%0 Journal Article %J Journal of Plasma Physics %D 2023 %T SDR, EVC, and SDREVC: Limitations and Extensions %A Hunter, E.D. %A Amsler, C. %A Breuker, H. %A Bumbar, M. %A Chesnevskaya, S. %A Costantini, G. %A Ferragut, R. %A Giammarchi, M. %A Gligorova, A. %A Gosta, G. %A Higaki, H. %A Killian, C. %A Kraxberger, V. %A Kuroda, N. %A Lanz, A. %A Leali, M. %A Maero, G. %A Malbrunot, C. %A Mascagna, V. %A Matsuda, Y. %A Mäckel, V. %A Migliorati, S. %A Murtagh, D.J. %A Nanda, A. %A Nowak, L. %A Parnefjord Gustafsson, F. %A Rheinfrank, S. %A Romé, M. %A Simon, M.C. %A Tajima, M. %A Toso, V. %A Ulmer, S. %A Ventrurelli, L. %A Weiser, A. %A Widmann, E. %A Yamazaki, Y. %A Zmeskal, J. %A The ASACUSA-Cusp Collaboration %B Journal of Plasma Physics %V 89 %P 955890501 %G eng %R 10.1017/S0022377823001022 %0 Journal Article %J Journal of Plasma Physics %D 2023 %T Slow positron production and storage for the ASACUSA-Cusp experiment %A Murtagh, D.J. %A Amsler, C. %A Breuker, H. %A Bumbar, M. %A Chesnevskaya, S. %A Costantini, G. %A Ferragut, R. %A Giammarchi, M. %A Gligorova, A. %A Gosta, G. %A Higaki, H. %A Hunter, E.D. %A Killian, C. %A Kraxberger, V. %A Kuroda, N. %A Lanz, A. %A Leali, M. %A Maero, G. %A Malbrunot, C. %A Mascagna, V. %A Matsuda, Y. %A Mäckel, V. %A Migliorati, S. %A Nanda, A. %A Nowak, L. %A Parnefjord Gustafsson, F. %A Rheinfrank, S. %A Romé, M. %A Simon, M.C. %A Tajima, M. %A Toso, V. %A Ulmer, S. %A Venturelli, L. %A Weiser, A. %A Widmann, E. %A Wolz, T. %A Yamazaki, Y. %A Zmeskal, J. %B Journal of Plasma Physics %V 89 %P 905890608 %G eng %R 10.1017/S0022377823001034 %0 Journal Article %J Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %D 2023 %T Upgrade of ASACUSA’s antihydrogen detector %A V. Kraxberger %A C. Amsler %A H. Breuker %A S. Chesnevskaya %A G. Costantini %A R. Ferragut %A M. Giammarchi %A A. Gligorova %A G. Gosta %A H. Higaki %A E.D. Hunter %A C. Killian %A V. Kletzl %A N. Kuroda %A A. Lanz %A M. Leali %A V. Mäckel %A G. Maero %A C. Malbrunot %A V. Mascagna %A Y. Matsuda %A S. Migliorati %A D.J. Murtagh %A Y. Nagata %A A. Nanda %A L. Nowak %A E. Pasino %A M. Romé %A M.C. Simon %A M. Tajima %A V. Toso %A S. Ulmer %A L. Venturelli %A A. Weiser %A E. Widmann %A T. Wolz %A Y. Yamazaki %A J. Zmeskal %K Antihydrogen %K antimatter %K Data acquisition %K Silicon photomultiplier %X The goal of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) CUSP experiment at CERN’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. %B Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %V 1045 %P 167568 %G eng %U https://www.sciencedirect.com/science/article/pii/S0168900222008609 %R https://doi.org/10.1016/j.nima.2022.167568 %0 Journal Article %J EPJ Web Conf. %D 2022 %T Minimizing plasma temperature for antimatter mixing experiments %A Hunter, E.D. %A Amsler, C. %A Breuker, H. %A Chesnevskaya, S. %A Costantini, G. %A Ferragut, R. %A Giammarchi, M. %A Gligorova, A. %A Gosta, G. %A Higaki, H. %A Kanai, Y. %A Killian, C. %A Kletzl, V. %A Kraxberger, V. %A Kuroda, N. %A Lanz, A. %A Leali, M. %A Mäckel, V. %A Maero, G. %A Malbrunot, C. %A Mascagna, V. %A Matsuda, Y. %A Migliorati, S. %A Murtagh, D.J. %A Nagata, Y. %A Nanda, A. %A Nowak, L. %A Pasino, E. %A Romé, M. %A Simon, M.C. %A Tajima, M. %A Toso, V. %A Ulmer, S. %A Uggerh\oj, U. %A Venturelli, L. %A Weiser, A. %A Widmann, E. %A Wolz, T. %A Yamazaki, Y. %A Zmeskal, J. %A (The ASACUSA-Cusp Collaboration) %B EPJ Web Conf. %V 262 %P 01007 %G eng %U https://doi.org/10.1051/epjconf/202226201007 %R 10.1051/epjconf/202226201007 %0 Journal Article %J Physics of Plasmas %D 2022 %T Reducing the background temperature for cyclotron cooling in a cryogenic Penning–Malmberg trap %A Amsler, C. %A Breuker, H. %A Chesnevskaya, S. %A Costantini, G. %A Ferragut, R. %A Giammarchi, M. %A Gligorova, A. %A Gosta, G. %A Higaki, H. %A Hunter, E. D. %A Killian, C. %A Kletzl, V. %A Kraxberger, V. %A Kuroda, N. %A Lanz, A. %A Leali, M. %A Mäckel, V. %A Maero, G. %A Malbrunot, C. %A Mascagna, V. %A Matsuda, Y. %A Migliorati, S. %A Murtagh, D. J. %A Nagata, Y. %A Nanda, A. %A Nowak, L. %A Pasino, E. %A Romé, M. %A Simon, M. C. %A Tajima, M. %A Toso, V. %A Ulmer, S. %A Venturelli, L. %A Weiser, A. %A Widmann, E. %A Wolz, T. %A Yamazaki, Y. %A Zmeskal, J. %X 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's Cusp trap, resulting in significantly reduced plasma temperature. %B Physics of Plasmas %V 29 %P 083303 %8 08 %G eng %U https://doi.org/10.1063/5.0093360 %R 10.1063/5.0093360 %0 Journal Article %D 2021 %T Measurement of the principal quantum number distribution in a beam of antihydrogen atoms %A Kolbinger, B. %A Amsler, C. %A Cuendis, S. Arguedas %A Breuker, H. %A Capon, A. %A Costantini, G. %A Dupre, P. %A Fleck, M. %A Gligorova, A. %A Higaki, H. %A Kanai, Y. %A Kletzl, V. %A Kuroda, N. %A Lanz, A. %A Leali, M. %A Mäckel, V. %A Malbrunot, C. %A Mascagna, V. %A Massiczek, O. %A Matsuda, Y. %A Murtagh, D. J. %A Nagata, Y. %A Nanda, A. %A Nowak, L. %A Radics, B. %A Sauerzopf, C. %A Simon, M. C. %A Tajima, M. %A Torii, H. A. %A Uggerhøj, U. %A Ulmer, S. %A Venturelli, L. %A Weiser, A. %A Wiesinger, M. %A Widmann, E. %A Wolz, T. %A Yamazaki, Y. %A Zmeskal, J. %X 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. %V 75 %P 91 %8 2021/03/08 %@ 1434-6079 %G eng %U https://doi.org/10.1140/epjd/s10053-021-00101-y %N 3 %! The European Physical Journal D %0 Journal Article %J Journal of Instrumentation %D 2019 %T Antiproton beams with low energy spread for antihydrogen production %A M. Tajima %A N. Kuroda %A C. Amsler %A H. Breuker %A C. Evans %A M. Fleck %A A. Gligorova %A H. Higaki %A Y. Kanai %A B. Kolbinger %A A. Lanz %A M. Leali %A V. Mäckel %A C. Malbrunot %A V. Mascagna %A Y. Matsuda %A D. Murtagh %A Y. Nagata %A A. Nanda %A B. Radics %A M. Simon %A S. Ulmer %A L. Venturelli %A E. Widmann %A M. Wiesinger %A Y. Yamazaki %X

