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Measurement of transverse emittances with a Solenoid (for GUN-0.1) - Jens Völker – (06.12.2011)

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Presentation on theme: "Measurement of transverse emittances with a Solenoid (for GUN-0.1) - Jens Völker – (06.12.2011)"— Presentation transcript:

1 Measurement of transverse emittances with a Solenoid (for GUN-0.1) - Jens Völker – (06.12.2011)

2 Technics and analysis for a Solenoid-Scan - Theory of a Solenoid-Scan - Simulation of the Solenoid Measurements Discussion Emittancemeasurement with a solenoid-scan (Jens Völker) Summary Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

3 SRF-Gun Solenoid Drive-Laser (λ=258nm) Pb-Cathode Faraday-Cup / dump YAG-screen (150µm thick) Bending- Magnet Schematic construction of the test facility Emittancemeasurement with a solenoid-scan (Jens Völker) Technics for a Solenoid-Scan Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

4 transverse beam width (rms) on screen: β-function determined by Twiss-Matrix L = Solenoid to Screen L eff = effective length of the Solenoid Emittancemeasurement with a solenoid-scan (Jens Völker) - SolenoidScan Theory of a Solenoid-Scan Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

5 transverse beam width (rms) on screen: β-function determined by Twiss-Matrix φ expansion to first order Emittancemeasurement with a solenoid-scan (Jens Völker) - SolenoidScan Theory of a Solenoid-Scan Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

6 transverse beam width (rms) on screen: β-function determined by Twiss-Matrix Emittancemeasurement with a solenoid-scan (Jens Völker) - SolenoidScan Theory of a Solenoid-Scan Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

7 transverse beam width (rms) on screen: β-function determined by Twiss-Matrix ? ? will be determined by simulations Emittancemeasurement with a solenoid-scan (Jens Völker) - SolenoidScan Theory of a Solenoid-Scan Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

8 1. step: calculations of the B-field in the Solenoid by Poisson-Superfish: Beam-pipe Coil-pack Iron-yoke Cu-cooling µ-Shield Emittancemeasurement with a solenoid-scan (Jens Völker) – Solenoid-Simulations Simulation of the Solenoid Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

9 2. step: Integrate the 3d-fields into ASTRA 3. step: determine the transfer-matrix by special particle-distributions (parallel-particle-beam and particle-spotlights) 1. step: calculations of the B-field in the Solenoid by Poisson-Superfish: Emittancemeasurement with a solenoid-scan (Jens Völker) – Solenoid-Simulations Simulation of the Solenoid Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

10 Fit-solutions: Emittancemeasurement with a solenoid-scan (Jens Völker) – Solenoid-Simulations Simulation of the Solenoid Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

11 not emittance conserving Emittancemeasurement with a solenoid-scan (Jens Völker) - Example Analysis by using an example Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

12 Simulations of Soleonoid-Scans by ASTRA min. bunch-width on Screen Emittances increase behind the focus-point! Emittancemeasurement with a solenoid-scan (Jens Völker) - Example Analysis by using an example Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

13 not emittance conserving high-cut Emittancemeasurement with a solenoid-scan (Jens Völker) - Example Analysis by using an example Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

14 x (mm) y (mm) x (mm/m) y (mm/m) Emittancemeasurement with a solenoid-scan (Jens Völker) - Example Analysis by using an example Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

15 roughness of the cathode surface bunch charges higher order effects: - aberrations - displacements - asymmetries All terms are generally correlated of each other and also depends on other effects (e.g. Shottky-effects) Theory: Emittancemeasurement with a solenoid-scan (Jens Völker) - Emittance Measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

16 emittances depends on : Laser spot size Laser intensity gradient of the electric field in Cavity and extraction phase of the bunch Emittancemeasurement with a solenoid-scan (Jens Völker) Measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

17 Emittancemeasurement with a solenoid-scan (Jens Völker) Measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

18 Emittancemeasurement with a solenoid-scan (Jens Völker) Measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

19 Emittancemeasurement with a solenoid-scan (Jens Völker) Measurements εyεy εxεx Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

20 What are the effects that dominate the emittance values? by cathode surfaceDisplacement of cavity and solenoid axis Beam misalignmentAsymetries of the E- or B-fields electronscattering in thick screen Emittancemeasurement with a solenoid-scan (Jens Völker) Discussion Emittance growthUncertainties in Measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

21 What are the effects that dominate the emittance values? - Solenoid will be movable in the transvers space for the next run: Emittancemeasurement with a solenoid-scan (Jens Völker) Discussion by cathode surfaceDisplacement of cavity and solenoid axis Beam misalignmentAsymetries of the E- or B-fields electronscattering in thick screen Emittance growthUncertainties in Measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

22 What are the effects that dominate the emittance values? - Solenoid will be movable in the transverse space - a small quadrupol will be installed behind the Solenoid for the next run: Emittancemeasurement with a solenoid-scan (Jens Völker) Discussion by cathode surfaceDisplacement of cavity and solenoid axis Beam misalignmentAsymetries of the E- or B-fields electronscattering in thick screen Emittance growthUncertainties in Measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

23 What are the effects that dominate the emittance values? - Solenoid will be movable in the transverse space - a small quadrupol will be installed behind the Solenoid for the next run: - new screen-station (4 screens) with varying thickness an material + a wire-scanner Emittancemeasurement with a solenoid-scan (Jens Völker) Discussion by cathode surfaceDisplacement of cavity and solenoid axis Beam misalignmentAsymetries of the E- or B-fields electronscattering in thick screen Emittance growthUncertainties in measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

24 What are the effects that dominate the emittance values? - Solenoid will be movable in the transverse space - a small quadrupol will be installed behind the Solenoid for the next run: - new screen-station (4 screens) with varying thickness an material + a wire-scanner - new methode for the measurement: slit-mask Emittancemeasurement with a solenoid-scan (Jens Völker) Discussion by cathode surfaceDisplacement of cavity and solenoid axis Beam misalignmentAsymetries of the E- or B-fields electronscattering in thick screen Emittance growthUncertainties in measurements Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

25 Thank you for your attention.

26 Extras Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011

27 Extras Emittance measurement with a solenoid-scan (Jens Völker) 06.12.2011


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