Rapid Recording of Powder Diffraction Patterns with Si(Li) X-Ray Energy Analysis System: W and Cu Targets and Error Analysis

Abstract

X-ray diffraction patterns using continuous radiation from copper and tungsten target x-ray tubes and detected with a Si(Li) energy analysis system are presented. Errors caused by a misaligned diffractometer and x-ray penetration into the sample are shown to be more difficult to correct and larger in magnitude than errors arising from energy calibration. All these errors can be minimized by mixing a standard with the unknown sample.

The energy resolution of the detector influences the breadth of the diffraction peaks more strongly than the standard slit systems available with commercial diffractometers. Thus, to reduce the recording time and maintain the same standard deviation for the data, one should increase the sizes of the front and receiving slits including the Soller slits. X-ray energy diffraction patterns can be recorded with standard deviations less than ±0.001 Å in the d spacing with only 200 sec measurement time using the standard diffractometer slit system. Copper targets are probably as useful as tungsten even though the continuous intensity is about three times less. Copper has fewer interfering characteristic lines, and its use permits convenient conversion to normal 0 scanning diffractometer operation.

Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation.