001513198 001__ 1513198
001513198 005__ 20160630060451.0
001513198 0247_ $$2DOI$$a10.1007/s10751-011-0396-3
001513198 0248_ $$aoai:cds.cern.ch:1513198$$pcerncds:CERN
001513198 035__ $$9Inspire$$a1357278
001513198 041__ $$aeng
001513198 100__ $$aButler, E$$uSwansea U.$$uCERN
001513198 245__ $$aTrapped antihydrogen
001513198 260__ $$c2012
001513198 520__ $$aPrecision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ∼1 T (∼0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be ‘born’ inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172 ms and then released—the first instance of a purely antimatter atomic system confined for any length of time (Andresen et al., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen et al. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000 s in the apparatus (Andresen et al., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state.
001513198 65017 $$2SzGeCERN$$aOther Fields of Physics
001513198 693__ $$aCERN AD$$eALPHA AD-5
001513198 690C_ $$aARTICLE
001513198 690C_ $$aCERN
001513198 700__ $$aAndresen, G B$$uAarhus U.
001513198 700__ $$aAshkezari, M D$$uSimon Fraser U.
001513198 700__ $$aBaquero-Ruiz, M$$uUC, Berkeley
001513198 700__ $$aBertsche, W$$uSwansea U.
001513198 700__ $$aBowe, P D$$uAarhus U.
001513198 700__ $$aCesar, C L$$uRio de Janeiro Federal U.
001513198 700__ $$aChapman, S$$uUC, Berkeley
001513198 700__ $$aCharlton, M$$uSwansea U.
001513198 700__ $$aDeller, A$$uSwansea U.
001513198 700__ $$aEriksson, S$$uSwansea U.
001513198 700__ $$aFajans, J$$uUC, Berkeley$$uLBL, Berkeley
001513198 700__ $$aFriesen, T$$uCalgary U.
001513198 700__ $$aFujiwara, M C$$uTRIUMF$$uCalgary U.
001513198 700__ $$aGill, D R$$uTRIUMF
001513198 700__ $$0AUTHOR|(CDS)2073671$$9#BEARD#$$aGutierrez, A$$uBritish Columbia U.
001513198 700__ $$aHangst, J S$$uAarhus U.
001513198 700__ $$aHardy, W N$$uBritish Columbia U.
001513198 700__ $$aHayden, M E$$uSimon Fraser U.
001513198 700__ $$aHumphries, A J$$uSwansea U.
001513198 700__ $$aHydomako, R$$uCalgary U.
001513198 700__ $$aJenkins, M J$$uSwansea U.
001513198 700__ $$aJonsell, S$$uStockholm U.
001513198 700__ $$aJørgensen, L V$$uSwansea U.
001513198 700__ $$aKemp, S L$$uCERN
001513198 700__ $$aKurchaninov, L$$uTRIUMF
001513198 700__ $$aMadsen, N$$uSwansea U.
001513198 700__ $$0AUTHOR|(CDS)2077247$$9#BEARD#$$aMenary, S$$uYork U., Canada
001513198 700__ $$aNolan, P$$uLiverpool U.
001513198 700__ $$aOlchanski, K$$uTRIUMF
001513198 700__ $$aOlin, A$$uVictoria U.$$uTRIUMF
001513198 700__ $$aPovilus, A$$uUC, Berkeley
001513198 700__ $$aPusa, P$$uLiverpool U.
001513198 700__ $$aRasmussen, C Ø$$uAarhus U.
001513198 700__ $$aRobicheaux, F$$uAuburn U.
001513198 700__ $$aSarid, E$$uNegev Nucl. Res. Ctr.
001513198 700__ $$aSeif el Nasr, S$$uBritish Columbia U.
001513198 700__ $$aSilveira, D M$$uWako, RIKEN$$uTokyo, U. Earth Sci. Astron.
001513198 700__ $$aSo, C$$uUC, Berkeley
001513198 700__ $$aStorey, J W$$uTRIUMF
001513198 700__ $$aThompson, R I$$uCalgary U.
001513198 700__ $$avan der Werf, D P$$uSwansea U.
001513198 700__ $$aWurtele, J S$$uLBL, Berkeley$$uUC, Berkeley
001513198 700__ $$aYamazaki,Y$$uWako, RIKEN$$uTokyo, U. Earth Sci. Astron.
001513198 710__ $$gALPHA Collaboration
001513198 773__ $$c15-29$$pHyperfine Interact.$$v212$$y2012
001513198 916__ $$sh$$w201305$$ya2013
001513198 960__ $$a13
001513198 962__ $$b1463866$$k15-29$$nvancouver20110427
001513198 980__ $$aARTICLE
001513198 980__ $$aConferencePaper