PPS and BCS Requirements for LCLSII Baseline Stan

PPS and BCS Requirements for LCLS-II (Baseline) Stan Mao 06/10/2015

Outline q. SLAC Radiation Safety System q. LCLS-II PPS requirements ng i q. PPS shut-off mechanism d el i q. LCLS-II BCS requirements sh N O U q BCS shut-off mechanism M q. BCS shut-off time D 10 q. Access BTH fenced areas (PPS, BCS) ST 61 , ST 6 q. Summary 0, D 2 2

SLAC Radiation Safety Systems Radiation Safety System Access Control System (PPS) Burn Through Monitors (BTM) Beam Shut- Off Ion Chambers (BSOIC) Radiation Control System Beam Containment System (BCS) Shielding ACM, PIC, LIONS LCLS-II DOE Review, April 7 -9, 2015 3

LCLS-II PPS Zones SC Linac PPS – From SC LINAC gun to FEE is one PPS zone ESB Muon shielding BSY D 2 BTHW BTH UH Dump FEE Undulator Complex PPS Zone (From BTHW to FEE) Cu Linac PPS - access Undulator Complex PPS Zone with PPS stoppers D 2 in 4

PPS Shut-off mechanism for SC LINAC Gun RF Power supply All RF ng Off off i d l ie h s N Beam O U M from gun No beam Injector PPS stopper In No beam after PPS stopper Gun dark No gun dark current ST 61 D 10 No gun dark current after PPS stopper Dark current from RF devices No dark current from RF devices , ST 6 0, D 2 5

Under Consideration q New PPS access options are being developed to compensate the baseline q SC LINAC gun local mode ng i ld q h. Access to BTH during SC beam on BSY dump ie q s Access to Sector 10 and upstream during FACET-II operation in N UO FACET-II project M D 10 ST 61 , ST 6 0, D 2 6

LCLS-II Beam Containment System (BCS) ESB BCS monitoring will include measurements BCS collimator system with BCS devices: contain the beam during mis-steering of the beam… 1) Current: conditions, RP is working Current Monitor (CM) • Measure peak and average current 2) Energy: Magnet Current Monitor (MCM) • Measure magnet current (main and trim) 3) Losses: 4) Cooling water Point beam loss monitor Flow meters • Protection Ion Chambers (PICs) or equivalent Line beam loss monitor • Long Ion Chambers (LIONs) or equivalent Current Comparator Compare peak and average current between CMs 7

BCS is critical radiation safety system for SC LINAC operation q LCLS-II beam power is much higher than in LCLS-I, but several systems and enclosures are preserved. q New controls and local shielding must be developed to compensate ng i d this el i q SC LINAC is capable to generate 1. 2 MW beam. If spreader kicker time sh N O system fails, the kickers could deliver 300 k. W beam from BSY dump line to U M SXR or HXR lines D 10 q the downstream beam dumps only absorb few hundred k. W of the beam ST 61 , ST 6 q Direct line from LINAC gallery to SC line through penetrations 0, D 2 q Unknown dark current from gun and cryo modulator 8

LCLS-II BCS Specification q High beam rate (up t o 1 MHz) requires fast BCS system q High power (up to 1. 2 MW) requires high accuracy current monitor sensors ng i d q High power operation requires robust BCS system to limit beam power el i and losses, and to contain the beam sh ON q UFast BCS shut-off time needs to be 100 µS to protect the stoppers/ and M dumps for 240 k. W beam D 10 ST 61 , ST 6 0, D 2 9

BCS devices in SC LINAC injector area BCS LION BCS CM PPS Stopper BCS LION Dark current block 10

BCS devices in SC LINAC L 1, BC 1, L 2, BC 2, L 3, Dog-leg and LINAC (S 13 – S 27) CID Sector 4 Sector 2 BC 1 B Gun Sector 11 Sector 13 BC 2 B L 3 L 2 L 1 Sector 10 CEDOG L 0 CEBC 1 DIAG 0 CY 11 CX 11 CY 12 CX 12 CEBC 2 DIAG 1 CY 21 CX 21 CY 22 CX 22 BCS CM CX 13 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 BX 31/BX 33 and BYD. 11

Current Monitor requirements g l ie h s N n di UO M 300 k. W limit 120 k. W limit 0 1 Dp m u DUM PLIN D B Y S SXR line E HXR line 120 k. W limit 5 k. W limit Existing Interlocked to Cu LINAC LC C u-LLSIN -I Ali. C ne lin e Sector 29 2 ft t 2 f Sector 28 12

BCS magnet current monitor for magnets g l ie h s N n di UO M 0 1 Dp m u DUM PLIN D B Y S SXR line E HXR line ST 61 /ST 6 0/D 2 BSY 1 Sector 30 p D um Y S LC C u-LLSIN -I Ali. C ne lin e Sector 29 2 ft t 2 f Sector 28 B 13

BCS collimators DRAFT (To be determined by ray-trace studies) hi s N i d el ng Collimator/BTM with PICs UO M DUM PLIN SXR line E HXR line Sector 30 2 ft LCLS -I lin Sector 29 e t 2 f Sector 28

Beam Transport Hall Collimator/BTM with PICs Group MCM SXR HXR BTHW BTH Group LIONs are existing and will be repurposed to trip individually (for 35 W) and as Groups (for 75 W) 15

