Transcript Beamstrahlung on the Septum Blade Karsten Büßer 01.04.2003 ECFA/DESY Workshop Amsterdam The Extraction Line Problem Beamstrahlung Incoming Beam Outgoing Beam 01.04.2003 Karsten Büßer - Beamstrahlung on the Septum Blade ECFA/DESY.

Beamstrahlung on the Septum Blade
Karsten Büßer
01.04.2003
ECFA/DESY Workshop
Amsterdam
The Extraction Line Problem
Beamstrahlung
Incoming Beam
Outgoing Beam
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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Beamstrahlung Distributions
N. Walker (Prague):
Realistic Beam
Effect of 10 σ offset
Expectation: Power on septum blade can reach several kW
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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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 ?
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
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Disclaimer
All I am going to present is right out of
the press and is therefore to be considered
VERY PRELIMINARY
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Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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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
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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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
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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Nominal Beam
• Total average
Beamstrahlung power:
~360 kW
• Integrated power in
septum blade area: ~60 W
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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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
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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Colliding with the Septum
5 GeV Photon
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Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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Nominal Beam
• Shadow:
Average deposited power:
~40 W
• Septum blade:
Average deposited power:
~0.3 W
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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Realistic Beam
• Shadow:
Average deposited power:
~15 kW
• Septum blade:
Average deposited power:
~80 W
01.04.2003
Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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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.
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Karsten Büßer - Beamstrahlung on the Septum Blade
ECFA/DESY Workshop Amsterdam
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