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AEgIS – Antimatter E xperiment: gravity , Interferometry , Spectroscopy Present status and future perspectives Stefano Aghion a,b on behalf of the AEgIS collaboration a Department of Physics, Politecnico di Milano, Milano, Italy
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AEgIS – AntimatterExperiment: gravity, Interferometry, Spectroscopy Present status and future perspectives Stefano Aghion a,bon behalf of the AEgIS collaboration a Department of Physics, Politecnico di Milano, Milano, Italy b INFN – IstitutoNazionale di FisicaNucleare, Milano, Italy QuAMP 2013, Swansea
OUTLINE /20 • THE AEgIS EXPERIMENT • Scientific aims • Basic Idea • Experimental layout • Measurement procedure • ACHIEVEMENTS 2012 • Status of the apparatus • Antiproton Catching and Cooling • Test on position sensitive detectors • FUTURE PERSPECTIVES • Ps excitation laser experiments QuAMP 2013, Swansea
AEgIS – SCIENTIFIC AIMS /20 Test of WEP (Weak Equivalence Principle) for antimatter AEgIS – 1st PHASE ? • Main goal: • Measurement of the Earth’s gravitational acceleration g on antihydrogen, within 1% of precision AEgIS – 2nd PHASE Test of CPT invariance (Charge Parity Time) • Antihydrogen spectroscopy QuAMP 2013, Swansea
AEgIS - BASIC IDEA /20 e+ e+/cold Ps converter Laser for Ps excitation in Rydberg states Charge Exchange Reaction moirèdeflectometer Ps* • Cross section σ of the order of 10-8 cm2 if: • nPs≈ 20-40 ( ) • vPs≤ 104 m/s • Cold -> Cold • Rydberg Ps ->Rydberg Kellerbauer A et al., 2008 Nucl. Instrum. Methods Phys. Res. B 266 351 QuAMP 2013, Swansea
AEgIS - EXPERIMENTAL LAYOUT /20 Positron trap and accumulator 5 T magnet + 1 T magnet Transfer line 107 5.3 MeV/100 s Antiprotons from AD Malbert-Penning trap Moirèdeflectometer QuAMP 2013, Swansea
AEgIS - EXPERIMENTAL LAYOUT /20 Positron apparatus Two stage Surko type Trap Positron trap Positron accumulator Positron source Na22 ≈108 e+/200 s 40 mCi Antiprotons from AD 107 5.3 MeV/100 s QuAMP 2013, Swansea
e+ p AEgIS - EXPERIMENTAL LAYOUT /20 5 Tesla region 4 K 1 Tesla region 100 mK Moire deflectometer e+/cold Ps converter Antiprotontrapping and cooling ≈108 e+ Antiprotons from AD 107 5.3 MeV/100 s QuAMP 2013, Swansea
Positronbeam SiO2 Si Ps Ps Ps Ps Ps AEgIS - EXPERIMENTAL LAYOUTPositronium Converter /20 NANO – CHANNELLED SILICA Time of Flight (TOF) • Channel diametersize 4-6 nm • High o-Ps production ≈ 40÷50 % • 2% of implanted e+ emitted as o-Ps with v<5•104 m/s • Scheduled TOF measurements at lower temperatures Mariazzi S, Brusa R S et al., 2010 Phys. Rev. Lett. 104, 243401 QuAMP 2013, Swansea
AEgIS- MEASUREMENT Antihydrogen formation /20 • Antiproton cloud @ 100 mK • ≈ 105 cold antiprotons • Laser excitement of cold Ps • Two step laser excitation1: • UV laser (λ=205 nm) nPs=1->3 • IR laser (λ=1670 nm) nPs=3->25-35 • ≈ 108 e+-> 5*106 excited Ps atoms • Cold and Rydberg • Charge exchange reaction -> • ≈ 102-103 /200 s • Maxwell-Boltzmann distribution with <v> ≈ 50 m/s • acceleration • Electric field gradients ->Stark effect [1]F. Castelli, I. Boscoli, S. Cialdi, D. Comparat, 2008 Phys. Rev. A 78 052512. QuAMP 2013, Swansea
AEgIS – MEASUREMENT /20 MOIRÉ DEFLECTOMETER Fringe pattern shift: g Fitting the experimental data -> g ! Spatial resolution <10μm to obtain 1% precision QuAMP 2013, Swansea
OUTLINE /20 • THE AEgIS EXPERIMENT • Scientific aims • Basic Idea • Experimental layout • Measurement • ACHIEVEMENTS 2012 • Status of the apparatus • Antiproton Catching and Cooling • Test on position sensitive detectors • FUTURE PERSPECTIVES • Ps excitation laser experiments QuAMP 2013, Swansea
ACHIVEMENTS – STATUS OF THE APPARATUS /20 5 T magnet and traps QuAMP 2013, Swansea
ACHIVEMENTS – STATUS OF THE APPARATUS /20 Laser system QuAMP 2013, Swansea
ACHIVEMENTS – STATUS OF THE APPARATUS /20 1 T magnets trap Positron system e+/Ps converter
ACHIVEMENTS – ANTIPROTON CATCHING AND COOLING /20 • Antiproton ( ) catching: • Linear dependence on trapping voltage • At 9 kV 1,2×105 p- caught on 3,1×107. Trapping efficiency of 0,4 % • Antiproton cooling: • 90% of antiprotons cooled to eV range within 20 s QuAMP 2013, Swansea
ACHIVEMENTS – TEST ON POSITION SENSITIVE DETECTORS /20 MINI-MOIRÈ with NUCLEAR EMULSION DETECTOR The mean shift of 8.6 μm is consistent with a mean parasitic force on antiprotons of 520 aN ! QuAMP 2013, Swansea
OUTLINE /20 • THE AEgIS EXPERIMENT • Scientific aims • Basic Idea • Experimental layout • Measurement • ACHIEVEMENTS • Status of the apparatus • Antiproton Catching and Cooling • Test on position sensitive detectors • FUTURE PERSPECTIVES • Ps excitation laser experiments QuAMP 2013, Swansea
PERSPECTIVES – POSITRONIUM PHYSICS /20 No antiprotons for 2013 and for a part of 2014 → Ps is one of the priority • Ps excitation laser experiments • Ps spectroscopy • Ps laser cooling QuAMP 2013, Swansea
SUMMARY /20 • Test on the AEgIS apparatus started in2012 • Positron apparatus • Antiprotons catching and cooling • Position sensitive detectors • Measurements on Ps formation and excitation will be performed at the end of 2013 • Test with protons are scheduled for the beginning of 2014 • Gravitational acceleration measurement scheduled for the end of 2014 QuAMP 2013, Swansea
THANKS FOR YOUR ATTENTION /20 QuAMP 2013, Swansea