SC-PAC2001-6.19.01 Operated by the Southeastern Universities Research Association for the U.S....

/SC-PAC2001-6.19.01

Operated by the Southeastern Universities Research Association for the U.S. Depart. Of Energy

Andrew Hutton IM Review 2004 Thomas Jefferson National Accelerator Facility

Managing CEBAF Accelerator OperationsManaging CEBAF Accelerator Operations

Andrew Hutton

Institutional Management Review

August 30/31, 2004

Andrew Hutton IM Review 2004


Thomas Jefferson National Accelerator Facility

OutlineOutline

CEBAF Accelerator Characteristics

Response to Hurricane Isabel

Accelerator Achievements in FY04

G0 Experiment completed

Hypernuclear Experiment completed

HAPPEx-He and HAPPEx-II initial runs completed

Operations Metrics

Preparing for Upcoming Challenges

Path forward – new Operations Vision

Summary

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Brief Description of CEBAFBrief Description of CEBAF




CContinuous ontinuous EElectron lectron BBeam eam AAccelerator ccelerator FFacilityacility

AB

C

A B C

A

B

C

Gain switched lasers @499 MHz, = 120

Pockels cell

Gun

0.6 GeV linac(20 cryomodules)

1497 MHz67 MeV injector

(2 1/4 cryomodules)1497 MHz

RF separators499 MHz

Double sidedseptum




CEBAF CapabilitiesCEBAF Capabilities CEBAF delivers independent beams to all three Halls

Energy – must be multiple of linac energy 1, 2, 3, 4, or 5-pass to any Hall All Halls can simultaneously have 5-pass beam

Current – fully independent Halls A & C take up to 140 μA Hall B takes up to 50 nA (and down to 100 pA!)

Polarization – orientation of longitudinal polarization depends on Hall energy due to precession At least 50% of experiments want longitudinal polarization

An increasing number of experiments want “parity quality” beams Small helicity-correlated change in current, position, angle, polarization




Dynamic Operational RequirementsDynamic Operational Requirements Unlike a storage ring, the operating conditions of CEBAF are changed

frequently based on User needs

In FY02, FY03, FY04 there were:

6 9 3 linac energy changes

21 15 5 pass changes in Hall A

8 6 5 pass changes in Hall B

4 10 4 pass changes in Hall C

25 30 14 accelerator state changes

On average, the accelerator state changes about once per operating week This does not include special set-ups for Moeller runs, energy

measurements, etc.

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Response to Hurricane IsabelResponse to Hurricane Isabel




Hurricane IsabelHurricane Isabel Isabel arrived ashore as a Category 1 hurricane on September 18, 2003

Removed electrical power from site for four days – specifically from CHL so cryomodules warmed up

Recovery took six weeks Aggressive preventive maintenance carried out on almost every

component - improved reliability during the year Engineering, SRF Institute, Operations

Accurate beam set-up provided a solid, reproducible base for operations CASA, Operations

Launched us into extremely successful year operating period

Details on Poster




Improving Hurricane PreparednessImproving Hurricane Preparedness Evaluated back-up power options

Full back-up power is expensive, requires active management Renting seems better (RFP is out)

Major investment in switchgear and long term contractual obligation

Decided to implement emergency power loop Provides power to critical systems

Pumps to maintain insulation on cryomodules, valve actuators Special funds from DOE awarded June 2004

Expect completion before next hurricane season (May 2005) Interim, temporary solution developed (extension cords, UPS, small

generators, etc.) Ready to implement if needed

Initiated aggressive tree-cutting near to offsite power line




Tree Clearing near Power LineTree Clearing near Power Line

Insert Photo Here

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Accelerator Achievements in FY03/4Accelerator Achievements in FY03/4




Experiment Successes FY03/FY04Experiment Successes FY03/FY04 G0 required 40 μA at 31.2 MHz – every 16th bucket filled

Bunch charge 6.5 times more than original specification “Parity quality” beam imposed optics constraints

