Arc-Evaporated Carbon Foils

Standard size foils are regularly available from stock.  Our foils are categorized by their areal density, with minimal variation (+/- 10% or +/- 0.2µg/sq.cm for the thinnest foils).  Tighter tolerances are available by quote. The areal density of our foils, also known as surface density, specific density, or mass per unit area, is in units of micrograms per square centimeter.  Foils are measured optically and/or by weighing in order to maximize accuracy.  Please see the ACF-Metals' "Product Information" for more properties of these foils, especially for information regarding flatness, smoothness, and light-tightness.

By using high-purity materials, we take particular care to manufacture foils from using the isotopic abundances of natural carbon, 98.9% carbon-12 and 1.1% carbon-13.  ACF-Metals does not produce hybrid carbon foils (ie. boron) which introduce additional problems for radiation safety in laboratories. See our Product Information for more about how some hybrid carbon foils can have serious risks associated with their use.  

Foils below 5.0µg/sq.cm may be difficult to mount over apertures larger than a few mm in diameter. When requested, ACF-Metals will add an additional coating of collodion on one side of the carbon foil. This provides additional support for the foil, and for some users, a longer foil lifetime.

In order to minimize issues associated with naturally occurring pinholes, some investigators will use multiple layers of carbon foils.  Light tightness may be particularly important when foils are used as optical filters, neutralizer foils, and windows for low-pressure gas-cell targets.  ACF-Metals offers layered carbon foils in certain thicknesses to help improve the light tightness.  Note: Pinholes are observed to form spontaneously in hybrid type boron-carbon foils at temperatures above 1800 K, another reason why ACF-Metals does not offer hybrid foils.

Quantity discounts are available on single shipments of carbon foils of the same size and areal density: 5% (quantity of 100+) or 10% (quantity of 1000+). Please contact ACF-Metals directly to place orders that would involve this discount.