A low energy antiproton transport from the ASACUSA's antiproton accumulation trap (MUSASHI trap) to the antihydrogen production trap (double cusp trap) is developed. The longitudinal antiproton energy spread after the transport line is 0.23±0.02 eV, compared with 15 eV with a previous method used in 2012. This reduction is achieved by an adiabatic transport beamline with several pulse-driven coaxial coils. Antihydrogen atoms are synthesized by directly injecting the antiprotons into a positron plasma, resulting in the higher production rate.

%B Journal of Instrumentation %V 14 %P P05009–P05009 %8 05/2019 %G eng %U https://doi.org/10.1088%2F1748-0221%2F14%2F05%2Fp05009 %R 10.1088/1748-0221/14/05/p05009 %0 Journal Article %J Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences %D 2018 %T The ASACUSA antihydrogen and hydrogen program: results and prospects %A Malbrunot, C. %A Amsler, C. %A Arguedas Cuendis, S. %A Breuker, H. %A Dupre, P. %A Fleck, M. %A Higaki, H. %A Kanai, Y. %A Kolbinger, B. %A Kuroda, N. %A Leali, M. %A Mäckel, V. %A Mascagna, V. %A Massiczek, O. %A Matsuda, Y. %A Nagata, Y. %A Simon, M. C. %A Spitzer, H. %A Tajima, M. %A Ulmer, S. %A Venturelli, L. %A Widmann, E. %A Wiesinger, M. %A Yamazaki, Y. %A Zmeskal, J. %X 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 ‘cold’ 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 2.7×10-9 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 ‘Antiproton physics in the ELENA era’. %B Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences %V 376 %G eng %U http://rsta.royalsocietypublishing.org/content/376/2116/20170273 %R 10.1098/rsta.2017.0273 %0 Journal Article %J Hyperfine Interactions %D 2018 %T Hyperfine spectroscopy of hydrogen and antihydrogen in ASACUSA %A Widmann, E. %A Amsler, C. %A Arguedas Cuendis, S. %A Breuker, H. %A Diermaier, M. %A Dupre, P. %A Evans, C. %A Fleck, M. %A Gligorova, A. %A Higaki, H. %A Kanai, Y. %A Kolbinger, B. %A Kuroda, N. %A Leali, M. %A Leite, A. M. M. %A Mäckel, V. %A Malbrunot, C. %A Mascagna, V. %A Massiczek, O. %A Matsuda, Y. %A Murtagh, D. J. %A Nagata, Y. %A Nanda, A. %A Phan, D. %A Sauerzopf, C. %A Simon, M. C. %A Tajima, M. %A Spitzer, H. %A Strube, M. %A Ulmer, S. %A Venturelli, L. %A Wiesinger, M. %A Yamazaki, Y. %A Zmeskal, J. %X

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.

%B Hyperfine Interactions %V 240 %P 5 %8 Dec %G eng %U https://doi.org/10.1007/s10751-018-1536-9 %R 10.1007/s10751-018-1536-9 %0 Journal Article %J Nuclear Inst. and Methods in Physics Research, B %D 2018 %T Imaging antimatter with a Micromegas detector %A Mäckel, V %A Radics, B %A Dupre, P %A Higaki, H %A Kanai, Y %A Kuroda, N %A Matsuda, Y %A Nagata, Y %A Tajima, M %A Widmann, E %A Yamazaki, Y %K 3D tracking %K Annihilation %K Antiproton %K Micromegas tracker %K Track reconstruction %X

The ASACUSA collaboration aims at measuring the ground state hyperfine splitting of antihydrogen for probing fundamental symmetries. A cryogenic trap for mixing antiprotons and positrons serves as an antihydrogen source for in-flight spectroscopy. In order to be able to monitor the antihydrogen formation process, a dedicated Micromegas tracking detector has been designed and built to record the annihilation distribution in the trap. In this paper, we present the first results from antiproton annihilation data recorded with the Micromegas, together with a description of the event reconstruction algorithm.

%B Nuclear Inst. and Methods in Physics Research, B %V 422 %P 1–6 %G eng %U https://doi.org/10.1016/j.nimb.2018.02.026 %R 10.1016/j.nimb.2018.02.026 %0 Journal Article %J Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %D 2018 %T Monte-Carlo based performance assessment of ASACUSA’s antihydrogen detector %A Y. Nagata %A N. Kuroda %A B. Kolbinger %A M. Fleck %A C. Malbrunot %A V. Mäckel %A C. Sauerzopf %A M.C. Simon %A M. Tajima %A J. Zmeskal %A H. Breuker %A H. Higaki %A Y. Kanai %A Y. Matsuda %A S. Ulmer %A L. Venturelli %A E. Widmann %A Y. Yamazaki %K Antihydrogen %K antimatter %K Calorimeter %K Detector %K Tracker %X

An antihydrogen detector consisting of a thin BGO disk and a surrounding plastic scintillator hodoscope has been developed. We have characterized the two-dimensional positions sensitivity of the thin BGO disk and energy deposition into the BGO was calibrated using cosmic rays by comparing experimental data with Monte-Carlo simulations. The particle tracks were defined by connecting BGO hit positions and hits on the surrounding hodoscope scintillator bars. The event rate was investigated as a function of the angles between the tracks and the energy deposition in the BGO for simulated antiproton events, and for measured and simulated cosmic ray events. Identification of the antihydrogen Monte Carlo events was performed using the energy deposited in the BGO and the particle tracks. The cosmic ray background was limited to 12 mHz with a detection efficiency of 81%. The signal-to-noise ratio was improved from 0.22 s−1∕2 obtained with the detector in 2012 to 0.26 s−1∕2 in this work.

