CN114280660A - Double-crystal reverse coincidence laminated detector with special shape - Google Patents
Double-crystal reverse coincidence laminated detector with special shape Download PDFInfo
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- CN114280660A CN114280660A CN202210007613.2A CN202210007613A CN114280660A CN 114280660 A CN114280660 A CN 114280660A CN 202210007613 A CN202210007613 A CN 202210007613A CN 114280660 A CN114280660 A CN 114280660A
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- 239000013078 crystal Substances 0.000 title claims abstract description 90
- 238000001228 spectrum Methods 0.000 claims abstract description 12
- 238000012545 processing Methods 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims abstract description 7
- 229910052751 metal Inorganic materials 0.000 claims abstract description 5
- 239000002184 metal Substances 0.000 claims abstract description 5
- 230000000630 rising effect Effects 0.000 claims description 4
- 229910052797 bismuth Inorganic materials 0.000 claims description 3
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 claims description 3
- XQPRBTXUXXVTKB-UHFFFAOYSA-M caesium iodide Chemical compound [I-].[Cs+] XQPRBTXUXXVTKB-UHFFFAOYSA-M 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 7
- 238000001514 detection method Methods 0.000 abstract description 6
- 238000004806 packaging method and process Methods 0.000 abstract description 6
- 230000008021 deposition Effects 0.000 abstract description 3
- 230000007547 defect Effects 0.000 abstract description 2
- 230000008878 coupling Effects 0.000 abstract 1
- 238000010168 coupling process Methods 0.000 abstract 1
- 238000005859 coupling reaction Methods 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000002131 composite material Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 2
- 239000004408 titanium dioxide Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000009206 nuclear medicine Methods 0.000 description 1
- 230000005658 nuclear physics Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 229910052716 thallium Inorganic materials 0.000 description 1
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses a double-crystal inverse coincidence laminated detector with a special shape, which comprises a metal detector shell, a crystal packaging reflecting layer, a main crystal, a secondary crystal, a photomultiplier, a voltage division circuit, a digital spectrometer and a data processing system. The method for reducing the peak-to-average ratio of the anti-coincidence laminated detector comprises the steps of embedding a cylindrical main crystal into a well-shaped secondary crystal, coupling by using the same photomultiplier, and counting a signal which is only subjected to energy deposition in the main crystal into an energy spectrum after the signal is processed by rear electronics. Aiming at the defect that the volume of a cylindrical crystal is overlarge, the double-crystal inverse coincidence laminated detector with the special shape is designed, and the method that the secondary crystal wrapped outside the main crystal is processed into a circular truncated cone shape or a truncated cone shape is adopted, so that the light collection capacity and the resolution ratio of the double-crystal inverse coincidence laminated detector can be improved on the basis of not excessively losing the inverse effect and the detection efficiency of the inverse coincidence detector. Has the advantages that: improve the light collection ability, improve detector resolution ratio.
Description
Technical Field
The invention belongs to the field of ray energy spectrum measurement, and particularly relates to a special-shaped double-crystal inverse coincidence laminated detector with a changed paracrystal shape.
Background
A scintillation detector is a detector that records by collecting and converting into an electrical signal the fluorescence produced when energy deposition occurs in a scintillation crystal. The device has the advantages of high detection efficiency, large sensitive volume, relatively simple electronic system, convenience in hand holding and the like, is very convenient to use whether singly or in array, and is widely applied to the fields of nuclear physics experiments, high-energy physics, nuclear medicine, modern industry, geological exploration and the like.
However, the gamma energy spectrum measured by the scintillation detector often has the problem of low peak-to-average ratio, and in order to improve the problem, on the basis of the traditional multi-probe anti-interference spectrometer, the idea of using a double-crystal laminated detector of the same photomultiplier and an electronic system is already proposed.
However, the conventional cylindrical crystal design often causes the composite crystal composed of the double crystals to have an excessively large volume, an excessively heavy weight, and an excessively large diameter and height of the cylinder, so that the optical path of the fluorescence photon is too long, the light collection of the photomultiplier is adversely affected, and the overall time performance and resolution of the detector are ultimately affected.
