阅读说明：本技术 一种利用虚拟仪器技术实现γ-γ数字符合测量的系统及方法 (System and method for realizing gamma-gamma digital coincidence measurement by using virtual instrument technology ) 是由 赵修良 贺三军 秦慧超 赵健为 周超 刘丽艳 于 2020-03-27 设计创作，主要内容包括：本发明公开了一种利用虚拟仪器技术实现γ-γ数字符合测量的系统及方法,包括第一探头、第一放大器、第二探头、第二放大器,第一探头与第一放大器的输入端连接,第二探头与第二放大器的输入端连接；还包括高速数据采集卡和虚拟仪器,虚拟仪器包括数据采集VI模块、能谱测量VI模块、相对时延分析VI模块、符合时间甄别VI模块,第一放大器和第二放大器的输出端均与高速数据采集卡电连接,高速数据采集卡与数据采集卡相连。本发明利用虚拟仪器技术,以通用的计算机硬件与操作系统为依托,通过集成工具开发平台编程软件,提供结构紧凑、扩展功能强、投入成本低、开发周期短、复用性强,具有多种测量和分析功能的γ-γ数字符合测量系统及方法。(The invention discloses a system and a method for realizing gamma-gamma digital coincidence measurement by utilizing a virtual instrument technology, which comprises a first probe, a first amplifier, a second probe and a second amplifier, wherein the first probe is connected with the input end of the first amplifier, and the second probe is connected with the input end of the second amplifier; the device comprises a high-speed data acquisition card and a virtual instrument, wherein the virtual instrument comprises a data acquisition VI module, an energy spectrum measurement VI module, a relative delay analysis VI module and a coincidence time discrimination VI module, the output ends of a first amplifier and a second amplifier are electrically connected with the high-speed data acquisition card, and the high-speed data acquisition card is connected with the data acquisition card. The invention provides a gamma-gamma digital coincidence measurement system and a method which have compact structure, strong expansion function, low investment cost, short development period, strong reusability and various measurement and analysis functions by utilizing a virtual instrument technology, relying on general computer hardware and an operating system and developing platform programming software through an integrated tool.)

1. A system for realizing gamma-gamma digital coincidence measurement by using a virtual instrument technology comprises a first probe (11), a first amplifier (21), a second probe (12) and a second amplifier (22), wherein the output end of the first probe (11) is electrically connected with the input end of the first amplifier (21), and the output end of the second probe (12) is electrically connected with the input end of the second amplifier (22); the device is characterized by further comprising a high-speed data acquisition card (4) and a virtual instrument (5), wherein the virtual instrument (5) comprises a data acquisition VI module (51), an energy spectrum measurement VI module (52), a relative time delay analysis VI module (53) and a coincidence time discrimination VI module (54), the output ends of a first amplifier (21) and a second amplifier (22) are electrically connected with the high-speed data acquisition card (4), and the high-speed data acquisition card (4) is connected with the data acquisition card, wherein:

high-speed data acquisition card (4): the analog signals output by the first amplifier (21) and the second amplifier (22) are converted into digital signals;

data acquisition VI module (51): the VI module is used for controlling the working parameters of the high-speed data acquisition card (4), acquiring the digital signals output by the high-speed data acquisition card (4), filtering and timing the digital signals and then providing the digital signals to the virtual instrument (5);

energy spectrum measurement VI module (52): the device is used for adjusting the size and the position of the gamma window and recording the number of pulses in the gamma window;

relative time delay analysis VI module (53): the method is used for eliminating the relative average time delay of the coincidence branch to adjust the coincidence resolution time to be optimal;

a coincidence time screening VI module (54): for recording the total coincidence event.

2. The system for performing gamma-gamma digital coincidence measurement using virtual instrument techniques of claim 1 wherein filtering is performed using an S-G filter.

3. The system for performing gamma-gamma digital coincidence measurements using virtual instrument techniques of claim 1 wherein the pulse signals are timed using a constant ratio timing scheme.