%B Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %V 910 %P 90 - 95 %G eng %U http://www.sciencedirect.com/science/article/pii/S0168900218311227 %R 10.1016/j.nima.2018.09.013 %0 Journal Article %J EPJ Web of Conferences %D 2018 %T Recent Developments from ASACUSA on Antihydrogen Detection %A Kolbinger, B. %A Amsler, C. %A Breuker, H. %A Diermaier, M. %A Dupre, P. %A Fleck, M. %A Gligorova, A. %A Higaki, H. %A Kanai, Y. %A Kobayashi, T. %A Leali, M. %A Mäckel, V. %A Malbrunot, C. %A Mascagna, V. %A Massiczek, O. %A Matsuda, Y. %A Murtagh, D.J. %A Nagata, Y. %A Sauerzopf, C. %A Simon, M.C. %A Tajima, M. %A Ulmer, S. %A Kuroda, N. %A Venturelli, L. %A Widmann, E. %A Yamazaki, Y. %A Zmeskal, J. %B EPJ Web of Conferences %V 181 %P 01003 %G eng %U https://doi.org/10.1051/epjconf/201818101003 %R 10.1051/epjconf/201818101003 %0 Journal Article %J JPS Conf. Proc. %D 2017 %T Antihydrogen Formation and Level Population Evolution During Passage Through a Positron Plasma %A B. Radics %A D.J. Murtagh %A Y. Yamazaki %A F. Robicheaux %B JPS Conf. Proc. %V 18 %P 011012 %G eng %R 10.7566/JPSCP.18.011012 %0 Journal Article %J JPS Conf. Proc. %D 2017 %T Antihydrogen Synthesis in a Double-Cusp Trap %A Naofumi Kuroda %A Minori Tajima %A Balint Radics %A Pierre Dupre %A Yugo Nagata %A Chikato Kaga %A Yasuyuki Kanai %A Marco Leali %A Evandro Lodi Rizzini %A Valerio Mascagna %A Takuya Matsudate %A Horst Breuker %A Hiroyuki Higaki %A Yasuyuki Matsuda %A Stefan Ulmer %A Luca Venturelli %A Yasunori Yamazaki %B JPS Conf. Proc. %V 18 %P 011009 %G eng %R 10.7566/JPSCP.18.011009 %0 Journal Article %J JPS Conf. Proc. %D 2017 %T The Development of the Antihydrogen Beam Detector: Toward the Three Dimensional Tracking with a BGO Crystal and a Hodoscope %A Y. Nagata %A N. Kuroda %A C. Sauerzopf %A B. Kolbinger %A C. Malbrunot %A A. A. Capon %A P. Dupre %A B. Radics %A M. Tajima %A C. Kaga %A M. Leali %A E. Lodi Rizzini %A V. Mascagna %A O. Massiczek %A T. Matsudate %A M. C. Simon %A H. Breuker %A H. Higaki %A Y. Kanai %A Y. Matsuda %A L. Venturelli %A E. Widmann %A Y. Yamazaki %B JPS Conf. Proc. %V 18 %P 011038 %G eng %R 10.7566/JPSCP.18.011038 %0 Journal Article %J Journal of Physics Communications %D 2017 %T Efficient antihydrogen detection in antimatter physics by deep learning %A P Sadowski %A B Radics %A Ananya %A Y Yamazaki %A P Baldi %X Antihydrogen is at the forefront of antimatter research at the CERN Antiproton Decelerator. Experiments aiming to test the fundamental CPT symmetry and antigravity effects require the efficient detection of antihydrogen annihilation events, which is performed using highly granular tracking detectors installed around an antimatter trap. Improving the efficiency of the antihydrogen annihilation detection plays a central role in the final sensitivity of the experiments. We propose deep learning as a novel technique to analyze antihydrogen annihilation data, and compare its performance with a traditional track and vertex reconstruction method. We report that the deep learning approach yields significant improvement, tripling event coverage while simultaneously improving performance in terms of AUC by 5%. %B Journal of Physics Communications %V 1 %P 025001 %G eng %U http://stacks.iop.org/2399-6528/1/i=2/a=025001 %0 Journal Article %J Nature Communications %D 2017 %T In-beam measurement of the hydrogen hyperfine splitting - towards antihydrogen spectroscopy %A Diermaier, M. %A Jepsen, C. B. %A Kolbinger, B. %A Malbrunot, C. %A Massiczek, O. %A Sauerzopf, C. %A Simon, M. C. %A Zmeskal, J. %A Widmann, E. %X

Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison to hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of {\$}\backslashnu{\_}\backslashmathrm{\{}HF{\}}{\$}={\$}1{\~{}}420{\~{}}405{\~{}}748.4(3.4)(1.6){\~{}}\backslashtextrm{\{}Hz{\}}{\$} with a relative precision of {\$}\backslashDelta{\$}{\$}\backslashnu{\_}\backslashmathrm{\{}HF{\}}{\$}/{\$}\backslashnu{\_}\backslashmathrm{\{}HF{\}}{\$}={\$}2.7\backslashtimes10{\^{}}{\{}-9{\}}{\$} constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the ppb level. Together with the recently presented observation of antihydrogen atoms {\$}2.7{\~{}}\backslashtextrm{\{}m{\}}{\$} downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.

%B Nature Communications %V 8 %P 1–9 %8 12/06/2017 %G eng %U https://doi.org/10.1038/ncomms15749 %R 10.1038/ncomms15749 %0 Journal Article %J JPS Conf. Proc. %D 2017 %T Manipulation and Transport of Antiprotons for an Efficient Production of Antihydrogen Atoms %A Minori Tajima %A Naofumi Kuroda %A Pierre Dupre %A Yugo Nagata %A Balint Radics %A Takuya Matsudate %A Marco Leali %A Valerio Mascagna %A Luca Venturelli %A Horst Breuker %A Hiroyuki Higaki %A Yasuyuki Kanai %A Evandro Lodi Rizzini %A Yasuyuki Matsuda %A Stefan Ulmer %A Yasunori Yamazaki %B JPS Conf. Proc. %V 18 %P 011008 %G eng %R 10.7566/JPSCP.18.011008 %0 Journal Article %J JPS Conf. Proc. %D 2017 %T Measurements and 3D Reconstruction of Antimatter Annihilations with the ASACUSA Micromegas Tracker %A B. Radics %A H. Breuker %A P. Dupre %A Y. Higashi %A C. Kaga %A M. Leali %A E. Lodi Rizzini %A V. Mascagna %A T. Matsudate %A D. J. Murtagh %A M. Tajima %A H. A. Torii %A S. Van Gorp %A H. Higaki %A Y. Kanai %A N. Kuroda %A Y. Matsuda %A S. Ulmer %A L. Venturelli %A Y. Yamazaki %B JPS Conf. Proc. %V 18 %P 011010 %G eng %R 10.7566/JPSCP.18.011010 %0 Journal Article %J JPS Conf. Proc. %D 2017 %T Progress of Antihydrogen Beam Production Using a Double Cusp Trap %A Y. Nagata %A N. Kuroda %A P. Dupre %A B. Radics %A M. Tajima %A A. A. Capon %A M. Diermaier %A C. Kaga %A B. Kolbinger %A M. Leali %A E. Lodi Rizzini %A C. Malbrunot %A V. Mascagna %A O. Massiczek %A T. Matsudate %A C. Sauerzopf %A M. C. Simon %A K. Suzuki %A J. Zmeskal %A H. Breuker %A H. Higaki %A Y. Kanai %A Y. Matsuda %A S. Ulmer %A L. Venturelli %A E. Widmann %A Y. Yamazaki %B JPS Conf. Proc. %V 18 %P 011007 %G eng %R 10.7566/JPSCP.18.011007 %0 Journal Article %J Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %D 2016 %T Annihilation detector for an in-beam spectroscopy apparatus to measure the ground state hyperfine splitting of antihydrogen %A Clemens Sauerzopf %A Aaron A. Capon %A Martin Diermaier %A Markus Fleck %A Bernadette Kolbinger %A Chloé Malbrunot %A Oswald Massiczek %A Martin C. Simon %A Stefan Vamosi %A Johann Zmeskal %A Eberhard Widmann %K Silicon photomultiplier %B Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %P - %G eng %U http://www.sciencedirect.com/science/article/pii/S0168900216305630 %R http://dx.doi.org/10.1016/j.nima.2016.06.023 %0 Journal Article %J Journal of Physics B: Atomic, Molecular and Optical Physics %D 2016 %T Antihydrogen level population evolution: impact of positron plasma length %A B Radics %A Y Yamazaki %X Antihydrogen is produced by mixing an antiproton and a positron plasma in a cryogenic electromagnetic trap. The dominant antihydrogen formation mechanism is three-body recombination, while the subsequent level population evolution is governed by various processes, mainly collisional (de)excitation, ionisation and radiative decay. In this work the impact of various positron plasma lengths on the level population evolution is investigated. The main interest is the ground-state antihydrogen atom yield. It is found that the ground state level population shows different power-law behaviors at short or longer positron plasma lengths. %B Journal of Physics B: Atomic, Molecular and Optical Physics %V 49 %P 064007 %G eng %U http://stacks.iop.org/0953-4075/49/i=6/a=064007 %0 Journal Article %J Hyperfine Interactions %D 2016 %T Antihydrogen synthesis in a double-CUSP trap towards test of the CPT-symmetry %A Radics, B. %A Ishikawa, S. %A Kuroda, N. %A Murtagh, D. J. %A Nagata, Y. %A Tajima, M. %A Van Gorp, S. %A Abo, Y. %A Dupre, P. %A Higashi, Y. %A Kaga, C. %A Leali, M. %A Mascagna, V. %A Venturelli, L. %A Zurlo, N. %A Breuker, H. %A Higaki, H. %A Kanai, Y. %A Rizzini, E. Lodi %A Matsuda, Y. %A Ulmer, S. %A Yamazaki, Y. %X

