Experiment
Title
Ion irradiation ($He^+$, $Ar^+$) of an Allende meteorite pellet probed by Raman spectroscopy
DOI
10.26302/SSHADE/EXPERIMENT_RB_20130101_001
Data reference
Brunetto, Rosario (2013): Ion irradiation ($He^+$, $Ar^+$) of an Allende meteorite pellet probed by Raman spectroscopy. SSHADE/DAYSY (OSUG Data Center). Dataset/Spectral Data. https://doi.org/10.26302/SSHADE/EXPERIMENT_RB_20130101_001
Publications
Database(s)
Experimentalists
Spectra preview
Experiment type
Type(s)
laboratory measurement
Description
Raman spectra of pellet n°1 and n°2 of the Allende meteorite, with different irradiation spots on the surface. Raman micro-spectroscopy was performed at the SMIS beamline at SOLEIL using a DXR Raman micro-spectrometer from Thermo Fisher with a 532 nm exciting laser radiation, and a power on the sample lower than 0.3 mW, producing power densities lower than 300 W/mm2.
Number of spectra
9
Variable type(s)
  • irradiation dose
Comments
We irradiated two pellets of Allende using the SIDONIE isotope separator in CSNSM, Orsay, using $He^+$ and $Ar^+$ ions at 40 keV. Sample were mounted vertically and ion irradiation was performed at normal incidence. We produced four separate irradiation spots (4 mm in diameter each) on each pellet, using different fluences: $5~10^{14}, 2~10^{15}, 1~10^{16}, 3~10^{16}$ for $He^+$ ions.$cm^{-2}$, and $1~10^{14}, 5~10^{14}, 2~10^{15}, 6~10^{15}$ for $Ar^+$ ions.$cm^{-2}$. Earlier irradiated spots were masked to protect them from contamination of sputter deposits from the subsequent irradiation steps. A central area (diameter 2 mm) of each pellet remained non-irradiated.
Laboratory
Spectroscopy and Microscopy in the Infrared using Synchrotron (SMIS)
Instrument #1
Instrument
Thermo DXR - Raman
Sample holder
samples mounted horizontally on X-Y stage of microscope
Standard medium
vacuum
Observation mode
spectrum
Spectral range type(s)
MIR, FIR
Valid spectral range(s)
Min - Max ($cm^{-1}$) Sampling ($cm^{-1}$) Resolution ($cm^{-1}$) Position accuracy ($cm^{-1}$) Absorption edge
#1 200.0 - 3400.0 0.9642 4.0 1.0
Comments
Raman shift with respect to laser at 532 nm
Observation geometry
other geometry
Observation mode
fixed angles
Comments
Confocal measurement with a x50 objective at long working distance
Observation mode
averaged
Spots number
20
Objective type
x50
Image size
1.0 x 1.0 ${\mu}m$
Comments
We recorded Raman maps of the different areas (virgin and irradiated) on the pellets to better cope with surface heterogeneity issues
Date begin - end
2013-01-01 - 2013-12-31

Versions

Release date
2018-01-31 23:51:01 UTC+0000
Version (Date)
#1 (2018-01-31 23:51:01 UTC+0000, Updated: 2019-10-26 09:48:10 UTC+0000)
Panel A: mosaic of optical microscope images obtained on one Allende pellet, with the indication of the irradiation conditions performed over diameters of 4 mm; a central area (2 mm in diameter) remained non-irradiated. Panel B: optical image (10x objective), showing the typical surface roughness and porosity, along with compositional heterogeneity reflected by different contrasts. Panel C: side and front views of irradiation geometry of the experimental setup; a mask is used to protect earlier irradiated spots from sputter deposits from the subsequent irradiation steps (4 mm hole); all sizes are given in millimeters. Panel D: a picture showing the two pellets installed in the SIDONIE sample holder. From Brunetto et al. (2014).
A typical first order micro-Raman spectrum of non-irradiated Allende's matrix is plotted in gray in the region of olivine and carbon bands, and compared to a spectrum of the $3~10^{16} He^+ cm^{-2}$ series showing very large D and G bands, and olivine bands heavily affected by the irradiation. Spectra are scaled to unity at the strongest peak, to facilitate the comparison.