Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminum layers T. Renger, M. Sznajder, U.R.M.E. Geppert Chart.

Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminum layers

T. Renger, M. Sznajder, U.R.M.E. Geppert

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degradation studies especially for thin foils

simultaneous irradiation to simulate the solar elm. and particle radiation:• photons 40nm < < 2500nm𝜆• electrons + protons 1…100keV

changes in the thermo-optical and elastic material properties

• measurement of αS and ε

• mass spectroscopy to evaluate the outgassing processes

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The Complex Irradiation Facility (CIF)

> Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminium layers > T. Renger > 04.04.2014

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For this special experiments:

• Low energy protons

• Thermal conditioning of the sample

• 7.5 µm Upilex-S® foil covered on both sides with 100 nm Al

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100 keV proton / electron dual beam irradiation system

> Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminium layers > T. Renger > 04.04.2014

Target mounting

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thermal conditioning: 80 K to 470 K

> Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminium layers > T. Renger > 04.04.2014

Test parameters

Sample T [K] E [keV] D [p+ cm-2] ts [days]

A1 300.0 2.5 4.3 x 1017 3.5

A2 300.0 6.0 5.9 x 1017 4.8

B1 323.0 2.5 7.8 x 1017 4.8

B2 323.0 2.5 8.2 x 1017 5.0

B3 323.0 2.5 1.3 x 1018 7.9

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See next talk by M.Sznajder

Picture of the sample and the spot

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Microscope pictures of sample B3(unirradiated and irradiated region)

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Microscope pictures of sample A1 and A2

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A1 (2.5 keV; 4.3 x 1017 p+cm-2; 300.0 K) A2 (6.0 keV; 5.9 x 1017 p+cm-2; 300.0 K)

> Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminium layers > T. Renger > 04.04.2014

SRIM simulation: Polyimide covered with 100 nm Al-layer

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2.5 keV protons 6.0 keV protons32.8 % pass through the Al-layer

> Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminium layers > T. Renger > 04.04.2014

Microscope pictures of sample B1, B2, and B3

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Average bubble radius:B1: 0.17 ± 0.05 µm (7.8 x 1017 p+cm-2; 2.5 keV; 323.0 K)

B2: 0.2 ± 0.05 µm (8.2 x 1017 p+cm-2; 2.5 keV; 323.0 K)

B3: 0.25 ± 0.05 µm (1.3 x 1018 p+cm-2; 2.5 keV; 323.0 K)

> Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminium layers > T. Renger > 04.04.2014

Height profile of sample B3

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B3:1.3 x 1018 p+cm-2 2.5 keV323.0 K

> Experimental studies of low energy proton irradiation of thin vacuum deposited Aluminium layers > T. Renger > 04.04.2014

Conclusion

• Molecular Hydrogen bubbles populate Aluminum surfaces under interplanetary space conditions, depending on energy and dose of incident protons and temperature of the surface

• The change of morphology of a thin Al-layer depends on the energy of protons. If it is higher then the critical energy, the protons pass through the Al-layer and other effects appear.

• The average bubble size increases with higher proton doses.

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