NSLSII Beam Containment System

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NSLS-II Beam Containment System
R. Casey Accelerator Systems Advisory Committee
October 22, 2009
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Beam Containment System

• Beam containment system (BCS) is the term used to
  describe the various active and passive devices
  designed to
• Localize electron beam losses to selected (well
  shielded) areas in the accelerator enclosures
• Detect excessive beam loss outside of well
  shielded areas
• Provide linkage to other systems to mitigate
  excessive losses when detected
• Area radiation monitoring systems complement BCS
  function by providing direct measurement of
  radiation levels in occupied areas.

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Beam Containment System (cont.)

• Objective - alert operators to excessive beam
  losses that create potential for increased
  radiation levels in occupied areas and provide
  mitigation as required.
• Mitigation measures include
• operator warnings and alarms
• direct curtailment of injection

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Beam Loss Assumptions in Shielding Design
Injection region shielded for 3 GeV at 1 Hz
injection rate
Extraction region shielded for 3 GeV at 1 Hz
extraction rate
Injection region shielded for 200 MeV and I Hz
injection rate
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Implications of Shielding Design

• Abnormal operating conditions need to be
  evaluated.
• Additional engineering or administrative controls
  will be specified based on severity of radiation
  levels under fault conditions.
• An area radiation monitoring system is needed to
  detect excessive radiation in occupied areas and
  will serve as the primary safety system to
  protect against radiation producing faults.
• BCS is provided to detect abnormal conditions or
  abnormal beam losses and provide warning to
  machine operators. System will also inhibit
  injection systems on alarm.

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Actions Taken to Define BCS Systems

• The radiological consequences of abnormal
  operating conditions have been described and
  analyzed as part of on-going safety assessments
• BCS task force appointed and work is underway to
  finalize design
• BCS functional requirements based on radiological
  analyses have been presented
• BCS components identified

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BCS Task Force Setup to Define and Document BCS

• Task Force Members S. Kramer, Y. Li, I. Pinayev,
  P.K. Job, D. Hseuh
• Other stake-holders R. Casey, O. Singh, P.
  Cameron, B. Delasio
• Working Group has been meeting regularly since
  Spring, 2009

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Examples of Abnormal Events and Consequences

• Full beam loss in Linac at design beam current
  (15 nA)
• Max. dose rate 8 mRem/h
• Full beam loss in Booster injection region at 200
  MeV
• Max. dose rate 1 mRem/h with 1 Hz injection
• Full beam loss in Booster extraction region at 3
  GeV
• Max. dose rate 2.5 mRem/h with 1 Hz injection

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Abnormal Events and Consequences (cont.)

• Full beam loss in remainder of booster at 3 GeV
• Max. dose rate 1500 mRem/h above berm, 375
  mRem/h in injection building with 1 Hz injection
• Full injected beam loss in Storage Ring (SR)
  injection region
• Max. dose rate 2.5 mRem/h with 1 Hz injection
• Full injected beam loss at one point in SR
  non-injection region
• Max. dose rate 400 mRem/h with 1 Hz injection

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Current Definition of BCS Components

• Scrapers in SR injection region (4)
• R D at NSLS for thin scraper design planned for
  FY 10
• Current Transformers (5)
• Linac (ICT)
• Linac to Booster transfer line (ICT)
• Booster (DCCT)
• Booster to SR transfer line (ICT)
• SR (DCCT)
• Beam loss monitors (Type and TBD)
• SR at potential high loss points (steering and
  energy dispersive maxima)
• R D at NSLS for Cerenkov BLM planned for FY 10

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Area Radiation Monitors

• 2 - linac klystron gallery
• 6 - injection building
• 30 - Storage ring wall (1 per cell)
• 6 - FOE wall
• Budgeted for 60 monitors

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BCS Functions

• Monitor and limit beam current in injection
  system and SR
• Detect high beam losses in injection or
  extraction processes in booster by comparison of
  current transformers (CTs) in transport line and
  booster
• Detect high beam losses in injection to SR by
  comparison of CTs in transport line and SR
• Provide scrapers and monitors in SR injection
  region to localize and confirm losses in that
  region (need for additional monitors in
  non-injection areas being evaluated)
• Alert machine operators to abnormal conditions
  and inhibit continued injection as warranted

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Interface between Systems for BCS

• Insure signals are available at rate needed,
  insure integrity of communication link
• Define the responsibility for calibration of
  these signals and their maintenance
• Issue Warnings if beam loss limit is being
  approached, suggest operator action needed
• Limit exceeded at present injection rate, issue
  Alarm that action is required within prescribed
  time.
• If exceeded for significant time interval, remove
  injection permit through BCS control network

Warnings Alarms to systems and operator
Linac transport CT signals
BCS Micro Booster injection OK Storage ring
injection OK Beam loss location OK Permit
Injection On/Off
Booster and transport CT signals
SR CT signals
Beam loss location monitors
BCS Controlled Device Interface Box Injection
On/Off
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BCS Summary Look Ahead

• BCS task force is appointed and work is underway.
  BCS function specified.
• Specification of BCS components is almost
  complete, more work required to specify location
  and type of beam loss monitors and ddesign of
  scrapers.
• Warning and alarm set points for BCS will be
  established through fault testing and radiation
  measurements during commissioning.
• BCS components will be subject to configuration
  control during installation, testing, operation,
  maintenance, and modification.
• BCS interlocking functions are intended for
  routine operation. During commissioning and
  other times of machine studies, BCS interlocking
  may be temporarily removed. Protective function
  will be provided through work controls approved
  for the time period of the study.

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• Questions or Comments?