@article {98, title = {SDR, EVC, and SDREVC: Limitations and Extensions}, journal = {Journal of Plasma Physics}, volume = {89}, year = {2023}, pages = {955890501}, doi = {10.1017/S0022377823001022}, author = {Hunter, E.D. and Amsler, C. and Breuker, H. and Bumbar, M. and Chesnevskaya, S. and Costantini, G. and Ferragut, R. and Giammarchi, M. and Gligorova, A. and Gosta, G. and Higaki, H. and Killian, C. and Kraxberger, V. and Kuroda, N. and Lanz, A. and Leali, M. and Maero, G. and Malbrunot, C. and Mascagna, V. and Matsuda, Y. and M{\"a}ckel, V. and Migliorati, S. and Murtagh, D.J. and Nanda, A. and Nowak, L. and Parnefjord Gustafsson, F. and Rheinfrank, S. and Rom{\'e}, M. and Simon, M.C. and Tajima, M. and Toso, V. and Ulmer, S. and Ventrurelli, L. and Weiser, A. and Widmann, E. and Yamazaki, Y. and Zmeskal, J. and The ASACUSA-Cusp Collaboration} } @article {99, title = {Slow positron production and storage for the ASACUSA-Cusp experiment}, journal = {Journal of Plasma Physics}, volume = {89}, year = {2023}, pages = {905890608}, doi = {10.1017/S0022377823001034}, author = {Murtagh, D.J. and Amsler, C. and Breuker, H. and Bumbar, M. and Chesnevskaya, S. and Costantini, G. and Ferragut, R. and Giammarchi, M. and Gligorova, A. and Gosta, G. and Higaki, H. and Hunter, E.D. and Killian, C. and Kraxberger, V. and Kuroda, N. and Lanz, A. and Leali, M. and Maero, G. and Malbrunot, C. and Mascagna, V. and Matsuda, Y. and M{\"a}ckel, V. and Migliorati, S. and Nanda, A. and Nowak, L. and Parnefjord Gustafsson, F. and Rheinfrank, S. and Rom{\'e}, M. and Simon, M.C. and Tajima, M. and Toso, V. and Ulmer, S. and Venturelli, L. and Weiser, A. and Widmann, E. and Wolz, T. and Yamazaki, Y. and Zmeskal, J.} } @article {96, title = {Upgrade of ASACUSA{\textquoteright}s antihydrogen detector}, journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, volume = {1045}, year = {2023}, pages = {167568}, abstract = {The goal of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) CUSP experiment at CERN{\textquoteright}s Antiproton Decelerator is to measure the ground state hyperfine splitting of antihydrogen in order to test whether CPT invariance is broken. The ASACUSA hodoscope is a detector consisting of two layers of 32 plastic scintillator bars individually read out by two serially connected silicon photomultipliers (SiPMs) on each end. Two additional layers for position resolution along the beam axis were scintillator fibres, which will now be replaced by scintillating tiles placed onto the existing bars and also read out by SiPMs. If the antiproton of antihydrogen annihilates in the centre of the hodoscope, particles (mostly pions) are produced and travel through the various layers of the detector and produce signals. The hodoscope was successfully used during the last data taking period at CERN. The necessary time resolution to discriminate between particles travelling through the detector from outside and particles produced in the centre of the detector was achieved by the use of waveform digitisers and software constant fraction discrimination. The disadvantage of this readout scheme was the slow readout speed, which was improved by two orders of magnitude. This was done by omitting the digitisers and replacing them with TDCs reading out the digital time-over-threshold (ToT) signal using leading edge discrimination.