Therefore, the double-crystal inverse coincidence laminated detector with the special shape is designed, the shape of the whole scintillator is changed by processing the auxiliary crystal wrapped outside the main crystal into a circular truncated cone shape or a truncated cone shape, the average optical path and the required time of scintillation photons reaching the photocathode are shortened, and on the basis of not excessively reducing the self inverse-coincidence effect and the detection efficiency of the inverse coincidence detector, the light collection capacity of the double-crystal inverse coincidence laminated detector is improved, and the energy resolution is improved.
Disclosure of Invention
The invention aims to provide a double-crystal anti-coincidence laminated detector with a special shape, which can improve the time performance and the resolution of the traditional anti-coincidence laminated detector and simultaneously does not excessively reduce the original detection efficiency and anti-coincidence effect.
The double-crystal anti-coincidence laminated detector with the special shape provided by the invention comprises a metal cylindrical detector shell, a crystal integrated packaging reflecting layer, a main crystal, a secondary crystal, a photomultiplier, a voltage division circuit, a digital spectrometer and a data processing system.
The primary crystal, the secondary crystal, the crystal integrated packaging reflection layer, the photomultiplier and the voltage division circuit are all arranged in a metal cylindrical detector shell to form a detector system in sequence.
The main crystal is bismuth germanate crystal, and the rise time of the pulse signal generated by the main crystal is T1Cylindrical in shape, 30 mm in diameter and 60 mm in height.
The secondary crystal is thallium-doped cesium iodide crystal, and the rise time of the generated pulse signal is T2The shape of the hole is a circular truncated cone with an opening in the middle, the inner diameter of the well-shaped hole is 30 mm, the well depth is 60 mm, the diameter of the upper bottom surface of the circular truncated cone is 50 mm, the diameter of the lower bottom surface of the circular truncated cone is 60 mm, the height of the circular truncated cone is 70 mm, and the taper is 1/7.
The main crystal is embedded into the hole of the secondary crystal and packaged together, the main crystal and the secondary crystal except the exit window are all surrounded by titanium dioxide as a crystal integrated packaging reflection layer, and the exit window of the composite crystal is coupled with a photomultiplier.
The back end of the photomultiplier is connected with a voltage division circuit, and the digital spectrometer converts the electric signal generated by the voltage division circuit into a digital signal and sends the digital signal to a data processing system.
Wherein, an electronic control method is loaded in the data processing system to process the signals into a spectrum, and the steps are as follows:
step one, recording the time required by the amplitude of the pulse signal to rise from 30% of the maximum value to 90%, and taking the time as the rising time T of the signal;
step two, comparing the time T, if T is less than (T)1+T2) And/2, considering the signal as a signal generated by the main crystal, and counting the number into an energy spectrum;
step three, if T is larger than (T)1+T2) And/2, the signal is considered to be the signal generated by the secondary crystal, and the signal is discarded without counting the energy spectrum.
The working principle of the invention is as follows:
for a scintillation detector, when gamma-rays compton scatter in the primary crystal, if the scattered photons produced by the gamma-rays do not further undergo energy deposition, but escape from the primary crystal, a portion of a continuous electron spectrum is formed in the last detected spectrum, which is the compton platform.
The working principle of the anti-coincidence detector using the same photomultiplier is that a hierarchical crystal is additionally arranged, and signals generated by a secondary crystal are removed during ray detection, so that the functions of reducing a Compton platform, improving the peak-to-Compton ratio and reducing the environmental background are realized.
The crystal structure has the defects that the volume and the mass of the composite crystal are too large, the optical path of the generated fluorescence photons is too long, the light collection effect of the photomultiplier is influenced, and the resolution of a detector is further deteriorated. According to the invention, the optical path and flight time of fluorescence photons are shortened by processing the traditional cylindrical secondary crystal into a truncated cone shape, the effect similar to focusing is realized by matching with the packaging reflection layer, and the time performance and resolution of the detector are improved on the basis of reducing the volume and weight of the crystal.