Hall A hypernuclear experiment required: Energy spread < 3x10-5 Scheduled in parallel with G0

HAPPEx-II and HAPPEx-He required: Tightest “helicity correlated asymmetries” ever

Position asymmetries < 2 nm Energy asymmetry < 0.6 ppm




G0 Parity Quality BeamG0 Parity Quality Beam

Beam Parameter

Achieved

(IN-OUT)/2

“Specs”

Charge asymmetry

-0.14 ± 0.32 ppm

1 ppm

x position differences

3 ± 4 nm 20 nm

y position differences

4 ± 4 nm 20 nm

x angle differences

1 ± 1 nrad 2 nrad

y angle differences

1.5 ± 1 nrad 2 nrad

Energy differences

29 ± 4 eV 75 eV

Total of 744 hours (103 Coulombs) of parity quality beam

All parity quality specs have been achieved!!




Hypernuclear Experiment Energy SpreadHypernuclear Experiment Energy SpreadE

nerg

y S

prea

d x

10-5 Spec

3x10-5

Data from April 21-29




New superlattice photocathode

Polarization >85%

Figure of Merit improves by ~30%

(over strained-layer cathode)

Electron onlyPhoton only Preliminary

HAPPEX-IIHAPPEX-II Photon Detector Signal/Background > 10

Demonstrated feasibility of maintaining Compton polarimeter background count rate: <100 Hz / A at 5mm (10-10)

“slug” number

x (

nano

met

ers)

CASA and EGG have worked closely with HAPPEX to meet stringent requirements on helicity-correlated position differences.

After correcting early problems at source, the ability to meet helicity-correlated specifications was demonstrated.




DOE Metrics for FY03DOE Metrics for FY03

Metrics for FY03 were excellent

Availability for multi-Hall Physics operation not as good as our Users would like, but performance better than DOE goal




DOE Metrics for October – July FY04DOE Metrics for October – July FY04

Post-hurricane maintenance

extremely effective

Hall A septum

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Preparing for Upcoming ChallengesPreparing for Upcoming Challenges

EnergyParity

Polarization




Energy Outlook for FY04/05Energy Outlook for FY04/05 Scheduled to deliver 5.75 GeV, 100 kW beams in September 04

Hurricane reduced accelerating voltage by ~40 MV/turn, 200MeV from top beam energy

Predicted RF trip rate will be “high” ~15/hour Will make operation of accelerator difficult

Required to reach goals of experimental program Compromise accepted by Users

Expect RF trip rate to improve when new 12 GeV prototype cryomodule replaces NL11 (operational by July 05) RF trip rate at 5.75 GeV will be acceptable ~10/hour

Refurbishment of existing cryomodules would provide 6 GeV operation by July 06 with acceptable trip rate (~10/hr)




Parity Violation Experiments at CEBAFParity Violation Experiments at CEBAF

Helicity-correlated asymmetry specifications

Achieved for G0 4 ± 4 nm -0.14 ± 0.32 ppm

ExperimentPhysics

Asymmetry

Max run-average helicity correlated

Position Asymmetry

Max run-average helicity correlated

Current Asymmetry

HAPPEX-I 13 ppm 10 nm 1.0 ppm

G0 2 to 50 ppm 20 nm 1.0 ppm

HAPPEX-He 8 ppm 3 nm 0.6 ppm

HAPPEX-II 1.3 ppm 2 nm 0.6 ppm

Lead 0.5 ppm 1 nm 0.1 ppm

Qweak 0.3 ppm 20 nm 0.1 ppm

1999

2007




Superlattice CathodeSuperlattice Cathode Polarization 87% (recent User measurement)

Typical polarization from traditional strained layer material ~75%

Quantum Efficiency ~ 1% Typical QE of traditional strained layer material 0.2%

Analyzing power 4% Factor 3 better than strained-layer material in the lab

Smaller intensity and position asymmetries on beam Improvement not yet seen in experimental data