The aim of the ASACUSA-CUSP experiment at CERN is to produce a cold, polarised antihydrogen beam and perform a high precision measurement of the ground-state hyperfine transition frequency of the antihydrogen atom and compare it with that of the hydrogen atom using the same spectroscopic beam line. Towards this goal a significant step was successfully accomplished: synthesised antihydrogen atoms have been produced in a CUSP magnetic configuration and detected at the end of our spectrometer beam line in 2012 [1]. During a long shut down at CERN the ASACUSA-CUSP experiment had been renewed by introducing a new double-CUSP magnetic configuration and a new semi-cylindrical tracking detector (AMT) [2], and by improving the transport feature of low energy antiproton beams. The new tracking detector monitors the antihydrogen synthesis during the mixing cycle of antiprotons and positrons. In this work the latest results and improvements of the antihydrogen synthesis will be presented including highlights from the last beam time.

%B Hyperfine Interactions %V 237 %P 156 %G eng %U http://dx.doi.org/10.1007/s10751-016-1368-4 %R 10.1007/s10751-016-1368-4 %0 Journal Article %J Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %D 2016 %T Direct detection of antihydrogen atoms using a BGO crystal %A Y. Nagata %A N. Kuroda %A M. Ohtsuka %A M. Leali %A E. Lodi-Rizzini %A V. Mascagna %A M. Tajima %A H.A. Torii %A N. Zurlo %A Y. Matsuda %A L. Venturelli %A Y. Yamazaki %K Antihydrogen %K antimatter %K Cosmic ray background suppression %K Detector %K Inorganic scintillator %X

Abstract The \{ASACUSA\} collaboration has developed a detector consisting of a large size \{BGO\} crystal to detect an atomic antihydrogen beam, and performed the direct detection of antihydrogen atoms. Energy spectra from antihydrogen annihilation on the \{BGO\} crystal are discussed in comparison to simulation results from the \{GEANT4\} toolkit. Background mainly originating from cosmic rays were strongly suppressed by analyzing the energy deposited in the \{BGO\} and requiring a multiplicity of charged pions. Thus antihydrogen events were identified.

%B Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %V 840 %P 153 - 159 %G eng %U http://www.sciencedirect.com/science/article/pii/S0168900216310440 %R http://dx.doi.org/10.1016/j.nima.2016.10.019 %0 Journal Article %J Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %D 2016 %T Intelligent Front-end Electronics for Silicon photodetectors (IFES) %A Clemens Sauerzopf %A Lukas Gruber %A Ken Suzuki %A Johann Zmeskal %A Eberhard Widmann %K Silicon photomultiplier %X Abstract While high channel density can be easily achieved for big experiments using custom made microchips, providing something similar for small and medium size experiments imposes a challenge. Within this work we describe a novel and cost effective solution to operate silicon photodetectors such as silicon photo multipliers (SiPM). The İFES\} modules provide the bias voltage for the detectors, a leading edge discriminator featuring time over threshold and a differential amplifier, all on one printed circuit board. We demonstrate under realistic conditions that the module is usable for high resolution timing measurements exploiting both charge and time information. Furthermore we show that the modules can be easily used in larger detector arrays. All in all this confirms that the İFES\} modules are a viable option for a broad range of experiments if cost-effectiveness and small form factor are required. %B Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment %V 819 %P 163 - 166 %G eng %U http://www.sciencedirect.com/science/article/pii/S0168900216300158 %R http://dx.doi.org/10.1016/j.nima.2016.02.098 %0 Journal Article %J Hyperfine Interactions %D 2016 %T Towards measuring the ground state hyperfine splitting of antihydrogen – a progress report %A Sauerzopf, C. %A Capon, A. A. %A Diermaier, M. %A Dupre, P. %A Higashi, Y. %A Kaga, C. %A Kolbinger, B. %A Leali, M. %A Lehner, S. %A Rizzini, E. Lodi %A Malbrunot, C. %A Mascagna, V. %A Massiczek, O. %A Murtagh, D. J. %A Nagata, Y. %A Radics, B. %A Simon, M. C. %A Suzuki, K. %A Tajima, M. %A Ulmer, S. %A Vamosi, S. %A Gorp, S. van %A Zmeskal, J. %A Breuker, H. %A Higaki, H. %A Kanai, Y. %A Kuroda, N. %A Matsuda, Y. %A Venturelli, L. %A Widmann, E. %A Yamazaki, Y. %X 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. %B Hyperfine Interactions %V 237 %P 103 %8 Jun %G eng %U https://doi.org/10.1007/s10751-016-1309-2 %R 10.1007/s10751-016-1309-2 %0 Journal Article %J Hyperfine Interactions %D 2015 %T The ASACUSA CUSP: an antihydrogen experiment %A Kuroda, N. %A Ulmer, S. %A Murtagh, D. J. %A Gorp, S. %A Nagata, Y. %A Diermaier, M. %A Federmann, S. %A Leali, M. %A Malbrunot, C. %A Mascagna, V. %A Massiczek, O. %A Michishio, K. %A Mizutani, T. %A Mohri, A. %A Nagahama, H. %A Ohtsuka, M. %A Radics, B. %A Sakurai, S. %A Sauerzopf, C. %A Suzuki, K. %A Tajima, M. %A Torii, H. A. %A Venturelli, L. %A Wünschek, B. %A Zmeskal, J. %A Zurlo, N. %A Higaki, H. %A Kanai, Y. %A Rizzini, E. Lodi %A Nagashima, Y. %A Matsuda, Y. %A Widmann, E. %A Yamazaki, Y. %X In order to test CPT symmetry between antihydrogen and its counterpart hydrogen, the ASACUSA collaboration plans to perform high precision microwave spectroscopy of ground-state hyperfine splitting of antihydrogen atom in-flight. We have developed an apparatus (``cusp trap'') which consists of a superconducting anti-Helmholtz coil and multiple ring electrodes. For the preparation of slow antiprotons and positrons, Penning-Malmberg type traps were utilized. The spectrometer line was positioned downstream of the cusp trap. At the end of the beamline, an antihydrogen beam detector was located, which comprises an inorganic Bismuth Germanium Oxide (BGO) single-crystal scintillator housed in a vacuum duct and surrounding plastic scintillators. A significant fraction of antihydrogen atoms flowing out the cusp trap were detected. %B Hyperfine Interactions %V 235 %P 13–20 %G eng %U http://dx.doi.org/10.1007/s10751-015-1205-1 %R 10.1007/s10751-015-1205-1 %0 Journal Article %J Review of Scientific Instruments %D 2015 %T The ASACUSA Micromegas Tracker: A cylindrical, bulk Micromegas detector for antimatter research %A Radics, B. %A Nagata, Y. %A Yamazaki, Y. %A Ishikawa, S. %A Kuroda, N. %A Matsuda, Y. %A Anfreville, M. %A Aune, S. %A Boyer, M. %A Chateau, F. %A Combet, M. %A Granelli, R. %A Legou, P. %A Mandjavidze, I. %A Procureur, S. %A Riallot, M. %A Vallage, B. %A Vandenbroucke, M. %X

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.

