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本文介绍一种精密的场效应管边限振荡器型核四极矩共振(NQR)谱仪。工作频率范围14MHz～35MHz,分段连续可调。这种谱仪的灵敏度高、波形失真小。在室温下,多晶粉未状氯酸钾样品中~(35)Cl的NQR频率测量精度大约3×10~(-6)。重结晶样品中~(35)Cl的NQR谱一次微分信号信噪比S/N≥150。用该谱仪对KClO_3、NaClO_3、NaCl样品进行测试,得到氯的同位素~(35)Cl和~(37)Cl的四极耦合常数比(eQq)~(35)Cl/(eQq)~(37)Cl的实测值分别为 1.2687363、1.2687306、1.2687361。在77K到393K温度区间测量了氯酸钾多晶粉未状样品中~(35)Cl的NQR共振频率和温度的关系,在冰水混合温度附近,温度每变化0.1K,NQR频率的变化是478Hz。
This article describes a sophisticated field-effect transistor edge-limited quadrupole resonance (NQR) spectrometer. Working frequency range 14MHz ~ 35MHz, subsection continuous adjustable. This spectrometer has high sensitivity and low waveform distortion. At room temperature, the NQR frequency of ~ (35) Cl in polycrystalline sample was about 3 × 10 -6. The NQR spectrum of ~ (35) Cl in the recrystallized sample shows the signal-to-noise ratio S / N≥150. The KClO_3, NaClO_3, NaCl samples were tested by this spectrometer to obtain the eqq ~ (35) Cl / (eQq) ~ (37) ) Cl of the measured values were 1.2687363,1.2687306,1.2687361. The relationship between the temperature and the NQR resonance frequency of ~ (35) Cl in non-shape samples of potassium chlorate was measured in the temperature range of 77K to 393K. The change of NQR frequency was 478Hz for each 0.1K temperature change near the ice-water mixing temperature.