Installed on Accelerator 5/17/04 Successfully operated for experimental program (HAPPEx) Lifetime was not good – attributed to bad vacuum

NEG pumps replaced in present accelerator shutdown

Will be standard for all experiments

Matt Poelker and Maud Baylac (Injector)




New Laser Clean Room for Injector New Laser Clean Room for Injector

Insert Photo

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Path Forward Path Forward New Operations VisionNew Operations Vision




Drivers for ChangeDrivers for Change Our accelerator operations are second to none

Biennial Workshop on Accelerator Operations initiated by JLab

Our Control System is one of the world’s best managed Karen White is regularly invited to lecture on managing software

But, we believe in continuous improvement (really)

Four main drivers for change: Main Control Room (MCC) needed renovating

Aging flooring, improve air conditioning, bad ergonomics, needed better integration of ODH alarms, fire alarms and access controls

ORACLE database available, needed EPICS integration Full accelerator model will be available soon and we should plan for it Must prepare to commission and operate 12 GeV

Goal – use these drivers to revamp operations processes




MCC UpgradeMCC Upgrade Layout modified to provide:

Crew Chief oversight of operators Station for Program Deputy accessible to support staff

Responsible for program oversight for two-week period Stations for Principle Investigators

Direct special machine set-ups and beam studies Improved teaching environment for operators Discussion area with “mirrored” computer screen

Existing tall racks replaced with desk height work stations Multiple small monitors replaced with few large screens

Better visibility of access controls (personnel safety system)

Integrated beam diagnostics displays

Managed by Mike Spata and Tom Oren (Operations)




Old MCCOld MCC




New MCC (three weeks later)New MCC (three weeks later)




Operations Vision Operations Vision Primary focus – are beams meeting User requirements?

Secondary focus – is each region performing correctly?

Provides common structure for thinking about accelerator operations, database, accelerator model, HLA, new installations Hierarchy based on the accelerator layout

Usual focus on kinds of element (magnets, steering, RF) - WBS Change to “functional segmentation system” derived from beam-

based set-up Highest level derived from User requirements

Halls, energies, currents, polarizations, beam specifications

Increases focus on diagnostics to ensure that beam meets specifications




Highest Hierarchical LevelHighest Hierarchical Level Defined standard set of beam specifications for Users

User may negotiate tighter specs when proposing experiment (TAC)

Experiment schedule defines which experiments are running User requirements are known – import requirements from database

Use these requirements to configure the accelerator Derive set-points for the machine set-up

Energy, current, polarization . . . . . Integrate beam specs with instrumentation to monitor compliance

Energy spread, spot size, helicity-correlated effects . . . . .

Highest level display shows if beam specifications are being met, and if not, which parameters are out of tolerance

Managed by Hari Areti (Experiment Coordinator)




Beam SpecificationsBeam Specifications

DC Beam Properties

There are also AC Beam Properties and Helicity-correlated Beam Properties




ExampleExample Experiment beam request

Experimental requirements

Parameter Measurement

Tool

Nominal

Value Stability

Helicity Correlated

Value

Current: ibc1h01 < .11 uA .21 uA .31 ppm

Position:

2x01

2C20

3C02

3C04

X: 1 um

Y: 22 um

X: 32 um

Y: 42 um

X: 52 um

Y: 62 um

X: 98 um

Y: 97 um

X: 92 um

Y: 102 um

X: 112 um

Y: 122 um

X: 132 um

Y: 142 um

X: 96 um

Y: 95 um

X: 172 ppb

Y: 182 ppb

X: 192 ppb

Y: 202 ppb

X: 212 ppb

Y: 222 ppb

X: 94 ppb

Y: 93 ppb

Energy: harps 1-4 253 Gev 263 MeV 273 ppm

Energy Spread: sli1c12 284 MeV 294 MeV

Bleedthrough: smrposa < 305 %

Polarization: No Data Entered ---

Spot Size: ipm1h04x ipm1h04y

326 mm 336 mm

346 mm 356 mm

366 ppm 376 ppm

Background: background tool 25 %

Angular

Divergence

at Target:

ipm 1h04z 398 mr 408 mr

418 mr 428 mr

438 ppm 448 ppm




DiagnosticsDiagnostics Each beam specification is mapped to at least one diagnostic