 

%B Review of Scientific Instruments %V 86 %G eng %U http://scitation.aip.org/content/aip/journal/rsi/86/8/10.1063/1.4927685 %R http://dx.doi.org/10.1063/1.4927685 %0 Journal Article %J Hyperfine Interactions %D 2015 %T An atomic hydrogen beam to test ASACUSA’s apparatus for antihydrogen spectroscopy %A Diermaier, M. %A Caradonna, P. %A Kolbinger, B. %A Malbrunot, C. %A Massiczek, O. %A Sauerzopf, C. %A Simon, M.C. %A Wolf, M. %A Zmeskal, J. %A Widmann, E. %K Antihydrogen %K Atomic hydrogen %K Ground state hyperfine structure %B Hyperfine Interactions %V 233 %P 35-40 %G eng %U http://dx.doi.org/10.1007/s10751-015-1151-y %R 10.1007/s10751-015-1151-y %0 Journal Article %J Journal of Physics B: Atomic, Molecular and Optical Physics %D 2015 %T Towards a precise measurement of the antihydrogen ground state hyperfine splitting in a beam: the case of in-flight radiative decays %A R Lundmark %A C Malbrunot %A Y Nagata %A B Radics %A C Sauerzopf %A E Widmann %K Antihydrogen %K ground state hyperfine splitting measurement %K radiative decay %X

The ASACUSA antihydrogen setup at the CERN Antiproton Decelerator (AD) consists of an antihydrogen source (cusp magnet coupled to a positron source and an antiproton catching magnet) followed by a spectrometer beamline. After production in the cusp, the antihydrogen atoms decay while they escape the trap leading to changes in their effective magnetic moment which in turn affect their trajectories in the beamline. Those sequential decays in the presence of a varying magnetic field strength from their production point in the cusp to their detection at the end of the spectrometer line can in principle greatly affect the prospects for a precision measurement of the antihydrogen hyperfine splitting given the so-far relatively low number of available anti-atoms. The impact of the antihydrogen decay in this context has for the first time been simulated. The implementation of atomic radiative decay has been done in Geant4 to extend the particle tracking capabilities originally embedded in Geant4 to excited atoms, and to allow studies of the effect of dynamic atomic properties on trajectories. This new tool thus allows the study of particle–matter interaction via the Geant4 toolkit while properly taking into account the atomic nature of the object under study. The implementation as well as impacts on the experimental sensitivity for antihydrogen spectroscopy are discussed in this paper.

%B Journal of Physics B: Atomic, Molecular and Optical Physics %V 48 %P 184001 %8 29/07/2015 %G eng %U http://stacks.iop.org/0953-4075/48/i=18/a=184001 %0 Journal Article %J 陽電子科学 %D 2015 %T カスプトラップを用いた反水素研究 %A Yugo Nagata %A Naofumi Kuroda %K Antihydrogen %K ASACUSA %K Atomic beam %K CPT symmetry %K cusp trap %K non-neutral plasma %X

In this review, we describe a planned experiment of the Atomic Spectroscopy And Collisions Using Slow Antiprotons (ASACUSA) collaboration at CERN to test CPT symmetry via atomic beam spectroscopy of the ground-state hyperfine splitting of antihydrogen using a cusp trap. The cusp trap which consists of a superconducting anti-Helmholtz coil and a stack of ring electrodes, is expected to produce a spin-polarized antihydrogen beam. Recently, the ASACUSA collaboration succeeded in producing antihydrogen atoms in the cusp trap and extracting an antihydrogen beam. This paves the way towards precision in-flight spectroscopy of the antihydrogen atom.

 

%B 陽電子科学 %V 4 %P 49-59 %8 Feb. %G eng %& 49 %0 Journal Article %J Phys. Rev. Lett. %D 2014 %T First Observation of a (1,0) Mode Frequency Shift of an Electron Plasma at Antiproton Beam Injection %A Kuroda, N. %A Mohri, A. %A Torii, H.A. %A Nagata, Y. %A Shibata, M. %X

The frequency shift of the center-of-mass oscillation, known as the (1,0) mode, of a trapped electron plasma and, furthermore, its time evolution were observed during the cooling of an injected antiproton beam for the first time. Here, antiprotons mixed with the electrons did not follow faster electron oscillations but contributed to the modification of the effective potential. The time evolution of the plasma temperature, deduced from the frequency shift of the excited (3,0) mode, suggested that there was an abnormal energy deposition of the antiproton beam in the electron plasma before thermalization.

%B Phys. Rev. Lett. %V 113 %P 025001 %8 Jul %G eng %U http://link.aps.org/doi/10.1103/PhysRevLett.113.025001 %N 2 %R 10.1103/PhysRevLett.113.025001 %0 Journal Article %J New Journal of Physics %D 2014 %T A novel property of anti-Helmholz coils for in-coil syntheses of antihydrogen atoms: formation of a focused spin-polarized beam %A Yugo Nagata %A Yasunori Yamazaki %K atomic and molecular beam sources and techniques %K beam optics %K exotic atoms and molecules %X

We demonstrate here that cold antihydrogen beams formed and extracted from a cusp magnet (anti-Helmholtz coils) are well focused and spin-polarized. A new discovery was the fact that the antihydrogen beam follows the well-known lens formula of optical lenses with its focal length properly scaled with the initial kinetic energy, the magnetic field strength and the magnetic moment. Furthermore, the simulation revealed that for a certain kinetic energy region of antihydrogen atoms, the optimum production position is upstream of the center of the cusp magnet, where a well-known nested potential configuration can be applied.

