Particle, manipulation techniques in AE IS. (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) C. Canali INFN sez. Genova (AEgIS coll.

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1 Particle, manipulation techniques in AE IS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) C. Canali INFN sez. Genova (AEgIS coll.) TCP2010 April 12-16, 2010 Saariselkä

2 TCP2010 April 12-16, 2010 Saariselkä C. Canali LAPP, Annecy, France D. Sillou Queen s U Belfast, UK G. Gribakin, H. R. J. Walters U of Qatar, Doha, Qatar I. Al-Qaradawi L. V. Jorgensen INFN Firenze, Italy G. Ferrari, M. Prevedelli CERN, Geneva, Switzerland J. Bremer, G. Burghart, M. Doser, A. Dudarev, T. Eisel, F. Haug, D. Perini INFN Genova, Italy C. Canali, C. Carraro, L. Di Noto, D. Krasnický, V. Lagomarsino, G. Manuzio, G. Testera, R. Vaccarone, S. Zavatarelli MPI-K, Heidelberg, Germany A. Kellerbauer, U. Warring U of Heidelberg, Germany P. Bräunig, F. Haupert, M. K. Oberthaler U of Lyon, France P. Nédélec INFN Milano, Italy I. Boscolo, F. Castelli, S. Cialdi, M. Giammarchi, M. Sacerdoti, D. Trezzi, F. Villa Politecnico di Milano, Italy G. Consolati, R. Ferragut, A. Dupasquier INR, Moscow, Russia A. S. Belov, S. N. Gninenko, V. A. Matveev New York U, USA H. H. Stroke Laboratoire Aimé Cotton, Orsay, France L. Cabaret, D. Comparat U of Oslo, Norway J. P. Hansen, O. Rohne, H. Sadake INFN Padova, Trento, Italy G. Nebbia, R. S. Brusa, S. Mariazzi INFN Pavia/Brescia, Italy G. Bonomi, L. Dassa, A. Fontana, C. Riccardi, A. Rotondi, A. Zenoni Czech Technical U, Prague, Czech Republic V. Petráček INRNE, Sofia, Bulgaria N. Djourelov ETH Zurich, Switzerland S. D. Hogan, F. Merkt

3 AEGIS Antimatter Experiment: Gravity, Interferometry, Spectroscopy Physical motivations: why antimatter? Gravity and antimatter AEGIS: measuring g on antihydrogen Apparatus overview Measuring g on H Inside AEgIS: particle manipulation techniques Diocotron jump of plasma at low magnetic field Cooling down antiprotons Conclusion

4 AEGIS Antimatter Experiment: Gravity, Interferometry, Spectroscopy Physical Motivations: why antimatter? Gravity and antimatter AEGIS: measuring g on antihydrogen Apparatus overview Measuring g on H Inside AEgIS: particle manipulation techniques Diocotron jump of plasma at low magnetic field Cooling down antiprotons Conclusion

5 Antimatter system: CPT: Gravity: e - e + e - e + (q/m) Magnetic moment (g - 2) WEP test p p Charge/mass (q/m) General Relativity test K 0 K 0 Mass differencef μ - μ + (g - 2) relative precision [P. B. Schwinberg et al., Phys. Lett. A 81 (1981) 119] [R. S. Van Dyck, Jr. et al., Phys. Rev. Lett. 59 (1987) 26] [G. Gabrielse et al., Phys. Rev. Lett. 82 (1999) 3198] [Y. B. Hsiung, Nucl. Phys. B (PS) 86 (2000) 312] [G. W. Bennett et al., Phys. Rev. Lett. 92 (2004) ] Spectroscopy on antihydrogen

6 High precision spectroscopy: The frequency of the 1S-2S transition in hydrogen has been measured with high precision: f = (46) Hz Gravity measurement (AEgIS): Charged particles are extremely sensitive to electric fields: we need a neutral system 7 E 610 V / m a 10 s m2 [M. Niering et al., Phys. Rev. Lett. 84 (2000) 5496] Antimatter gravity has to this day never been investigated directly! WEP test Spectroscopy on antihydrogen could be a very precise test of CPT We need neutral (cold) antimatter: Anti-hydrogen!

7 General relativity is a classical (non quantum) theory! V m m G r ae r / v Tensor Newton, always attractive Vector repulsive between like charges Scalar always attractive be r / s The non-newtonian terms could (almost) cancel out if a b and v s, but would produce a striking effect on antimatter Matter-matter: matter-antimatter: a b 0 a b 0 [T. Goldman, M. Nieto Phys. Lett 112B (1982)] [ E. Fischbach, C. Talmadge The search for Non Newtonian Gravity Springer]

8 AEGIS Antimatter Experiment: Gravity, Interferometry, Spectroscopy Physical Motivations: why antimatter? Gravity and antimatter AEGIS: measuring g on antihydrogen Apparatus overview Measuring g on H Inside AEgIS: particle manipulation techniques Diocotron jump of plasma at low magnetic field Cooling down antiprotons Conclusion

9 The AD Antiproton Decelerator 10 7 antiprotons every ~90 s 0.1 GeV/c 200 ns bunches asacusa alpha Stochastic cooling Electron cooling Goal: producing an horizontal beam of antihydrogen And measuring its vertical deflection over a path of 1m. [J. Y. Hémery & S. Maury, NPA 655 (1999) 345c] [Proposed antimatter gravity measurement with an antihydrogen beam. By AEGIS Proto Collaboration (A. Kellerbauer et al.) pp. Nucl.Instrum.Meth.B266: ,2008. ] 1% precision is expected in the first phase.