Diagnostics are of three main types Run-time monitors that function at all times

BPMs, Synchrotron light monitors, OTR, beam loss monitors, experiment detectors, Compton back-scattering

Invasive monitors that cannot take full power Screens, Harps

Infrequent monitors that require special set-up Moeller and Mott measurements, current and energy calibrations

Long term goal is to monitor all beam specifications to required accuracy non-invasively over complete range of operating conditions

Diagnostics must be integrated with software packages and tightly coupled to User-specific beam specifications

Managed by Arne Freyberger (CASA)




DatabaseDatabase Master copy of all information will be held in a database

“Authoritative source”

All other instances will reference database to obtain current value Vital for maintaining control over machine changes

Information will be assigned to one of two databases, depending on the frequency of change We already have a dynamic, “run-time” database – EPICS Adding master database for static and slowly changing data - ORACLE

Databases will eventually manage all accelerator data Database will be the information source for everyone

Engineering support groups, operations, controls

Managed by Theo Larrieu (Controls)




Impact on Control SystemImpact on Control System Robustness requires nested checks at all levels of software

Example of making tools robust: BPM passes self-check Feedback system uses model to determine best corrector, BPM

configuration based on Optics System measures BPM response to corrector kicks Compare corrector-BPM response to model Downstream elements monitored to ensure feedback system is

performing desired function

Providing all necessary hooks requires global re-examination of Control System at every level Device drivers, low-level applications (Matt Bickley) High level applications, communication protocols (Brian Bevins)

Managed by Karen White (Controls)




Optics Model-Database RelationshipOptics Model-Database Relationship Model obtains input from

ORACLE Component layout derived from Survey group Component specifications from Engineering Support Groups Impacts all Support Groups Vehicle for configuration control

Global settings Configured from User Requirements Off-line optics calculation by CASA

Result goes into Oracle database

Set points calculated for dipoles, quadrupoles, RF

Model server output is available to all high level applications Eventually, all high level applications will be model driven

Managed by Yves Roblin (Controls)




Optics Model ImprovementsOptics Model Improvements Model requires accurate knowledge of magnets over wide energy range

We have ~2000 magnets, not all properly characterized Uncertainty due to dipole gradients from remanant fields Additional uncertainty from orbit-related focusing errors due to badly

characterized “gold orbit” Diagnostics added in spreaders and recombiners

Beam-based measurements being used to measure errors Requires special optics (weak focusing)

Data taken over last year, dedicated period at end of last run Evaluated during the summer accelerator down Will be used for setting up the machine in September

Managed by Mike Tiefenback (CASA) and Tommy Hiatt (Engineering)




Implementation StatusImplementation Status MCC refurbishment complete (MCC visit during Tour)

Planning, implementation and result are fantastic success

Requirements Document for Control System being written “Executive Summary” complete

Ensures coherency of Vision across Division Some aspects already implemented

Model under active development

Guiding principles of the Vision will be integrated into new and upgraded software for years to come Expect positive impact on operations within six months Changes the way we do business for years to come Prepares operations for commissioning and operating 12 GeV




SummarySummary FY03 operations were excellent, FY04 were outstanding

G0, an incredibly difficult experiment, got more data than requested, beam exceeded all specifications

Hypernuclear experiment received beam with outstanding energy spread – run average ~2.2 X 10-5 Even more impressive as experiments ran in parallel

HAPPEx tight parity quality specs achieved

Availability for Physics much improved since hurricane due to additional maintenance that was performed

New Vision will improve Operations in coming months Motivates and energizes multiple Groups Prepares for commissioning and operating 12 GeV Upgrade

SC-PAC2001-6.19.01 Operated by the Southeastern Universities Research Association for the U.S....

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