PPS and BCS Requirements for LCLS-II(Baseline)

Stan Mao 06/10/2015

2

Outline

D10

ST61, ST60, D2

MUON shieldin

g

SLAC Radiation Safety SystemLCLS-II PPS requirements

PPS shut-off mechanismLCLS-II BCS requirements

BCS shut-off mechanismBCS shut-off time

Access BTH fenced areas (PPS, BCS)Summary

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SLAC Radiation Safety Systems

Access ControlSystem (PPS)

Radiation ControlSystem

Beam Containment

System (BCS)

Shielding

Radiation Safety System

Burn ThroughMonitors (BTM)

Beam Shut- Off Ion

Chambers (BSOIC)

ACM, PIC, LIONS

LCLS-II DOE Review, April 7-9, 2015

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LCLS-II PPS Zones

SC Linac PPS – From SC LINAC gun to FEE is one PPS zone

ESB

BTH UH

Muon shielding BSY

BTHW Dump FEE

Undulator Complex PPS Zone (From BTHW to FEE)

D2

Cu Linac PPS - access Undulator Complex PPS Zone with PPS stoppers D2 in

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PPS Shut-off mechanism for SC LINAC

D10

ST61, ST60, D2

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 Gun RF Power supplyOff

 All RF off

 Injector PPS stopper In

Beam from gun

No beam   No beam afterPPS stopper

Gun dark current

No gun dark current   No gun dark current after PPS stopper

Dark current from RF devices

  No dark current from RF devices

 

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Under Consideration

D10

ST61, ST60, D2

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New PPS access options are being developed to compensate the baseline

SC LINAC gun local mode Access to BTH during SC beam on BSY dump Access to Sector 10 and upstream during FACET-II operation in

FACET-II project

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LCLS-II Beam Containment System (BCS)

BCS monitoring will include measurements of the beam…1) Current:

Current Monitor (CM)• Measure peak and average current

2) Energy: Magnet Current Monitor (MCM)• Measure magnet current (main and trim)

3) Losses: Point beam loss monitor• Protection Ion Chambers (PICs) or equivalentLine beam loss monitor• Long Ion Chambers (LIONs) or equivalentCurrent ComparatorCompare peak and average current between CMs

SXU

HXU

proposed FACET-II LCLS-ILCLS-II Superconducting LINAC

bypass linem-wall

B-lineSector - 10

Injector

extension lineL3L2L1FEE

NITNARC

SARCSIT

NEH

ESA

Sector - 20 Sector - 30

BCS collimator system with BCS devices:contain the beam during mis-steeringconditions, RP is working

ESB

4) Cooling waterFlow meters

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BCS is critical radiation safety system for SC LINAC operation

D10

ST61, ST60, D2

MUON shieldin

g

LCLS-II beam power is much higher than in LCLS-I, but several systems and enclosures are preserved.

New controls and local shielding must be developed to compensate this

SC LINAC is capable to generate 1.2 MW beam. If spreader kicker time system fails, the kickers could deliver 300 kW beam from BSY dump line to SXR or HXR lines

the downstream beam dumps only absorb few hundred kW of the beam

Direct line from LINAC gallery to SC line through penetrations Unknown dark current from gun and cryo modulator

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LCLS-II BCS Specification

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ST61, ST60, D2

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High beam rate (up t o1 MHz) requires fast BCS systemHigh power (up to 1.2 MW) requires high accuracy current monitor sensors High power operation requires robust BCS system to limit beam power and losses, and to contain the beamFast BCS shut-off time needs to be 100 µS to protect the stoppers/ and dumps for 240 kW beam

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BCS devices in SC LINAC injector area

BCS LION

BCS LION

Dark current block

BCS CM

PPS Stopper

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BCS devices in SC LINAC L1, BC1, L2, BC2, L3, Dog-leg and LINAC (S13 – S27)

CID Sector 10

Sector 11

Sector 13

Sector 4

Sector 2

Gun

L0

L1 L2 L3

BC1B BC2B

CEDOG

DIAG0

CEBC1 CEBC2

DIAG1

CY11CX11CY12CX12

CY21CX21CY22CX22

CX13BCS CM

Magnet current monitors for CEDOG will be used as reference point to control SC LINAC energies. The currents of all magnets located downstream will be compared with these magnet currents by PLC.LCLS-I used one power supply for BTH dogleg BX31/BX33 and BYD.

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2 ft

2 ft

D10MUON shield

ing

LCLS-I line

DUMPLINE SXR line

HXR line

Current Monitor requirements

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BSY Dum

p

MUON shieldin

g

2 ft

MUON shieldin

g

Cu-LINAC line

DUMPLINE SXR line

HXR line

Sector 28

Sector 29

5 kW limitExistingInterlocked to Cu LINAC

120 kW limit

120 kW limit300 kW limit

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2 ft

2 ft

D10MUON shield

ing

LCLS-I line

DUMPLINE SXR line

HXR lineST61/ST60/D2

BCS magnet current monitor for magnets

13

BSY Dum

p

MUON shieldin

g

2 ft

BSY Dum

p

MUON shieldin

g

Cu-LINAC line

DUMPLINE SXR line

HXR lineST61/ST60/D2

Sector 28

Sector 29

Sector 30

BSY 1

BCS collimators DRAFT (To be determined by ray-trace studies)

MUON shieldin

g

LCLS-I line

DUMPLINE

SXR line

HXR line

Sector 28

Sector 29

Sector 30

2 ft

2 ft

Collimator/BTM with PICs

Collimator/BTM with PICs

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Beam Transport Hall

BTHW BTH

SXR

HXR

Collimator/BTM with PICsGroup

LIONs are existing and will be repurposed to trip individually (for 35 W) and as Groups (for 75 W)

