DEVELOPMENT OF 350MHz PULSED EPR SPECTROMETER

自由基在活体中的行为研究已成为病理学、生理学和药理学研究的重要内容。我们研制了一台专门用于大鼠全身原位测量的350 MHz脉冲EPR谱仪，并取得了以下结果。(1)对于弛豫时间常数T_2=10- 100 ns的生物自由基，谐振腔的最佳脉宽和品质因数Q分别为10- 68 ns和10-60;对于弛豫时间常数T_2=100- 800 ns的固体材料，谐振腔的最佳脉宽和品质因数Q分别为68- 158 ns和60-280。(2)利用该谱仪对γ辐照石英粉样品进行了电子自旋回波（ESE）信号的探测。信号电压为3- 5 mV，脉冲间隔为1，400 -1，600 ns。(3)经γ辐照的石英的弛豫时间常数为778 ns，与我们实验室在1.3GHz时测得的759 ns相当。(4)需要降低谐振器的Q值以使得生物自由基的测量成为可能。

The study of the behavior of free radicals in a living body has recently become very important in pathology, physiology and pharmacology, We have developed a 350MHz pulsed EPR(Electron paramagnetic resonance) spectrometer especially used for in situ measurement of a rat's whole body, and obtained the following results.(1) Optimum pulse width and quality factor Q of the resonator are 10-68ns and 10-60, respectively, for the relaxation time constant T_2=10-100ns of bio-radicals, and 68-158ns and 60-280, respectively, for T_2=100-800ns of radicals in solid materials.(2) Using this spectrometer, the signal of electron spin echo(ESE) was detected for the sample of gamma-irradiated quartz powder. Signal voltage was 3-5mV for 1,400-1 , 600ns of pulse interval.(3) Relaxation time constant of gamma-irradiated quartz is estimated to be 778 ns, This value is nearly equal to 759 ns obtained at 1.3 GHz in our laboratory.(4) It is required to reduce the Q value of the resonator to make the measurement of bio radicals possible.