High current CW beam profile monitors using transisiton radiation at CEBAF

One way of measuring the profile of CEBAF`s low emittance and high power beam is to use the Optical Transition Radiation (OTR) emitted from a thin foil surface when the electron beam passes through it. We present the design of a monitor using the forward OTR emitted from a 0.25 {mu}m carbon foil. We believe that the monitor will resolve three main issues: (i) whether the max temperature of the foil stays below the melting point, (ii) whether the beam loss remains below 0. 5%, in order not to trigger the machine protection system, and (iii) whether the monitor resolution (unlike that of synchrotron radiation monitors) is better than the product {lambda}{gamma}. It seems that the most serious limitation for CEBAF is the beam loss due to beam scattering. We present results from Keil`s theory and simulations from the computer code GEANT as well as measurements with Al foils with a 45 MeV electron beam. We also present a measurement of a 3.2 GeV beam profile that is much smaller than {lambda}{gamma}, supporting Rule & Fiorito`s calculations of the OTR resolution limit due to diffraction.