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April 6th 2009Olympus Meeting at DESY, F.Brinker1 Vacuum system Available beam scraper Beam dimensions, Target cell Machine Studies on February 7 th 2009 Further machine studies DORIS

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April 6th 2009Olympus Meeting at DESY, F.Brinker2 Straight section from the arc to the IP Vertical scraper Horizontal scraper Main source of synchrotron radiation Horizontal scraper

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April 6th 2009Olympus Meeting at DESY, F.Brinker3 Horizontal and vertical scraper Water cooled copper rod, 30mm diam.

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April 6th 2009Olympus Meeting at DESY, F.Brinker4 Acceptance and Beam sizes at 4.5 GeV ( ~E ) The acceptance, defined by existing aperture limitations, is a bit larger than the space needed for the injection

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April 6th 2009Olympus Meeting at DESY, F.Brinker5 Vacuum system current position to be removed new position current position new position valves Adapter chambers

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April 6th 2009Olympus Meeting at DESY, F.Brinker6 Geometry of new IP region may be a bit more

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April 6th 2009Olympus Meeting at DESY, F.Brinker7 Machine studies on February 7 th Injection into 10 bunches Final current 170 mA after 6 minutes Varying efficiency probably due to effects at DESY: DESY operated at normal maximum energy of 4.5 GeV At 2.3 GeV the beam is not fully damped to its equilibrium emittance Possibly beam blow up due to resonances Room for improvements: New power supplies with higher stability Extraction when beam is decelerated Optimization of top energy

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April 6th 2009Olympus Meeting at DESY, F.Brinker8 Machine studies on February 7 th Stored beam with good conditions: I = 150 mA Lifetime = 8.5 hours Not so nice: Longitudinal beam excitation (oscillation with ~1cm Amplitude) Limits lifetime at higher currents maybe increased particle background

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April 6th 2009Olympus Meeting at DESY, F.Brinker9 Vacuum pressure in cavities 3.1/3.2 Observation: Pressure increase at cavities 3.1/3.2 Probable explanation: The high bunch currents excite a higher order mode in these cavities leading both to an pressure increase and a longitudinal beam excitation

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April 6th 2009Olympus Meeting at DESY, F.Brinker10 Longitudinal oscillations at 4.5 GeV Increased cavity temperature Test: reduced temperature of Cav. 3.2

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April 6th 2009Olympus Meeting at DESY, F.Brinker11 Further machine studies in 2009/10: Injection at 2.3 / 2.0 GeV Maximize transport line transmission Optimize DESY parameter Try to eject during deceleration Longitudinal Oscillations Effect of cav. temperatures at 4.5 GeV Installation of second RF-amplifier for long. FB ( July 2009 ) Repeat measurements at 2.3 / 2.0 GeV Scraper studies ( with background counters ? ) Simulate dimensions of target cell Verify beam sizes/ acceptance with scrapers at low energies Injection tests with closed scrapers ( background spikes? )