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Commissioning of the Radio Frequency Quadropole Buncher Cooler TRIµP – Trapped Radioactive Isotopes: µ-laboratories for fundamental Physics U Dammalapati, S. De, P G Dendooven, O Dermois L. Huisman, K Jungmann, A.J. Mol, G Onderwater, A Rogachevskiy, M Sohani, E Traykov, L Willmann and H W Wilschut Lorenz Willmann SMI-06, Groningen 27/28.3.2006 TRImP project and facility Magnetic Separator Ion Catcher RFQ Cooler Atomic Physics Production Target Nuclear Physics AGOR cyclotron Wedge Q MeV D Particle Physics Q Q Q D D Q Q D keV Production target Q Q eV Thermo Ionizer: Thermo-ioniser meV Talk by M. Sohani MOT Beyond the Standard Model TeV Physics Magnetic separator RFQ cooler/buncher neV AGOR cyclotron MOT MOT Low energy beam line Trapped Radioactive Isotopes: micro-laboratories for Fundamental Physics Experimental Program of TRImP group Investigating discrete symmetry violations C, P, and T. • Origin of Parity Violation in Weak Interactions • details of b-decays Na, Ne isotopes • Dominance of Matter over Antimatter CP - Violation Time Reversal Symmetry Parity Violation permanent electric dipole moments Ra isotopes Why do we need neutral atom traps? The role of atom trapping • long storage times • isotope (isomer) selective • spin manipulation • point source, no substrate • recoil ion momentum spectrometry • state preparation (for APNC,edm…) • “low” EM fields (otherwise ion traps) • Ideal environment for precision experiments Magnetic Separator Ion Catcher RFQ Cooler Atomic Physics Production Target Nuclear Physics AGOR cyclotron TRImP project and facility Magnetic separator Wedge Q MeV D Q Q Particle Physics D D Q Q D keV Production target Q Q eV meV AGOR cyclotron MOT Beyond the Standard Model TeV Physics Q MOT neV MOT Low energy beam line Trapped Radioactive Isotopes: micro-laboratories for Fundamental Physics TRImP RFQ cooler/buncher concept • RF capacitive coupling • DC drag resistor chain 2 x 330 mm U+VcosWt -(U+VcosWt) • Standard vacuum parts (NW160) • UHV compatible design and materials • RF: 05-1.5MHz, 200Vpp, Buffer gas pressure (He): ~10-1 10eV ~10-3 mbar RFQ ion cooler thermal Trap position mbar RFQ ion buncher Switching on end electrodes RFQ System/Drift Tube Pulsed extraction tube RFQ buncher RFQ cooler Ion Pulses to experiments pHe ~ 10-6 mbar Beam from TI pHe ~ 10-3 mbar pHe ~ 10-1 mbar Background pressure 10-8 mbar RFQ Rods: • Many UHV resistors • segments individually coupled • flexible axial potential design • few RF connections Drift tube Accelerator: • ideal for pulsed setup • no HV platform Transmission efficiencies with He buffer gas 80 23Na+ ions @ 10 eV, 15 eV 70 60 pA pA U(acc) = 10 V, V 15 V p(1): p(1) =from 3.5*10 10-6-2 to mbar 10-1 mbar U(4): from 0 V to +36 V (EL2), EL3 and (EL3) (10)and connected (10) to pA-meter connected to pA-meter (11) at same potential as (1) pA 50 40 30 20 10 0 -10 0 -20 EL1 EL2 EL3 MCP Ion Source (1) p(1) (8) (11) (7) (9) (10) p(2) (3) (5) (4) Low Energy beam line (RFQ1) = I(EL3+10)/I(load) = = I(10) 50÷70% Both I(EL2) and increase with increase of difference between U(3,5) and U(4) (DU 14 V) (RFQ2) = I(10)/I(EL3+10) = = 50÷80% 22 10 20 9 18 8 I(EL2) RF off 16 7 12 10 8 6 I [pA] 14 6 5 I(EL3) 4 3 I(EL2) 2 4 2 Drift tube 1 0 I(10) 0 1.0E-05 0 5 10 1.0E-04 15 20 25 U(3,5) - U(4) [V] 1.0E-03 I(EL3) I(10) 30 35 40 1.0E-02 Acceleration-deceleration (RFQ1+RFQ2) = I(10)/I(load) = essential for transmission = 25÷40% between RFQ1 and RFQ2! I(load) = max.(I(EL2)+I(EL3)+I(10)) 1.0E-01 Simple Diagostic Tool: MCP with phosphor screen • Positional resolution, transverse emittance • Counting mode for low rate -2 119 V pp 2 2 y [mm] y [mm] 2 -2 2 -2 -2 x [mm] x [mm] 120 V pp Filling of trap with different loading rates Space charge limited Heater Current On ion source Storage times of RFQ buncher Storage time limitations: - Space charge effect - Impurities in the gas 3.5.10-4 mbar He gas (~10-8 mbar background) Na+ ions remaining in trap [%] . 100 10 1 0 5 10 Storage time [s] without baking of system and standard gas purity (Helium 5.0) 15 Direct detection of ion pulse on readout electrode Signal [V] Charge integrating amplifier • rise time 40 nsec • integration time 20 msec • sensitivity 1 mV/1500 ions • noise 3 mV Storage time 100 msec 10 msec 1 msec Extraction pulse Drift tube pulse Time [ms] Data averaged over 128 extraction cycles TRImP RFQ cooler buncher system • Storage time several seconds achieved -> purity of buffer gas expected 21Na production rate fills trap in 1s • Drift tube accelerator -> no high voltage platform • Good transmission > 70% of RFQ • Vacuum conditions good to couple to Magneto-optical Trap More results in the forthcoming thesis of Emil Traykov Coupling of RFQ and Low Energy beamline to MOT Trapping while operating RFQ achieved last Friday -> good differential pumping