%B New Journal of Physics %V 16 %P 083026 %G eng %U http://stacks.iop.org/1367-2630/16/i=8/a=083026 %N 8 %R doi:10.1088/1367-2630/16/8/083026 %0 Journal Article %J Phys. Rev. A %D 2014 %T Scaling behavior of the ground-state antihydrogen yield as a function of positron density and temperature from classical-trajectory Monte Carlo simulations %A Radics, B. %A Murtagh, D. J. %A Yamazaki, Y. %A Robicheaux, F. %B Phys. Rev. A %V 90 %P 032704 %8 Sep %G eng %U http://link.aps.org/doi/10.1103/PhysRevA.90.032704 %R 10.1103/PhysRevA.90.032704 %0 Journal Article %J Nat Commun %D 2014 %T A source of antihydrogen for in-flight hyperfine spectroscopy %A Kuroda, N. %A Ulmer, S. %A Murtagh, D. J. %A Van Gorp, S. %A Nagata, Y. %A Diermaier, M. %A Federmann, S. %A Leali, M. %A Malbrunot, C. %A Mascagna, V. %A Massiczek, O. %A Michishio, K. %A Mizutani, T. %A Mohri, A. %A Nagahama, H. %A Ohtsuka, M. %A Radics, B. %A Sakurai, S. %A Sauerzopf, C. %A Suzuki, K. %A Tajima, M. %A Torii, H. A. %A Venturelli, L. %A Wu¨nschek, B. %A Zmeskal, J. %A Zurlo, N. %A Higaki, H. %A Kanai, Y. %A Lodi Rizzini, E. %A Nagashima, Y. %A Matsuda, Y. %A Widmann, E. %A Yamazaki, Y. %X

Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart—hydrogen—is one of the most precisely investigated and best understood systems in physics research. High-resolution comparisons of both systems provide sensitive tests of CPT symmetry, which is the most fundamental symmetry in the Standard Model of elementary particle physics. Any measured difference would point to CPT violation and thus to new physics. Here we report the development of an antihydrogen source using a cusp trap for in-flight spectroscopy. A total of 80 antihydrogen atoms are unambiguously detected 2.7 m downstream of the production region, where perturbing residual magnetic fields are small. This is a major step towards precision spectroscopy of the ground-state hyperfine splitting of antihydrogen using Rabi-like beam spectroscopy.

%B Nat Commun %V 5 %8 21/01/2014 %G eng %U http://dx.doi.org/10.1038/ncomms4089 %0 Journal Article %J Hyperfine Interactions %D 2014 %T Spectroscopy apparatus for the measurement of the hyperfine structure of antihydrogen %A Malbrunot, C. %A Caradonna, P. %A Diermaier, M. %A Dilaver, N. %A Friedreich, S. %A Kolbinger, B. %A Lehner, S. %A Lundmark, R. %A Massiczek, O. %A Radics, B. %A Sauerzopf, C. %A Simon, M. %A Widmann, E. %A Wolf, M. %A Wünschek, B. %A Zmeskal, J. %K Antihydrogen %K CPT symmetry %K Hyperfine spectroscopy %B Hyperfine Interactions %P 1-6 %G eng %U http://dx.doi.org/10.1007/s10751-014-1013-z %R 10.1007/s10751-014-1013-z %0 Journal Article %J Hyperfine Interactions %D 2014 %T Towards a spin polarized antihydrogen beam %A Kuroda, N. %A Ulmer, S. %A Murtagh, D.J. %A Van Gorp, S. %A Nagata, Y. %A Diermaier, M. %A Federmann, S. %A Leali, M. %A Malbrunot, C. %A Mascagna, V. %A Massiczek, O. %A Michishio, K. %A Mizutani, T. %A Mohri, A. %A Nagahama, H. %A Ohtsuka, M. %A Radics, B. %A Sakurai, S. %A Sauerzopf, C. %A Suzuki, K. %A Tajima, M. %A Torii, H.A. %A Venturelli, L. %A Wünschek, B. %A Zmeskal, J. %A Zurlo, N. %A Higaki, H. %A Kanai, Y. %A Lodi-Rizzini, E. %A Nagashima, Y. %A Matsuda, Y. %A Widmann, E. %A Yamazaki, Y. %K Antihydrogen %K Atomic beam %K CPT invariance %K Rydberg atom %B Hyperfine Interactions %P 1-10 %G eng %U http://dx.doi.org/10.1007/s10751-014-1016-9 %R 10.1007/s10751-014-1016-9 %0 Journal Article %J Annalen der Physik %D 2013 %T CPT symmetry tests with cold p¯ and antihydrogen %A Yamazaki, Yasunori %A Ulmer, Stefan %K antimatter %K CPT symmetry %K Fundamental Interactions %X

Precision comparisons of the properties of particles and their corresponding antiparticles are highly relevant because the Standard Model of elementary particle physics, a local, Lorentz-invariant field theory, is necessarily symmetric with respect to the combined CPT operation. This symmetry defines exact equality between the fundamental properties of particles and their anti-images. Any measured and confirmed violation constitutes a significant challenge to the Standard Model. Recent results of different CPT-tests are summarized, with emphasis to the high-precision measurement of the magnetic moment of the proton and the antiproton, as well as the precision investigation of antihydrogen ground state hyperfine splitting.

%B Annalen der Physik %V 525 %P 493–504 %G eng %U http://dx.doi.org/10.1002/andp.201300060 %R 10.1002/andp.201300060 %0 Journal Article %J J. Plasma Fusion Res. %D 2013 %T From Synthesis To Physics of Anti-Hydrogen – Cooling, Recombination, and Trapping of Antiprotons and Positrons %A H. Higaki %A F. Robicheaux %A Torii, H.A. %A N. Kuroda %A K. Michishio %A Y. Enomoto %A Y. Nagata %A M.C. Fujiwara %A M. Hori %B J. Plasma Fusion Res. %V 89 %P 11 %G eng %0 Journal Article %J Hyperfine Interactions %D 2013 %T Measurement of the hyperfine structure of antihydrogen in a beam %A Widmann, E. %A Diermaier, M. %A Juhasz, B. %A Malbrunot, C. %A Massiczek, O. %A Sauerzopf, C. %A Suzuki, K. %A Wünschek, B. %A Zmeskal, J. %A Federmann, S. %A Kuroda, N. %A Ulmer, S. %A Yamazaki, Y. %K Antihydrogen %K CPT %K Precision spectroscopy %B Hyperfine Interactions %V 215 %P 1-8 %G eng %U http://dx.doi.org/10.1007/s10751-013-0809-6 %R 10.1007/s10751-013-0809-6 %0 Journal Article %J AIP Conference Proceedings %D 2013 %T Towards the production of anti-hydrogen beams %A H. Higaki %A Y. Enomoto %A N. Kuroda %A K. Michishio %A D. J. Murtagh %A S. Ulmer %A S. Van Gorp %A C. H. Kim %A Y. Nagata %A Y. Kanai %A Torii, H.A. %A M. Corradini %A M. Leali %A E. Lodi-Rizzini %A V. Mascagna %A L. Venturelli %A N. Zurlo %A K. Fujii %A M. Otsuka %A K. Tanaka %A H. Imao %A Y. Nagashima %A Y. Matsuda %A B. Juhász %A A. Mohri %A Y. Yamazaki %E Xabier Sarasola %E Lutz Schweikhard %E Thomas Sunn Pedersen %K antimatter %K atomic beams %K hydrogen neutral atoms %K hyperfine structure %K particle beam diagnostics %B AIP Conference Proceedings %V 1521 %P 134-143 %G eng %U http://link.aip.org/link/?APC/1521/134/1 %R 10.1063/1.4796069 %0 Journal Article %J Hyperfine Interactions %D 2012 %T Antihydrogen atom formation in a CUSP trap towards spin polarized beams %A Kuroda, N. %A Enomoto, Y. %A Michishio, K. %A Kim, C.H. %A Higaki, H. %A Nagata, Y. %A Kanai, Y. %A Torii, H.A. %A Corradini, M. %A Leali, M. %A Lodi-Rizzini, E. %A Venturelli, L. %A Zurlo, N. %A Fujii, K. %A Ohtsuka, M. %A Tanaka, K. %A Imao, H. %A Nagashima, Y. %A Matsuda, Y. %A Juhasz, B. %A Widmann, E. %A Mohri, A. %A Yamazaki, Y. %K Antihydrogen %K Atomic beam %K CPT invariance %K Rydberg atom %B Hyperfine Interactions %V 212 %P 31-40 %G eng %U http://dx.doi.org/10.1007/s10751-012-0646-z %R 10.1007/s10751-012-0646-z %0 Journal Article %J Physical Review Special Topics - Accelerators and BeamsPhys. Rev. ST Accel. Beams %D 2012 %T Development of a monoenergetic ultraslow antiproton beam source for high-precision investigation %A Kuroda, N. %A Torii, H. A. %A Nagata, Y. %A Shibata, M. %A Enomoto, Y. %A Imao, H. %A Kanai, Y. %A Hori, M. %A Saitoh, H. %A Higaki, H. %A Mohri, A. %A Fujii, K. %A Kim, C. H. %A Matsuda, Y. %A Michishio, K. %A Nagashima, Y. %A Ohtsuka, M. %A Tanaka, K. %A Yamazaki, Y. %B Physical Review Special Topics - Accelerators and BeamsPhys. Rev. ST Accel. Beams %V 15 %P 024702 - %8 2012/02/17/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevSTAB.15.024702 %0 Journal Article %J Hyperfine Interactions %D 2012 %T Synthesis of antihydrogen atoms in a CUSP trap %A Kuroda, Naofumi %A Enomoto, Yoshinori %A Michishio, Koji %A Kim, Chanhyoun %A Higaki, Hiroyuki %A Nagata, Yugo %A Kanai, Yasuyuki %A Torii, Hiroyuki %A Corradini, Maurizzio %A Leali, Marco %A Lodi-Rizzini, Evandro %A Mascagna, Valerio %A Venturelli, Luca %A Zurlo, Nicola %A Fujii, Koki %A Ohtsuka, Miki %A Tanaka, Kazuo %A Imao, Hiroshi %A Nagashima, Yasuyuki %A Matsuda, Yasuyuki %A Juhász, Bertalan %A Widmann, Eberhard %A Mohri, Akihiro %A Yamazaki, Yasunori %X

