1. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Development of non-intersecting transverse and longitudinal Profile Monitors P. Forck, A. Bank, W. Barth, C. Dorn, A. Peters, H. Reeg Gesellschaft für Schwerionenforschung, Darmstadt HIPPI Meeting 2005, Oxford Non intersecting methods for: Preventing destruction of intersecting material Parallel observation at different locations Monitoring of possible time-varying processes Goal: Same precision as intersecting methods Outline: Transverse profile monitor by Beam Induced Fluorescence BIF Bunch Structure Monitor BSM based on residual gas electron spectroscopy Transmission control by transformers

2. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors High Current Injector (RFQ&IH) Alvarez DTL Single Gap Resonators The UNILAC Facility at GSI Achieved current for U-beam (t pulse = 200 μs) U 4+ : 16 emA U 28+ : 5 emA U 73+ : 2 emA 1.4 MeV/u 11.4 MeV/u

3. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Basics of Beam Induced Fluorescence Physics of fluorescence for N 2 residual gas: p + N 2  p + (N 2 + ) * + e -  p + N 2 + +  + e - Excitation of residual gas molecules by beam’s energy loss Decay of N 2 + levels generate light, blue light 390 nm < < 470 nm, lifetime  = 60 ns. Realizations at Los Alamos, CERN, Orsay/Saclay, Uni-Frankfurt, GSI, COSY …. Fluorescence of 200 keV p in N 2 (1961) Spectrum confirmed at CERN-PS/SPS from 1 to 450 GeV. LANL (D. Gilpatrick et al.) p at MeV in 5*10 -5 mbar N 2

4. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Image Intensifier used at GSI-LINAC Technical realization of image intensifier at GSI: Photo cathode S20 UV: γ -e - conversion, 15 to 25 % efficiency, 200 nm < λ < 650 nm Two step MCP (25 mm diameter): 10 6 fold amplification P 46 phosphor: e - - γ conversion, 300 ns decay, 500 nm < λ < 600 nm Minifying taper coupling to CCD chip (1/2’’): 7% transmission Digital camera (Basler A311f): Firewire interface

5. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Test Setup at GSI-LINAC Compact chamber with 150 mm insertion: Installation behind Alvarez at 11 MeV/u

6. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Typical Result at GSI-LINAC Features: Single photon counting High resolution (here 0.3 mm/pixel), can easily be matched to application Low background (sometime larger contribution by neutrons and  ) Beam parameters at GSI-LINAC: 4.7 MeV/u Ar 10+ beam I=2.5 mA equals to 10 11 particles One single macro pulse of 200  s Vacuum pressure: p=10 -5 mbar (N 2 ) bump restricted ~1 m,  no influence to beam detected

7. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Application of Beam Induced Fluorescence Special application Variation during the macro pulse detectable: Switching of image intensifier  Exposure window during macro-pulse Signal treatment Statistics offers ‘offline’ optimization statistics  integration time  resolution Beam parameter: Ar 10+ at 11 MeV/u with 8 mA

8. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors In Preparation: Digital Interface for Firewire Digital camera offers: no loss of data-quality, versatile trigger, variable exposure time CCD-camera: Basler A311f featuring 649x494 pixels, 12 bit, 50 frames/s, IEEE 1394b Iris/MCP-gain variation: Remote controlled iris by local, ethernet based DAC Readout: HUB  optical fiber  real-time controller running RT-LabVIEW (NI) Status: DAQ in preliminary design phase LabVIEW Software: DAQ System:

9. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Novel Device for non-intersecting Bunch Shape Measurement Bunch-Shape seldom measured ! Scheme for novel device: Secondary electrons for residual gas Acceleration by electric field Target localization by apertures and electro-static analyzer (Δy = 0.2 to 2 mm, Δz=0.2 to 1 mm) rf-resonator as ‘time-to-space’ converter same as intersecting method (INR-Moscow) Readout Ø70 mm MCP + Phosphor + CCD Measurement done within one macro-pulse (not yet achieved due to back-ground)

10. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Realization for Bunch Shape Monitor at UNILAC E-field and the energy-analyzer: Installation for beam based tests:

11. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors First Results from Bunch Shape Measurement at UNILAC Features:  Single electron detection  Recorded within few macro-pulses  Resolution better 50 ps = 2 0 @108MHz  Pressure bump required Back-ground should be suppressed Beam parameters: Ni 14+ at 11.4 MeV/u I=1.5 mA, 200 μs macro pulse Average: 8 macro pulses Pressure p=2*10 -6 mbar Deflector power P=15 W Time information carried by the residual gas e - is transferred to spatial differences:

12. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors First Application from Bunch Shape Measurement Variation of buncher: Bunch shape was determined, influeneced by buncher Pick-up: No measurable influence Emittance determination possible Beam parameters: Ni 14+ at 11.4 MeV/u I=2 emA, 200 μs macro pulse Average: 4 macro pulses Pressure p=10 -5 mbar

13. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Beam Space Charge Contribution Simulation method: e - trajectory calc. inside beam pipe & linear optics for energy analyzer Simulation parameter: E kin = 11.4 MeV/u Parabolic bunch shape ∓ 0.5 ns longitudinal root points ∓ 5 mm transversal root points Variation of current (as for Ni 14+ ) Simulation result:  stronger influence as for standard method, but still acceptable The residual gas e- are influenced by beam’s E-field in addition to the monitor E-field  Simulation of influence for different currents:

14. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Dynamic Transmission control at UNILAC ACCT clamping Integration window ACCT signal 40 μs/div Variation of maximal loss via software input: 8 different input thresholds  8 different macro-pulse duration by electric chopper in front of RFQ  Save protection of equipment. FPGA-electronics: ACCT  V/f-converter  Up/down-counter: 1 st ACCT ↑, 2 nd ↓  Digital comparator  chopper

15. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Conclusion and Outlook Beam Induced Fluorescence BIF: First prototype in operation for ‘single photon counting’, usable during UNILAC operation Data acquisition in design phase (responsible engineer just hired) More investigation with high current required possible problems: broadening by space charge field, two-step excitation…. Non-intersecting Bunch Shape Monitor: Prove-of-principle performed, resolution lower than 50 ps = 2 0 @ 108 MHz Improvements for back-ground suppression in preparation  beam test necessary Calculations and measurements of signal deformation due to beam space charge required Device in experimental condition  engineering design for operation required Dynamic Transmission control: System design finished Hardware in operation Improvements of operation control required

16. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Comparison for different Gases at p Source (Saclay) Choice of fluorescence gas: High fluorescence yield at optical wave-length Short lifetime of excited level Good vacuum pumping Results:  Profile is independent of gas Care: Long lifetime (N 2 + : 60 ns)  broadening by beam space charge Light emitted by primary ions e.g. p + N 2  H* + N 2 + (only important for E kin <1 MeV) At large N 2 density (p>10 -3 mbar): Two-step processes e.g. N 2 + e -  N 2 * + e - possible Profiles from different gasses Example: Ion source 100 keV, 100 mA protons P. Ausset et al. (Orsay/Saclay) N 2, Ne Ar, Kr Xe

17. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Non-intercepting Profile Measurement based on Energy Loss Target e - -density ~ 1/E kin (for E kin > 1GeV nearly constant) Strong dependence on projectile charge  Profile determination from ionization and excitation of residual gas. M. Plum et al.: p in N 2 at CERN-PS Standard monitors: SEM-Grid, Wire-Scanner, Scintillation Screen, OTR-Screen… Disadvantage: intercepting, problems for time-varying processes Non-intercepting profile measurement: Large beam power can destroy the material Synchrotron: Monitoring during full cycle LINAC: Monitoring at different locations, variation during the macro-pulse Physics: electronic stopping power Bethe-Bloch formula: - dE/dx = const · Z t ρ t /A t · Z p 2 · 1/β 2 · [ ln(const ·γ 2 β 2 /I) – β 2 ] cross section α dE/dx pc [GeV]

18. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Technical Realization Possibilities for BIF Double MCP: + single photon, 10 6 -fold amp. - resolution limited (MCP-channels) Example: GSI-LINAC (300 μm/pixel) Single MCP: - lower 10 3 -fold amp. + higher resolution Example: CERN-SPS (160 μm/pix), R. Jung et al. Photo-cathode: Only for required wavelength interval to avoid dark currents, e.g. S20UV: 200<λ<650 nm  dark rate 500 e - /cm 2 /s, S25red: 300<λ<900 nm  30000 e - /cm 2 /s Phosphor: Fast decay ↔ lower sensitivity e.g. P47: τ = 0.1 μs, P43: τ = 1000 μs  I P43 ~ 4 · I P47 Problem: Radiation hardness of CCD camera

19. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors BIF at Synchrotrons Example: CERN SPS and PSB,PS (R. Jung, M. Plum et al.) Photon yield scales like Bethe-Bloch energy loss ΔE d for p with 100 MeV < E kin < 450 GeV Comparison to wire scanner at SPS Gas N 2 Xe ΔE /photon3.6 keV46 keV lifetime58 ± 0.3 ns59 ± 1 ns Method: fluorescence decay by ~5 ns long bunches

20. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Realization of Bunch Shape Monitor at UNILAC

21. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Standard Bunch Shape Determination Standard intersecting method developed by INR-Moscow (A. Feschenko, P. Ostrumov et al.):  Insertion of a 0. 1 mm wire at 10 kV  Emission of e - within < 0.1 ps  Acceleration toward 1mm slit  Rf-deflector as time-to-space converter  Detection with Slit+Cup or MCP  Resolution better 1 o or 10 ps

22. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors Dynamic Transmission control at UNILAC 40 μs/div Verification for transmission control: Artificial beam loss by quadrupole variation  chopper window decrease

23. L. Groening, Sept. 15th, 2003 GSI-Palaver, Dec. 10 th, 2003, A dedicated proton accelerator for p-physics at the future GSI facilities Peter Forck (GSI), HIPPI meeting, Oxford Non-intersecting transverse and longitudinal Profile Monitors High Current Transmission control at UNILAC FPGA