Effect of symmetrical background error in the Warren-Averbach analysis

The mean-square values of strain and particle size obtained from the Warren-Averbach analysis are strongly dependent on measurement errors affecting the line profiles. The method is particularly sensitive to errors in the choice of background level since the background level is easily overestimated thereby producing a truncation error in the line profiles. The effect is discussed of this error from truncation of the line profile on its Fourier transform, on the mean-square values of strain and particle size and on the plots relating the squared strain and particle-size coefficients to the column length. An `instrument' profile and two orders of reflexions from the total 'observable' profile, corresponding to a predetermined degree of deformation, were simulated. The Warren-Averbach analysis was applied to these two sets of reflexions, taking into account the effect of a symmetrical truncation of 3, 6 or 10% of the peak area on the two sets of reflexions, on the instrument profile, and on both.