The CERN Antiproton Physics Programme - The Antiproton Decelerator (AD) & ELENA Dániel Barna Wigner Research Centre for Physics, Budapest, Hungary ● The CERN antiproton facilities ● Experiments, their programmes and results The CERN Antiproton Decelerator ● Deceleration: 3.57 GeV/c → 100 MeV/c (Ekin=5.3 MeV) ● Stochastic and electron cooling ● 1 bunch (~107 P) / 100 s (beam steering is painfully slow...) ELENA – The future of antiprotons @ CERN ● ELENA = Extra Low ENergy Antiproton ring – under construction! ● Extension to the Antiproton Decelerator, 30.4 m circumference ● Further decelerate antiprotons to 100 keV to improve efficiency of experiments ● Allow simultaneous running of multiple experiments The ELENA Ring electron cooler ELENA: electrostatic beamlines p/H- source for commissioning and quick beamline setup ELENA: electrostatic beamlines p/H- source for commissioning and quick beamline setup pin pout The ELENA Ion Switch Installed and commissioned with 100 keV H- beam ELENA: electrostatic beamlines 4 bunches (1 μs) per shot: 4 experiments can run in parallel Quick electrostatic switches distribute beam to 4 experiments running parallel ELENA: electrostatic beamlines Static spherical deflectors where no quick switching is needed Quick switches and deflectors FastFast deflector deflector (<1 (<1 μs) μ givings) giving 220220 mrad mrad kick kick (J. (J.Borburgh Borburgh et.al.) et.al.) Spherical electrostatic deflector giving 33o deflection ELENA: electrostatic beamlines Straight sections: electrostatic quadrupoles - FODO transport Quadrupole doublet + steerer unit The antiproton physics programme at CERN Running and planned experiments at the AD & ELENA ● ATRAP (Antihydrogen TRAP) H laser spectroscopy (to come), p magnetic moment & q/m ● ALPHA (Antihydrogen Laser PHysics Apparatus) H laser & mw spectroscopy, gravity (to come) ● Asacusa (Atomic Spectroscopy And Collisions Using Slow Antiprotons) H mw spectroscopy, p-He laser spectroscopy (mp/me), antiproton dE/dx, σannihil in matter ● BASE (Baryon Antibaryon Symmetry Experiment) p magnetic moment & q/m ● AEGIS (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) H gravity ● GBAR (Gravitational Behaviour of Antihydrogen at Rest) Future, with ELENA: H gravity ● ACE (Antiproton Cell Experiment) cancer therapy, finished Running and planned experiments at the AD & ELENA ● ATRAP (Antihydrogen TRAP) H laser spectroscopy (to come), p magnetic moment & q/m ● s ALPHA (Antihydrogen Laser PHysics Apparatus) nt H laser & mw spectroscopy, gravity e im ● Asacusa (Atomic Spectroscopy And Collisions Using Slow Antiprotons)er H mw spectroscopy, p ex p-He laser spectroscopy (m /m ), p e ed antiproton dE/dx, σ in matter s annihil ba ● - BASE (Baryon Antibaryon Symmetry Experiment) ap p magnetic moment & q/m Tr ● AEGIS (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) H gravity ● GBAR (Gravitational Behaviour of Antihydrogen at Rest) Future, with ELENA: H gravity ● ACE (Antiproton Cell Experiment) cancer therapy, finished The antiproton physics programme ● Most experiments want to compare proton- antiproton properties: test CPT ● ... which works very well so far. Need to find very tiny differences. High-precision physics. ● Antiproton physics is interesting: these experiments are the highlight visit targets when LHC is running... ● ... it produces important physics results as well! Antiproton physics is on the headlines ALPHA experiment Antiproton physics is on the headlines ATRAP experiment ASACUSA experiment Antiproton physics is on the headlines am! n be roge hyd Anti ASACUSA experiment Antiproton physics is on the headlines ASACUSA experiment Antiproton physics is on the headlines Assuming CPT, antiprotonic helium results contribute to the official value of proton/electron mass ratio ACE Antiproton Cell Experiment Antiproton Cell Experiment ● Goal: highest localised energy deposition in the tissues, without damaging the surroundings charged particles photons (protons) antiprotons Antiprotons can be more efficient Simulation Antiproton Cell Experiment ● Until they stop, they deposit about the same energy as protons ● Annihilation: ~ 30 MeV strongly localised energy deposition π π π π p n p p p n n π π π π n Nucleus recoil: to o slow, low range h p Fission Relativistic pions have fragments small energy deposition slow, short range Antiproton Cell Experiment Target: cells suspended in gel Sliced after irradiation to measure survival rate 50 MeV antiproton beam Survival probability rate survival higher zone: non-targeted Protons A ntiproton Depth C ell E rate survival smaller zone: Targeted xperiment Antiprotons Depth ALPHA Synthesis of antihydrogen Laser & MW spectroscopy, gravity e+ source Superconducting Penning trap Production and trapping of antihydrogen