Author/Authors :
Atchison، نويسنده , , F. and Bergmaier، نويسنده , , A. and Daum، نويسنده , , M. and D?beli، نويسنده , , M. and Dollinger، نويسنده , , G. and Fierlinger، نويسنده , , P. and Foelske، نويسنده , , A. and Henneck، نويسنده , , R. and Heule، نويسنده , , S. and Kasprzak، نويسنده , , M. and Kirch، نويسنده , , K. and Knecht، نويسنده , , A. and Kuzniak، نويسنده , , M. and Pichlmaier، نويسنده , , A. and Schelldorfer، نويسنده , , R. and Zsigmon، نويسنده ,
Abstract :
We report the characterization of diamond-like carbon (DLC) surfaces to be used for the storage of ultracold neutrons (UCN). The samples investigated were 100–300-nm-thick tetragonal amorphous carbon (ta-C) coatings produced by vacuum-arc technology on thin foils (0.1–0.2 mm aluminum, stainless steel, PET). The diamond sp3 fraction was determined by X-ray photoelectron spectroscopy (XPS) to be in the range 45–65%. Secondary-ion mass spectroscopy (SIMS) and elastic recoil detection analysis (ERDA) yielded consistent results for the hydrogen contribution (about 1×1016 cm−2 within the top 20 nm), strongly concentrated within a surface layer of 1 nm thickness. The boron contamination was found to be around 50 at. ppm. The fractional hole area of the coatings is on a level of about 1×10−4. Temperature cycling of mechanically pre-stressed samples between 77 and 380 K revealed no detrimental effect.
Keywords :
Diamond-like carbon (DLC) , Elastic Recoil Detection Analysis (ERDA) , Storage of ultracold neutrons , X-ray-induced photoelectron spectroscopy (XPS) , Secondary-ion mass spectroscopy (SIMS) , sp3 content
