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June, 1998
Proceedings of the Workshop on the

SLAC Damping Rings in the 21st Century


Woodside, California

April 6-7, 1998

Stanford Linear Accelerator Center

Stanford University, Stanford, California 94309


P. Krejcik

J. Clendenin

R. Nixon

The Proceedings of the Workshop on the SLAC Damping Rings in the 21st Century (DR2000) have been published as a SLAC Workshop Proceedings (SLAC-WP-10, June 1998), and are also available for viewing here by clicking on the individual presentations listed below in the Table of Contents. (The page numbers in the Table of Contents refer to the bound copy of the Proceedings)

Table of Contents

Collection of IMAGES of conference participants  
Preface xi
Workshop Schedule xiii
Introduction 1
P. Krejcik (Accelerator Department)  
I. Reliability Issues  
Session Summary

M. Munro (Mechanical Engineering)

Mechanical Systems Reliability Issues

B. McKee (Accelerator Department)

Damping Ring Radiation Doses

M. Ross (Accelerator Department)

II. Operations  
Session Summary

D. Schultz (Accelerator Department)

Operational Experience at SPEAR

J. Corbett (SSRL)

Damping Ring Operations and Plans

R. Pennacchi (Accelerator Department)

Damping Ring Operational Issues

M. Stanek (Accelerator Department)

Simultaneous Long Pulse Operation

R. Erickson (Accelerator Department)

III. Beam Dynamics  
Session Summary

P. Krejcik (Accelerator Department)

Low Energy Operation of the SLC Damping Rings

T. Raubenheimer* (NLC) and K. Bane (ARDA)

Implementation of 750 MeV Lattice for N/S Damping Ring Complex

M. Woodley (Accelerator Department)

Ring Enhancements Through Magnetic Modifications

J. Spencer (ARDA)

Emittance Reduction via Dynamic RF Frequency Shift at the SLC Damping Rings

M. Minty (Accelerator Department), R. Akre (Klystron), F.J. Decker (Accelerator Department), J. Frisch (Accelerator Department) , S. Kuroda (KEK), and F. Zimmermann* (ARDA)

IV. RF Systems  
Session Summary

J. Frisch (Accelerator Department)

A PEP-II-Style Cavity for the Damping Rings?

R. Rimmer (LBNL)

Damping Ring RF Source

R. Akre (Klystron)

Damping Ring Klystron Relocation - abstract

Damping Ring Klystron Relocation

A. Hill (Klystron)

Damping Ring RF Interlock Upgrade - abstract

Damping Ring RF Interlock Upgrade

A. Hill (Klystron)

Low Level RF Control

P. Courredoura (Klystron)

 - Summary

DR2000 with PEP-II Style Low-Level RF System

R. Tighe (Klystron)

Damping Ring S-Band Beam Phase Lock System

J. Judkins (Klystron)

Plans for Existing Windows, Tuners, Pumps:  
1. DR2000 Window Design - abstract

DR2000 Window Design

M. Neubauer (Klystron)

2. Damping Ring Tuner Upgrade

H. Schwarz (Klystron)

3. Mechanical Considerations - abstract

Mechanical Considerations for Existing Tuners, Windows, and Pumps

B. McKee (Accelerator Department)

Adjustable Stub-Line Tuner

H. Schwarz (Klystron)

V. Diagnostics  
Session Summary

M. Ross (Accelerator Department)

Diagnostics for Damping Rings 2000: Transverse and Longitudinal Beam Size MonitorsT. Kotseroglou* (Accelerator Department) and P. Krejcik (Accelerator Department) 325
Energy Spread Monitoring Before and After the Damping Rings

J. Turner (Accelerator Department)

Workshop Summary

P. Krejcik (Accelerator Department)

Appendix - Table of Beam Requirents for Damping Rings 355
DR2000 Workshop Participants 357


"The purpose of the Workshop is to assess the status and needs of the Damping Rings for the era of PEP-II. The goal is to have the Rings perform to produce the specified beam parameters with an insignificant amount of downtime. We want to achieve this status by improving the Rings where necessary, not by increasing the maintenance effort. The things that we can act upon in the immediate future are largely engineering issues to improve the integrated availability of the damping rings.

"However, we are also looking for ways of improving the beam quality, the machine tunability and beam diagnostics and instrumentation. Some of these issues might be motivated by studies into future linear collider issues, or they may be pre-emptive for PEP-II future requirements for a higher brightness injector. In either case, we would like to gather all suggestions for improved performance and operation."

The statement above was distributed in the first announcement for the Workshop. The response of the SLAC staff is heartening as is documented in these proceedings. The proceedings are organized as close as possible in the order of the original Workshop Schedule which was divided into five sessions: reliability issues, operations, beam dynamics, rf systems, and diagnostics. In most cases only transparencies are available for a given presentation, but where possible an abstract or summary has been added. Each session is also summarized. The Appendix giving the beam requirements shows not only the requirements for PEP-II as discussed in the Workshop introduction, but also for two approved experiments that will require use of the Rings. These requirements are for the most part less stringent than the SLC requirements, which are given for comparison.