Group

MCM

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Undulator Hall

Undulator

SXRSS PICs

SXR

HXR

SXRSS

HXRSS

SXRSS

SXRSS PICs

Tune-up Dump and PICs

Protection Collimator and PICs

Protection Collimator and PICs

Protection Collimator and PICs

Protection Collimator and PICs

Tune-up Dump and PICs

PICs located in the front of undulator

PICs

Add one pairs of PICs in front of undulator for each lineUse LIONs to protect BCS collimators

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Dumpline

DUMPLine

SXR

HXR

BYD Magnet Setand PICsLCLS-II CM

comparatorToroid 1

Permanent Magnet

Permanent Magnet

BYD Magnet Setand PICs

Protection Collimator and PICs

LCLS-II CMcomparator

Toroid 2

Protection Collimator and PICs

Protection Collimator and PICs

LCLS-II CMcomparator

Toroid 1

LCLS-II CMcomparator

Toroid 1

PICsMCM

Both SXR and HXR lines have permanent magnets and safety dumplines

Protection Collimator and PICs

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BCS Shut-off mechanism

BCS CM

PPS Stopper

BCS fault from SC LINAC1. Shut off laser

No beam (<100 uS)

2. After Laser is shut off (10 uS), to check laser and BCS CM

3. If Laser intensity or BCS CM reading is still high (10 uS), interrupt Gun RFNo beam and no dark current from Gun

1. Shut off Spreader kickersBeam to BSY dump (< 100 uS)

Gu

n R

F

4. If still has BCS fault (PICs and LIONs) from SC LINAC (50 mS), BCS send signal to PPS to shut off CM RF in 5 SecondNo CM RF

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BCS Shut-off time

D10

ST61, ST60, D2

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For those BCS devices used to protect BCS collimator or PPS stopper from radiation damage, the shut-off time should be equal or less than 100 µS Based on RP-RPG-140506-MEM-02, 240 kW LCLS-II beam (300 pC/pulse) will not damage (Al, Cu, SS, Nb, Ti) stoppersFor other BCS devices, the shut-off time should be equal or less than 600 mS for beam, and should be equal or less than 5 S for Cryo Modulator dark current

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D10

ST61, ST60, D2

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BTH beam losses, BTH PPS fenced areas and access requirements

21LCLS-II DOE Status Review, Sept. 30 - Oct. 2, 2014

LCLS-I:

6’

Long ION chambers

- Normal Beam Loss* = 5 W (0.1 % bp)

S.B.

BTH

- MCI: 100 kW

LIONs = 5 W

- Beam Power = 5 kW

LCLS-I: 5 W

Existing facility• 6’ walls• 6’ roof under SB• 4’ roof elsewhere

BTH \ LCLS-II shielding & BCS(slide from Mario Santana talk on LCLS-II DOE Status Review)

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BTH \ LCLS-II shielding & BCS(slide from Mario Santana talk on LCLS-II DOE Status Review)

LCLS-II:

6’

Local shielding around collimators, etc.

2 x 1 W/m

Long ION chambers

- Normal Beam Loss* = 1 W/m

S.B.

BTH

18’

- MCI: 2 MW

• No access to S.B. & trenches

• 32” additional concrete

OR 18’ PPS fence

• Shielding on mazes

and collimators,…

LION setting = 35 W

32”

- Beam Power = 2 x 120 kW

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2 ft

2 ft

D10MUON shield

ing

LCLS-I line

DUMPLINE SXR line

HXR lineST61/ST60/D2

Cu LINAC and SC Spreader lines

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BSY Dum

p

MUON shieldin

g

2 ft

BSY Dum

p

MUON shieldin

g

Cu-LINAC line

DUMPLINE SXR line

HXR lineST61/ST60/D2

D10

Lambertson

SXR Kicker OFF

HXR Kicker offLambertsonD10D10

Sector 28

Sector 29

Sector 30

BSY 1

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SC-HXR and SC-SXP operation

Research Yard PPS Fence

Research Yard PPS Fence

interlocked to BSY kickers

BCS LIONs set at 35 W

35 W

35 W

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Cu-HXR operation

BCS LIONs set at 5 W

5 W

5 WKickers are off

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Summary

D10

ST61, ST60, D2

MUON shieldin

g

LCLS-II beam power is much higher than in LCLS-I, but several systems and enclosures are preserved. New controls and local shielding are being developed to compensate thisLCLS-II baseline defined one PPS zone (from LCLS-II gun to FEE). It conflicts the LCLS-II commissioning plan, also may affect the LCLS-II operation.BTH requires a PPS interlocked fence at 18 ft distance. Additional shielding is required at the mazes and at high beam loss points. Robust, fast shut off, high accuracy and reliable BCS devices are being developed to contain SC LINAC high rate and high power beam

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D10

ST61, ST60, D2

MUON shieldin

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Back-up slide

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BCS Shut-off mechanism (2)If BCS still fault after BCS Shut-off mechanism (1)

D10

ST61, ST60, D2

MUON shieldin

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BCS100 µS

Option Stage120 µS

Third Stage< 5 S

Path

 Laser Laser shutterPockels Cells or Acousto-optic Modulator 

 Gun RF interrupted

 Shut off CM RF through PPS

Injector PPS stopper In

Beam from gun

No beam from gun No beam from gun

No beam afterPPS stopper

Gun dark current

  No gun dark current

No gun dark current after PPS stopper

Dark current from CM RF

No CM dark current

No CM dark current from L0