10 AD SIDE The AEgIS apparatus Positrons source Positrons accumulator Positrons Transfer line 5 Tesla Magnet 4K region Cathing pbars from AD 1Tesla Magnet 100mK region Pbars cooling Hbar prod. Moire deflect. g-meas. p

11 Trap scheme Catching and cooling Antiprotons from A.D. Ps* production (target + lasers) Moire deflectometer B = 5 T T = 4 K B = 1 T Position sensitive detector Positrons and electrons are in plasma regime Collective behaviour! Pbars cooling (100 mk region) Antihydrogen production: p Ps * H * e Antihydrogen atoms are produced at temperature of pbars prior to recombination!!!

12 + Catching pbars B = 5 T T = 4 K HV ON > 10 4 pbars confined and cooled in the 4K trap HV ON Electron plasma 10 8 e - electron cooling (t 10 s) [1] S. L. Rolston and G. Gabrielse Cooling antiprotons in an ion trap Volume 44, Numbers 1-4 / March, 1989 [2] The ATHENA antihydrogen apparatus Nucl. Inst.Meth. Phys. Res. A 518, (2004)

13 + Antihydrogen production B = 1 T 100 mk region e + Positrons transfer and diocotron jump on target p Cooling of antiprotons Down to 100mK The temperature of Pbars here will determine the temperature of produced H-bar! [J. Fajans et al., PHYS. REV. LETT. 82,22] [J. R. Danielson, T. R. Weber, and C. M. Surko PHYS. OF PLASMAS 13, ]

14 + Beam formation and g meas. e + nanoporous material target (Ps conversion) p 0.75 ev n=3 n= ev p Ps * H * e Stark accelerator n=1 [E. Vliegen & F. Merkt, J. Phys. B 39 (2006) L241]

15 x The beam is produced using a stark accelerator: H is in Rydberg state Interactions between electric dipole moment and a non-uniform electric field: F 3 2 nke Δv of several 100 m/s within about 1 cm Electric fields: few 100 V/cm (limited by field ionization) Already working with Rydberg hydrogen! [E. Vliegen & F. Merkt, J. Phys. B 39 (2006) L241] V h = 600 m/s V h = 400 m/s V h = 300 m/s V h = 250 m/s counts

16 AEGIS Antimatter Experiment: Gravity, Interferometry, Spectroscopy Physical Motivations: why antimatter? Gravity and antimatter AEGIS: measuring g on antihydrogen Apparatus overview Measuring g on H Inside AEgIS: particle manipulation techniques Diocotron jump of plasma at low magnetic field Cooling down antiprotons Conclusion

17 Diocotron off-axis jump of plasma: Off axis jump must be precise (θ,d) e + reproducible High efficiency (no particle loss) only small expansions of plasma are tolerable Positrons confined into the MP trap, are in plasma regime and have collective behaviour! N 10 7 n 10 8 e+/cm 3 R,z mm This techniques has been studied by [1]. AEgIS requires to implement it into a lower magnetic field and to different shape of plasma Several tests have been performed in our apparatus with electrons matching the condition of the AEgIS apparatus Results will be presented in the following slides [1] [J. R. Danielson, T. R. Weber, and C. M. Surko PHYS. OF PLASMAS 13, ] [J. Fajans et al., PHYS. REV. LETT. 82,22]

18 N 10 E+6 Experimental setup INFN Genova, Italy C. Canali, C. Carraro, L. Di Noto, D. Krasnický, V. Lagomarsino, G. Manuzio, G. Testera, R. Vaccarone, S. Zavatarelli MCP + Phosphor screen electron source Trap radious r = 7 mm B = 0.5-2T Faraday cup CCD T=300K P=10-10 mbar Electrons confined into the MP trap, are in plasma regime and have collective behaviour! Load electrons into the trap Applying rotating wall Diagnostic on plasma N = 10 8 N e- n = 10 8 e- / cm3 R P < 1 mm Z p = 2-3 cm T [s]

19 Diocotron excitation B cne R R f R R f W P E W P D 2 2 For a long plasma column (L P >>R P ) the linear frequency of diocotron motion (m θ =1) is: R P and R W are the plasma and the trap radius. For large displacements a non linear shift in the frequency arise: w D NL R d f f There is a relationship between f NL and d Bringing the plasma diocotron mode in resonance to a certain frequency is equivalent to move it off axis to a distance d. Rw d