}, keywords = {Antihydrogen, antimatter, Data acquisition, Silicon photomultiplier}, issn = {0168-9002}, doi = {https://doi.org/10.1016/j.nima.2022.167568}, url = {https://www.sciencedirect.com/science/article/pii/S0168900222008609}, author = {V. Kraxberger and C. Amsler and H. Breuker and S. Chesnevskaya and G. Costantini and R. Ferragut and M. Giammarchi and A. Gligorova and G. Gosta and H. Higaki and E.D. Hunter and C. Killian and V. Kletzl and N. Kuroda and A. Lanz and M. Leali and V. M{\"a}ckel and G. Maero and C. Malbrunot and V. Mascagna and Y. Matsuda and S. Migliorati and D.J. Murtagh and Y. Nagata and A. Nanda and L. Nowak and E. Pasino and M. Rom{\'e} and M.C. Simon and M. Tajima and V. Toso and S. Ulmer and L. Venturelli and A. Weiser and E. Widmann and T. Wolz and Y. Yamazaki and J. Zmeskal} } @article {97, title = {Minimizing plasma temperature for antimatter mixing experiments}, journal = {EPJ Web Conf.}, volume = {262}, year = {2022}, pages = {01007}, doi = {10.1051/epjconf/202226201007}, url = {https://doi.org/10.1051/epjconf/202226201007}, author = {Hunter, E.D. and Amsler, C. and Breuker, H. and Chesnevskaya, S. and Costantini, G. and Ferragut, R. and Giammarchi, M. and Gligorova, A. and Gosta, G. and Higaki, H. and Kanai, Y. and Killian, C. and Kletzl, V. and Kraxberger, V. and Kuroda, N. and Lanz, A. and Leali, M. and M{\"a}ckel, V. and Maero, G. and Malbrunot, C. and Mascagna, V. and Matsuda, Y. and Migliorati, S. and Murtagh, D.J. and Nagata, Y. and Nanda, A. and Nowak, L. and Pasino, E. and Rom{\'e}, M. and Simon, M.C. and Tajima, M. and Toso, V. and Ulmer, S. and Uggerh\oj, U. and Venturelli, L. and Weiser, A. and Widmann, E. and Wolz, T. and Yamazaki, Y. and Zmeskal, J. and (The ASACUSA-Cusp Collaboration)} } @article {95, title = {Reducing the background temperature for cyclotron cooling in a cryogenic Penning{\textendash}Malmberg trap}, journal = {Physics of Plasmas}, volume = {29}, year = {2022}, month = {08}, pages = {083303}, abstract = {Magnetized nonneutral plasma composed of electrons or positrons couples to the local microwave environment via cyclotron radiation. The equilibrium plasma temperature depends on the microwave energy density near the cyclotron frequency. Fine copper meshes and cryogenic microwave absorbing material were used to lower the effective temperature of the radiation environment in ASACUSA{\textquoteright}s Cusp trap, resulting in significantly reduced plasma temperature.}, issn = {1070-664X}, doi = {10.1063/5.0093360}, url = {https://doi.org/10.1063/5.0093360}, author = {Amsler, C. and Breuker, H. and Chesnevskaya, S. and Costantini, G. and Ferragut, R. and Giammarchi, M. and Gligorova, A. and Gosta, G. and Higaki, H. and Hunter, E. D. and Killian, C. and Kletzl, V. and Kraxberger, V. and Kuroda, N. and Lanz, A. and Leali, M. and M{\"a}ckel, V. and Maero, G. and Malbrunot, C. and Mascagna, V. and Matsuda, Y. and Migliorati, S. and Murtagh, D. J. and Nagata, Y. and Nanda, A. and Nowak, L. and Pasino, E. and Rom{\'e}, M. and Simon, M. C. and Tajima, M. and Toso, V. and Ulmer, S. and Venturelli, L. and Weiser, A. and Widmann, E. and Wolz, T. and Yamazaki, Y. and Zmeskal, J.} } @article {94, title = {Measurement of the principal quantum number distribution in a beam of antihydrogen atoms}, volume = {75}, year = {2021}, month = {2021/03/08}, pages = {91}, abstract = {The ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration plans to measure the ground-state hyperfine splitting of antihydrogen in a beam at the CERN Antiproton Decelerator with initial relative precision of $$10^{-6}$$or better, to test the fundamental CPT (combination of charge conjugation, parity transformation and time reversal) symmetry between matter and antimatter. This challenging goal requires a polarised antihydrogen beam with a sufficient number of antihydrogen atoms in the ground state. The first measurement of the quantum state distribution of antihydrogen atoms in a low magnetic field environment of a few mT is described. Furthermore, the data-driven machine learning analysis to identify antihydrogen events is discussed.