Ion irradiation (He^+, Ar^+) of an Allende meteorite pellet probed by IR spectroscopy in the MIR range | DAYSY

Experiment

Title: Ion irradiation ( $He^+$ , $Ar^+$ ) of an Allende meteorite pellet probed by IR spectroscopy in the MIR range

DOI

10.26302/SSHADE/EXPERIMENT_RB_20130101_003

Data reference

Brunetto, Rosario (2013): Ion irradiation (

$He^+$ ,

$Ar^+$ ) of an Allende meteorite pellet probed by IR spectroscopy in the MIR range. SSHADE/DAYSY (OSUG Data Center). Dataset/Spectral Data. https://doi.org/10.26302/SSHADE/EXPERIMENT_RB_20130101_003

Publications

Brunetto et al., 2014, Icarus, 237, 292

Owner

Database(s)

DAYSY

Experimentalists

Rosario Brunetto

Spectra preview

Experiment type

Type(s): laboratory measurement
Description: Mid-IR spectra of pellet n°2 of the Allende meteorite, with different irradiation spots on the surface.
Number of spectra: 3

Variable parameters

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.

Location

Laboratory: Spectroscopy and Microscopy in the Infrared using Synchrotron (SMIS)

Instrument #1

Instrument: SMIS NEXUS 6700 - confocal reflexion Mid-IR
Sample holder: samples mounted horizontally on X-Y stage of microscope

Spectral parameters

Standard medium

vacuum

Observation mode

spectrum

Spectral range type(s)

MIR

Valid spectral range(s)

	Min - Max ( $cm^{-1}$ )	Sampling ( $cm^{-1}$ )	Resolution ( $cm^{-1}$ )	Position accuracy ( $cm^{-1}$ )	Absorption edge
#1	740.0 - 1020.0	0.96425	2.0	1.0

Angular parameters

Definition: incidence and emergence angles are positive with origin at nadir, and vary in same direction. Azimuth origin (increasing clockwise) is for i = e (opposition geometry).

Observation geometry: biconical
Observation mode: fixed angles

Comments: Confocal measurement with a x50 objective at long working distance

Spatial parameters

Observation mode: averaged
Spots number: 25
Objective type: x32
Image size: 15.0 x 15.0 ${\mu}m$

History

Date begin - end: 2013-01-01 - 2013-12-31

Versions

Release date: 2018-01-31 23:51:01+0000 UTC
Version (Date): #1 (2018-01-31 23:51:01+0000 UTC, Updated: 2019-10-26 10:01:20+0000 UTC)

Image

The mid-IR confocal microscopic (spot of about 15 micron) reflectance spectra obtained at the SOLEIL synchrotron on Allende’s pellets before (black) and after irradiation at maximum fluence for Ar+ (red) and He+ (blue) beams. Two vertical lines are drawn to guide the eye and stress the irradiation-induced redshift of olivine bands. For each range, spectra are scaled to unity at strongest band peak to facilitate the comparison.