4. The system for implementing gamma-gamma digital coincidence measurement using virtual instrument technology as claimed in claim 1 wherein the coincidence time discriminating VI module (54) is further used for coincidence measurement activity calculation, calculating the activity of the measured sample or source by lane CH1, lane CH2 and coincidence count.

5. A method for realizing gamma-gamma digital coincidence measurement by using virtual instrument technology, which is characterized in that the system for realizing gamma-gamma digital coincidence measurement by using virtual instrument technology according to any one of claims 1-4 comprises the following steps:

a, a first amplifier (21) amplifies and shapes an analog signal acquired by a first probe (11) and outputs the analog signal, and a second amplifier (22) amplifies and shapes an analog signal acquired by a second probe (12) and outputs the analog signal;

step B, controlling the working parameters of the high-speed data acquisition card (4) by using the data acquisition VI module (51), and converting the analog signals output by the first amplifier (21) and the second amplifier (22) in the step A into digital signals by the high-speed data acquisition card (4);

step C, a data acquisition VI module (51) acquires digital signals output by the high-speed data acquisition card (4), filters and provides the digital signals to a VI module in the virtual instrument (5) after timing;

step D, the energy spectrum measurement VI module (52) adjusts the size and the position of a gamma window and records the pulse number in the gamma window;

step E, a relative time delay analysis VI module (53) eliminates the relative average time delay of the coincidence branch, so that the coincidence resolution time is adjusted to be optimal;

step F, the coincidence time screening VI module (54) records the total coincidence event.

6. The method of claim 5, wherein filtering is performed using an S-G filter.

7. The method of claim 5 wherein the pulse signal is timed using a constant ratio timing scheme.

8. The method for implementing gamma-gamma digital coincidence measurement using virtual instrument technology as claimed in claim 5, wherein in step F, coincidence time discriminating VI module (54) also performs coincidence measurement activity calculation, calculating the activity of the measured sample or source by CH1 lane, CH2 lane and coincidence lane count.

Technical Field

The invention belongs to the technical field of radioactivity measurement, and particularly relates to a system and a method for realizing gamma-gamma digital coincidence measurement by utilizing a virtual instrument technology.

Background

The coincidence method is one of the most accurate methods for measuring the radioactivity activity, and has wide application in the fields of radioactivity measurement, neutron physics, nuclear reaction research and the like. With the advent and development of high performance ADCs and large scale programmable digital devices, high speed a/D conversion devices can be used to convert analog signals to digital signals and enable digital processing in a number of different ways. Compared with the traditional analog coincidence, the digital coincidence can realize data return visit, can arbitrarily set the number, the size and the position of a threshold window, can also arbitrarily adjust delay time, and accords with the size of resolution time, which is a breakthrough in the field of radionuclide metering. However, in a general gamma-gamma digital coincidence measurement system, the problem that the system is increasingly difficult to repair and update is very obvious, a user is difficult to adjust and optimize the functions of the instrument according to the requirements of the user, and an electronic instrument with an independent function is expensive.

Disclosure of Invention

The invention aims to provide a system and a method for realizing gamma-gamma digital coincidence measurement by using a virtual instrument technology, which aim to overcome the defects of the prior art, and provide the gamma-gamma digital coincidence measurement system and the method which have compact structure, strong extended function, low investment cost, short development period, strong reusability and various measurement and analysis functions by using the virtual instrument technology and relying on general computer hardware and an operating system and developing platform programming software through an integrated tool; the user only needs to master simple programming knowledge, and the functions of the whole system can be adjusted and optimized according to actual requirements.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a system for realizing gamma-gamma digital coincidence measurement by using a virtual instrument technology comprises a first probe, a first amplifier, a second probe and a second amplifier, wherein the output end of the first probe is electrically connected with the input end of the first amplifier, and the output end of the second probe is electrically connected with the input end of the second amplifier; the device is characterized by further comprising a high-speed data acquisition card and a virtual instrument, wherein the virtual instrument comprises a data acquisition VI module, an energy spectrum measurement VI module, a relative time delay analysis VI module and a coincidence time discrimination VI module, the output ends of the first amplifier and the second amplifier are electrically connected with the high-speed data acquisition card, and the high-speed data acquisition card is connected with the data acquisition card, wherein:

a high-speed data acquisition card: the first amplifier is used for converting the analog signals output by the first amplifier and the second amplifier into digital signals;

a data acquisition VI module: the VI module is used for controlling the working parameters of the high-speed data acquisition card, acquiring the digital signals output by the high-speed data acquisition card, filtering and timing the digital signals and providing the digital signals to the virtual instrument;

energy spectrum measurement VI module: the device is used for adjusting the size and the position of the gamma window and recording the number of pulses in the gamma window;

relative delay analysis VI module: the method is used for eliminating the relative average time delay of the coincidence branch to adjust the coincidence resolution time to be optimal;

a coincidence time discrimination VI module: for recording the total coincidence event.

As a preferred way, an S-G filter is used for filtering.

Preferably, the pulse signal is timed using a constant ratio timing method.

Further, the coincidence time screening VI module is also used for coincidence measurement activity calculation, and the activity of the measured sample or source is calculated through the CH1 lane, the CH2 lane and the coincidence lane count.

Based on the same inventive concept, the invention also provides a method for realizing gamma-gamma digital coincidence measurement by utilizing a virtual instrument technology, which is particularly a system for realizing gamma-gamma digital coincidence measurement by utilizing the virtual instrument technology, and comprises the following steps:

a, a first amplifier amplifies and shapes an analog signal acquired by a first probe and outputs the analog signal, and a second amplifier amplifies and shapes an analog signal acquired by a second probe and outputs the analog signal;

step B, controlling the working parameters of a high-speed data acquisition card by using a data acquisition VI module, and converting the analog signals output by the first amplifier and the second amplifier in the step A into digital signals by using the high-speed data acquisition card;

step C, the data acquisition VI module acquires digital signals output by the high-speed data acquisition card, filters the digital signals and provides the digital signals to the VI module in the virtual instrument after timing;

step D, the energy spectrum measurement VI module adjusts the size and the position of a gamma window and records the pulse number in the gamma window;

step E, the relative time delay analysis VI module eliminates the relative average time delay of the coincidence branch, so that the coincidence resolution time is adjusted to be optimal;

and F, recording a total coincidence event by the coincidence time screening VI module.

As a preferred way, an S-G filter is used for filtering.

Preferably, the pulse signal is timed using a constant ratio timing method.

Further, in the step F, the coincidence time screening VI module further performs coincidence measurement activity calculation, and calculates the activity of the measured sample or source through the CH1 lane, the CH2 lane and the coincidence lane count.

Compared with the prior art, the invention utilizes the virtual instrument technology, relies on general computer hardware and an operating system, and develops platform programming software through an integrated tool, thereby providing the gamma-gamma digital coincidence measurement system and method which have compact structure, strong extended function, low investment cost, short development period, strong reusability and various measurement and analysis functions; the user only needs to master simple programming knowledge, and the functions of the whole system can be adjusted and optimized according to actual requirements.

Drawings

Fig. 1 is a structural schematic diagram of a gamma-gamma digital coincidence measuring system of the invention.

Fig. 2 is a schematic diagram of an embodiment of a data acquisition VI module.

Fig. 3 is a schematic diagram of an embodiment of a power spectrum measurement VI module.

Fig. 4 is a schematic diagram of an embodiment of a relative delay analysis VI module and a coincidence time screening VI module.

Fig. 5 is a gamma-gamma digital coincidence virtual instrument software interface diagram.

Fig. 6 is a schematic diagram of the gamma-gamma digital coincidence measuring method of the invention.

FIG. 7 is a diagram of the analog pulse signal input to the data acquisition card.

FIG. 8 is an example of the constant ratio timing for S-G filtering and a trigger ratio of 0.2.