}, isbn = {1434-6079}, url = {https://doi.org/10.1140/epjd/s10053-021-00101-y}, author = {Kolbinger, B. and Amsler, C. and Cuendis, S. Arguedas and Breuker, H. and Capon, A. and Costantini, G. and Dupre, P. and Fleck, M. and Gligorova, A. and Higaki, H. and Kanai, Y. and Kletzl, V. and Kuroda, N. and Lanz, A. and Leali, M. and M{\"a}ckel, V. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Matsuda, Y. and Murtagh, D. J. and Nagata, Y. and Nanda, A. and Nowak, L. and Radics, B. and Sauerzopf, C. and Simon, M. C. and Tajima, M. and Torii, H. A. and Uggerh{\o}j, U. and Ulmer, S. and Venturelli, L. and Weiser, A. and Wiesinger, M. and Widmann, E. and Wolz, T. and Yamazaki, Y. and Zmeskal, J.} } @article {88, title = {The ASACUSA antihydrogen and hydrogen program: results and prospects}, journal = {Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences}, volume = {376}, year = {2018}, abstract = {The goal of the ASACUSA-CUSP collaboration at the Antiproton Decelerator of CERN is to measure the ground-state hyperfine splitting of antihydrogen using an atomic spectroscopy beamline. A milestone was achieved in 2012 through the detection of 80 antihydrogen atoms 2.7 m away from their production region. This was the first observation of {\textquoteleft}cold{\textquoteright} antihydrogen in a magnetic field free region. In parallel to the progress on the antihydrogen production, the spectroscopy beamline was tested with a source of hydrogen. This led to a measurement at a relative precision of 2.7{\texttimes}10-9 which constitutes the most precise measurement of the hydrogen hyperfine splitting in a beam. Further measurements with an upgraded hydrogen apparatus are motivated by CPT and Lorentz violation tests in the framework of the Standard Model Extension. Unlike for hydrogen, the antihydrogen experiment is complicated by the difficulty of synthesizing enough cold antiatoms in the ground state. The first antihydrogen quantum states scan at the entrance of the spectroscopy apparatus was realized in 2016 and is presented here. The prospects for a ppm measurement are also discussed.This article is part of the Theo Murphy meeting issue {\textquoteleft}Antiproton physics in the ELENA era{\textquoteright}.}, issn = {1364-503X}, doi = {10.1098/rsta.2017.0273}, url = {http://rsta.royalsocietypublishing.org/content/376/2116/20170273}, author = {Malbrunot, C. and Amsler, C. and Arguedas Cuendis, S. and Breuker, H. and Dupre, P. and Fleck, M. and Higaki, H. and Kanai, Y. and Kolbinger, B. and Kuroda, N. and Leali, M. and M{\"a}ckel, V. and Mascagna, V. and Massiczek, O. and Matsuda, Y. and Nagata, Y. and Simon, M. C. and Spitzer, H. and Tajima, M. and Ulmer, S. and Venturelli, L. and Widmann, E. and Wiesinger, M. and Yamazaki, Y. and Zmeskal, J.} } @article {91, title = {Hyperfine spectroscopy of hydrogen and antihydrogen in ASACUSA}, journal = {Hyperfine Interactions}, volume = {240}, year = {2018}, month = {Dec}, pages = {5}, abstract = {

The ASACUSA collaboration at the Antiproton Decelerator of CERN aims at a precise measurement of the antihydrogen ground-state hyperfine structure as a test of the fundamental CPT symmetry. A beam of antihydrogen atoms is formed in a CUSP trap, undergoes Rabi-type spectroscopy and is detected downstream in a dedicated antihydrogen detector. In parallel measurements using a polarized hydrogen beam are being performed to commission the spectroscopy apparatus and to perform measurements of parameters of the Standard Model Extension (SME). The current status of antihydrogen spectroscopy is reviewed and progress of ASACUSA is presented.

