Cornell University Unit Name

CESR Damping Ring Test Accelerator (CesrTA)

This is the homepage of the CesrTA Collaboration which is carrying out R&D for the design of future Linear Collider Damping Rings.

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News

• The next CESR Test Accelerator Run is scheduled to begin April 2016.
• The next CesrTA Collaboration meeting will take place Tuesday, April 19 at 5PM US EST.

Overview

The CESR-c/CLEO-c high energy physics program concluded on March 3, 2008. Since that time, the LEPP accelerator group has converted CESR to a configuration suitable for ILC Damping Ring (ILCDR) research, CesrTA. CesrTA offers an effective and economical route to meet a number of critical ILCDR R&D needs, in particular, for the evaluation of electron cloud effects and their amelioration in wigglers. Because CesrTA is able to operate with positrons, this will be a complementary effort to work presently underway at the Advanced Accelerator Test Facility (ATF) at KEK.

The baseline configuration for the ILC damping rings was initially chosen to be a single ~6.7 km ring for electrons and two ~6.7 km rings for positrons. The choice of two rings for positrons was driven by concerns about the electron cloud instability as determined from detailed simulations. More recently, based on promising simulations for electron cloud mitigation techniques in dipoles and wigglers, the Reference Design Report configuration has been modified to a single ring for positrons.

This makes the demonstration of suitable electron cloud mitigation techniques extremely critical during the ILC Engineering Design Report(EDR) phase between now and the end of 2009. Thus we propose to use CesrTA to determine how the development of the electron cloud depends on beam parameters, local magnetic fields, and vacuum chamber design. We will place a special emphasis on exploring electron cloud mitigation techniques in the CESR-c damping wigglers which form the basis for the ILC damping wiggler design. Electron cloud instability thresholds will also be measured. A comparison of the measurements with the simulation results will be used to validate the models that are the basis of the ILC damping ring design and help to insure that viable solutions to the electron cloud problem are implemented.

An experimental program to understand the relevant electron cloud physics requires a positron beam, very small vertical emittance, and high field damping wigglers. Flexibility of the bunch structure of the positron beam is essential to explore the dependence of the electron cloud density on bunch spacing and train length. Ideally, the zero current limit of the vertical emittance should be comparable to the specifications of the ILC damping ring so that we will be sensitive to emittance diluting effects of the interaction with the electron cloud. Simulations indicate that, in the absence of techniques to suppress the electron cloud and with small vertical aperture vacuum chambers, the equilibrium density in a damping ring will typically be highest in the wigglers. We propose to test these predictions in detail using the large aperture CESR-c wigglers.

CESR-c represents the only operational wiggler-dominated storage ring and the CESR-c superferric wigglers have been designated as the technology choice of the ILC damping rings RDR configuration. The CesrTA concept envisions placing the 12 CESR-c wigglers in zero-dispersion locations in the ring for ultra-low emittance operation. 6 of the 12 wigglers will be located in an 18 meter straight section (the former north interaction region) which will facilitate the installation of vacuum diagnostics for the study of electron cloud effects as well as vacuum chambers designed to suppress the cloud effects in wigglers. This section will also provide a location for testing a prototype of the final ILC damping wigglers.

The following table provides a set of baseline parameters for CesrTA operation:

Parameter	Value
E	2.0 GeV
No. Wigglers	12
Bmax	2.1 T
εx	2.25 nm
Qx	0.59
Qy	0.63
Qz	0.098
σE/E	8.6 x 10-4
τx,y	47 ms
σz	6.8 mm
αp	6.4 x 10-3
Nb	1-2 x 10^10

We are presently targeting vertical emittances in the 20pm range as part of the reduced scope CesrTA program. Preliminary evaluations of beam-based alignment techniques suggest that it should be possible to approach these levels. We are presently exploring the impact of beam dynamics effects leading to emittance growth for finite current beams. Our goal is to be able to operate with bunch currents corresponding to the ILC damping ring specification for electron cloud growth measurements and to explore the impact of the electron cloud on ultra low emittance beams using detailed witness bunch studies.

CesrTA Operations and R&D

Operations

• CesrTA Schedule: Experimental and downtime schedule information
• CesrTA Procedures: Procedures for CesrTA experimental activities

Experimental Activities

• CesrTA Data: Central link for obtaining access to CesrTA data
• CesrTA Lattice and Layout Information
• CesrTA Electron Cloud Modeling Parameters
• Machine Studies Request Template
• Machine Studies

Engineering Resources

• CESR-c and ILC Wiggler Information including field maps
• CesrTA Engineering Design Information

Meeting Pages

Please note: Access to some meeting pages is restricted to CesrTA Collaboration members. If you are not a collaboration member, please send an email requesting to be added to the membership list. We will try to quickly respond to all such requests.

