Palmer, M.

Paper	Title	Page
WEL00	Workshop Introduction
	M. Palmer Cornell University - CLASSE
	Introduction to the Workshop
	Slides
MIT01	Electron Cloud Mitigation Investigations at CesrTA	41
	J. Calvey, J. Makita, M. Palmer, R. Schwartz, C. Strohman Cornell University - CLASSE S. Calatroni, G. Rumolo CERN K. Kanazawa, Y. Suetsugu KEK M. Pivi, L. Wang SLAC National Accelerator Laboratory
	Over the course of the CesrTA program at Cornell, over 30 Retarding Field Analyzers (RFAs) have been installed in the CESR storage ring. These devices, which measure the local electron cloud density and energy distribution, have been deployed in drift, dipole, quadrupole, and wiggler field regions. They can be used to evaluate the efficacy of cloud mitigation techniques in each magnetic field element. Techniques investigated so far include different beam pipe coatings, grooves, and clearing electrodes. This talk will provide an overview of the electron cloud mitigation program at CESR, give a preliminary evaluation of the effectiveness of various mitigation techniques, and discuss methods used to obtain quantitative information about vacuum chamber properties via simulation.
	Slides
DYN03	Studies of the Electron-Cloud-Induced Beam Dynamics at CesrTA	60
	G. Dugan, M. Billing, R. Meller, M. Palmer, G. Ramirez, J. Sikora, K. Sonnad, H. Williams Cornell University - CLASSE R. Holtzapple California Polytechnic State University
	This talk will review recent data and simulation results related to electron-cloud induced beam dynamics studies at Cesr-TA.
	Slides
PST01	Implementation and Operation of Electron Cloud Diagnostics for CesrTA	83
	Y. Li, X. Liu, V. Medjidzade, J. Conway, M. Palmer Cornell University - CLASSE
	The vacuum system of Cornell Electron Storage Ring (CESR) was successfully reconfigured to support CesrTA physics programs, including electron cloud (EC) build-up and suppression studies. One of key features of the reconfigured CESR vacuum system is the flexibility for exchange of various vacuum chambers with minimized impact to the accelerator operations. This is achieved by creation of three short gate-valve isolated vacuum sections. Over the last three years, many vacuum chambers with various EC diagnostics (such as RFAs, shielded pickups, etc) were rotated through these short experimental sections. With these instrumented test chambers, EC build-up was studied in many magnetic field types, including dipoles, quadrupoles, wigglers and field-free drifts. EC suppression techniques by coating (TiN, NEG and a-C), surface textures (grooves) and clearing electrode are incorporated in these test chambers to evaluate their effectiveness. We present the implementation and operations of EC diagnostics.
PST03	Methods for Quantitative Interpretation of Retarding Field Analyzer Data	91
	J. Calvey, J. Crittenden, G. Dugan, M. Palmer Cornell University - CLASSE K. Harkay Argonne National Laboratory
	A great deal of Retarding Field Analyzer (RFA) data has been taken as part of the CesrTA program at Cornell. Obtaining a quantitative understanding of this data requires use of cloud simulation programs, as well as a detailed model of the RFA itself. In some cases the RFA can be modeled by postprocessing the output of a simulation codes, and one can obtain “best fit” values for important simulation parameters using a systematic method to improve agreement between data and simulation. In other cases, in particular in high magnetic field regions, the presence of the RFA can have an effect on the cloud, and one needs to include a model of the RFA in the simulation program itself.
PST07	Techniques for Observing Beam Dynamical Effects Caused by the Presence of Electron Clouds	108
	M. Billing, G. Dugan, R. Meller, M. Palmer, G. Ramirez, H. Williams, J. Sikora Cornell University - CLASSE R. Holtzapple California Polytechnic State University
	During the last several years CESR has been studying the effects of electron clouds on stored beams in order to understand their impact on future linear-collider damping ring designs. One of the important issues is the way that the electron cloud alters the dynamics of bunches within the train. Techniques for observing the dynamical effects of beams interacting with the electron clouds have been developed. These methods and examples of measurements are presented here.
PST09	Electron Cloud Modeling Results for Time-Resolved Shielded Pickup Measurements at CesrTA	123
	J. Crittenden, Y. Li, X. Liu, M. Palmer, J. Sikora Cornell University - CLASSE S. Calatroni, G. Rumolo CERN N. Omcikus University of California at Los Angeles
	The Cornell Electron Storage Ring Test Accelerator (CesrTA) program includes investigations into electron cloud buildup, applying various mitigation techniques in custom vacuum chambers. Among these are two 1.1-m-long sections located symmetrically in the east and west arc regions. These chambers are equipped with pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. Carbon-coated, TiN-coated and uncoated aluminum chambers have been tested. Electron and positron beams of 2.1, 4.0 and 5.3 GeV with a variety of bunch populations and spacings in steps of 4 and 14 ns have been used. Here we report on results from the ECLOUD modeling code which highlight the sensitivity of these measurements to model parameters such as the photoelectron azimuthal and energy distributions at production, and the secondary yield parameters including the true secondary, rediffused, and elastic yield values. In particular, witness bunch studies exhibit high sensitivity to the elastic yield by providing information on cloud decay times.
