基于荧光猝灭原理,以共轭荧光聚合物MEH—PPV为荧光指示剂,采用塑料光纤作为传感和传光元件进行硝基芳烃类爆炸物检测。实验采用探测荧光指示剂荧光寿命的方法进行爆炸物检测,荧光指示剂的荧光寿命利用相移法进行测量。测量了不同荧光指示剂浓度时系统对爆炸物检测的灵敏度,发现当MEH—PPV质量浓度为10mg/L时,系统的灵敏度最高;研究了U形、双锥形、螺旋形塑料光纤传感头对系统灵敏度的影响,发现双锥形传感头的灵敏度最高;测试了荧光指示剂MEH—PPV的稳定性,实验表明光照会加快MEH—PPV的漂白速度。
An aromatic explosives sensor system based on fluorescence quenching method is reported. MEH-PPV is used as fluorescence indictor and plastic optical fiber as sensor head and light transmitting element. Fluorescence lifetime of fluorescence indictor measured by phase shifting method is used to detect the explosives concentration. The effect of fluorescence indictor concentration on system sensitivity is measured, and we find that when MEH-PPV concentration is 10 mg/L the system sensitivity reaches the highest point. We also measure the system sensitivity under different shaped sensor heads (U-shaped, biconical-shaped, spiral-shaped), and it is found that biconical-shaped is most suitable for the sensing system. The stability of MEH-PPV is studied, and the experimental results indicate that the bleaching rate of fluorescence indictor will get faster under the exposure of daylight .