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Evaluation of Rock Powdering Methods to Obtain Fine-grained Samples for CHEMIN, a Combined XRD/XRF InstrumentA miniature XRD/XRF (X-ray diffraction / X-ray fluorescence) instrument, CHEMIN, is currently being developed for definitive mineralogic analysis of soils and rocks on Mars. One of the technical issues that must be addressed to enable remote XRD analysis is how best to obtain a representative sample powder for analysis. For powder XRD analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the X-ray beam. Although a two-dimensional detector as used in the CHEMIN instrument will produce good results even with poorly prepared powder, the quality of the data will improve and the time required for data collection will be reduced if the sample is fine-grained and randomly oriented. A variety of methods have been proposed for XRD sample preparation. Chipera et al. presented grain size distributions and XRD results from powders generated with an Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL. The USDC was shown to be an effective instrument for sampling rock to produce powder suitable for XRD. In this paper, we compare powder prepared using the USDC with powder obtained with a miniaturized rock crusher developed at JPL and with powder obtained with a rotary tungsten carbide bit to powders obtained from a laboratory bench-scale Retsch mill (provides benchmark mineralogical data). These comparisons will allow assessment of the suitability of these methods for analysis by an XRD/XRF instrument such as CHEMIN.
Document ID
20040062508
Document Type
Conference Paper
Authors
Chipera, S. J. (Los Alamos National Lab. NM, United States)
Vaniman, D. T. (Los Alamos National Lab. NM, United States)
Bish, D. L. (Indiana Univ. Bloomington, IN, United States)
Sarrazin, P. (Apparati, Inc. Mountain View, CA, United States)
Feldman, S. (NASA Ames Research Center Moffett Field, CA, United States)
Blake, D. F. (NASA Ames Research Center Moffett Field, CA, United States)
Bearman, G. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Bar-Cohen, Y. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Publication Information
Publication: Lunar and Planetary Science XXXV: Missions and Instruments: Hopes and Hope Fulfilled
Subject Category
Lunar and Planetary Science and Exploration
Distribution Limits
Public
Copyright
Public Use Permitted.

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