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W. Bayer – ABI Workshop, Bad KreuznachEmittance measurements at GSI UNILAC11. Dez. 2008 Emittance Measurement at GSI UNILAC – Results and Requirements.

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Presentation on theme: "W. Bayer – ABI Workshop, Bad KreuznachEmittance measurements at GSI UNILAC11. Dez. 2008 Emittance Measurement at GSI UNILAC – Results and Requirements."— Presentation transcript:

1 W. Bayer – ABI Workshop, Bad KreuznachEmittance measurements at GSI UNILAC11. Dez Emittance Measurement at GSI UNILAC – Results and Requirements – W. Bayer, W. Barth, L. Dahl, P. Forck L. Groening, S. Yaramyshev P. Gerhard, M. Maier – ABI Workshop – Bad Kreuznach,

2 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Overview Motivation GSI UNILAC – Parameters and beam diagnostics Procedures for Experiments Results of UNILAC measurements –at 1.0 emA 40 Ar 10+ at DTL entry –at 7.1 emA 40 Ar 10+ at DTL entry Conclusion

3 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Overview Motivation GSI UNILAC – Parameters and beam diagnostics Procedures for Experiments Results of UNILAC measurements –at 1.0 emA 40 Ar 10+ at DTL entry –at 7.1 emA 40 Ar 10+ at DTL entry Conclusion

4 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Note about FAIR (Facility for Antiproton an Ion Research) Important data: Z = -1, 1 … 92 intensity of secundary radioactive ion beam : up to times more intensity of primary beam : 100 to 1000 times more energy: 35 to 45 GeV/u …

5 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Design parameters and requirements for FAIR Present 90% trans. emittances of 15 emA 238 U 28+ at 11.4 MeV/u due to DYNAMION * simulations: x = 1.1 mm mrad y = 3.6 mm mrad UNILAC upgrade program until 2009 one aim: increase of high intensity beam brilliance * S. Yaramyshev et al., NIM A 558 (2006) 90

6 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez HIPPI Project Overview CARE:Integrating Activity within FP6 Coordinated Accelerator R&D in Europe 2004 – 2008, i.e. 5 years HIPPI:Joint Research Activity within CARE High Intensity Pulsed Proton Injector Total GSI cost: 1476 k, provided by EU to GSI: 363 k GSI – Activities: Beam dynamics code development & benchmarking Beam dynamics experiment campaign (1 week in May/November 2006, resp.) Beam diagnostics development Thanks to HIPPI the accelerator division acts for the first time as experimentalist at GSI

7 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Measurements Required: better understanding of correlation between space charge forces and focusing during acceleration Within HIPPI: experiments & simulations ( code benchmarking by A. Franchi) For Benchmarking: experiments without & with space charge forces Alvarez quadrupoles yet are not sufficient to provide for the required phase advances for high current 238 U 28+ beam (part of upgrade program) As space charge force 7.1 emA 40 Ar 10+ instead of 15 emA 238 U 28+ for experiments

8 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Overview Motivation GSI UNILAC – Parameters and beam diagnostics Procedures for Experiments Results of UNILAC measurements –at 1.0 emA 40 Ar 10+ at DTL entry –at 7.1 emA 40 Ar 10+ at DTL entry Conclusion

9 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Overview of GSI UNIversal Linear ACcelerator High Current Injector (HSI) Alvarez Single Gap Resonators

10 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Parameters of UNILAC Alvarez DTL 5 independent rf-tanks + 2 re-bunchers 108 MHz, 50 Hz, 5 ms 192 rf-cells DTL based on F-D-D-F focusing dc-quads grouped to 13 families Inter-tank focusing : D-F-D Transv. acceptance (norm.) = 15 m Synchr. rf-phases -(30°,30°,30°,25°,25°) E kin [MeV/u]: Tank : A1 A2a A4 A2b m Re-Buncher A3

11 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Overview of Beam Diagnostics Equipments Stripper & matching section with selected beam diagnostics transverse emittances Beam diagnostic devices: longitudinal emittance phase probe beam current transformer beam profile grid

12 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Longitudinal Bunch Structure & Emittance before DTL TOF measurement with Multi Channel Plate & diamond detector in relation to rf timing; Methode suited especially for low ion beam energies; Very sensitive methode (view ions per rf-periode sufficient).

