测量乙醇体系中~(32)P的契伦柯夫辐射及具测量效率的改进

通常在水溶液体系中利用液体闪烁计数器来探测契伦柯夫辐射,具有无化学淬灭、成本低等优点。但是,水中的契伦柯夫辐射测量效率低,使用普通光电倍增管的仪器效率只有31％。契伦柯夫辐射的测量效率与被测核素能量大小有关,又与体系的折光率有关,增大测量体系的折光率也是提高测量效率的一条途径。乙醇体系较水体系有较高的折光率,且~(32)P在乙醇体系中的测量对生物医学是非常有用的。例如~(32)P标记的核苷酸大部分是醇介质,可直接用此法测强度;由于乙醇易于用化学法除去,对于生物医学实验中需转换体系的样品也是合适的,临床医学的许多样品亦可直接溶解于乙醇中测量,而不必转为固相再用计数管测量。本文叙述了~(32)P在乙醇体系中契伦柯夫测量的一般条件和化学淬灭、颜色淬灭对测量效率的影响;乙醇体系内加入微量闪烁液,可提高测量效率,并基本保持体系不受化学淬灭的影响,最后对这种提高效率作用的机制作了一些探讨。

The measurement of Cerenkov radiation of ~(32)P in ethanol system and an improvement on raising efficiency

The common methods and conditions of measuring Cerenkov radiation of 32P by liquid scintillation counters have been reported. The efficiency is higher in ethanol system than in water. By adding a little scintillation solution to ethanol system, the efficiency can be further raised; meantime the system remains basically unquenched by chemical substance. If the wave length shifter is put into ethanol system instead of scintillation solution, the chemical substance can result in an apparent quenching. The quenching effect of colour in ethanol system containing scintillator is shown.