The invention has the beneficial effects that:
the double-crystal inverse coincidence laminated detector with the special shape provided by the invention realizes the focusing effect on the basis of reducing the volume and the weight of the crystal, shortens the optical path and the flight time of fluorescence photons, improves the resolution and the time performance of the detector, and can not excessively reduce the original detection efficiency and the inverse effect compared with a cylindrical design.
Drawings
FIG. 1 is a schematic diagram of the overall structure of a bi-crystal anti-coincidence laminated detector with a special shape provided by the present invention.
1. Primary crystal 2, secondary crystal
3. Photomultiplier tube 4, data processing system 5, and metal cylindrical detector housing
Detailed Description
Please refer to fig. 1:
in this embodiment, the main crystal is bismuth germanate crystal, and the rise time T is1Cylindrical in shape, 30 mm in diameter and 60 mm in height.
The secondary crystal is thallium doped cesium iodide crystal, and the rise time T2The shape of the hole is a circular truncated cone with an opening in the middle, the inner diameter of the well-shaped hole is 30 mm, the well depth is 60 mm, the diameter of the upper bottom surface of the circular truncated cone is 50 mm, the diameter of the lower bottom surface of the circular truncated cone is 60 mm, the height of the circular truncated cone is 70 mm, and the taper 1/7 is about 0.143.
The primary crystal is embedded in the secondary crystal, the parts of the primary crystal and the secondary crystal except the exit window are coated with a crystal integrated packaging reflecting layer made of titanium dioxide materials, and a photomultiplier is coupled with the exit window of the composite crystal.
The photomultiplier tube was selected as model 9305KB and the manufacturer was ET Enterprises, United kingdom, with a transit time of 42 ns.
The voltage divider circuit is of type C636AFN2, and the manufacturer is ET Enterprises, uk.
The reflecting layer, the main crystal, the secondary crystal, the photomultiplier and the voltage dividing circuit are arranged in the aluminum alloy shell, and a high-voltage interface and a signal interface are led out from the voltage dividing circuit.
The digital spectrometer adopts a PCIe-6962 type data acquisition card of Shanghai simple instrument technology, and a signal interface led out from a voltage division circuit is connected to a signal input interface of the data acquisition card.
The digital spectrometer is connected with a computer through a PCIE interface of a desktop computer, and an electronic control method is integrated in a data processing system on the computer, and the method comprises the following specific steps:
step one, recording the time required by the amplitude of the pulse signal to rise from 30% of the maximum value to 90%, and taking the time as the rising time T;
step two, comparing the time T, if T is less than (T)1+T2) And/2, considering the signal as a signal generated by the main crystal and counting the signal into an energy spectrum;
step three, if T is larger than (T)1+T2) And/2, considering the signal as the signal generated by the secondary crystal, discarding the signal, and not countingEnergy spectrum.
Claims (5)
1. A double-crystal anti-coincidence laminated detector with a special shape is characterized in that: the cylindrical main crystal (1) is embedded into the secondary crystal (2) in a circular truncated cone shape, the main crystal and the secondary crystal are coupled with an exit window of the secondary crystal by using the same photomultiplier (3), and then connected with a data processing system (4), and all components are arranged in a metal cylindrical detector shell (5).
2. A special shaped bi-crystal inverse coincidence stacking detector as claimed in claim 1 wherein: the main crystal (1) is a bismuth germanate crystal, is cylindrical, and has a diameter of 30 mm and a height of 60 mm.
3. A special shaped bi-crystal inverse coincidence stacking detector as claimed in claim 1 wherein: the secondary crystal (2) is a thallium-doped cesium iodide crystal, is in the shape of a truncated cone with an opening in the middle, and has a well-shaped hole with the inner diameter of 30 mm, the well depth of 60 mm, the diameter of the upper bottom surface of the truncated cone of 50 mm, the diameter of the lower bottom surface of the truncated cone of 60 mm, the height of 70 mm and the taper of 1/7.
4. A special shaped bi-crystal inverse coincidence stacking detector as claimed in claim 1 wherein: the secondary crystal (2) forms the rising time T of the pulse signal2Greater than the rise time T of the main crystal (1)13 times of the total weight of the product.