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.

%B Hyperfine Interactions %V 209 %P 35-41 %G eng %U http://dx.doi.org/10.1007/s10751-012-0560-4 %0 Journal Article %J 日本物理學會誌 %D 2011 %T 折り返し点を通過した冷反水素研究 : カスプトラップによる反水素の生成と磁気瓶への閉じ込め %A N. Kuroda %A H. Higaki %A Y. Yamazaki %B 日本物理學會誌 %V 66 %P 594-602 %8 aug %G eng %U http://ci.nii.ac.jp/naid/110008688061/ %0 Journal Article %J Journal of Physics: Conference Series %D 2010 %T Positron accumulation and manipulation for antihydrogen synthesis %A H Imao %A K Michishio %A Y Kanai %A N Kuroda %A Y Enomoto %A H Higaki %A K Kira %A A Mohri %A H A Torii %A Y Nagata %A C Kim %A Y Matsuda %A Y Nagashima %A Y Yamazaki %X

Our group ASACUSA-MUSASHI has established an efficient way for accumulating antiprotons in the cusp trap, a combination of an anti-Helmholz superconducting coil and a multi-ring electrode trap. The last piece for synthesizing antihydrogens in the cusp trap is positron. We have developed a compact system to effectively accumulate positrons based on N 2 gas-buffer scheme with a specially designed high precision cylindrical multi-ring electrode trap. Millions of positrons were accumulated in the pre-accumulator just using polycrystalline tungsten moderators. The accumulated positrons were transported as a pulsed beam via three guiding coils and caught in the cusp trap under cryogenic and ultra high vacuum conditions without serious loss. Confinement of two kinds of numerous antiparticles, e.g., 10 8 positrons and 10 7 antiprotons, in the cusp trap becomes feasible.

%B Journal of Physics: Conference Series %V 225 %P 012018 %G eng %U http://stacks.iop.org/1742-6596/225/i=1/a=012018 %0 Journal Article %J Physical Review LettersPhys. Rev. Lett. %D 2010 %T Synthesis of Cold Antihydrogen in a Cusp Trap %A Enomoto, Y. %A Kuroda, N. %A Michishio, K. %A Kim, C. H. %A Higaki, H. %A Nagata, Y. %A Kanai, Y. %A Torii, H. A. %A Corradini, M. %A Leali, M. %A Lodi-Rizzini, E. %A Mascagna, V. %A Venturelli, L. %A Zurlo, N. %A Fujii, K. %A Ohtsuka, M. %A Tanaka, K. %A Imao, H. %A Nagashima, Y. %A Matsuda, Y. %A Juhasz, B. %A Mohri, A. %A Yamazaki, Y. %B Physical Review LettersPhys. Rev. Lett. %V 105 %P 243401 - %8 2010/12/07/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevLett.105.243401 %0 Journal Article %J Physical Review LettersPhys. Rev. Lett. %D 2010 %T Target Structure Induced Suppression of the Ionization Cross Section for Very Low Energy Antiproton-Hydrogen Collisions %A Knudsen, H. %A Torii, H. A. %A Charlton, M. %A Enomoto, Y. %A Georgescu, I. %A Hunniford, C. A. %A Kim, C. H. %A Kanai, Y. %A Kristiansen, H.-P. E. %A Kuroda, N. %A Lund, M. D. %A McCullough, R. W. %A Tökesi, K. %A Uggerhøj, U. I. %A Yamazaki, Y. %B Physical Review LettersPhys. Rev. Lett. %V 105 %P 213201 - %8 2010/11/17/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevLett.105.213201 %0 Journal Article %J Hyperfine Interactions %D 2009 %T ASACUSA MUSASHI: New progress with intense ultra slow antiproton beam %A Imao, H. %A Tarek, M. %A Michishio, K. %A Enomoto, Y. %A Shimoyama, T. %A Kanai, Y. %A Kuroda, N. %A Mohri, A. %A Higaki, H. %A Saitoh, H. %A Torii, H.A. %A Nagata, Y. %A Toyoda, H. %A Matsuda, Y. %A Nagashima, Y. %A Yamazaki, Y. %K Antihydrogen %K Antiproton %K Positron %B Hyperfine Interactions %V 194 %P 71-76 %G eng %U http://dx.doi.org/10.1007/s10751-009-0032-7 %R 10.1007/s10751-009-0032-7 %0 Journal Article %J Journal of Physics: Conference Series %D 2009 %T Atomic collision and spectroscopy experiments with ultra-low-energy antiprotons %A Torii, H.A. %A Yugo Nagata %A Hiroshi Toyoda %A Hiroshi Imao %A Naofumi Kuroda %A Victor L Varentsov %A Yasunori Yamazaki %A Asacusa collaboration %X

Antiproton, the antiparticle of proton, is a unique projectile in the study of atomic collision physics, which can be treated theoretically either as a 'negative proton' or a 'heavy electron'. 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 'pure' 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 × 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 .

