1. CESR Vacuum System Monitoring and Component Quality Assurance
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
CESR Vacuum System Monitoring and Component Quality Assurance
Yulin Li
Wilson Lab Cornell University Ithaca, NY 14853, USA
Work supported by the US National Science Foundation

2. CESR Accelerator Complex
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
CESR Accelerator Complex
CESR Tunnel
500 MHz SRF Cavities
Superconducting Wigglers

3. CESR Operation Modes
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
Historically, CESR delivers beams at 5.2 GeV for simultaneous High Energy Physics (CLEO) and Synchrotron Sources (CHESS) runs
After CESR-c conversion, CESR runs at a time-sharing scheme between three programs  50% CLEO-c HEP runs  30% CHESS users  20% Accelerator Physics and Technology runs
The time-sharing running has been successful, but demanding machine reliability

4. Vacuum Pumping Systems
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
CESR Vacuum 1. Dominated by ion pumps, both noble-diode lumped ion pumps & distributed in the arcs 2. Dominated by TiSPs in the interaction regions 3. Adsorption by the conditioned wall, ‘wall-pumping’, provides sufficient pumping during 2 GeV CESR-c runs 4. Additional NEG pumps near SRF cavities for hydrogen pumping
Synchrotron Vacuum – Diffusion pumps
Linac Vacuum – Ion pumps
Cryo-stats Pumping – Diffusion pumps and cryo-pumping

5. CESR Vacuum Instrumentation
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
CESR vacuum performance is monitored by 70+ cold cathode gauges (CCGs, HPS Model 421)  Rugged design, no filaments, etc.  Less interaction to the vacuum environment and the beam  Ion pump currents are flooded by photo-electrons  CCG and ion pump signals are logged at 1/minute rate by CESR control system to the disk servers
Additional information from 14 RGAs  RGAs are installed near critical sub-systems, such as Interaction region, SRF cavities, electro-static separators, etc.  RGAs are connected by RS485 network  RGA data management is somewhat difficult

6. CESR Vacuum Performance – Snapshot
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
CESR Vacuum Performance – Snapshot
200 mA
No beam

7. CESR Vacuum Performance – dP/dI
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
CESR Vacuum Performance – dP/dI

8. CESR Vacuum System Safety
~1,000 TCs are installed on various vacuum components to ensure proper cooling and to detect beam related heating problems
The TCs data are recorded by CESR control system, and a SENTRY system will detect and warn any over-heating
Micro-switches are on all cooling water valves
CESR/Synchrotron/Linac vacuum systems are sectored by GVs and a vacuum interlock system closes GVs when detecting any faulty vacuum event
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University

9. CESR Vacuum Component Database
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
CESR Vacuum Component Database
A online database of CESR installed vacuum components provides very useful information for the operations and management
Locations of the components, base on the survey information
Type and description of the components
Defined geometric information of “standard” components provides input to the SR calculation
The database is extremely helpful in upgrade planning

10. Vacuum Component Database
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
Vacuum Component Database
20-m sectors with Quad No. reference
Graphic with legends showing component type at a glance
Detail information of components

11. Vacuum Components Quality Control
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
Vacuum Components Quality Control
(External Sources)
Develop specification or Technical Parameters  Use or incorporate existing industrial standards as much as possible  Develop and document lab specification for frequently used special materials (explosion bonded transition metals, for example) and services (surface treatment, etc.)  Be very clear about special requirements (such as machining lubricant, package material, etc.)
Material specifications and certifications  Problems – verification of a certification, some properties not specified in the industrial standards (magnetic permeability, etc.)

12. Vacuum Components Quality Control
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
Vacuum Components Quality Control
(Internal Sources)
Design stage Designated experts certifying vacuum properties, SR power and cooling, HOM/impedance, aperture, and installation (fixture, survey, etc.)
Fabrication stage Work flow sheet through Drafting, Shop, ChemRoom, welding, etc.
Inspection and acceptance
Components maintenance/rebuilding procedure development
Documentations of all shutdown activities

13. Vacuum Components Quality Control
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
Vacuum Components Quality Control

14. Vacuum Components Quality Control
OLAV-I, CERN, April 11, 12, 2005
Yulin Li, Cornell University
Vacuum Components Quality Control
Documentation of Shutdown Activities