radiation

Paper	Title	Other Keywords	Page
MIT03	Experimental Efforts at LNF to Reduce Secondary Electron Yield in Particle Accelerators	electron, vacuum, synchrotron, synchrotron-radiation	46
	R. Cimino, M. Commisso, T. Demma, D. Grosso INFN/LNF N. Mahne, A. Giglia CNR-IOM
	A common effort in most of the accelerator centers is to develop new technologies to produce and test beam pipe inner walls of particle accelerators with an as low as possible Secondary Electron Yield (SEY). This item, in fact, is crucial in controlling Electron Cloud formation and in reducing its effects, that are well known to be a potential bottle-neck to the performances obtainable from present and future accelerators. Frascati has a longstanding experience in qualifying materials in terms of surface parameters of interest to e-cloud issues. We are routinely measuring SEY, its dependence from electron energy, temperature and scrubbing and we are about to be ready to study not only Photo Electron Yield (PEY) by using synchrotron radiation beamlines in construction at DAΦNE, but more importantly, to characterize in situ the surface chemical composition and eventual modifications occurring during electron or photon irradiation. Such characterization effort is also suggesting ways to produce Low SEY materials. Some preliminary results will be here discussed.
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PST08	Synrad3D Photon Propagation and Scattering Simulation	photon, vacuum, site, scattering	118
	G. Dugan, D. Sagan Cornell University - CLASSE
	As part of the Bmad software library, a program called Synrad3d has been written to track synchrotron radiation photons generated in storage rings. The purpose of the program is primarily to estimate the intensity and distribution of photon absorption sites, which are critical inputs to codes which model the growth of electron clouds. Synrad3d includes scattering from the vacuum chamber walls using X-ray data from an LBNL database. Synrad3d can handle any planar lattice and a wide variety of vacuum chamber profiles. A description of the program will be given, together with some examples of results.
PST12	In Situ SEY Measurements at CesrTA	electron, gun, vacuum, controls	140
	J. Kim, J. Conway, S. Greenwald, Y. Li, T. Moore, M. Palmer, V. Medjidzade, D. Asner, C. Strohman Cornell University - CLASSE
	Measuring secondary electron yields (SEYs) on technical surfaces in accelerator vacuum systems provides essential information for many accelerator R&D projects, such as the ILC Damping Rings, regarding to electron cloud growth and suppression. As a part of CesrTA research program, we developed and deployed SEY in-situ measurement systems. Two such SEY systems were installed to expose samples with direct and scattered synchrotron radiation (SR), and the SEYs of the samples were measured as a function of SR dosages. In this poster, we describe the in-situ SEY measurement systems and the initial results on bare aluminum and TiN-coated aluminum samples.
MOD01	Analysis of Synchrotron Radiation using SYNRAD3D and Plans to Create a Photoemission Model	photon, wiggler, electron, damping	147
	L. Boon, A. Garfinkel Purdue University K. Harkay Argonne National Laboratory
	Electron cloud data from electron rings suggest that the photoelectron model in electron cloud generation codes is incomplete. The photoelectron model will be important in modeling the cloud generation on components downstream of wigglers, which can produce a very high photon flux on the wall in a local region. The code SYNRAD3D has been developed in the context of the Bmad accelerator physics software library. SYNRAD3D includes computation of synchrotron radiation and propagation in 3D through a vacuum chamber. The probability of reflection vs. absorption of the photons on the chamber wall is included, using data from the literature. We used SYNRAD3D to model the photon flux for the ILC damping ring. For simplicity in modeling, we started with a round chamber and varied parameters such as the number of simulation-generated photons, bin size, photon energy cutoff, and whether photons reflect off the wall. With a realistic photon flux and distribution, we can study models for the photoemission. Preliminary work has begun to develop a photoelectron model using Retarding Field Analyzer (RFA) data. The work to date and future plans are described.
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DIA04	Status of COLDDIAG: a Cold Vacuum Chamber for Diagnostics	electron, vacuum, diagnostics, synchrotron	190
	S. Gerstl, T. Baumbach, S. Casalbuoni, A. Grau, M. Hagelstein, D. Saez de Jauregui Karlsruhe Institute of Technology R. Cimino, M. Commisso, B. Spataro, A. Mostacci INFN/LNF J. Clarke, D. Scott Science and Technology Facilities Council (STFC/DL/ASTeC) Daresbury Laboratory Accelerator Science and Technology Centre M. Cox, J. Schouten Diamond Light Source Ltd (Diamond) R. Jones, I. Shinton Cockcroft Institute E. Wallen Lund University - MAX-Lab R. Weigel Max-Planck Institute for Metal Research, Stuttgart V. Baglin CERN C. Boffo, G. Sikler Babcock Noell GmbH (BNG) T. Bradshaw Science and Technology Facilities Council (STFC/RAL) Rutherford Appleton Laboratory
	One of the still open issues for the development of superconducting insertion devices is the understanding of the heat load induced by the beam passage. With the aim of measuring the beam heat load to a cold bore and in order to gain a deeper understanding in the beam heat load mechanisms, a cold vacuum chamber for diagnostics is under construction. We plan to have access with the same set-up to a number of different diagnostics, so we are implementing: i) retarding field analyzers to measure the electron flux, ii) temperature sensors to measure the total heat load, iii) pressure gauges, iv) and mass spectrometers to measure the gas content. The inner vacuum chamber will be removable in order to test different geometries and materials. COLDDIAG is built to fit in a short straight section at ANKA, but we are proposing its installation in different synchrotron light sources with different energies and beam characteristics. A first installation in DIAMOND is planned in June 2011. Here we describe the technical design report of this device and the planned measurements with beam.
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