}, issn = {1572-9540}, doi = {10.1007/s10751-018-1536-9}, url = {https://doi.org/10.1007/s10751-018-1536-9}, author = {Widmann, E. and Amsler, C. and Arguedas Cuendis, S. and Breuker, H. and Diermaier, M. and Dupre, P. and Evans, C. and Fleck, M. and Gligorova, A. and Higaki, H. and Kanai, Y. and Kolbinger, B. and Kuroda, N. and Leali, M. and Leite, A. M. M. and M{\"a}ckel, V. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Matsuda, Y. and Murtagh, D. J. and Nagata, Y. and Nanda, A. and Phan, D. and Sauerzopf, C. and Simon, M. C. and Tajima, M. and Spitzer, H. and Strube, M. and Ulmer, S. and Venturelli, L. and Wiesinger, M. and Yamazaki, Y. and Zmeskal, J.} } @article {87, title = {The Development of the Antihydrogen Beam Detector: Toward the Three Dimensional Tracking with a BGO Crystal and a Hodoscope}, journal = {JPS Conf. Proc.}, volume = {18}, year = {2017}, pages = {011038}, doi = {10.7566/JPSCP.18.011038}, author = {Y. Nagata and N. Kuroda and C. Sauerzopf and B. Kolbinger and C. Malbrunot and A. A. Capon and P. Dupre and B. Radics and M. Tajima and C. Kaga and M. Leali and E. Lodi Rizzini and V. Mascagna and O. Massiczek and T. Matsudate and M. C. Simon and H. Breuker and H. Higaki and Y. Kanai and Y. Matsuda and L. Venturelli and E. Widmann and Y. Yamazaki} } @article {81, title = {Progress of Antihydrogen Beam Production Using a Double Cusp Trap}, journal = {JPS Conf. Proc.}, volume = {18}, year = {2017}, pages = {011007}, doi = {10.7566/JPSCP.18.011007}, author = {Y. Nagata and N. Kuroda and P. Dupre and B. Radics and M. Tajima and A. A. Capon and M. Diermaier and C. Kaga and B. Kolbinger and M. Leali and E. Lodi Rizzini and C. Malbrunot and V. Mascagna and O. Massiczek and T. Matsudate and C. Sauerzopf and M. C. Simon and K. Suzuki and J. Zmeskal and H. Breuker and H. Higaki and Y. Kanai and Y. Matsuda and S. Ulmer and L. Venturelli and E. Widmann and Y. Yamazaki} } @article {77, title = {Annihilation detector for an in-beam spectroscopy apparatus to measure the ground state hyperfine splitting of antihydrogen}, journal = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, year = {2016}, pages = {-}, keywords = {Silicon photomultiplier}, issn = {0168-9002}, doi = {http://dx.doi.org/10.1016/j.nima.2016.06.023}, url = {http://www.sciencedirect.com/science/article/pii/S0168900216305630}, author = {Clemens Sauerzopf and Aaron A. Capon and Martin Diermaier and Markus Fleck and Bernadette Kolbinger and Chlo{\'e} Malbrunot and Oswald Massiczek and Martin C. Simon and Stefan Vamosi and Johann Zmeskal and Eberhard Widmann} } @article {80, title = {Towards measuring the ground state hyperfine splitting of antihydrogen {\textendash} a progress report}, journal = {Hyperfine Interactions}, volume = {237}, year = {2016}, month = {Jun}, pages = {103}, abstract = {We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector.}, issn = {1572-9540}, doi = {10.1007/s10751-016-1309-2}, url = {https://doi.org/10.1007/s10751-016-1309-2}, author = {Sauerzopf, C. and Capon, A. A. and Diermaier, M. and Dupre, P. and Higashi, Y. and Kaga, C. and Kolbinger, B. and Leali, M. and Lehner, S. and Rizzini, E. Lodi and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Murtagh, D. J. and Nagata, Y. and Radics, B. and Simon, M. C. and Suzuki, K. and Tajima, M. and Ulmer, S. and Vamosi, S. and Gorp, S. van and Zmeskal, J. and Breuker, H. and Higaki, H. and Kanai, Y. and Kuroda, N. and Matsuda, Y. and Venturelli, L. and Widmann, E. and Yamazaki, Y.} } @article {70, title = {The ASACUSA Micromegas Tracker: A cylindrical, bulk Micromegas detector for antimatter research}, journal = {Review of Scientific Instruments}, volume = {86}, year = {2015}, abstract = {

The ASACUSA Micromegas Tracker (AMT; ASACUSA: Atomic Spectroscopy and Collisions Using Slow Antiprotons) was designed to be able to reconstruct antiproton-nucleon annihilation vertices in three dimensions. The goal of this device is to study antihydrogen formation processes in the ASACUSA cusp trap, which was designed to synthesise a spin-polarised antihydrogen beam for precise tests of Charge, Parity, and Time (CPT) symmetry invariance. This paper discusses the structure and technical details of an AMT detector built into such an environment, its data acquisition system and the first performance with cosmic rays.

