .

in,

1 is a photosensitive device array, 11 is a first group of photosensitive devices, 12 is a second group of photosensitive devices, 2 is a scintillation crystal module, and 3 is a strip type scintillation crystal unit.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In order to solve the above problems, an embodiment of the present invention provides a composite photosensitive device obliquely arranged high-energy ray detector, including a scintillation crystal module, a composite photosensitive device array and a decoding module. Specifically, the composite photosensitive device array, used to detect scintillation light and output signals, includes a first group of photosensitive devices and a second group of photosensitive devices, and at least five photosensitive devices are arranged obliquely. In one embodiment of the present invention, wherein the sizes of the two groups of photosensitive devices are different, the size of the first group of photosensitive devices is larger than the size of the second group of photosensitive devices, and the photosensitive devices in the first group of photosensitive devices are referred to as For large-size photosensitive devices, the photosensitive devices in the second group of photosensitive devices are called small-size photosensitive devices. In one embodiment of the present invention, the number of large-size photosensitive devices is 4, the number of small-size photosensitive devices is 1, and the small-size photosensitive device is located at the center of a rhombus formed by four large-size photosensitive devices.

As shown in FIG. 4 , the first group of photosensitive devices 11 includes four large-sized photosensitive devices A, B, C, and D arranged in a rhombus, and the centers of the four photosensitive devices are on a rhombus. The second group of photosensitive devices 12 includes a photosensitive device E of small size. The small-sized photosensitive device E is placed in the center of the above-mentioned rhombus. The angle of the rhombus can be determined by the size of the large-size photosensitive device and the small-size photosensitive device, and can allow the small-size photosensitive device and part of the large-size photosensitive device to be closely arranged. As shown in FIG. 4 , the small-sized photosensitive device E and two opposite large-sized photosensitive devices A and D are placed next to each other.

Wherein, the photosensitive device types of the first group of photosensitive devices and the second group of photosensitive devices include: photomultiplier tubes, silicon photomultiplier tubes, and avalanche diodes. The types of photosensitive devices of the first group of photosensitive devices and the second group of photosensitive devices may be the same or different.

In addition, the composite photosensitive device obliquely arranged high-energy ray detector also includes a scintillation crystal module 2 for generating scintillation light, and the scintillation crystal module 2 is formed by arranging strip-shaped scintillation crystal units 3 along the width direction of the strip-shaped scintillation crystal units . Wherein, the width direction of the elongated scintillation crystal unit 3 is a square, a rectangle or a rhombus, and the width direction shown in FIG. 4 is a square.

The elongated scintillation crystal unit 3 can use one of the crystals of the following materials: bismuth germanate, lutetium silicate, yttrium lutetium silicate, gadolinium silicate, yttrium silicate, barium fluoride, sodium iodide, cesium iodide, tungsten Lead acid, yttrium aluminate, lanthanum bromide, lanthanum chloride, cerium bromide, lutetium silicate, lutetium aluminate, lutetium iodide.

The aforementioned elongated scintillation crystal units 3 for capturing high-energy rays are arranged into a scintillation crystal module 2 . Wherein, the cross-section of the elongated crystal unit 3 and the shape of the scintillation crystal module 2 composed include a square, a rectangle or a rhombus.

The scintillation crystal module 2 is bonded with reflective films of different lengths at different positions, the places where the reflective film is not bonded are filled with silicone oil, and the scintillation crystal module 2 is fixed with optical glue. Wherein, in order to improve the coupling between the scintillation crystal module 2 and the photosensitive device array, the scintillation crystal module can be further processed, cut and polished into other polygons.

In one embodiment of the present invention, the composite photosensitive device obliquely arranged high-energy ray detector uses optical glue to directly bond the scintillation crystal module 2 and the obliquely arranged composite photosensitive device array together. In another embodiment of the present invention, the above-mentioned scintillation crystal module can also be used to couple the light guide material and then couple the oblique photosensitive device array. Wherein, the light guide material is one of the following materials: organic plastic, glass and optical fiber.

After the high-energy ray is incident on the scintillation crystal module 2, scintillation light is generated, which is detected by the photosensitive device. The photosensitive device converts and amplifies the detected signal to obtain an electric pulse signal, which is output to the decoding module. The decoding module uses the weight distribution of the pulse signal in the photosensitive device array to obtain the coordinates of the high-energy rays in the scintillation crystal module.

Wherein, the decoding module includes two methods for decoding the pulse signal.

Method 1: Use the Cartesian coordinate system XOY.

