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AC Conductivity Test. Dean Walters & Soon-Hong Lee LCLS-APS-ANL. Sample Criteria. Group 1 samples were to confirm the method with published data Pure copper Pure aluminum Group 2 samples were to simulate the materials that are under consideration Stainless steel/aluminum #1
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AC Conductivity Test Dean Walters&Soon-Hong LeeLCLS-APS-ANL
Sample Criteria • Group 1 samples were to confirm the method with published data • Pure copper • Pure aluminum • Group 2 samples were to simulate the materials that are under consideration • Stainless steel/aluminum #1 • Industrial #8 surface, thicker oxide resultant from aqueous cleaning process • Stainless steel/aluminum #2 (S4) • Improved surface finish and flatness, native oxide on aluminum thin film only. • Aluminum alloy • Surface finish similar to best extruded and then Electropolished surface.
Samples for AC conductivity • Pure Copper • Copper foil (99.999%, 100 mm x 100mm x 1 mm) was purchased from Good Fellow • Punch to size then polished by lapping. • Pure Aluminum • Aluminum foil (99.999%, 100 mm x 100mm x 1 mm) was purchased from Good Fellow • Punch to size then polished by lapping • Aluminum Alloy 6063-T5 • Cut to 35 x 50 x 2 mm sheets from Extruded Al vacuum chamber • Punch to size then polished by sanding • Aluminum coated Stainless Steel 304 (#1) • Mirror finished stainless steel sheet (0.5 mm) was supplied from Hwa Yang Stainless Steel Corp. • Punch to size • Pure Al sputter coated onto the mirror-finished surface • Aluminum coated Stainless Steel 304 (#2) • 2B finished 304 stainless steel sheet (2 mm) • Punch to size then polished by lapping • Pure Al sputter coated onto the mirror-finished surface
Pure Aluminum Pure Copper Aluminum Alloy 6063-T5 Characteristics of Samples Surface Roughness - Profilometer
Aluminum Alloy 6063-T5 Al coated Stainless Steel Pure Aluminum Pure Copper Too rough for AFM to measure reliably Characteristics of Samples Surface Roughness – Atomic Force Microscopy
AC conductivity tests at BNL • The following slides were made by Jiufeng Tu of CCNY. He performed the reflectance measurements that are shown below.
Preliminary Reflectivity Data on Metals Jiufeng J. Tu Physics Department The City College of New York LCLS Project
Raw Infrared Reflectivity Data of Metallic Samples • Experimental Details: • ● Use a stainless mirror together with the sample to normalize the intensity drift of the source; • ● In situ Au evaporation onto the sample in ultrahigh vacuum to divide out the interference effects and other systematic errors due to surface imperfections, etc; • ● The Au film also provides the absolute reflectance standard; • ● Careful characterization of the Au films: error in R is < 0.1%. 1meV=8 cm-1 1000 cm-1=10 mm
Reflectivity Data over the Whole Region 20000 cm-1= 500 nm 1 eV=8065 cm-1
Preliminary Kramers-Kronig Analysis 1 meV = 8 cm-1 1000 cm-1 = 10 mm 33 cm-1 = 300 mm