}, doi = {http://dx.doi.org/10.1063/1.4927685}, url = {http://scitation.aip.org/content/aip/journal/rsi/86/8/10.1063/1.4927685}, author = {Radics, B. and Nagata, Y. and Yamazaki, Y. and Ishikawa, S. and Kuroda, N. and Matsuda, Y. and Anfreville, M. and Aune, S. and Boyer, M. and Chateau, F. and Combet, M. and Granelli, R. and Legou, P. and Mandjavidze, I. and Procureur, S. and Riallot, M. and Vallage, B. and Vandenbroucke, M.} } @article {72, title = {An atomic hydrogen beam to test ASACUSA{\textquoteright}s apparatus for antihydrogen spectroscopy}, journal = {Hyperfine Interactions}, volume = {233}, year = {2015}, pages = {35-40}, keywords = {Antihydrogen, Atomic hydrogen, Ground state hyperfine structure}, issn = {0304-3843}, doi = {10.1007/s10751-015-1151-y}, url = {http://dx.doi.org/10.1007/s10751-015-1151-y}, author = {Diermaier, M. and Caradonna, P. and Kolbinger, B. and Malbrunot, C. and Massiczek, O. and Sauerzopf, C. and Simon, M.C. and Wolf, M. and Zmeskal, J. and Widmann, E.} } @article {67, title = {Spectroscopy apparatus for the measurement of the hyperfine structure of antihydrogen}, journal = {Hyperfine Interactions}, year = {2014}, pages = {1-6}, keywords = {Antihydrogen, CPT symmetry, Hyperfine spectroscopy}, issn = {0304-3843}, doi = {10.1007/s10751-014-1013-z}, url = {http://dx.doi.org/10.1007/s10751-014-1013-z}, author = {Malbrunot, C. and Caradonna, P. and Diermaier, M. and Dilaver, N. and Friedreich, S. and Kolbinger, B. and Lehner, S. and Lundmark, R. and Massiczek, O. and Radics, B. and Sauerzopf, C. and Simon, M. and Widmann, E. and Wolf, M. and W{\"u}nschek, B. and Zmeskal, J.} } @article {35, title = {Towards the production of anti-hydrogen beams}, journal = {AIP Conference Proceedings}, volume = {1521}, year = {2013}, pages = {134-143}, keywords = {antimatter, atomic beams, hydrogen neutral atoms, hyperfine structure, particle beam diagnostics}, doi = {10.1063/1.4796069}, url = {http://link.aip.org/link/?APC/1521/134/1}, author = {H. Higaki and Y. Enomoto and N. Kuroda and K. Michishio and D. J. Murtagh and S. Ulmer and S. Van Gorp and C. H. Kim and Y. Nagata and Y. Kanai and Torii, H.A. and M. Corradini and M. Leali and E. Lodi-Rizzini and V. Mascagna and L. Venturelli and N. Zurlo and K. Fujii and M. Otsuka and K. Tanaka and H. Imao and Y. Nagashima and Y. Matsuda and B. Juh{\'a}sz and A. Mohri and Y. Yamazaki}, editor = {Xabier Sarasola and Lutz Schweikhard and Thomas Sunn Pedersen} } @article {50, title = {Antihydrogen atom formation in a CUSP trap towards spin polarized beams}, journal = {Hyperfine Interactions}, volume = {212}, year = {2012}, pages = {31-40}, keywords = {Antihydrogen, Atomic beam, CPT invariance, Rydberg atom}, issn = {0304-3843}, doi = {10.1007/s10751-012-0646-z}, url = {http://dx.doi.org/10.1007/s10751-012-0646-z}, author = {Kuroda, N. and Enomoto, Y. and Michishio, K. and Kim, C.H. and Higaki, H. and Nagata, Y. and Kanai, Y. and Torii, H.A. and Corradini, M. and Leali, M. and Lodi-Rizzini, E. and Venturelli, L. and Zurlo, N. and Fujii, K. and Ohtsuka, M. and Tanaka, K. and Imao, H. and Nagashima, Y. and Matsuda, Y. and Juhasz, B. and Widmann, E. and Mohri, A. and Yamazaki, Y.} } @article {49, title = {Synthesis of antihydrogen atoms in a CUSP trap}, journal = {Hyperfine Interactions}, volume = {209}, year = {2012}, pages = {35-41}, abstract = {

