Linear Collider Machine Protection Issues M. Palmer Injection System Injector Damping Rings Bunch Compressor and Transfer Sections Main LINAC Beam Delivery System Questions

Injection System NLCTESLA Injector ??? e + undulator located before IP Damping Rings GeV GeV Permanent wigglers Ring protection issues similar to existing rings Bunch Compressor and Transfer Sections Diagnostics? Beam dump(s) before main LINAC Diagnostic section Possible beam dump before main LINAC

Main NLC LINAC MAID System Monitor orbit tolerance Generate permit for DR extraction Hardware verification required for DR extraction Klystron/Modulator, Magnets, Movers, Timing, Control System 100  s polling timescale Specific concern: Possible back-phasing of RF sector. Implications? Pre-LINAC beam dumps? Keep as much of machine active as possible during fault Pilot Pulse Require low intensity pulse to avoid damage  I  10x,  h  10x,  v  1000x Operative when break in operation of < 1 sec. Detailed ramp to full intensity

Main TESLA LINAC TTF methods Monitor current losses Inhibit gun (3-5  s ) Similar methods may be applied in final design Orbit tolerance monitoring easily added Easily applicable at LINAC start Beam remains in DR on LINAC inhibit Beam expected to continue thru LINAC on magnet or module failure Fast Emergency Extraction Line (FEXL) at end of LINAC Diverts beam from BDS in 1-2 bunches Inhibits DR extraction within ~200 bunches of problem Serves as bypass during commissioning

LINAC Bunches & Current Densities NLCTESLA Q bunch (nC) N bunch N fault to BDS N fault to LINAC 190~200 EntranceExitEntranceExit  x,y (  m) 31, , , 1660, 3  pC /  m 2)

Beam Delivery System NLCTESLA Post-LINAC Kickers Final Focus Kicker Verifies ramp Inhibit available 100  s before DR extraction FEXL can fire within 1-2 bunches. General Collimation X 0 spoilers 20 X 0 downstream absorbers 1 X 0 spoilers 20 X 0 downstream absorbers Energy Collimation O(few  s ) failure response  withstand 190 bunches Magnetic Energy Spoiler  displacement plus  v  Betatron Collimation SLC experience  few evts/run Chromaticity Collimation Detector implications of beam halo hitting CC spoilers Halo Suppression Octupole tail folding

Questions Injector System/Damping Rings Stability issues for downstream fault Beam dump between DR and LINAC Permanent Magnet Wiggler/Undulator protection issues LINAC Early LINAC protection scenarios RF phasing System Issues Startup and recovery plans  Alignment  Optics validation Protection system failure analysis Collimation Issues Spoilers  Near miss damage  Replacement/maintenance issues  Material damage limits Absorber  Energy distribution Beam Halo Implications for Detectors