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Beamstrahlung on the Septum Blade. 01.04.2003 ECFA/DESY Workshop Amsterdam. The Extraction Line Problem. Beamstrahlung. Incoming Beam. Outgoing Beam. Beamstrahlung Distributions. N. Walker (Prague):. Realistic Beam. Effect of 10 σ offset.
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Beamstrahlung on the Septum Blade 01.04.2003 ECFA/DESY Workshop Amsterdam
The Extraction Line Problem Beamstrahlung Incoming Beam Outgoing Beam Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Beamstrahlung Distributions N. Walker (Prague): Realistic Beam Effect of 10 σ offset Expectation: Power on septum blade can reach several kW Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Questions Formation of a working group to revisit the design of the extraction line. First Meeting on December 3rd 2002 identified the following questions: • Septum magnet design • Failure modes • What power can the thin blade cope with ? • Reliability of electro-static separators • IR is a highly charged environment • Power loss from the charged particle extraction ? • Is a (small or large) crossing angle a solution ? • 800 GeV upgrade How much energy is really deposited in the septum blade ? Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Disclaimer All I am going to present is right out of the press and is therefore to be considered VERY PRELIMINARY Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Simulating the Extraction Line Part of the extraction line included in BRAHMS: Shadow: • Distance from IP: 45m • 2m long • 5mm thick • 7mm vertical distance from nominal beam (~156 µrad) • Copper Septum Blade: • Distance from IP: 47m • 16m long • 5mm thick • ~7mm vertical distance from nominal beam • Copper Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Realistic Beams Simulation of the complete machine done by Glen White. Using: • LINAC: PLACET (D. Schulte) • BDS: MERLIN (N. Walker) • Beam-beam: GUINEA-PIG (D. Schulte) Takes into account: • Simulation of feedback loop • Orbit injection errors into LINAC • Wakefield effects in LINAC • Vibration of quads in BDS • Energy spread of e- due to undulator • Resolutions of BPMs • Jitter on kicker signals Beams and backgrounds are available through database at hepwww.ph.qmul.ac.uk/lcdata Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Nominal Beam • Total average Beamstrahlung power: ~360 kW • Integrated power in septum blade area: ~60 W Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Realistic Beam • Feedback system brings beams into stable collisions after ~100 BX • Total average Beamstrahlung power: ~500 kW (TDR 360 kW !) • Integrated power in septum blade area: ~35 kW Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Colliding with the Septum 5 GeVPhoton Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Nominal Beam • Shadow: Average deposited power: ~40 W • Septum blade: Average deposited power: ~0.3 W Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Realistic Beam • Shadow: Average deposited power: ~15 kW • Septum blade: Average deposited power: ~80 W Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam
Conclusion • Under realistic beam conditions, 30-40 kW of Beamstrahlung are emitted under vertical angles larger than 0.155 mrad. • Roughly half of the emitted energy is deposited in the septum shadow. • Septum blade receives on average 80W. • Information from Efremov: 15 kW has to be cooled away from septum blade due to normal operation. • Septum will probably undergo no mechanical damage. • 40 kW of Beamstrahlung will irradiate the septum environment. To be done • Check backgrounds for the detector. • Backscattering • Pairs, neutrons with realistic beam • Check charged particle extraction losses. Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY Workshop Amsterdam