ASACUSA collaboration has been making a path to realize high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atom in flight for stringent test of the CPT symmetry. Recently, we have succeeded in synthesizing our first cold antihydrogen atoms employing a CUSP trap. It is expected that synthesized antihydrogen atoms in the low-field-seeking states are preferentially focused along the cusp magnetic field axis whereas those in the high-field-seeking states are not focused, resulting in the formation of a spin-polarized antihydrogen beam. We report the recent results of antihydrogen atom synthesis and beam production developed with the CUSP trap.

}, issn = {0304-3843}, url = {http://dx.doi.org/10.1007/s10751-012-0560-4}, author = {Kuroda, Naofumi and Enomoto, Yoshinori and Michishio, Koji and Kim, Chanhyoun and Higaki, Hiroyuki and Nagata, Yugo and Kanai, Yasuyuki and Torii, Hiroyuki and Corradini, Maurizzio and Leali, Marco and Lodi-Rizzini, Evandro and Mascagna, Valerio and Venturelli, Luca and Zurlo, Nicola and Fujii, Koki and Ohtsuka, Miki and Tanaka, Kazuo and Imao, Hiroshi and Nagashima, Yasuyuki and Matsuda, Yasuyuki and Juh{\'a}sz, Bertalan and Widmann, Eberhard and Mohri, Akihiro and Yamazaki, Yasunori} } @article {22, title = {Synthesis of Cold Antihydrogen in a Cusp Trap}, journal = {Physical Review LettersPhys. Rev. Lett.}, volume = {105}, year = {2010}, month = {2010/12/07/}, pages = {243401 -}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.105.243401}, author = {Enomoto, Y. and Kuroda, N. and Michishio, K. and Kim, C. H. and Higaki, H. and Nagata, Y. and Kanai, Y. and Torii, H. A. and Corradini, M. and Leali, M. and Lodi-Rizzini, E. and Mascagna, V. and Venturelli, L. and Zurlo, N. and Fujii, K. and Ohtsuka, M. and Tanaka, K. and Imao, H. and Nagashima, Y. and Matsuda, Y. and Juhasz, B. and Mohri, A. and Yamazaki, Y.} } @article {21, title = {Target Structure Induced Suppression of the Ionization Cross Section for Very Low Energy Antiproton-Hydrogen Collisions}, journal = {Physical Review LettersPhys. Rev. Lett.}, volume = {105}, year = {2010}, month = {2010/11/17/}, pages = {213201 -}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.105.213201}, author = {Knudsen, H. and Torii, H. A. and Charlton, M. and Enomoto, Y. and Georgescu, I. and Hunniford, C. A. and Kim, C. H. and Kanai, Y. and Kristiansen, H.-P. E. and Kuroda, N. and Lund, M. D. and McCullough, R. W. and T{\"o}kesi, K. and Uggerh{\o}j, U. I. and Yamazaki, Y.} } @article {31, title = {Atomic collision and spectroscopy experiments with ultra-low-energy antiprotons}, journal = {Journal of Physics: Conference Series}, volume = {185}, year = {2009}, pages = {012049}, abstract = {

