论文部分内容阅读
除了样品因素外,第四纪地质样品~(40)Ar/~(39)Ar测年的关键在于测试和年龄计算中的误差控制。信号强度(随测量时刻)的拟合值可以采用最小二乘法进行直线或二次多项式拟合计算,但拟合值的误差不能通过拟合方程系数的误差进行计算,而应选择合适的计算方法以便获得与实测值误差相协调的拟合值误差。减小质量歧视系数D的相对误差并控制~(36)Ar的原始误差,才能有效的降低质量歧视校正带给~(39)Ar的相对误差。~(40)Ar_(rad)的相对误差来源于~(40)Ar测量值的相对误差、~(36)Ar测量值的相对误差、~(36)Ar_(Ca)的相对误差、吸附大气氩~(36)Ar_(air)的相对误差以及样品经反应堆辐照后产生的~(39)Ar_K的相对误差等。当样品极年轻且含有较多吸附大气氩时,~(40)Ar_(rad)的相对误差就会变大;当样品极年轻且受到过度辐照时,~(39)Ar_K的相对误差对~(40)Ar_(rad)相对误差的贡献也会增大;当反应堆中热中子比例较高且样品辐照过程中没有Cd屏蔽时,校正系数α的相对误差对其贡献也不可忽略。当标样年龄小于100Ma时,J值相对误差等于标样测量值R_S的相对误差平方、衰变常数相对误差平方及标样年龄相对误差平方加和的平方根。当标样年龄大于100Ma时,衰变常数相对误差平方及标样年龄相对误差平方将被不同程度的放大(1倍多到几倍)后传递到J值相对误差中,从而增大了这两个来源的误差对J值相对误差的影响。
In addition to the sample factors, the key to dating the ~ (40) Ar / ~ (39) Ar quaternary geological samples lies in the control of errors in the test and age calculations. The fitted values of the signal intensity (with the measurement time) can be calculated by using the least-square method for linear or quadratic polynomial fitting. However, the error of the fitting value can not be calculated by the error of the coefficients of the fitting equation, but a suitable calculation method should be selected In order to obtain the error of fitting with the measured value error. Reducing the relative error of mass discrimination coefficient D and controlling the original error of ~ (36) Ar can effectively reduce the relative error of ~ (39) Ar caused by mass discrimination correction. The relative error of ~ (40) Ar rad is from the relative error of ~ (40) Ar, the relative error of ~ (36) Ar, ~ (36) the relative error of Ar ~ ~ (36) Ar ~ (air) and the relative error of ~ (39) Ar_K produced by the sample irradiated by the reactor. The relative error of ~ (40) Ar_ (rad) becomes larger when the sample is very young and contains more argon, and the relative error of ~ (39) Ar_K is ~ (40), the contribution of the relative error of Ar rad (rad) will also increase. When the ratio of thermal neutrons in the reactor is high and there is no Cd shielding during irradiation, the relative error of the correction coefficient α can not be neglected. When the sample’s age is less than 100Ma, the relative error of J is equal to the square of the relative error square of the sample measurement R_S, the square of the relative error of the decay constant and the square of the square of the relative error of the sample’s age. When the sample’s age is more than 100Ma, the relative error squared decay constant and the relative square error of the sample’s age will be magnified (more than 1 times to several times) to the relative error of J value, thus increasing these two The Influence of Source Error on Relative Error of J Value.