多探测器型无源灰分仪的研究与设计

    Research and design of non-radioactive ash meter with multiple γ-ray detectors

    • 摘要: 针对单探测器型无源灰分仪在低天然放射性煤炭灰分测量时信号计数率不足,无法覆盖宽带宽输送机煤流全横断面,以及易受环境本底波动干扰等问题,研究设计了多探测器型无源灰分仪,以提升测量系统性能与适用范围。选用体积为2 L的NaI(Tl)闪烁探测器作为核心探测组件;单套设备最多配置4台主探测器与1台环境本底探测器,主探测器通过横向线阵或纵向面阵灵活布置,环境探测器用于本底补偿,横向线阵可覆盖18002200 mm带宽,纵向面阵可延长测量区域;采用 TEC 半导体温控技术保证探测器24 h温度波动小于 0.5 ℃;通过高压电源动态调节技术提高无源灰分仪的稳定性,可将1460 keV特征能量峰稳定在多道能谱图中的256 道左右。对蒙东低放射性煤样进行单/双探测器对比测试,对广旺矿区精煤煤样开展测量分辨力、精密度及长期稳定性评估。结果表明:与单探测器相比,双探测器型无源灰分仪可实现有效测量。对低放射性煤样的检测中,双探测器的计数率约为单探测器的2倍,随机误差降低至70%;精煤测量中,单位负荷计数率为0.75 cps,灰分每增加1%对应计数率增加5.4 cps,测量精密度达0.19%,线性相关度R2为0.96;长期稳定性方面,24 h连续测量极差 < 0.18%,完全满足现场应用要求。多探测器型无源灰分仪通过提升计数率、拓展探测区域及优化环境补偿,可满足低放射性煤和高精度精煤测量需求,性能优势显著,具有校高的市场推广价值和应用前景。

       

      Abstract: To address the limitations of non-radioactive meter with single γ-ray detectors —including inadequate counting rates for low natural radioactivity coal ash measurement, inability to cover the full cross section of wide conveyor belts, and susceptibility to environmental background fluctuations—a non-radioactive meter with multiple γ-ray detector is developed to enhance system performance and applicability. A 2 L NaI (Tl) scintillation detector is selected as the core detection component; each unit can be configured with up to 4 main detectors and 1 environmental background detector. The main detectors are flexibly arranged in transverse linear arrays or longitudinal area arrays, while the environmental detector is used to compensate for background interference. Transverse linear arrays cover 18002200 mm bandwidth, and longitudinal area arrays extend the measurement zone. TEC semiconductor temperature control technology ensures detector temperature fluctuations remain below 0.5 °C within 24 hours. Dynamic regulation of high-voltage power supply improves the stability of the non-radioactive meter, stabilizing the 1460 keV characteristic energy peak around channel 256 in the multi-channel spectrum. Comparative single/double-detector tests are conducted on low-radioactivity coal samples from Eastern Inner Mongolia, and measurement resolution, precision, and long-term stability evaluations are performed on clean coal samples from Guangwang Mining Area. Results indicate that compared with single detector systems, dual detector meters achieve effective measurements. For low-radioactivity coal samples, the counting rate of dual detectors is approximately twice that of single detectors, the random error is reduced to 70%. In clean coal measurements, the unit load counting rate is 0.75 cps, with a 5.4 cps increase per 1% ash content rise. Measurement precision reaches 0.19%, and linear correlation (R2) is 0.96. Regarding long-term stability, the range of 24-hour continuous measurements is lower than 0.18%, fully meeting on-site application requirements. By enhancing counting rates, expanding detection coverage, and optimizing environmental compensation, the non-radioactive meter with multiple γ-ray detectors satisfies measurement demands for low-radioactivity coal and high-precision clean coal, demonstrating significant performance advantages and considerable market potential with promising application prospects.

       

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