Maintaining the Accelerator
Safety Envelope
P. Ingrassia, L. Ahrens, R. Olsen
Collider Accelerator Department
Brookhaven National Laboratory
Upton, NY 11973
USARHIC-AGS Complex at BNL

11 March, 2003

WAO 2003 -- Peter Ingrassia -- BNL

2BNL Collider-Accelerator
Department Accelerators
Accelerator Energy Intensitycomments

Tandem MP715 MV

55 microA (Au)Species d - U

Tandem MP6

15 MV

150 microA (d)Species d - U

Linac

200 MeV90 TPP

7.5 HzBooster

2 GeV

15 TPP

7.5 HzAGS

28 GeV

70 TPP

43 years old

RHIC Yellow

100 GeV/n 0.8e9 Au/bunchsuperconducting

RHIC Blue

100 GeV/n 0.8e9 Au/bunchsuperconducting

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WAO 2003 -- Peter Ingrassia -- BNL

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Accelerator Safety Envelope• Result of DOE order• Accelerator Specific SafetyRequirements• Includes for example– Integrity of Fire Protection Systems– Integrity of Access Controls Systems– Control Room Staffing– Limits on Beam Loss/Intensity
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WAO 2003 -- Peter Ingrassia -- BNL

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Radiological Area Definitions
AREA

Allowable dose rate

UNCONTROLLED< 25 mRem/yr

CONTROLLED25 mRem/yr<d<100 mRem/yr

RADIATION> 5 mRem/hr

HIGH RADIATION> 100 mRem /hr

VERY HIGH
RADIATION>500 mRem/hr

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WAO 2003 -- Peter Ingrassia -- BNL

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RHIC (UN)CONTROLLED AREAS

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WAO 2003 -- Peter Ingrassia -- BNL

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THE CHALLENGE• The uncontrolled area lies in the path of
the injected beam for the yellow
accelerator• Uncontrolled areas require unrestricted
access• Uncontrolled area classification requiresthat individuals receive a dose nogreater than 25 mRem per year.
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WAO 2003 -- Peter Ingrassia -- BNL

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BLAM Dependencies• Post Mortem Server– Reads loss monitors
after an abort ordump event• Loss Analysis
Server– Determines if abortor dump is clean• specMan– Species and energy
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WAO 2003 -- Peter Ingrassia -- BNL8

Calculating Effective Dose0.8

 Energy − RESTenergy 
DoseIons = Ions *  InjEnergy − RESTenergy 0.8
 Energy − RESTenergy 
DoseIons = Ions * −InjEnergyRESTenergy

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WAO 2003 -- Peter Ingrassia -- BNL

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A BLAM evolution

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WAO 2003 -- Peter Ingrassia -- BNL10BLAM Evolution – Blue Ring
• @A
• @B1
• @B2
• @C1
• @C2

inject deuterons and pause
deuteron injection completed
some beam is lost and counted
all of the deuteron beam is lostthe lost beam is counted– the loss is above the 90% threshold– BLAM sends an alarm

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WAO 2003 -- Peter Ingrassia -- BNL

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BLAM Evolution – Blue Ring
• @D
the Loss Analysis server has
determined that the beam went to thebeam dump
– LA server issues a “CREDIT”– BALM turns off alarm• @E
One hour has elapsed since theloss occurred at B2 – the loss “expires”

11 March, 2003

WAO 2003 -- Peter Ingrassia -- BNL

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BLAM Evolution – Blue Ring
• @F1 One hour has elapsed since theloss occurred at time C2. The loss
expires and causes “negative” losses onthe display• @F2 One hour has elapsed since theLA server issued the credit at time D.
The credit expires and losses return tozero
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WAO 2003 -- Peter Ingrassia -- BNL

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Summary• BLAM generates an alarm when 50% of
the “allowable limit” of ions are lost in
the RHIC or in one of the injection arcs.
– The 50% alarm serves as a warning for theoperators.
– The operators take no action– The alarm will go away in 5 minutes if thedump was “clean” or after an hour if there
are “no further losses
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WAO 2003 -- Peter Ingrassia -- BNL

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Summary• BLAM generates an alarm when 90% of
the “allowable limit” of ions are lost in
the RHIC or in one of the injection arcs.

– The 90% alarm serves as a trigger for theoperators.

11 March, 2003

WAO 2003 -- Peter Ingrassia -- BNL

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Summary• BLAM generates an alarm when 90% of
the “allowable limit” of ions are lost inthe RHIC or in one of the injection arcs.
– The operators are not permitted to inject
more beam until enough time has elapsed
such that the “limiting number” of ionscannot be lost in an hour
– The alarm will go away in five minutes if
the dump was “clean” or after an hour if
there are “no further losses
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WAO 2003 -- Peter Ingrassia -- BNL

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Summary• BLAM is the tool used to enforce theASE requirement that the uncontrolledarea at RHIC – the office building –remains an uncontrolled area.
• BLAM is a tool that makes a potentiallychallenging task a relatively easy one
for the operators

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WAO 2003 -- Peter Ingrassia -- BNL17