Low Z Thin Film Stripper Foils, Targets and X-Ray Windows

The latest rare isotope and ion beam accelerator facilities used for important nuclear physics experiments require free standing thin film stripper foils, targets and x-ray windows made from low atomic number (low Z) elements such as Be, B and C. It is expected that the currently used thin films will need to be improved due to the much higher beam power densities in the next generation nuclear research facilities including the Facility for Rare Isotope Beams (FRIB). The overall goal of this project is to develop technologies for the production of free standing low Z multi-layer nano-crystalline thin films in the range from a few ug/cm2 to over 100mg/cm2 for applications as charge strippers and targets in heavy ion accelerators as well as x-ray windows for gaseous detectors. During Phase I, the feasibility of the proposed technical approach was experimentally established by fabrication of stress controlled multi-layer films made from low-Z nano-layers, which showed the following results: (i) 3-4X increase in stripper foil lifetime when irradiated with 78Kr14+ beam at NSCL-MSU, (ii) 5X increase in stripper foil lifetime when irradiated with H+ beam at Cardinal Health, and (iii) Pin-hole free hybrid (C-B) windows with low energy x-ray transmission better than the current state-of-the-art 8 micron Be windows. In addition, this technology is being made available to the DOE community through MICROMATTER, which became a UHV subsidiary in July 2014. During the proposed Phase II, a commercially viable, fully automated process and equipment will be designed and assembled for low cost mass production of free standing low Z thin films based on the technology developed in Phase I. These free standing Super thin films will be extensively tested and evaluated for use as stripper foils, high energy targets and low energy xray windows for detectors. The quantitative performance goals for Phase II are: (i) Foil Lifetime : 10X improvement over standard carbon foils for both H+ and heavy ions, (ii) x-ray transmission better than 50% transmission at 525eV (O peak), and (iii) cost: $10-25 per square inch depending on thickness and quantity. To achieve success in this project, UHV has assembled a team of experts with extensive experience in nuclear accelerators, thin film fabrication and analysis, thin film equipment manufacturing, and high energy ion beam testing. These improved thin films will have very significant impact on the operating conditions of the next generation nuclear accelerator facilities, that are used not only for scientific research but also for medical and commercial isotope manufacturing. As an example, the radio-pharmaceuticals manufactured in these facilities are used to treat (radiation therapy) millions of people with cancer around the world. These nano-layered thin films will be immediately added to UHV's product line to make them commercially available through existing sales channels (www.MICROMATTER.com, www.nanoRANCH.com and www.nanoXRF.com).