It is expected that these proceedings will now provide a valuable resource for planning future modifications æ both to the equipment and to the operating parameters æ to the Rings in the spirit of the purpose and goals stated above.

The Workshop was held in the nearby Santa Cruz Mountains in the Boulevard Restaurant that for these two days was made available for our exclusive use. The large picture windows of the restaurant look east through the redwoods, into the Stanford hills, and on to the San Francisco Bay beyond, resulting in both a scene of beauty and a sense of isolation­an excellent setting for a workshop of this type as evidenced by both the quantity of presentations and their individual quality.

We would like to thank each of the speakers and session chairpersons for providing their transparencies and summaries or in some cases formal manuscripts. We also want to thank the staff of the Boulevard Restaurant for their assistance throughout and for the excellent lunches and snacks that were prepared.

The Workshop was sponsored by the SLAC Accelerator Department.

Workshop Organizers:

P. Krejcik

J. Clendenin

DR2000 Workshop Program

SLAC Damping Rings in the 21st Century

April 6-7, 1998 at the Boulevard, Woodside

  Monday Tuesday
9:30 Coffee Coffee
  Introduction - P. Krejcik 

I. Reliability Issues - M. Munro

1. Mechanical Systems - B.Mckee

2. Radiation doses - M.Ross

II. Operations - D. Schultz

1. Spear experience - . J. Corbett

2. Damping Rings Operations and Plans - R. Pennacchi, M.Stanek

3. Simultaneous Long Pulse Operation - R. Erickson

IV. RF Systems - J. Frisch 

1. PEP II style cavity at 714 Mhz - R. Rimmer

2. Klystron options - R. Akre

3. Klystron Relocation upstairs - A. Hill et. al.

4. Upgrading interlocks- A. Hill

5. Low level RF control - P. Corredoura

6. Pulsed operation - R. Tighe

7. Precision phase control - J. Judkins

12:00-13:00 Lunch Lunch
  III. Beam Dynamics - P. Krejcik 

1. Low energy operation - T. Raubenheimer

2. Implementation of low energy lattice - M. Woodley

3. Magnet enhancements - J. Spencer

4. Partition number change - F. Zimmerman

5. New ideas!?

IV. RF Systems - cont.

8. Plans for existing windows, tuners, pumps - Schwarz, Akre, McKee

9. Adjustable stubline tuners - H. Schwarz

V. Diagnostics - M. Ross

1. Review of beam size monitors - T. Kotseroglou

2. Inj. and Ext. energy spread and bunch length monitoring - 

Summary - P.Krejcik

16:30 Depart for SLAC Depart for SLAC

Appendix - Table of Beam Requirements for Damping Rings


Linac repetition rate (Hz) 120 120 (S0-10) 120 10 10
    60 (S11-19)      
No. of e- bunches in NDR 2 1 1 1 1
No. of e+ bunches in SDR 2 1 NA NA NA
Particles/bunch (1010) 4 1 1 1-3 4
*Bunch length at end of linac (mm) 1.2     0.6 0.6
*Energy spread at end of linac (%) 0.15       1
(10-5 m-rad) 3.2-3.6 NA 10 3 6
(10-5 m-rad) 0.3-0.5 NA 10 3 1.5
(10-5 m-rad) 3.7-4.5 5 NA NA NA
(10-5 m-rad) 0.15-0.3 1.5 NA NA NA
*Primarily linac issues.          

DR2000 Workshop Participants

Name Department
Akre, Ron Klystron
Anderson, Scott Accelerator
Anthony, Perry EFD
Bharadwaj, Vinod Accelerator
Burrows, Kathy Accelerator
Clendenin, Jym Accelerator
Colocho, William  Accelerator
Corbett, Jeff SSRL
Corredoura, Paul Klystron
Decker, Franz-Josef Accelerator
Erickson, Roger Accelerator
Frisch, Josef Accelerator
Hill, Alan Klystron
Humphrey, Rusty Controls
Jobe, Keith Accelerator
Judkins, Jim Klystron
Kotseroglou, Theo Accelerator
Krejcik, Patrick Accelerator
Kuroda, Shigeru KEK
McKee, Bobby Accelerator
Munro, Morrison Accelerator
Neubauer, Mike Klystron
Pennacchi, Roslind Accelerator
Raubenheimer, Tor NLC
Rimmer, Bob LBNL
Ross, Marc Accelerator
Schultz, David Accelerator
Schwarz, Heinz Klystron
Seeman, John  PEP-II
Sheppard, John Accelerator
Smith, Howard Accelerator
Smith, Tonee Accelerator
Spencer, Jim ARDA
Stanek, Mike Accelerator
Stege, Robert Accelerator
Tighe, Richard Klystron
Turner, Jim Accelerator
Woodley, Mark Accelerator
Zimmermann, Frank ARDA

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