Beamstrahlung on the Septum Blade

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Karsten Büßer Beamstrahlung on the Septum Blade 01.04.2003 ECFA/DESY Workshop Amsterdam

description

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. - PowerPoint PPT Presentation

Transcript of Beamstrahlung on the Septum Blade

Page 1: Beamstrahlung  on the  Septum  Blade

Karsten Büßer

Beamstrahlung on the Septum Blade

01.04.2003ECFA/DESY Workshop

Amsterdam

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The Extraction Line Problem

Incoming Beam

Outgoing Beam

Beamstrahlung

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Beamstrahlung Distributions

Realistic Beam Effect of 10 σ offset

N. Walker (Prague):

Expectation: Power on septum blade can reach several kW

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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 ?

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All I am going to present is right out ofthe press and is therefore to be considered

VERY PRELIMINARY

Disclaimer

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Simulating the Extraction LinePart 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

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Realistic BeamsSimulation 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 athepwww.ph.qmul.ac.uk/lcdata

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Nominal Beam

• Total average Beamstrahlung power: ~360 kW

• Integrated power in septum blade area: ~60 W

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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

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Colliding with the Septum

5 GeV Photon

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Nominal Beam

• Shadow:Average deposited power: ~40 W

• Septum blade:Average deposited power:~0.3 W

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Realistic Beam

• Shadow:Average deposited power: ~15 kW

• Septum blade:Average deposited power:~80 W

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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.