Pulse gating type neutron detector and detection method thereof
阅读说明：本技术 脉冲选通式中子探测器及其探测方法 (Pulse gating type neutron detector and detection method thereof ) 是由 易涛 詹夏宇 宋仔峰 陈铭 肖云青 陈家斌 于 2019-12-12 设计创作，主要内容包括：本发明公开了一种脉冲选通式中子探测器及其探测方法,包括金属管,金属管一端安装有金属滤片,金属管内部设有闪烁体和光电倍增管,还包括前置光电探头,该前置光电探头连接有数据采集器和脉冲信号发生器,其中数据采集器与光电倍增管连接,脉冲信号发生器通过第一控制线连接有高压模块,高压模块安装在金属管上,数据采集器与脉冲信号发生器之间通过第二控制线连接。本发明的有益效果是：通过光电探头产生的电脉冲触发高压电源,并按照预设的延迟时间产生高压加载到光电倍增管上,使得光电倍增管工作时错开伽马脉冲,只接受中子辐照信号,从而消除了伽马射线对中子探测的干扰。(The invention discloses a pulse gating neutron detector and a detection method thereof, wherein the pulse gating neutron detector comprises a metal tube, a metal filter is installed at one end of the metal tube, a scintillator and a photomultiplier are arranged in the metal tube, the pulse gating neutron detector also comprises a front photoelectric probe, the front photoelectric probe is connected with a data collector and a pulse signal generator, the data collector is connected with the photomultiplier, the pulse signal generator is connected with a high-voltage module through a first control line, the high-voltage module is installed on the metal tube, and the data collector is connected with the pulse signal generator through a second control line. The invention has the beneficial effects that: the high-voltage power supply is triggered by the electric pulse generated by the photoelectric probe, and high voltage is generated according to preset delay time and loaded on the photomultiplier, so that the gamma pulse is staggered when the photomultiplier works, only neutron irradiation signals are received, and the interference of gamma rays on neutron detection is eliminated.)
1. The utility model provides a pulse-gated neutron detector, includes tubular metal resonator (2), metal filter (1) are installed to tubular metal resonator (2) one end, and tubular metal resonator (2) are inside to be equipped with scintillator (3) and photomultiplier (4), its characterized in that: still include leading photoelectric probe (6), this leading photoelectric probe (6) are connected with data collection station (11) and pulse signal generator (14), wherein data collection station (11) are connected with photomultiplier (4), pulse signal generator (14) are connected with high-voltage module (5) through first control line (13), and high-voltage module (5) are installed on tubular metal resonator (2), be connected through second control line (12) between data collection station (11) and pulse signal generator (14).
2. The pulse gating neutron detector of claim 1, wherein: the front photoelectric probe (6) is connected with the data collector (11) and the pulse signal generator (14) through the shunt (8).
3. The pulse gating neutron detector of claim 2, wherein: the front photoelectric probe (6) is connected with the branching unit (8), the branching unit (8) is connected with the data acquisition unit (11), and the branching unit (8) is connected with the pulse signal generator (14) through the radio frequency cable (7).
4. The pulsed gated neutron detector of claim 1, 2 or 3, wherein: the scintillator (3) is arranged at one end of the photomultiplier (4) close to the metal filter disc (1).
5. The pulse gating neutron detector of claim 4, wherein: the high-voltage module (5) is arranged at one end, far away from the metal filter disc (1), of the metal pipe (2).
6. A neutron detection method, characterized by the following steps:
the method comprises the following steps: removing the metal filter (1) and illuminating the neutron detector of any of claims 1 to 5 with a pulsed flash of light;
step two: the preposed photoelectric probe (6), the scintillator (3) and the photomultiplier (4) respectively output an electric pulse under the irradiation of light and are collected by a data collector (11);
step three: analyzing and comparing data collected by the data collector (11) to obtain a time difference t0 between each pulse;
step four: setting a delay time t of the pulse signal generator (14), wherein t is t0-t1+ t2, t1 is the response time of the high-voltage module (5), and t2 is the duration of the gamma pulse;
step five: reinstalling the metal filter disc (1);
step six: the preposed photoelectric probe (6) outputs electric pulses, the electric pulses enter the pulse signal generator (14) through the shunt (8), the pulse signal generator (14) generates trigger pulses after delay time t to the high-voltage module (5), the high-voltage module (5) pressurizes the photomultiplier (4), and then the neutron detector starts to record neutron signals.
Technical Field
The invention belongs to the technical field of neutron detection, and particularly relates to a pulse gating neutron detector and a detection method thereof.
Background
A neutron is an uncharged particle. The working principle of the neutron detector is as follows: when the neutron reacts with certain nucleus, charged particles are released, the charged particles generate gas ionization when moving in the gas, and the neutron fluence rate level is determined by measuring the gas ionization amount.
In fusion neutron measurement, measurement of neutrons can be interfered by strong gamma rays, and in practical application, the difficulty in eliminating the interference is large, and common means are as follows:
the method for eliminating the interference of the gamma ray in the neutron measurement process by using the flight time method specifically comprises the following steps: the separation of two signals in time is realized through the difference of gamma rays and neutron velocity, however, in the neutron measurement process, a high-voltage signal needs to be loaded to a photomultiplier in advance, and since the gamma rays reach a detector before the neutrons, a scintillator for recording reacts, so that the photomultiplier generates strong light output and even saturation, and subsequent neutron measurement is directly influenced.