13 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Longitudinal Emittance in TK Sketch by P. Gerhard Beam behind dispersive section Rhomb aperature dE dt "Pencil" like beam from core of main beam Vertical chopper Luminescent screen & CCD camera SlitGrid Online measurement

14 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Overview Motivation GSI UNILAC – Parameters and beam diagnostics Procedures for Experiments Results of UNILAC measurements –at 1.0 emA 40 Ar 10+ at DTL entry –at 7.1 emA 40 Ar 10+ at DTL entry Conclusion

15 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez High Current Matching of the Alvarez DTL Measurement of transverse Twiss parameters and rms-emittances Measurement of the longitudinal Twiss parameters and rms-emittance Calculation of 6 Twiss parameters and 3 emittances at entrance of 1 st re-buncher regarding the settings of the doublet, the 1 st re-buncher and the measured emittances as input parameters for matching routine Variation of quadrupol strengths and re-buncher amplitudes to match the periodic solution at DTL entrance; routine based on rms envelope tracking of space charge affected beams ( * ) Measurements of transverse emittances behind DTL before & after applying calculated settings to verify improvement ( * ) see T. Wangler, Principles of RF Linear Acc., p. 217 & 287

16 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Example of DTL Matching 40 Ar 10+, 9.5 emA, 1.4 MeV/u vertical horizontal after manual matching meas. transmission = 93% after systematic matching meas. transmission = 96% matching quads

17 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Evaluation of Measured Phase Space Distributions with ProEMI Level Mode Intensity Mode Amplifier noise like a carpet Cut noise at certain level (normally < 2%) Remove remaining pixels that obviously do not belong to beam signals Evaluate with intensity mode

18 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Overview GSI UNILAC – Parameters and beam diagnostics Motivation Matching of the Alvarez DTL Results of UNILAC measurements –at 1.0 emA 40 Ar 10+ at DTL entry –at 7.1 emA 40 Ar 10+ at DTL entry Most recent results Conclusion

19 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Results of HIPPI I: Long. Emittance Before DTL Before optimisation: After optimisation: 40 Ar 13+ (1emA 40 Ar 10+ ) p stripper = 480 mbar DW/W ±2.5%, j ±160° (core) j ±430° (with satellite) 40 Ar 10+ (1emA 40 Ar 10+ ), p stripper = 2000 mbar DW/W ±2.0%, j ±120° Design values: DW/W = ±0.5%, j = ±90° Normalised emittances for f = 108 MHz Normalised emittances for f = 108 MHz (1 emA 40 Ar 10+ )

20 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Results of HIPPI I: Trans. Emittance Before DTL Before optimisation: After optimisation: (1 emA 40 Ar 10+ )

21 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Results of HIPPI I: Trans. Emittance After DTL Before optimisation: After optimisation: (1 emA 40 Ar 10+ )

22 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Summary of These Results Longitudinal Emittance Before DTL: tot,90 = 34.1 mm mrad tot,90 = 20.3 mm mrad Transverse Emittance before DTL: x,tot,90 = 0.63 mm mrad, = 2.3, =1.3 mm/mrad y,tot,90 = 0.64 mm mrad, = 1.6, =1.9 mm/mrad x,tot,90 = 0.69 mm mrad, =-0.3, =12.4 mm/mrad y,tot,90 = 0.62 mm mrad, = 2.2, = 3.8 mm/mrad Transverse Emittance after DTL: x,tot,90 = 1.61 mm mrad emi. growth: 2.56 y,tot,90 = 1.63 mm mrad emi. growth: 2.55 x,tot,90 = 0.88 mm mrad emi. growth: 1.28 y,tot,90 = 0.68 mm mrad emi. growth: 1.10 blue: before optimisation red: after optimisation (1 emA 40 Ar 10+ )

23 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Results of HIPPI I: Beam Energy & Emittance Main transverse emittance growth took place in tank A1 Possible reason: still remaining mismatch of tank A1 (1 emA 40 Ar 10+ )

24 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Results of HIPPI I: Alvarez Buncher Alvarez Bunchers OffAlvarez Bunchers On 1st buncher focusing 2nd buncher defocusing (1 emA 40 Ar 10+ )

25 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Overview GSI UNILAC – Parameters and beam diagnostics Motivation Matching of the Alvarez DTL Results of UNILAC measurements –at 1.0 emA 40 Ar 10+ at DTL entry –at 7.1 emA 40 Ar 10+ at DTL entry Most recent results Conclusion

