Experimental techniques continued errors

As experimental techniques continue to improve, systematic errors in technique or interpretation of data will be revealed, but it appears that these systematic errors are also rapidly approaching a negligible limit. At the present time it appears that the reactor parameters of slightly enrlched-uranium water lattices, as measured in subcritical assemblies and in critical assemblies, are in agreement within the limits of experimenhtl errors. 

The mathematical basis for the exponential series method is Eq. (5.3), the use of which has recently been criticized by Phillips and Lyke.(19) Based on their analysis of the one-sided Laplace transform of model excited-state distribution functions, it is concluded that a small, finite series of decay constants cannot be used to represent a continuous distribution. Livesey and Brouchon(20) described a method of analysis using pulse fluorometry which determines a distribution using a maximum entropy method. Similarly to Phillips and Lyke, they viewed the determination of the distribution function as a problem related to the inversion of the Laplace transform of the distribution function convoluted with the excitation pulse. Since Laplace transform inversion is very sensitive to errors in experimental data,(21) physically and nonphysically realistic distributions can result from the same data. The latter technique provides for the exclusion of nonrealistic trial solutions and the determination of a physically realistic solution. These authors noted that this technique should be easily extendable to data from phase-modulation fluorometry. 

To understand this discrepancy, we need to remember that there is a second source of error in any experiment systematic error that causes a shift in the measured values from the true value and reduces the accuracy of the result. By making more measurements, we can reduce the uncertainty due to random errors and improve the precision of our result however, if systematic errors are present, the average value will continue to deviate from the true value. Such systematic errors may result from a miscalibration of the experimental apparatus or from a fundamental inadequacy in the technique for measuring a property. In the case of Millikan s experiment, the then-accepted value for the viscosity of air (used in calculating the charge e) was subsequently found to be wrong. This caused his results to be systematically too high. 

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