Highly stable small type Gamma detection system and gain stabilization method based on temperature correction

Abstract

The invention discloses highly stable small type Gamma detection system and gain stabilization method based on temperature correction. In the system, the temperature of a detector is measured by usinga digital temperature sensor and a thermal insulation layer to improve the accuracy of temperature measurement at different environmental temperature rates, especially at the temperature abrupt change; adjusting a FIR filter and forming parameters in real time according to the monitored temperature change, and reducing the influence of the noise characteristic change caused by temperature on theenergy resolution; a gain stabilization module is realized directly in the FPGA by using the pulse amplitude real-time compensation technology. The measures such as external high-voltage regulation oramplifier gain adjustment and the like are not needed. The use of a digital-to-analog converter is avoided. The system complexity is effectively reduced. The digital signal processing technology simultaneously realizes the energy spectrum measurement and the gain stabilization system. The system noise suppression parameter is optimized by utilizing the temperature feedback method. For miniaturized Gammaradioactive monitoring device which is required to operate in a rapidly temperature changing environment, the system has good application prospect.

Description

technical field [0001] The invention belongs to the field of radioactive environment monitoring, and in particular relates to a small gamma detection system and a gain stabilization method. technical background [0002] The development of nuclear energy has brought huge economic benefits to human society, but at the same time it is also facing the problem of nuclear safety assurance. Strengthening radioactive environmental monitoring is an important means to promote the safe development of nuclear energy. The gamma detection system is an important key equipment. After obtaining the energy spectrum, it can be used for nuclide activity analysis, type analysis and content analysis, etc., for radioactive level assessment, nuclear accident early warning and emergency nuclear accident evolution judgment and security personnel. important role in safety. [0003] Compared with ordinary photomultiplier tubes, the use of silicon photomultiplier tubes in scintillator detectors has the...

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Problems solved by technology

[0003] Compared with ordinary photomultiplier tubes, the use of silicon photomultiplier tubes in scintillator detectors has the advantages of high gain, insensitivity to magnetic fields, small volume and mass, and good spectral matching with CsI(T1) scintillators. However, the ambient temperature Changes will lead to large changes in the gain of silicon photomultiplier tubes, resulting in energy spectrum drift and energy resolution deterioration, which seriously interferes with radioactivity analysis.

Using high-voltage adjustment to stabilize the gain of the detector requires high-precision adjustable high-voltage power supply and high-precision digital-to-analog converter hardware, which greatly increases the design complexity and cost of the gamma detection system, and is not conducive to the development of the gamma detection system. miniaturization

[0004] In addition, the multi-channel analysis system is the key to realize the core functions such as forming algorithm, baseline recovery and accumulation rejection. The traditional analog multi-channel analysis system is increasingly unable to meet the requirements in terms of system integration, stability and data processing capabilities.

Temperature changes will bring about changes in noise characteristics. If fixed filters and pulse shaping parameters are used, high-flexibility pulse processing cannot be satisfied, and the filtering effect of the system will also be reduced, resulting in reduced noise suppression capabilities and reduced energy resolution.

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