PST10	Using Coherent Tune Shifts to Evaluate Electron Cloud Effects on Beam Dynamics at CesrTA	130
	D. Kreinick, J. Crittenden, G. Dugan, Z. Leong, M. Palmer Cornell University - CLASSE R. Holtzapple, M. Randazzo California Polytechnic State University M. Furman, M. Venturini LBNL
	One technique used at CesrTA for studying the effects of electron clouds on beam dynamics is to measure electron and positron bunch tunes under a wide variety of beam energies, bunch charge, and bunch train configurations. Comparing the observed tunes with the predictions of various simulation programs allows the evaluation of important parameters in the cloud formation models. These simulations will be used to predict the behavior of the electron cloud in damping rings for future linear colliders.
PST12	In Situ SEY Measurements at CesrTA	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.
FTR01	CesrTA Preliminary Recommendations for the ILC Positron Damping Ring	202
	M. Palmer Cornell University - CLASSE
	The first phase of the CesrTA experimental program is now complete. Electron cloud research over the course of the last 2.5 years has focused on two principle topics. The first is the characterization of methods to mitigate the electron cloud build-up in each of the magnetic field regions of concern for damping ring design. The second is the characterization of the cloud's impact on ultra-low emittance beams. Our intent is now to incorporate these results into the technical design of the positron damping ring for the International Linear Collider. Implications for the ILC DR design will be discussed. While no paper is available here, two references were published covering our recommendations: M. T.F. Pivi, L. Wang, L. E. Boon, K. C. Harkay, J. A. Crittenden, G. Dugan, M. A. Palmer, T. Demma, S. Guiducci, M. A. Furman, K. Ohmi, K. Shibata, Y. Suetsugu, J. Urakawa, C. Yin Vallgren, "Recommendation for Mitigations of the Electron Cloud Instability in the ILC", (TUPC030) Proceedings of IPAC 2011, San Sebastián, Spain. J. A. Crittenden, J. V. Conway, G. Dugan, M. A. Palmer, D. L. Rubin, L. E. Boon, K. C. Harkay, M. A. Furman, S. Guiducci, M. T.F. Pivi, L. Wang, "Investigation into Electron Cloud Effects in the ILC Damping Ring Design", (TUPPR063) Proceedings of IPAC 2012, New Orleans, Louisianna, USA.
	Slides
FTR02	Simulation of Electron Cloud Induced Instabilities and Emittance Growth for CesrTA	203
	M. Pivi SLAC National Accelerator Laboratory G. Dugan, M. Palmer, K. Sonnad Cornell University - CLASSE
	As part of the international Linear Collider (ILC) collaboration, we have compared the electron cloud (EC) effect for different Damping Ring (DR) designs respectively with 6.4 km and 3.2 km circumference and investigated the feasibility of the shorter damping ring with respect to the electron cloud build-up and related beam instabilities. The studies for a 3.2 km ring were carried out with beam parameters of the ILC Low Power option. A reduced damping ring circumference has been proposed for the new ILC baseline design and would allow considerable reduction of the number of components, wiggler magnets and costs. We also present the results for the luminosity upgrade option with shorter 3ns bunch spacing. In particular we will go through the evaluation of mitigation techniques for the ILC DR and discuss the integration of the CesrTA results into the Damping Ring design. Furthermore (with Kiran Sonnad, Cornell) we have performed detailed simulations using the CMAD code for CesrTA single-bunch instability and linear emittance growth below threshold and preliminary comparisons with experimental data are discussed here in view of the validation of the simulation codes prediction for the ILC DR.
	Slides
PST02	Bunch-By-Bunch Instrumentation Upgrades For CESR, Based On Requirements For The CESR Test Accelerator Research Program	88
	N. Rider, J. Alexander, M. Billing, C. Conolly, N. Eggert, E. Fontes, W. Hopkins, B. Kreis, A. Lyndaker, R. Meller, M. Palmer, D. Peterson, M. Rendina, P. Revesz, D. Rubin, J. Savino, R. Seeley, J. Shanks, C. Strohman Cornell University - CLASSE R. Holtzapple California Polytechnic State University J. Flanagan KEK
	The research focus of the CESR Test Accelerator program requires new instrumentation hardware, software and techniques in order to accurately investigate beam dynamics in the presence of electron cloud effects. These new instruments are also required to develop low emittance beam conditions which are key to the success of the damping ring design for the International Linear Collider. This poster will detail some of the architecture and tools which have been developed to support these efforts. Emphasis will be placed on the 4 nS bunch by bunch Beam Position Monitoring system as well as the 4 nS capable X-ray Beam Size Monitor.