TRI  P RFQ design, simulations and tests E. Traykov TRI  P project and facility RFQ tests and design Simulations Conclusion TRI  P Group: G.P. Berg, U. Dammalapati, S. De, S. Dean, P.G. Dendooven, O. Dermois, G. Ebberink, M.N. Harakeh, R. Hoekstra, L. Huisman, K. Jungmann, H. Kiewiet, R. Morgenstern, J. Mulder, G. Onderwater, A. Rogachevskiy, M. Sohani, M. Stokroos, R. Timmermans, E. Traykov, L. Willmann and H.W. Wilschut Uppsala, Sweden, 2-6 May 2005 Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

TRI  P project and facility Ion Catcher RFQ Cooler MOT Beyond the Standard Model TeV Physics Nuclear Physics Atomic Physics Particle Physics Production Target Magnetic Separator MeV meV keV eV neV AGOR cyclotron AGOR cyclotronIon catcher (thermal ioniser or gas-cell) Low energy beam line RFQ cooler/buncher MOT D D D D Q Q Q Q Q Q Q Q Magnetic separator Production target Wedge Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Our RFQ cooler/buncher concept Buffer gas pressure (He): ~10 -1 mbar RFQ ion coolerRFQ ion buncher 10eVthermal Trap position U+Vcos  t -(U+Vcos  t) 2 x 330 mm Switching on end electrodes RF capacitive coupling DC drag resistor chain Electronics designed for large range of isotopes UHV compatible design and materials Standard vacuum parts (NW160) ~10 -3 mbar Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

RFQ cooler prototype tests RFQ in vacuum Transverse cooling Velocity damping With and without a drag voltage on the segments Tests: Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

RFQ cooler/buncher design Pressure cooler: ~10 -1 mbar ~10 -3 mbar He buffer gas Separate connections for trap segments Changeable separation electrodes with different aperture diameters Buffer gas: Helium for light ions (i.e. Na-21) (Heavier gas may be considered for Ra ions) Kapton foil 12.5  m 120 pF Stainless steel rods OFHC copper Preset frequencies: 0.5MHz, 1 MHz, 1.5 MHz RF amplitude: 150 V (peak-to-peak) UHV compatible resistors for drag voltage : Uncoated, 2.2 k  Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Simulations and calculation of E field Simulations Real 3D geometry Material properties Geometry separated to smaller parts Fine mesh and grid size 3D electric field map (RF and DC) RF electric potentialDC drag potential FEMLAB calculation examples: F (x,y,z,t) = m * (dV (x,y,z,t) /dt) F (x,y,z,t) = E (x,y,z,t) * q dV (x,y,z,t) =(E (x,y,z,t) * q/m) * dt dr (x,y,z,t) =dV (x,y,z,t) * dt Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Program input: Ion charge Ion mass KE Phase space distribution Electric field map (RF and DC) f RF RF amplitude Drag voltage step Gas pressure Standard ion mobility Number of ions Time step Program output: Single ion tracing Phase space distribution Confinement Transmission through exit aperture Ion tracing and distributions Mathieu equation: aUaU qVqV q max = RF only (U=0) Ion tracing in RFQ guide Buffer gas cooling + DC drag Phase space distributions Ion trapping and extraction Confinement and transmission Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Optimization using the simulations Main goal: collect all ions Confinement and transmission Optimize parameters (regions of stable operation): pressure and type of gas aperture diameters beam settings at entrance drag voltage step potentials on separation electrodes accumulation time (buncher) trap potential depth and shape Questions: phase dependence (cooler-buncher) phase dependence (switching) where do we loose ions (why?) ~ 2 eV q=0.5 p=0.025 mbar drag voltage=0.5V Buffer gas pressure RF: 1500 kHz, 21 Na +, 10 eV 950 m/s maximum transverse velocity 0.5 V drag voltage step Gas pressure  drag voltage Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Drag voltage and pressure dependence Drag voltage step 21 Na +, 10 eV Pressure: 0.01 mbar RF: 1500 kHz 950 m/s maximum transverse velocity  2 mm aperture 0.01 mbar – too low, exit energy high Drag voltage step 21 Na +, 10 eV Pressure: mbar RF: 1500 kHz 950 m/s maximum transverse velocity  2 mm aperture mbar low pressure limit Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Frequency and focus dependence Frequency 21 Na +, 10 eV 0.1 mbar buffer gas pressure 950 m/s maximum transverse velocity 0.5 V drag voltage step  2 mm aperture Higher frequency is preferred Maximum transverse velocity 21 Na +, 10 eV 1500 kHz radio frequency 950 m/s maximum transverse velocity 0.5 V drag voltage step  2 mm aperture Beam properties at entrance: just focus Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Cool and select Mass selectivity for 23 Na + / 21 Na + Scan line: U/V = const=0.17 m>M M m<M mass resolution  frequency q a RF and DC operation: Mass filter Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

LEBL and optimization of parameters (work in progress) LEBL parts: Extraction tube Einzel lenses Electrostatic steerers Quadrupole deflectors Low energy beam line RFQ cooler/buncher MOT EL QD ET Ion catcher Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics

Magneto-Optical Traps for 21 Na decay studies (work in progress) Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics Collector MOT - Designed for optimal collection - Large laser beam diameter Decay MOT - 4  recoil collection - Multi-detector setup for  -detection  - detectors ports Equipotential rings MCP for recoils Lasers not shown! Atom cloud position

Conclusion TRI  P on track and facility ready for users RFQ cooler and buncher system ready All parts to be tested together soon Trapped Radioactive Isotopes:  icro-laboratories for Fundamental Physics