26 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Longitudinal Emittance Before Alvarez DTL Contrary to HIPPI I two intensity centres in the longitudinal phase space appearance of double peak structure not yet fully understood Only weak correlation, i. e. -1 < < 1 All DTL matching routines were based on the measurement calculated new quadrupole strength & adapted buncher amplitudes reduced emittance growth Design (7.1 emA 40 Ar 10+ )

27 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Investigations on Long. Emittance Measurement (in 2007) Measurement of energy spread & phase width reliable but correlation, i. e. too small Setup-Changes in 2007: new Ta-foil due to damages (no double peak?) improved DAQ re-alignment of the setup 40 Ar 7+, stripped, IH2 off influence on correlation? 40 Ar 4+, unstripped, IH2 off (7.1 emA 40 Ar 10+ )

28 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Measurement of ( 0 ) – Procedure Procedure: –Changing all phase advance quadrupoles to the desired 0 ; –Calculation of the re-buncher, doublet & triplet settings with the matching routine; –Changing doublet & triplet settings to calculated values, adapted buncher settings. (7.1 emA 40 Ar 10+ )

29 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Examples of phase space distributions for different 0 after DTL 0 = 35° 0 = 60° 0 = 90° 0 = 45° tot,90 = 2.44 mm mrad tot,90 = 3.23 mm mrad tot,90 = 2.07 mm mrad tot,90 = 2.15 mm mrad tot,90 = 1.74 mm mrad tot,90 = 1.79 mm mrad tot,90 = 2.89 mm mrad tot,90 = 2.00 mm mrad Transverse emittances at DTL entry: x,tot,90 = 0.57 mm rad, y,tot,90 = 0.92 mm mrad (All emittance values are normalised ones!) (7.1 emA 40 Ar 10+ )

30 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Measurement of ( 0 ) – Procedure & Reproducibility Procedure: –Changing all phase advance quadrupoles to the desired 0 ; –Calculation of the re-buncher, doublet & triplet settings with the matching routine; –Changing doublet & triplet settings to calculated values, adapted buncher settings. Reproducibility: values remeasured after finishing the complete scan. (7.1 emA 40 Ar 10+ )

31 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Results of 0 Variation Simulations with Parmila & Dynamion were & are performed (7.1 emA 40 Ar 10+ )

32 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Transverse Emittance Growths at 0 = 60° (7.1 emA 40 Ar 10+ ) Horizontal emittance growth: 3.33 Vertical emittance growth: 1.69

33 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Transverse Emittance Growths at 0 = 45° (1.0 emA 40 Ar 10+ ) Horizontal emittance growth: 1.28 Vertical emittance growth: 1.10 (Zero current)

34 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Summary & Outlook Overview of beam diagnostics mounted at GSI UNILAC Measurement principles of longitudinal emittance Procedures of experiments & data processing Results of measurements at low & high 40 Ar 10+ beam intensities: –Low int.: (E) emittance growths for 0 = 45°: 1.28/ 1.10; –High int.: ( 0 ) minimal trans. emittances at 60°: 1.74/ 1.79 mm mrad; –High int.: (E) emittance growths for 0 = 60°:1.69/ Investigations on the longitudinal emittance measurement before DTL: –Improvements of new installed DAQ –Investigations of new detectors to improve time resolution –Answer the question Why results measurement in 0 Longitudinal emittance measurements in transfere channel to SIS18 –Installation of new DAQ for fluorescence screen observation –Quantification of emittance value of slit-grid measurement

35 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Appendix

36 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez. 2008Motivation Presented at previous HIPPI Meetings: –Results of low current beam (space charge forces neglectable) experiments at GSI UNILAC; –Results of corresponding simulations with the DYNAMION code; Results fit to each other. 2 truncated Gaussian distribution (DYNAMION generated distribution for given Twiss parameters)

37 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Energy Parasites Beam fractions ( 10%) with lower energy emittance growth caused by longitudinal mismatch at the transition from 36 to 108 MHz rf section beam energy spread and phase width exceed design values longitudinal mismatch between DTL sections inhomogenous density profile of gas stripper jet Measured beam profiles in dispersive section:

38 W. Bayer – ABI Workshop, Bad Kreuznach Emittance measurements at GSI UNILAC 11. Dez Transverse Emittance Growths at 0 = 45° (7.1 emA 40 Ar 10+ ) Horizontal emittance growth: 2.96 Vertical emittance growth: 3.04 Data aquired under different conditions as in ( 0 ) measurements!


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