As shown in Figure 4, the output signals of the five photosensitive devices are V _A , V _B , V _C , V _D , and _VE , then the spatial positions X, Y and energy E of high-energy rays are determined by the following formulas:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}}{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}}{\mathrm{<span\; class="notranslate">\; E.</span>}}\end{array}\right.$

Method 2: Use the oblique coordinate system XOY'.

As shown in Figure 4, the output signals of the five photosensitive devices are V _A , V _B , V _C , V _D , V _E , and θ is the angle between Y' and X, then the spatial position X, Y and energy E of the high-energy ray are determined by the following formulas, respectively:

$\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}\end{array}\right.$

Different spatial resolutions in the X and Y directions can be obtained through the above method. As shown in FIG. 4 , it can be concluded that the resolution in the Y direction is better than that in the X direction from the arrangement characteristics of the photosensitive devices. Calculate the position of each high-energy ray particle according to the above method, and draw it in a two-dimensional histogram to obtain a pan-field histogram or a two-dimensional configuration map. Several high-energy ray particles incident on the same elongated crystal unit will output different X and Y signals, reflected in the pan-field histogram that each crystal block presents a white mass. According to the distribution of the white clusters on the pan-field histogram, determine their boundary lines and record them in the lookup table. During data collection, according to the X and Y signals generated by each incident event and the look-up table, it can be judged which elongated crystal unit the incident particle entered, so as to obtain the position code of the corresponding crystal block in the detector module.

Hereinafter, the present invention will be further described by taking a high-energy ray detector in which scintillation crystal modules form a 9×9 square matrix with 9 rows and 9 columns as an example.

Among them, the scintillation crystal material is yttrium lutetium silicate, and the size of the elongated scintillation crystal unit is 5.7mm×5.7mm×20mm; the scintillation crystal array: 9 rows and 9 columns form a 9×9 square matrix, 52mm×52mm.

The composite photosensitive device array is:

The first group of photosensitive devices: 4 Hamamatsu R9779 (diameter 51mm), photomultiplier tubes, four large-size photomultiplier tubes obliquely arranged Angle: small diamond-shaped angle of 86 degrees. Photomultiplier tube cathode voltage: -1500V, photomultiplier tube anode voltage: 0V (grounded).

The second group of photosensitive devices: 1 Photonis XP1912 (diameter 19mm), the center of the small-sized photomultiplier tube is on the center of the rhombus.

Gamma ray source: cesium (Cs-137) point source, intensity 0.4μCi, energy 662KeV

Data acquisition: The photomultiplier tube signal enters the ADC module (analog-to-digital conversion module) through the preamplifier, extracts time and position information, and transmits it to the Flow board module (data receiving module), receives and transmits it to the PC with PowerPC, and uses the LabView program collection.

Analysis of results:

The photosensitive device of the obliquely arranged high-energy ray detector adopts a photomultiplier tube, and the scintillation crystal array is a 9×9 square array. The cesium (Cs-137) gamma source is 30cm away from the detector, which can be approximated as a flood source. After the gamma rays are incident on the scintillation crystal array, the scintillation crystals are excited, and the scintillation crystals are de-excited to generate visible light. The visible light is converted into electrical signals by four photomultiplier tubes, amplified and output to the data acquisition part. The final histogram of the pan field is shown in Figure 5, where the 9×9 array structure is clearly visible. The grayscale of the image represents the count rate, and the whiter the color, the higher the intensity of gamma rays at that location.

The first group of photosensitive devices and the second group of photosensitive devices shown in Figure 4 are both circular, and the composite photosensitive device obliquely arranged high-energy ray detector provided by the embodiment of the present invention can also be implemented as a combination of different types of photosensitive devices. . As shown in FIG. 6 , the first group of photosensitive devices is a circular photomultiplier tube, and the second group of photosensitive devices is a rectangular avalanche diode. Specifically, the photosensitive devices A, B, C, and D are circular photomultiplier tubes, and the photosensitive device E is a rectangular avalanche diode.

Moreover, the composite photosensitive device obliquely arranged high-energy ray detector provided in the above embodiments can be expanded. That is, the detector modules can be spliced and expanded into plane, arc or ring detectors. Fig. 7 shows a schematic diagram of the principle of expanding the obliquely arranged high-energy ray detector of photosensitive devices into a planar detector. As shown in Figure 7, the first group of photosensitive devices includes 9 photosensitive devices, and the second group of photosensitive devices includes 4 photosensitive devices. Four adjacent large-size photosensitive devices, that is, the first group of photosensitive devices are arranged obliquely, and small-sized photosensitive devices, that is, the second group of photosensitive devices are placed at the center of the rhombus.

