Abstract
Usually, it is desirable to prepare thin films that are self-supporting so that any extraneous support materials will not interfere with experimental measurements. However, films with very low areal densities, films other than metals or films covering large areas may require the use of a backing or support. Two classes of supported thin films are being developed by the Isotope Research Materials Laboratory (IRML). Electrodeposition of oxide thin films is a fairly common target preparation technique that is usually performed on backings such as thin metal foils or low atomic number materials like Be and to a lesser extent, C foils. Techniques have been developed by IRML that result in electrodeposition of oxide films up to 500 μg/cm2 on carbon foils or aluminized mylar. Electrodeposition is a very attractive target fabrication method since it is very efficient in the usage of rare and/or valuable isotopes. The ability to prepare these films on carbon or mylar foils provides a target that has, in most applications, far less interference resulting from the backing. Thin films of carbon, aluminum, boron and titanium are being used as stripper foils in the generation of neutral (H- → H0) particle beams with energies of 50 MeV or greater. Neutralizer foils as large as 25 cm × 25 cm have been pr from Al and C in thicknesses ranging from 5 to 12 μg/cm2 that are mounted on thin nickel grids with a transmittance of approximately 90%. Significantly larger foils are currently under development.
| Original language | English |
|---|---|
| Pages (from-to) | 147-152 |
| Number of pages | 6 |
| Journal | Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |
| Volume | 282 |
| Issue number | 1 |
| DOIs | |
| State | Published - Oct 1 1989 |
Funding
The Isotope Research Materials Laboratory (IRML) in the Chemical Technology Division at the Oak Ridge National Laboratory (ORNL) performs research and development to derive or improve processing methods for separated stable and radioactive isotopes . Custom- order fabrication of isotopes into forms useful to the international research community is also performedby IRML on a cost-recovery basis. In addition to increasingly stringent materials specifications requested by experimenters, the dwindling supplies of valuable, enriched isotopes present many areas of challenge. A major area of research materials production and R&D activities for IRML involves accelerator targets. In most cases, self-supported thin films are preferred for use as accelerator targets; however, films with very low areal densities, films other than metal, or films that cover relatively large surface areas usually require the use of a secondary material to provide support for the thin film. While metal foils can be used as backings for the desired films, they are frequently too thick or have too high an atomic number for experimental purposes, or they are too fragile for preparative and handling procedures. As a result, carbon foils are a common choice for a backing material because of their strength and stabil- * Research sponsored by the Office of Basic Energy Sciences, U.S. Department of Energy under Contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.