Production of carbon stripper foils for high-power cyclotrons

New methods for testing cyclotron carbon stripper foils

“…Foil materials and deposition methods under investigation include: (1) laser ablation, trying for random crystallite distribution in the resulting foils [25], (2) wellcharacterized arc at ultra-high vacuum, for highest uniformity and reproducibility [26], (3) controlled ac/dc arcs, to adjust competing properties of foils for best compromise [1], (4) admixtures of boron and other elements to reduce shrinkage [1], (5) diamond foils made by chemical vapor deposition, for greater strength and heat tolerance [1,3]. Till now, most experience has been with arcevaporated foils, conveniently made in the areal density range 1-1000 mg/cm 2 ; above this range, graphite foils are typically used.…”

“…(3) Foils at areal densities 4200 mg/cm 2 may, depending upon deposition conditions, spontaneously separate from their substrates, curl and break up if made in a single deposition. With particular care in evaporation, this phenomenon can sometimes be avoided [26]. Thinner foils may curl and break up as they are floated off.…”