The high-energy ray detector provided according to the embodiment of the present invention has the following characteristics and advantages:

1. The size of the photosensitive device can be flexibly selected: the rhombus angle formed by the large-sized photosensitive device can be determined according to the size of the small-sized photosensitive device, and the inclination angle of the arrangement can be changed arbitrarily, so photosensitive devices of various sizes can be used.

2. A combination of different types of photosensitive devices can be selected. As shown in FIG. 5 , it can be composed of a circular photosensitive device such as a photomultiplier tube and a rectangular photosensitive device such as an avalanche diode.

3. Can obtain different spatial resolutions in the X and Y directions: as shown in Figure 4, the resolution in the Y direction is better than that in the X direction according to the arrangement characteristics of the photosensitive devices.

4. More efficient detection of high-energy rays: The gap area between the obliquely arranged composite photosensitive devices is smaller than that of the traditional square-arranged photosensitive device array, so the obliquely arranged composite photosensitive devices have a smaller blind area for detection by high-energy ray detectors.

5. Expandable: The detector modules can be spliced and expanded into large flat-panel detectors, arc or ring detectors.

The high-energy ray detector provided by the invention can obtain a smaller detection dead zone and different spatial resolutions in two directions by flexibly selecting the size of the photosensitive device.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also It should be regarded as the protection scope of the present invention.

Claims (11)

1. A composite photosensitive device oblique arrangement type high-energy ray detector, is characterized in that, comprises scintillation crystal module, composite photosensitive device array and decoding module, The scintillation crystal module is used to generate scintillation light, and the scintillation crystal module is composed of strip-shaped scintillation crystal units arranged along the width direction of the strip-shaped scintillation crystal units; The composite photosensitive device array is used to detect the scintillation light from the scintillation crystal module and output signals, the composite photosensitive device array includes a first group of photosensitive devices and a second group of photosensitive devices, and the first group of photosensitive devices The size is larger than the size of the second group of photosensitive devices, the first group of photosensitive devices includes four photosensitive devices arranged in a rhombus, the second group of photosensitive devices includes one photosensitive device, placed in the center of the rhombus, the The second group of photosensitive devices is closely adjacent to some of the photosensitive devices in the first group of photosensitive devices; The decoding module is used to obtain the spatial position and energy of the high-energy ray according to the signal from the composite photosensitive device array. 2. The high-energy ray detector according to claim 1, wherein the composite photosensitive device array comprises a plurality of arrays composed of the first group of photosensitive devices and the second group of photosensitive devices. 3. The high-energy ray detector according to claim 1, wherein the photosensitive devices of the first group of photosensitive devices and the second group of photosensitive devices comprise photomultiplier tubes, silicon photomultiplier tubes or avalanche diodes. 4. The high-energy ray detector according to claim 1, wherein the second group of photosensitive devices is closely adjacent to two opposite photosensitive devices in the first group of photosensitive devices. 5. The high-energy ray detector according to claim 1, wherein the width direction of the elongated scintillation crystal unit is square, rectangular or rhombus. 6. The high-energy ray detector according to claim 1, wherein the elongated scintillation crystal unit is one of the crystals of the following materials: Bismuth germanate, lutetium silicate, yttrium lutetium silicate, gadolinium silicate, yttrium silicate, barium fluoride, sodium iodide, cesium iodide, lead tungstate, yttrium aluminate, lanthanum bromide, bluestone chloride, bromine Cerium oxide, lutetium silicate, lutetium aluminate, lutetium iodide. 7. The high-energy ray detector according to claim 1, characterized in that, the scintillation crystal module is square, rectangular or processed and ground into a polygon. 8. The high-energy ray detector according to claim 1, wherein the composite photosensitive device array and the scintillation crystal module are bonded by optical glue or photoconductive material. 9. The high-energy ray detector according to claim 8, wherein the light guide material is one of the following materials: organic plastic, glass and optical fiber. 10. The high-energy ray detector according to claim 1, characterized in that, the high-energy ray detector is a single piece or multiple pieces spliced into a plane, an arc or a ring. 11. The high-energy ray detector according to claim 1, wherein the decoding module obtains the spatial position and energy of the high-energy ray, including one of the following methods: When using a direct coordinate system, $\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}}{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}}{\mathrm{<span\; class="notranslate">\; E.</span>}}\end{array}\right.<span\; class="notranslate">\; ;</span>$ When using an oblique coordinate system, $\left\{\begin{array}{c}\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}\\ \mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; E.</span>}}\end{array}\right.$ Among them, X and Y are the horizontal position and vertical position in the spatial position of the high-energy ray; E is the energy of the high-energy ray; V _A , V _B , V _c , V _D are the four photosensitive devices in the first group of photosensitive devices Output signal; V _E is the output signal of the second group of photosensitive devices; θ is the angle between Y' and X.

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