Disclosure of Invention
In view of this, the present invention provides a pulse-gated neutron detector, which can avoid interference of gamma rays on neutron detection and only receive neutron irradiation signals.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the utility model provides a pulse-gated neutron detector, includes the tubular metal resonator, the metal filter disc is installed to tubular metal resonator one end, and the tubular metal resonator is inside to be equipped with scintillator and photomultiplier, and its key lies in: the photoelectric detector is characterized by further comprising a front photoelectric probe, wherein the front photoelectric probe is connected with a data collector and a pulse signal generator, the data collector is connected with a photomultiplier, the pulse signal generator is connected with a high-voltage module through a first control line, the high-voltage module is installed on the metal tube, and the data collector is connected with the pulse signal generator through a second control line.
By adopting the structure, the time difference among the preposed photoelectric probe, the scintillator and the photomultiplier pulse can be obtained by analyzing and comparing through the data acquisition unit before detection, so that the delay time of the pulse signal generator can be calculated; when the neutron is formally detected, the electric pulse is generated to the pulse signal generator through the front photoelectric probe, then the pulse signal generator triggers the high-voltage module according to the preset delay time to generate high voltage to be loaded on the photomultiplier, so that the gamma pulse is staggered when the photomultiplier works, only the neutron irradiation signal is received, and the interference of the gamma ray on the neutron detection is eliminated.
Preferably, the method comprises the following steps: the front photoelectric probe is connected with the data collector and the pulse signal generator through the shunt. By adopting the structure, the prepositive photoelectric probe can be effectively connected with the data acquisition unit and the pulse signal generator, so that the prepositive photoelectric probe can output pulses conveniently.
Preferably, the method comprises the following steps: the front photoelectric probe and the shunt, the shunt and the data collector, and the shunt and the pulse signal generator are connected through radio frequency cables. By adopting the structure, the anti-interference capability is strong, and the radiation loss is small.
Preferably, the method comprises the following steps: the scintillator is arranged at one end of the photomultiplier close to the metal filter.
Preferably, the method comprises the following steps: the high-voltage module is arranged at one end, far away from the metal filter disc, of the metal pipe.
Compared with the prior art, the invention has the beneficial effects that:
the high-voltage power supply is triggered by the electric pulse generated by the photoelectric probe, and high voltage is generated according to preset delay time and loaded on the photomultiplier, so that the gamma pulse is staggered when the photomultiplier works, only neutron irradiation signals are received, and the interference of gamma rays on neutron detection is eliminated.
The invention also provides a neutron detection method, which is characterized by comprising the following steps:
the method comprises the following steps: taking down the metal filter disc, and irradiating the pulse gating neutron detector by using pulse flash;
step two: leading the preposed photoelectric probe, the scintillator and the photomultiplier to respectively output an electric pulse under the light irradiation and to be collected by a data collector;
step three: analyzing and comparing data acquired by the data acquisition unit to obtain a time difference t0 between pulses;
step four: setting the delay time t of the pulse signal generator, wherein t is t0-t1+ t2, t1 is the response time of the high-voltage module, and t2 is the duration of the gamma pulse;
step five: reinstalling the metal filter disc;
step six: the preposed photoelectric probe outputs electric pulses, the electric pulses enter the pulse signal generator through the shunt, the pulse signal generator generates trigger pulses after delay time t and sends the trigger pulses to the high-voltage module, the high-voltage module pressurizes the photomultiplier, and then the neutron detector starts to record neutron signals.
By adopting the method, the system is calibrated firstly, the time of gamma rays reaching the detector is measured through the front photoelectric probe, the delay value of the pulse generator is set through the control line by utilizing the measured reaching time and combining the response time of the high-voltage module and the time width of the gamma pulse, and then high voltage is generated according to the preset delay time and is loaded on the photomultiplier, so that the gamma pulse is staggered when the photomultiplier works.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
Detailed Description
The present invention will be further described with reference to the following examples and the accompanying drawings.
As shown in fig. 1, the pulse-gated neutron detector structurally comprises a
The method for neutron detection by using the detector comprises two steps of system calibration and formal test. Wherein the system calibration consists of the following steps:
the method comprises the following steps: taking down the metal filter 1, and irradiating the neutron detector by using pulse flash;
step two: leading the preposed photoelectric probe 6, the
step three: analyzing and comparing data acquired by the data acquisition unit 11 to obtain a time difference t0 between each pulse;
step four: the delay time t of the pulse signal generator 14 is set, and t is t0-t1+ t2, where t1 is the response time of the high voltage module 5 and t2 is the duration of the gamma pulse.
The system can be formally tested after being calibrated, and the formally testing comprises the following steps:
step five: reinstalling the metal filter disc 1;
step six: the front photoelectric probe 6 collects optical signals and converts the optical signals into electric pulses, the electric pulses enter the pulse signal generator 14 through the shunt 8, the pulse signal generator 14 generates trigger pulses after delaying the time t and sends the trigger pulses to the high-voltage module 5, the high-voltage module 5 pressurizes the photomultiplier tube 4, and then the neutron detector starts to record neutron signals.
After high voltage is generated according to the time t delay and is loaded on the photomultiplier tube 4, gamma pulses can be staggered when the photomultiplier tube 4 works, and only neutron irradiation signals are received, so that the interference of gamma rays on neutron detection is eliminated.
Finally, it should be noted that the above-mentioned description is only a preferred embodiment of the present invention, and those skilled in the art can make various similar representations without departing from the spirit and scope of the present invention.
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