20 Diocotron drive Plasma enter in autoresonance regime 30 Phase difference Φ d θ Diocotron signal f 1 = 3 khz t 1 = 5 ms f 2 = 6 khz t 2 = 5 ms f 3 = 9 khz t 3 = 5 ms 30 Dump pulse trigger (Plasma is ejected on the MCP) d = displacement from trap center θ = angle

21 Φ = 0 Φ = 180 Φ = Dump Pulse trigger Dump Pulse trigger Dump Pulse trigger

22 Plasma angle [deg] Ne = d n = 10 8 cm -3 R p = 0.7 mm θ Diocotron Phase [deg] The angle θ can be precisely controlled by synchronizing diocotron excitation signal and the dump pulse

23 Radial displacement is controlled by the driving frequency The diocotron jump works at low field with The desidered shape of plasma B = 2T B = 0.5 T 12 khz (5.5 mm) 9 khz (2.5 mm) khz (5.0 mm) 20 khz (2.0 mm) 6.5 khz (0.5 mm) khz (0.6mm)

24 AEGIS Antimatter Experiment: Gravity, Interferometry, Spectroscopy Physical Motivations: why antimatter? Gravity and antimatter AEGIS: measuring g on antihydrogen Apparatus overview Measuring g on H Inside AEgIS: particle manipulation techniques Diocotron jump of plasma at low magnetic field Cooling down antiprotons Conclusion

25 Cooling of antiprotons can be performed with several tecniques: Electron cooling (thermal equilibrium between antiprotons and electron plasma) [S.L. ROLSTON and G. GABRIELSE Hyperfine Interactions 44 (1988) ] 4 K 0.5 K p e- Resistive cooling (electron plasma is cooled using a tuned circuit) [Lowell S. Brown and Gerald Gabrielse Rev. Mod. Phys. 58, (1986)] 0.5 K 0.1 K 100 mk 50 m/s pbar L C Sympatetic cooling with negative ions (heavy negative ions are laser cooled and placed ) [A. Kellerbauer & J. Walz, New J. Phys. 8 (2006) 45] mk

26 Resistive cooling: In a magnetic field electrons radiate their cyclotron energy and they come into equilibrium with the environment At temperature lower than few Kelvin electron cooling procedure is limited for quantum reasons: minimum cyclotron energy (n=0) is 0.5 K (100 µk) B=1T E C ( n 1) 2 c Still the axial motion of electrons can be further cooled down: L C R = Qω z L An electron sees a real impedance R with a value proportional to the Q of the tuned circuit: R = Qω z L

27 Tuned circuit: L C 50 mk region of diluition cryostat LNA 4-10 K Resonant frequency MHz The resonant circuit has been 4K: Superconducting coil: Copper coil: The Q-Factor of the circuit seems to be limited by the capacitor, not by the coil A LNA cryogenic can be used For a non destructive diagnostic on confined particles

28 Sympathetic cooling of antiprotons with negative ions: ion plasma X / Suggested by: [A. Kellerbauer & J. Walz, New J. Phys. 8 (2006) 45]

29 Sympathetic cooling antiprotons with negative ions: Os is the only known negative ion with transition suitable for laser cooling The possibility of using Os - for indirect laser cooling is under investigation, Some important milestones have been reached MPI-K, Heidelberg, Germany Alban Kellerbauer Arne Fischer (grad student) Ulrich Warring (Ph.D. student) Raoul Heyne (grad student) Marco Amoretti (post-doc), Jan Meier (grad student) Christoph Morhard (Ph.D. student) Carlo Canali (post-doc) [A. Kellerbauer & J. Walz, New J. Phys. 8 (2006) 45]

30 High-Resolution Laser Spectroscopy on the Negative Osmium Ion has been performed: ν = (30) THz λ = (14) nm (factor 100 improvement) σ 0 = 2.5(7) cm 2 [U. Warring et al., Phys. Rev. Lett. 102 (2009) ]

31 The hyperfine structure of the bound bound transition in two Os isotopes with a non-zero nuclear spin has been measured: 187 Os Os - Using the knowledge of the ground and excited state angular momenta, the full energy level diagram in an external magnetic field was calculated [A. Fischer, Laser spectroscopy on the negative osmium ion, Diploma thesis, University of Heidelberg (2009). Phys. Rev. Lett. 104 (2010)

32 This suggest a scheme for laser cooling based on a double laser wavelenght: [A. Fischer, Laser spectroscopy on the negative osmium ion, Diploma thesis, University of Heidelberg (2009). Phys. Rev. Lett. 104 (2010)

33 Conclusions: AEgIS intend to measure the gravity acceleration of antihydrogen This will be the first direct measurement of gravity on antimatter Several weel-estabilished techniques (experience of past experiments), and some innovative scheme have to be tested or implemented in AEgIS Some experimental results on plasma manipulation have been shown Some ideas about the cooling of antiprotons have been discussed The AEgIS apparatus is under construction

34 Thanks for your attention