Undulator Hall Tune-up Dump and PICs SXRSS PICs Protection Collimator and PICs located in the front of undulator PICs SXRSS HXRSS Tune-up Dump and PICs SXRSS PICs Undulator Protection Collimator and PICs Add one pairs of PICs in front of undulator for each line Use LIONs to protect BCS collimators 16

Dumpline LCLS-II CM comparator Toroid 1 BYD Magnet Set and PICs Protection Collimator and PICs LCLS-II CM comparator Toroid 1 Protection Collimator and PICs Permanent Magnet MCM PICs Permanent Magnet SXR HXR LCLS-II CM comparator Toroid 1 BYD Magnet Set and PICs Protection Collimator and PICs DUMPLine Protection Collimator and PICs LCLS-II CM comparator Toroid 2 Both SXR and HXR lines have permanent magnets and safety dumplines 17

BCS Shut-off mechanism ser a l f f S) o u t 0 u 0 h 1. S am (<1 e No b BCS fault from SC LINAC 1. Shut off Spreader kickers Beam to BSY dump (< 100 u. S) 2. After Laser is shut off (10 u. S), to check laser and BCS CM Gun RF PPS Stopper 3. If Laser intensity or BCS CM reading is still high (10 u. S), interrupt Gun RF No beam and no dark current from Gun 4. If still has BCS fault (PICs and LIONs) from SC LINAC (50 m. S), BCS send signal to PPS to shut off CM RF in 5 Second No CM RF 18

BCS Shut-off time q. For those BCS devices used to protect BCS collimator or PPS stopper from radiation damage, the shut-off time should ng i d be equal or less than 100 µS el i sh Based on RP-RPG-140506 -MEM-02, 240 k. W LCLS-II N O U beam (300 p. C/pulse) will not damage (Al, Cu, SS, Nb, M Ti) stoppers D 10 q. For other BCS devices, the shut-off time should be equal or ST 61 , ST 6 less than 600 m. S for beam, and should be equal or less than 0, D 2 5 S for Cryo Modulator dark current 19

g n di l ie h s N O U M D 10 BTH beam losses, BTH PPS fenced areas ST 61 and access requirements , S T 60, D 2 20

BTH LCLS-II shielding & BCS (slide from Mario Santana talk on LCLS-II DOE Status Review) LCLS-I: - Beam Power = 5 k. W - Normal Beam Loss* = 5 W (0. 1 % bp) LIONs = 5 W - MCI: 100 k. W Existing facility • 6’ walls • 6’ roof under SB • 4’ roof elsewhere S. B. Long ION chambers BTH 6’ LCLS-I: 5 W LCLS-II DOE Status Review, Sept. 30 - Oct. 2, 2014 21

BTH LCLS-II shielding & BCS (slide from Mario Santana talk on LCLS-II DOE Status Review) LCLS-II: - Beam Power = 2 x 120 k. W - Normal Beam Loss* = 1 W/m LION setting = 35 W - MCI: 2 MW • 32” additional concrete S. B. OR 18’ PPS fence • No access to S. B. & trenches • Shielding on mazes and collimators, … Long ION chambers BTH 6’ 2 x 1 W/m 18’ Local shielding around collimators, etc. 32” 22

Cu LINAC and SC Spreader lines Lambertson hi s N i d el SXR Kicker OFF ng Lambertson UO M 0 1 Dp m u DUM PLIN D B Y S 0 1 D HXR Kicker off SXR line E HXR line ST 61 /ST 6 0/D 2 BSY 1 Sector 30 p D um Y S LC C u-LLSIN -I Ali. C ne lin e Sector 29 2 ft t 2 f Sector 28 B 23

SC-HXR and SC-SXP operation Res e inte arch Y rloc a ked rd PP S to B SY Fence kick 35 W ers 35 W Res earc h Ya rd P PS F enc e BCS LIONs set at 35 W 24

Cu-HXR operation 5 W Kickers are off BCS LIONs set at 5 W 25

Summary q 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 this ng i d q LCLS-II baseline defined one PPS zone (from LCLS-II gun to FEE). It el i conflicts the LCLS-II commissioning plan, also may affect the LCLS-II sh N O operation. U M q BTH requires a PPS interlocked fence at 18 ft distance. Additional D 10 shielding is required at the mazes and at high beam loss points. q Robust, fast shut off, high accuracy and reliable BCS devices are being ST 61 , ST 6 developed to contain SC LINAC high rate and high power beam 0, D 2 26

g n di l ie h s N O U M D 10 ST 61 , ST 6 0, D 2 Back-up slide 27

BCS Shut-off mechanism (2) If BCS still fault after BCS Shut-off mechanism (1) BCS 100 µS ng i d. Laser l e Path shi Laser shutter N O Pockels Cells or U M Acousto-optic Modulator ST 61 Beam No beam from gun , ST 6 0, D 2 from gun Gun dark current Dark current from CM RF Option Stage 120 µS Gun RF interrupted Third Stage < 5 S Shut off CM RF Injector PPS through PPS stopper In D 10 No beam from gun No beam after PPS stopper No gun dark current after PPS stopper No CM dark current from L 0 28