• A. Xiao
  ANL, Argonne

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Intrabeam scattering (IBS) may become an issue for linac-based fourth-generation light sources such as X-ray free-electron lasers and energy recovery linacs (ERLs), both of which use high-brightness electron beams with extremely small emittance and energy spread. Any degradation of the extremely high beam quality could significantly reduce the X-ray performance. We present here a strategy first used in the code elegant for simulating IBS effects for high brightness linac beams. We also present an application to a possible ERL upgrade of the Advanced Photon Source.

• M. Borland, V. Sajaev
  ANL, Argonne

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
An Energy Recovery Linac (ERL) is one possibility for an upgrade to the Advanced Photon Source (APS). In addition to the linac itself, our concept involves a large turn-around arc (TAA) at 7 GeV that would eventually accommodate many new beamlines. Previously, we based the TAA design on isochronous triple-bend archromat (TBA) cells, since these are expected to provide some immunity to the effects of coherent synchrotron radiation. In the present work, we compare the previous TBA-based design to a new design based on double-bend achromat cells, in terms of emittance growth, energy spread growth, and energy recovery. We also explore the trade-off between optimization of the beta functions in the straight sections and minimization of emittance growth.

• S. Ohsawa, M. Ikeda, N. Sakabe, T. Sugimura
  KEK, Ibaraki

A new type of rotating anticathode X-ray generator has been developed, in which the electron beam irradiates the inner surface of a U-shaped anticathode. A high-flux electron beam is focused on the inner surface by optimizing the shape of the bending magnet. In order to minimize the sizes of the X-ray source, the electron beam is focused strongly in a short distance by the bending magnet which is small and is close to the rotating anticathode. The power of the electron beam can be increased to the point at which the irradiated part of the inner surface is melted, because a strong centrifugal force fixes the melted part on the inner surface. We have achieved emission of X-rays 10 times more brilliant than can be attained by a conventional rotating anticathode. The development is still in progress. New results will be reported in detail.

• C.K. Allen, W. Blokland, S.M. Cousineau, J. Galambos
  ORNL, Oak Ridge, Tennessee

Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Charged-particle beam diagnostic devices such as wire scanners, wire harps, and laser scanners all provide data sets describing the one-dimensional density distributions of the beam at a particular location; these data are commonly called profile data. We use these data for further computations, usually beam properties such as position and size, but to do so requires a certain level of accuracy in the data. Thus, we must make real world considerations as to its information content. Specifically, we consider noise in the data and the fact that it is sampled. The operation of a typical profile device is outlined in order to create a general model for the data sets. Using signal processing techniques we identify the minimal sampling requirements for maintaining information content. Using Bayesian analysis we identify the most probable Gaussian signal within the data (the mean and standard deviation of the Gaussian signal can then be used for computations). Time permitting we present techniques for direct computation of beam properties using noisy, sampled profile data.