Fig. 9 is a relative time delay analysis spectrum.

The device comprises a first probe 11, a second probe 12, a first amplifier 21, a second amplifier 22, a first high-voltage power supply 31, a second high-voltage power supply 32, a high-speed data acquisition card 4, a virtual instrument 5, a data acquisition VI module 51, an energy spectrum measurement VI module 52, a relative delay analysis VI module 53 and a coincidence time discrimination VI module 54.

Detailed Description

The technical principle of the invention is that a gamma cascade ray measuring device is built according to the gamma-gamma coincidence measuring principle, the device reserves a front-end electronic module, amplifies and shapes analog signals, reduces the requirement on the performance of a rear-end high-speed data acquisition card 4 under the condition of ensuring that relative time information between coincident branches is not lost, and combines virtual instrument processing software, the high-speed data acquisition card 4 and the gamma cascade ray device together by utilizing a virtual instrument technology and using L ABVIEW graphical language programming virtual instrument processing software to form a gamma-gamma digital coincidence measuring system.

As shown in fig. 1, the system for implementing γ - γ digital coincidence measurement by using virtual instrument technology of the present invention includes a first probe 11, a first amplifier 21, a second probe 12, a second amplifier 22, wherein an output end of the first probe 11 is electrically connected to an input end of the first amplifier 21, an output end of the second probe 12 is electrically connected to an input end of the second amplifier 22, and further includes a high-speed data acquisition card 4 and a virtual instrument 5 (in this embodiment, L abeew is selected as a development platform of the virtual instrument 5), the virtual instrument 5 includes a data acquisition VI module 51, an energy spectrum measurement VI module 52, a relative delay analysis VI module 53, and a coincidence time discrimination VI module 54, output ends of the first amplifier 21 and the second amplifier 22 are electrically connected to the high-speed data acquisition card 4, and the high-speed data acquisition card 4 is connected to the data acquisition card, wherein:

a high-speed data acquisition card 4: for converting the analog signals output from the first amplifier 21 and the second amplifier 22 into digital signals;

the data acquisition VI module 51: a VI module used for controlling the working parameters of the high-speed data acquisition card 4, acquiring the digital signals output by the high-speed data acquisition card 4, filtering and timing the digital signals and providing the digital signals to the virtual instrument 5;

energy spectrum measurement VI module 52: the device is used for randomly adjusting the size and the position of the gamma window and recording the number of pulses in the gamma window;

relative delay analysis VI module 53: the method is used for eliminating the relative average time delay of the coincidence branch to adjust the coincidence resolution time to be optimal;

coincidence time screening VI module 54: for recording a total coincidence event; also used for coincidence measurement activity calculations, activity of the measured sample or source was calculated by lane CH1, lane CH2, and lane coincidence counts.

The system for implementing gamma-gamma digital coincidence measurement using virtual instrument technology further comprises a first high voltage power supply 31 and a second high voltage power supply 32 for supplying power to the first probe 11 and the second probe 12, respectively.

In this embodiment, an S-G filter is used for filtering. And timing the pulse signal by adopting a constant ratio timing mode.

The gamma-gamma digital coincidence measurement system front-end electronic module is preferably selected, the time characteristic and the forming width of the analog signal are adjusted on the basis of keeping the relative time information of the coincidence branch unchanged, and the requirement on the sampling frequency of the A/D conversion equipment is reduced.

An embodiment of the data acquisition VI module 51 is shown in fig. 2, an embodiment of the energy spectrum measurement VI module 52 is shown in fig. 3, an embodiment of the relative delay analysis VI module 53 and the coincidence time discrimination VI module 54 is shown in fig. 4, the programmed VI modules are combined with each other according to a designed data processing scheme to form a virtual instrument measurement system with multiple measurement and analysis functions, and combined with the high-speed data acquisition card 4 and the gamma cascade ray measurement device to realize gamma-gamma digital coincidence measurement, and a gamma-gamma digital coincidence virtual instrument software interface diagram is shown in fig. 5.