• CESR BPM development
• Optical Stochastic Cooling General Meeting - ZOOM https://cornell.zoom.us/j/933895602
• OSC documents
• General Meetings - Weekly project meetings at Cornell (Friday, 9am Eastern Time)
• Working Group Meetings - Links to various topical meeting pages (some may be LEPP-restricted)
• CesrTA Steering Committee Meetings (Restricted Access)
• Supporting Information for participation in various workshops.

Collaborator Resources

• Visitor Forms to be completed by collaborators coming to Cornell for experiments
• Accommodations for visiting collaborators
• Register on the CU-LEPP International Linear Collider Wiki
• CesrTA Collaboration Mailing List:
  • An email list has been set up to assist communication and co-ordination for the CesrTA collaboration. Click on the subscribe link below to join the list. You should send the email from the address that you wish to be subscribed. Anyone who is subscribed can send email to the list at cesrta-collaboration-l@list.cornell.edu. You can unsubscribe by means of the unsubscribe link below.
  • Subscribe - Please make sure the body of your message is blank
  • Unsubscribe - Please make sure the body of your message is blank

Reports and Publications

• Publications Listing
• Phase I Report: Report summarizing the initial 3-year research program.

Cost Account Manager and Coordinator Resources (some pages are restricted access)

• Replicon Timesheet Information: Summary of CesrTA Project and CESR General Operations and Maintenance time reporting categories
• WBS & Accounting Information: LEPP project WBS and CAM purchase information

Phase III proposal

• Phase III Project Description: The proposal for Cesr-TA Phase III is part of a larger, comprehensive proposal for accelerator physics research at Cornell.

Advisory Committee CesrTA Program Review (September 11, 2012)

An advisory committee reviewed the CesrTA program on September 11, 2012 at Cornell. Presentations can be found here.

Joint NSF and DOE Review (July 16-17, 2007)

A review of the CesrTA Proposal by NSF and DOE was conducted July 16-17 in Washington, DC. Presentations can be found on the review web-site.

February 2008 Impact Statement describing the changes and impacts of the de-scoping from the original proposal.

De-scoped proposal document.

Selected Talks and Presentations

• LEPP Accelerator Physics Seminar 8 November 2013. Observation of Electron Trapping by CESRTA by J.A. Crittenden (pdf)
• American Physical Society Meeting 11-15 April 2008: Poster by J.A. Crittenden (pdf ppt)
• April 24, 2007 Seminar at LBNL - M. Palmer
• LEPP Journal Club Talk by M. Palmer (Oct. 6, 2006).
• Presentation(M. Palmer) at the Oxford Laserwire Miniworkshop (July 3, 2006)
• EPAC06 paper (pdf) and poster (ppt).
• CESR_Future.ppt: Mark Palmer's presentation at the 2nd International Linear Collider Workshop (Snowmass 2005). Also available in a pdf version.
• emittance_memo.pdf: Mark Palmer's memo on minimum emittance in a wiggler-dominated ring.
• Rubin-CESR-DRTestFacility.ppt: Dave Rubin's Presentation at the CERN Meeting (Nov. 2005). Also available in a pdf version.
• CesrTF_Instrumentation_Alignment.ppt: Items for Discussion with UK Collaborators. Also available in a pdf version.

ILC Damping Ring Links and Resources

• ILC Damping Ring Web Page maintained by Andy Wolski.
• In order to subscribe to the ILC.ILC damping ring mailing list, you should send mail to mailto:majordomo@listserv.lbl.gov with "subscribe ilcdr" in the body. To unsubscribe, send mail to the same address with "unsubscribe ilcdr" in the body.
• International Linear Collider Web Site
• Baseline Configuration Document for the ILC.

Working Areas (Obsolete)

• Alignment Issues
• Low-Emittance Tuning
• Cryogenics Issues
• Electron Cloud
• Intrabeam Scattering
• Instrumentation and Feedback Issues
• CesrTA Lattice Information
• UCLC Proposal
• REU Projects for 2006
• Vacuum Systems Development

• CesrTA Weekly Project Meetings
• Members and Assignments
• ILC Accelerator R&D Meetings are held every Thursday at 3pm in the Wilson Small Conference Room. All are welcome!
  • Presentations Area for posting of presentations for the weekly ILC Accelerator R&D Meetings

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• sey_collabo_mtg_2013jan22.pdf: sey_collabo_mtg_2013jan22.pdf

• sey_collabo_mtg_2013jan22.pptx: sey_collabo_mtg_2013jan22.pptx

• 20130122-DesignOfNewCodedAperture.ppt: 20130122-DesignOfNewCodedAperture.ppt

• 20130122-DesignOfNewCodedAperture.pdf: 20130122-DesignOfNewCodedAperture.pdf

• CesrTA_ODR_2013_0219.pptx: CesrTA_ODR_2013_0219.pptx

• project_description_references_nsf_accphys.pdf: project_description_references_nsf_accphys.pdf

• camMay15.pdf: camMay15.pdf