Pellet of Murchison powder (n°2) | DAYSY

Sample

Name: Pellet of Murchison powder (n°2)

Owner of sample

Database

DAYSY

Experimentalists

Rosario Brunetto

Origin of sample

Date: 2013-01-01
Provider: IAS, Orsay

Image

Left: mosaic of optical microscope (10x objective) images obtained on Murchison pellet n°2, with irradiation on four spots performed over diameters of 4 mm; a central area (2 mm in diameter) remained non-irradiated. Right: optical image (10x objective), showing the typical surface roughness and porosity, along with compositional heterogeneity reflected by different contrasts.

Physical characteristics

Thickness: 200.0 $\pm$ 100.0 ${\mu}m$
Diameter: 13000.0 ${\mu}m$
Mass: 0.1 $\pm$ 0.02 $g$
Substrate material: KBr
Substrate comments: KBr window, 2 mm thick, 13 mm diameter. The KBr is used as a substrate to avoid meteorite pellet break.
Comments: Pellet prepared by pressing (7 tons for 10 min) about 100 mg of the original dust (grain size 1–100 µm) on top of a KBr substrate pellet. The KBr is used as a substrate to avoid pellet break. Thickness of the meteorite pellet is large enough (>200 µm) to avoid contribution of KBr to the spectra.
Area D, irradiated with $3~10^{16}$ $He^+$ $cm^{-2}$

Sample environment: Temperature

Temperature: 300.0 $\pm$ 5.0 $K$
Temperature max: 300.0 $\pm$ 5.0 $K$

Sample environment: Fluid

Type: ambient air
Fluid pressure: 1.0 $mbar$

Sample environment: Irradiation

Source: ions accelerator
Chronology: before spectrum
Comments: Selected spectrum of the $3~10^{16}$ $He^+$ . $cm^{-2}$ irradiated area, showing the most disordered (most irradiated) polyaromatic carbon (large D and G bands), thus representative of the irradiated layer (see Lantz et al., 2015, for details). We used ion currents in the 0.1–0.3 µA. $cm^{-2}$ range to avoid macroscopic heating of the samples.

Particle

Family: atoms and molecules
Type: atomic ions
Particle: $He^+$
Energy: 40.0 $keV.particle^{-1}$
Particle fluence: 3e+16 $particle.m^{-2}$

Documentation and publication

Publications

Lantz et al., 2015, Astron. Astrophys., 577, A41

Layers in sample

Number

Layers

Pellet of Murchison powder , 200.0 ${\mu}m$

Sample processings

Title

Murchison pellet preparation

Precursors

Matters

Produced sample

Sample

Pellet of Murchison powder (n°2) (this sample)

Processing steps

Step	Chronology	Date	Type	Process	Changes
#1	before layer formation	2013-01-01	mechanical	pressing granular KBr to form the pellet substrate
#2	during layer formation	2013-01-01	mechanical	pressing Murchison powder on top of the KBr substrate (7 tons for 10 min)