Development of Hybrid Long-Lived Carbon Foil with High Durability at 1,800K

Abstract

Thin carbon foils are extensively used not only for targets and their backing foils in the field of fundamental and experimental physics, but also for stripper foils in high intensity accelerators. We have succeeded in fabricating long-lived boron mixed carbon stripper foils for high-power accelerators. Foils of 10-700μg/cm^2 thick were made by a controlled AC/DC arc-discharge method. The lifetime of the foils was tested with three kinds of beams of 3.2MeV Ne^+ DC ion from a Van de Graaff accelerator, 650keV H^- DC ion from a Cockcroft-Walton accelerator, and 800-MeV, pulsed H^- ion and proton beams in the proton storage ring at the Los Alamos National Laboratory in USA. The 3μA, 3.2MeV, Ne^+ beam deposited a significant energy of about 80W/(300μg/cm^2) which nearly corresponded to the effect of the 400-MeV proton beam of J-PARC. The maximum lifetime was found to be extremely long; 100 and 360 times longer than those of diamond and commercially available carbon foils. Also, the foils were free from any shrinkage during irradiation, and showed an extremely low thickness reduction, even at a high temperature of 1,800K.