for laser spectroscopy 1) Capturing antiprotons Penning-Malmberg trap (=multiring trap) Longitudinal magnetic field p (5.3 MeV) Production and trapping of antihydrogen for laser spectroscopy 1) Capturing antiprotons 2) Cooling by electrons in the same trap Production and trapping of antihydrogen for laser spectroscopy 3) To capture oppositely charged positrons in the same trap: modify the potential antiprotons positrons V1 V2 V3 V7 Production and trapping of antihydrogen for laser spectroscopy 4) Antihydrogen synthesis Antiprotons need to get in contact with positrons, at low velocities antiprotons ● Excite axial motion of antiprotons... positrons ● ...in an anharmonic potential (frequency is a function of amplitude) ● Use a frequency-chirped excitation (frequency is function of time) to precisely control the oscillation amplitude... ● ...and align the 'turnover' point of antiprotons (v=0) with positrons ● Autoresonant excitation (C.Amole, et.al., Phys. Plasmas 20, 043510 (2013)) Production and trapping of antihydrogen for laser spectroscopy 5) Trap antihydrogen for laser spectroscopy The neutral antihydrogen escapes the Penning-Malmberg trap immediately. Add a multipole magnetic field (“Ioffe-Pritchard” trap) with H minimal magnetic field at the centre. Nature 7 The “low field seeking” spin-states of H can be trapped if initial kinetic energy < trap depth (for more than 1000 s!) (2011), 558 Alpha achievements ● H synthesized and trapped routinely (1 trapped H per attempt (20min) & 104 p), practically arbitrarily long (Nature 7 (2011), 558) ● Shining on-resonance MW onto trapped H induced spin-flip and escape from trap resonant MW on (yes-no experiment, no spectroscopy yet) (Nature 483(2012), 439) Will be improved in future ● Quickly switch off magnetic trap and observe “free fall” (annihilation position) time [s] -65 < mH,grav / mH,inertial < 75 (95% conf.lev) Dedicated setup (vertical trap) is planned in the future ● 1s-2s laser spectroscopy is coming this summer, probably. Spectroscopy of antihydrogen TODAY: ALPHA: ~ 1 trapped H per attempt (104 p ) ATRAP: ~ 5 trapped H per attempt (106 p, 2 heures) FUTURE (probably this year): laser spectroscopy of trapped antihydrogen H 1s-2s laser spectroscopy with a single atom? ● H has a finite oscillation in the trap ● Overlap with the focussed laser beam? ● Need long interaction time. Cosmic background would exceed the signal over a long period (remember: there is probably just 1 H in the La trap) ser ● After a 1s --> 2s transition a second photon from the same laser ionizes the H ● Keep the charged-particle trap ON as well, which captures p after the ionization ● Integrate over a long time ● Then suddenly switch off the trap and detect if there was a p ATRAP Antihydrogen synthesis and laser spectroscopy, p q/m and μ Antihydrogen production by Cesium (ATRAP) Cs Cs (excited) Antihydrogen production by Cesium (ATRAP) e+e+ e-e- e+e+ e+e+ e-e- e-e- e+e+ e-e- Cs+ Antihydrogen production by Cesium (ATRAP) e+e+ pp e-e- H (excited) Possible to control H state by the laser energy Magnetic moment of antiproton: ATRAP B~5.7 Tesla Penning trap -V Oscillation in longitudinal electric +V potential p +V -V Magnetic moment of antiproton: ATRAP Penning trap + magnetic bottle -V +V +V -V Magnetic moment of antiproton: ATRAP Penning trap + magnetic bottle -V Slower oscillation +V p +V -V Magnetic moment of antiproton: ATRAP Penning trap + magnetic bottle -V Faster oscillation +V ● p Measure frequency to determine spin- state +V ● Induce spin flips via MW -V ● Determine spin-flip probability vs. MW frequency Magnetic moment of antiproton: ATRAP p Resonance Line shape due to p sampling the inhomogeneous B field of the trap J. DiSciacca, et.al., PRL 110(2013), 130801 Magnetic moment of antiproton: ATRAP p Precision: μp = μp (5 ppm) J. DiSciacca, et.al., PRL 110(2013), 130801 BASE Baryon Antibaryon Symmetry Experiment antiproton & proton: q/m & μ Antiproton charge-to-mass ratio ● Measure cyclotron frequencies of a p and a H- alternatingly in the same trap ● -11 (q/m)p – (q/m)p = 1 ± 7·10 BASE - S.Ulmer, et.al., Nature 524 (2015), 196 Magnetic moment of antiproton Double-trap: BASE Try to make spin-flip via MW excitation Magnetic bottle – detect spin-state Magnetic moment of antiproton Double-trap: BASE Try to make spin-flip via MW excitation Magnetic bottle – detect spin-state Today: Δμ/μ = 3 x 10-9 with a single proton Repeat with a single antiproton! (A. Mooser, et.al.: Nature 509 (2014), 596) Asacusa experiment Antihydrogen group MW spectroscopy of H/H (Asacusa) RFQ decelerator (100 keV) Positron Superconducting Penning accumulator trap – capture and cooling Positron source Synthesis trap MW spectroscopy of H/H (Asacusa) MW cavity – try to make a transition to a high- field-seeking