Cover Image

Abstract

The cover image is based on the Special Issue Article Optimization of SIMS analytical parameters for water content measurement of olivine by Wan‐Feng Zhang et al., https://doi.org/10.1002/sia.6729.

Ultralow H2O content analysis with a large-geometry secondary ion mass spectrometer

“…The actual sample thickness was determined with a Mitutoyo digital micrometer to be 7480 to 9130 mm, with a measurement uncertainty of 9-10 mm (Table 1). In addition, a set of olivine reference materials for water content was also measured by SIMS, 30 mainly for comparison with the previous analysis procedure.…”

“…These drawbacks of FTIR can potentially be resolved by the increasingly popular secondary ion mass spectrometry (SIMS) technique. 1,3,[23][24][25][26][27][28][29][30][31][32] Major obstacles to accurately measuring ultralow hydrogen samples by SIMS, however, are the relatively high hydrogen background and/or poor detection limit. 1,33,34 To meet this challenge, pioneering improvements include the resin-free mounting technique and vacuum quality enhancement (in the analysis chamber) for the various SIMS models, particularly the CAMECA IMS 3f-7f series and CAMECA Nano-SIMS.…”

“…1,3,16,17,23,24,27,32,35 Nevertheless, large geometry ion microprobes (LG-SIMS) such as SHRIMP (Sensitive High Resolution Ion MicroProbe) or CAMECA IMS 1270 and its upgraded series are generally not used for low-concentration water measurements despite their higher inherent sensitivity, as their large volumes including transfer and coupling column might lead to an unmanageable vacuum in the sample chamber (generally ∼10 −8 mbar vs. ∼10 −10 mbar for small geometry ones) and affect water molecule desorption on the mount surface, resulting in a high limit of detection (LOD). Although recent developments have reduced the LOD to a few ppm, 30,36,37 they are still insufficient to analyze the samples with <10 ppm H 2 O content, such as the lunar samples returned from the Apollo and Chang'E missions. 14,15 In this study, we present an improved LG-SIMS (CAMECA IMS 1280-HR) procedure for achieving sub-ppm LOD for water analysis, proofed by analyzing new quartz working reference materials with ultralow H 2 O content.…”

Potential clinopyroxene and orthopyroxene reference materials for SIMS water content analysis

“…KLB-1 is a peridotite xenolith with a size of 4-5 cm collected from the Kilborne Hole crater of New Mexico, USA. The detailed description on this sample has been given by Zhang et al 20 Few randomly selected fragments (∼200 mg and ∼1 × 0.5 mm in size) were investigated in this study. They include both darkgreen chrome diopside and pale-brown aluminous opx, and both of them contain very few visible impurities under the microscope.…”

“…12 Although un-oriented crystals with one direction polished can also be used when the polarized absorbance is < 0.3 and the mineral is less anisotropic, the analytical accuracy is lower. 13 With the recent development of sample preparation with a Sn-Bi alloy instead of epoxy or indium metal, 14 large geometry secondary ion mass spectrometry (LG-SIMS) has been used to simultaneously measure the water content and oxygen/hydrogen isotopes of ne-grained samples, such as zircon [15][16][17][18][19] and olivine, 20 providing high precision, high spatial resolution and rapid analysis for NAMs.…”