The invention is realized by firstly carrying out model selection on a first probe 11, a second probe 12(NaI (Tl) probe), a first amplifier 21 and a second amplifier 22, converting an analog signal into a digital signal by using a high-speed data acquisition card 4 after adjusting the time characteristic and the forming width of the signal, and programming a VI module required by gamma-gamma processing software on L abVIEW to realize gamma-gamma digital coincidence measurement:

as shown in fig. 6, the method for implementing gamma-gamma digital coincidence measurement by using virtual instrument technology according to the present invention, the system for implementing gamma-gamma digital coincidence measurement by using virtual instrument technology, includes the following steps:

in step a, the first amplifier 21 amplifies and shapes the analog signal collected by the first probe 11 and outputs the amplified and shaped analog signal, and the second amplifier 22 amplifies and shapes the analog signal collected by the second probe 12 and outputs the amplified and shaped analog signal.

And step B, controlling the working parameters of the high-speed data acquisition card 4 by using the data acquisition VI module 51, and converting the analog signals output by the first amplifier 21 and the second amplifier 22 in the step A into digital signals by the high-speed data acquisition card 4.

And step C, the data acquisition VI module 51 acquires the digital signals output by the high-speed data acquisition card 4, filters the digital signals and provides the digital signals to the VI module in the virtual instrument 5 after timing.

In this embodiment, an S-G filter is used for filtering.

The frequency domain filtering method can generate a group time shift effect, the original time information of the pulse signal is lost, the signal can be widened and shortened by a common time domain filtering method, the S-G time domain filtering method can avoid the defects of the frequency filtering method and overcome the defects of the time domain filtering method, an S-G filter VI module is called on an L abVIEW back panel, a proper order and a proper window width are set, the shape and the width of the signal before and after filtering are unchanged, and the purpose of effectively retaining the original signal time and amplitude information is achieved.

In this embodiment, a constant ratio timing mode is used to time the pulse signal.

Constant ratio timing is not only a simple and accurate timing method, but also can effectively reduce the influence caused by time jitter, so that a pulse signal is timed by using a constant ratio timing mode. In order to enable peak searching and timing results to be more accurate, a least square method is used for fitting the digital signals, and influences caused by insufficient sampling frequency are reduced. And calling a peak detection VI module to determine the amplitude value and the peak position of the filtered digital signal, and determining the timing position according to the set trigger ratio.

And step D, the energy spectrum measurement VI module 52 adjusts the size and the position of the gamma window and records the pulse number in the gamma window. Specifically, according to the principle of multi-channel energy spectrum measurement, the obtained pulse signal peak value forms an energy spectrum, and a cursor attribute node of an energy spectrum display control is called to obtain the position of a cursor in real time. The position of the vernier can be freely adjusted, the difference between the number of the two vernier channels is the size of the gamma window, and the number of pulses in the gamma window is recorded.

Step E, the relative delay analysis VI module 53 eliminates the relative average delay of the coincidence branch, so that the coincidence resolving time is adjusted to be optimal. Specifically, the relative delay of the coincidence branch is determined by using relative delay analysis, namely, coincidence events within 1000ns are recorded, and a relative delay analysis spectrum is formed by taking the difference of the timing time of the pulse signals of the CH1 branch and the CH2 branch as an abscissa. The relative average time delay is an indication of the spectral peak value, and the time window should be half of the spectral peak broadening. The relative average time delay is deducted, so that the coincidence distinguishing time is optimal, the probability of accidental coincidence occurrence can be reduced, and the detection limit can also be reduced.

Step F, the coincidence time discrimination VI module 54 discriminates coincidence events according to the determined optimal coincidence resolution time, and records total coincidence events; activity of the measured sample or source is calculated by lane CH1, lane CH2, and lane coincident count according to the equation for activity measurement calculation.

Examples of partial data of the present embodiment are shown in fig. 7 to 9.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.