5. A special shaped bi-crystal anti-coincidence stack detector as claimed in claim 1 or 4, wherein: the control method of the data processing system is as follows:
step one, recording the time required by the amplitude of the pulse signal to rise from 30% of the maximum value to 90%, and taking the time as the rising time T;
step two, comparing the time T, if T is less than (T)1+T2) And/2, considering the signal as a signal generated by the main crystal, and counting the number into an energy spectrum;
step (ii) ofIf T is greater than (T)1+T2) And/2, the signal is considered to be the signal generated by the secondary crystal, and the energy spectrum is discarded and not counted.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210007613.2A CN114280660A (en) | 2022-01-06 | 2022-01-06 | Double-crystal reverse coincidence laminated detector with special shape |
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| CN202210007613.2A CN114280660A (en) | 2022-01-06 | 2022-01-06 | Double-crystal reverse coincidence laminated detector with special shape |
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100680595B1 (en) * | 2005-12-15 | 2007-02-09 | 한국원자력연구소 | Phoswich detector for simultaneous detection of alpha and beta rays in a pipe |
| US20130020488A1 (en) * | 2011-07-19 | 2013-01-24 | Saint-Gobain Cristaux Et Detecteurs | Detector with a Conical Scintillator |
| CN104614754A (en) * | 2015-01-26 | 2015-05-13 | 苏州瑞派宁科技有限公司 | Combined scintillation crystal, combined scintillation detector and radiation detection device |
| CN105353400A (en) * | 2015-11-13 | 2016-02-24 | 中国计量科学研究院 | Inlaying source device used for scintillation crystal detector gain automatic control |
| US20170212251A1 (en) * | 2014-07-25 | 2017-07-27 | The Regents Of The University Of California | Multiple spatial resolution scintillation detectors |
| US20170350995A1 (en) * | 2014-12-22 | 2017-12-07 | Commissariat à l'énergie atomique et aux énergies alternatives | Method for calibrating an ionising radiation detector and associated device |
| US20180203131A1 (en) * | 2015-07-09 | 2018-07-19 | Umc Utrecht Holding B.V. | Device and method for simultaneous x-ray and gamma photon imaging with a stacked detector |
| CN109917444A (en) * | 2019-04-08 | 2019-06-21 | 中国工程物理研究院核物理与化学研究所 | A kind of measurement85The lamination anticoincidence detector of Kr |
| CN113835114A (en) * | 2021-08-25 | 2021-12-24 | 吉林大学 | Compact high-energy gamma ray anti-coincidence laminated detector |
-
2022
- 2022-01-06 CN CN202210007613.2A patent/CN114280660A/en active Pending
Patent Citations (9)
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|---|---|---|---|---|
| KR100680595B1 (en) * | 2005-12-15 | 2007-02-09 | 한국원자력연구소 | Phoswich detector for simultaneous detection of alpha and beta rays in a pipe |
| US20130020488A1 (en) * | 2011-07-19 | 2013-01-24 | Saint-Gobain Cristaux Et Detecteurs | Detector with a Conical Scintillator |
| US20170212251A1 (en) * | 2014-07-25 | 2017-07-27 | The Regents Of The University Of California | Multiple spatial resolution scintillation detectors |
| US20170350995A1 (en) * | 2014-12-22 | 2017-12-07 | Commissariat à l'énergie atomique et aux énergies alternatives | Method for calibrating an ionising radiation detector and associated device |
| CN104614754A (en) * | 2015-01-26 | 2015-05-13 | 苏州瑞派宁科技有限公司 | Combined scintillation crystal, combined scintillation detector and radiation detection device |
| US20180203131A1 (en) * | 2015-07-09 | 2018-07-19 | Umc Utrecht Holding B.V. | Device and method for simultaneous x-ray and gamma photon imaging with a stacked detector |
| CN105353400A (en) * | 2015-11-13 | 2016-02-24 | 中国计量科学研究院 | Inlaying source device used for scintillation crystal detector gain automatic control |
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| CN113835114A (en) * | 2021-08-25 | 2021-12-24 | 吉林大学 | Compact high-energy gamma ray anti-coincidence laminated detector |
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