Antiproton, the antiparticle of proton, is a unique projectile in the study of atomic collision physics, which can be treated theoretically either as a {\textquoteright}negative proton{\textquoteright} or a {\textquoteright}heavy electron{\textquoteright}. Atomic capture of an antiproton will result in formation of a highly excited exotic atom. Antiprotonic helium atom has been studied intensively by means of precision laser spectroscopy, which has led to a stringent determination of antiproton mass and charge to a level of ppb. Comparison of these values with those of proton gives one of the best tests of CPT invariance, the most fundamental symmetry in physics. However, the dynamic processes of antiproton capture remain unclarified. With an aim to produce an antiproton beam at atomic-physics energies for {\textquoteright}pure{\textquoteright} collision experiments, we have so far developed techniques to decelerate, cool and confine antiprotons in vacuo, using a sequential combination of the Antiproton Decelerator (AD) at CERN, a Radio-Frequency Quadrupole Decelerator (RFQD), and an electromagnetic trap. Our recent success in stable extraction of monoenergetic ultra-slow antiprotons, about 3 {\texttimes} 10 5 in number available every 5 minutes, has opened up the possibility to study ionization and atomic capture processes between an antiproton and an atom under the single collision condition. Our design and strategy of the cross-beam experiments are presented, together with technical challenges in the detection system to identify the rare events with a reaction rate of 10 -4 .

}, url = {http://stacks.iop.org/1742-6596/185/i=1/a=012049}, author = {Torii, H.A. and Yugo Nagata and Hiroshi Toyoda and Hiroshi Imao and Naofumi Kuroda and Victor L Varentsov and Yasunori Yamazaki and Asacusa collaboration} } @article {20, title = {On the double ionization of helium by very slow antiproton impact}, journal = {Proceedings of the Fourth International Conference on Elementary Processes in Atomic Systems}, volume = {267}, year = {2009}, month = {2009/1//}, pages = {244 - 247}, keywords = {Antiproton, CERN AD, Electron correlation, Ionization}, isbn = {0168-583X}, url = {http://www.sciencedirect.com/science/article/pii/S0168583X08011373}, author = {Knudsen, H. and Kristiansen, H.-P. E. and Thomsen, H. D. and Uggerh{\o}j, U. I. and Ichioka, T. and M{\o}ller, S. P. and Hunniford, C. A. and McCullough, R. W. and Charlton, M. and Kuroda, N. and Nagata, Y. and Torii, H. A. and Yamazaki, Y. and Imao, H. and Andersen, H. H. and T{\"o}kesi, K.} } @article {19, title = {Ionization of Helium and Argon by Very Slow Antiproton Impact}, journal = {Physical Review LettersPhys. Rev. Lett.}, volume = {101}, year = {2008}, month = {2008/07/25/}, pages = {043201 -}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.101.043201}, author = {Knudsen, H. and Kristiansen, H.-P. E. and Thomsen, H. D. and Uggerh{\o}j, U. I. and Ichioka, T. and M{\o}ller, S. P. and Hunniford, C. A. and McCullough, R. W. and Charlton, M. and Kuroda, N. and Nagata, Y. and Torii, H. A. and Yamazaki, Y. and Imao, H. and Andersen, H. H. and T{\"o}kesi, K.} } @article {27, title = {Antiproton and Electron Plasma Behavior and its Control for Production of Ultraslow Antiproton Beams}, journal = {AIP Conference Proceedings}, volume = {796}, year = {2005}, pages = {321-324}, keywords = {plasma electrostatic waves, proton beams}, doi = {10.1063/1.2130188}, url = {http://link.aip.org/link/?APC/796/321/1}, author = {N. Kuroda and H. A. Torii and M. Shibata and Y. Nagata and D. Barna and M. Hori and A. Mohri and K. Komaki and Y. Yamazaki}, editor = {Dieter Grzonka and Rafa{\l} Czy{\.z}ykiewicz and Walter Oelert and Tomasz Ro{\.z}ek and Peter Winter} }