%B Journal of Physics: Conference Series %V 185 %P 012049 %G eng %U http://stacks.iop.org/1742-6596/185/i=1/a=012049 %0 Journal Article %J Hyperfine Interactions %D 2009 %T Cross-beam atomic collision experiment between ultra-low-energy antiprotons and a supersonic gas jet %A Torii, H.A. %A Nagata, Y. %A Toyoda, H. %A Imao, H. %A Kuroda, N. %A Varentsov, V.L. %A Yamazaki, Y. %K Cross-beam atomic collision %K Supersonic gas jet %K Ultra-low-energy antiprotons %B Hyperfine Interactions %V 194 %P 37-43 %G eng %U http://dx.doi.org/10.1007/s10751-009-0027-4 %R 10.1007/s10751-009-0027-4 %0 Journal Article %J Proceedings of the Fourth International Conference on Elementary Processes in Atomic Systems %D 2009 %T On the double ionization of helium by very slow antiproton impact %A Knudsen, H. %A Kristiansen, H.-P. E. %A Thomsen, H. D. %A Uggerhøj, U. I. %A Ichioka, T. %A Møller, S. P. %A Hunniford, C. A. %A McCullough, R. W. %A Charlton, M. %A Kuroda, N. %A Nagata, Y. %A Torii, H. A. %A Yamazaki, Y. %A Imao, H. %A Andersen, H. H. %A Tökesi, K. %K Antiproton %K CERN AD %K Electron correlation %K Ionization %B Proceedings of the Fourth International Conference on Elementary Processes in Atomic Systems %V 267 %P 244 - 247 %8 2009/1// %@ 0168-583X %G eng %U http://www.sciencedirect.com/science/article/pii/S0168583X08011373 %0 Journal Article %J AIP Conference Proceedings %D 2009 %T Radial compression of antiproton cloud for production of ultraslow antiproton beams %A N. Kuroda %A Y. Nagata %A H. A. Torii %A D. Barna %A J. Eades %A D. Horváth %A M. Hori %A H. Imao %A K. Komaki %A A. Mohri %A M. Shibata %A Y. Yamazaki %E James R. Danielson %E Thomas Sunn Pedersen %K particle traps %K plasma %K plasma simulation %B AIP Conference Proceedings %V 1114 %P 157-162 %G eng %U http://link.aip.org/link/?APC/1114/157/1 %R 10.1063/1.3122278 %0 Journal Article %J Review of Scientific InstrumentsRev. Sci. Instrum. %D 2008 %T Compact cryogenic system with mechanical cryocoolers for antihydrogen synthesis %A Shibata, M. %A Mohri, A. %A Kanai, Y. %A Enomoto, Y. %A Yamazaki, Y. %K cryogenics %K exotic atoms %K hydrogen %K vacuum techniques %B Review of Scientific InstrumentsRev. Sci. Instrum. %V 79 %P 015112 - 4 %8 2008/01/00/ %G eng %U http://dx.doi.org/10.1063/1.2834876 %0 Journal Article %J Physical Review LettersPhys. Rev. Lett. %D 2008 %T Ionization of Helium and Argon by Very Slow Antiproton Impact %A Knudsen, H. %A Kristiansen, H.-P. E. %A Thomsen, H. D. %A Uggerhøj, U. I. %A Ichioka, T. %A Møller, S. P. %A Hunniford, C. A. %A McCullough, R. W. %A Charlton, M. %A Kuroda, N. %A Nagata, Y. %A Torii, H. A. %A Yamazaki, Y. %A Imao, H. %A Andersen, H. H. %A Tökesi, K. %B Physical Review LettersPhys. Rev. Lett. %V 101 %P 043201 - %8 2008/07/25/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevLett.101.043201 %0 Journal Article %J AIP Conference Proceedings %D 2008 %T Observation of Ultra-Slow Antiprotons using Micro-channel Plate %A H. Imao %A H. A. Torii %A Y. Nagata %A H. Toyoda %A T. Shimoyama %A Y. Enomoto %A H. Higaki %A Y. Kanai %A A. Mohri %A Y. Yamazaki %E Yasuyuki Kanai %E Yasunori Yamazaki %K elementary particles %K nuclear fragmentation %K protons %B AIP Conference Proceedings %V 1037 %P 311-317 %G eng %U http://link.aip.org/link/?APC/1037/311/1 %R 10.1063/1.2977850 %0 Journal Article %J Physical Review APhys. Rev. A %D 2008 %T Radial compression of a non-neutral plasma in a cusp trap for antihydrogen synthesis %A Saitoh, H. %A Mohri, A. %A Enomoto, Y. %A Kanai, Y. %A Yamazaki, Y. %B Physical Review APhys. Rev. A %V 77 %P 051403 - %8 2008/05/27/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevA.77.051403 %0 Journal Article %J Physical Review LettersPhys. Rev. Lett. %D 2008 %T Radial Compression of an Antiproton Cloud for Production of Intense Antiproton Beams %A Kuroda, N. %A Torii, H. A. %A Shibata, M. %A Nagata, Y. %A Barna, D. %A Hori, M. %A Horvath, D. %A Mohri, A. %A Eades, J. %A Komaki, K. %A Yamazaki, Y. %B Physical Review LettersPhys. Rev. Lett. %V 100 %P 203402 - %8 2008/05/19/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevLett.100.203402 %0 Journal Article %J Physical Review LettersPhys. Rev. Lett. %D 2006 %T Cooling by Spontaneous Decay of Highly Excited Antihydrogen Atoms in Magnetic Traps %A Pohl, T. %A Sadeghpour, H. R. %A Nagata, Y. %A Yamazaki, Y. %B Physical Review LettersPhys. Rev. Lett. %V 97 %P 213001 - %8 2006/11/22/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevLett.97.213001 %0 Journal Article %J AIP Conference Proceedings %D 2005 %T Antiproton and Electron Plasma Behavior and its Control for Production of Ultraslow Antiproton Beams %A N. Kuroda %A H. A. Torii %A M. Shibata %A Y. Nagata %A D. Barna %A M. Hori %A A. Mohri %A K. Komaki %A Y. Yamazaki %E Dieter Grzonka %E Rafał Czyżykiewicz %E Walter Oelert %E Tomasz Rożek %E Peter Winter %K plasma electrostatic waves %K proton beams %B AIP Conference Proceedings %V 796 %P 321-324 %G eng %U http://link.aip.org/link/?APC/796/321/1 %R 10.1063/1.2130188 %0 Journal Article %J AIP Conference Proceedings %D 2005 %T ASACUSA Gas-Jet Target: Present Status And Future Development %A V. L. Varentsov %A N. Kuroda %A Y. Nagata %A H. A. Torii %A M. Shibata %A Y. Yamazaki %E Yasunori Yamazaki %E Michiharu Wada %K atomic beams %K computer aided analysis %K hadronic atoms %K helium %K jets %K supersonic flow %B AIP Conference Proceedings %V 793 %P 328-340 %G eng %U http://link.aip.org/link/?APC/793/328/1 %R 10.1063/1.2121994 %0 Journal Article %J Physical Review Letters %D 2005 %T Confinement of a Large Number of Antiprotons and Production of an Ultraslow Antiproton Beam %A Kuroda, N. %A Torii, H. A. %A Franzen, K. Yoshiki %A Wang, Z. %A Yoneda, S. %A Inoue, M. %A Hori, M. %A Juhasz, B. %A Horvath, D. %A Higaki, H. %A Mohri, A. %A Eades, J. %A Komaki, K. %A Yamazaki, Y. %B Physical Review Letters %V 94 %P 023401 - %8 2005/01/18/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevLett.94.023401 %0 Journal Article %J AIP Conference Proceedings %D 2005 %T Control of plasmas for production of ultraslow antiproton beams %A N. Kuroda %A H. A. Torii %A M. Shibata %A Y. Nagata %A D. Barna %A D. Horváth %A M. Hori %A J. Eades %A A. Mohri %A K. Komaki %A Y. Yamazaki %E Yasunori Yamazaki %E Michiharu Wada %K atomic beams %K hadronic atoms %K particle traps %K plasma %B AIP Conference Proceedings %V 793 %P 307-317 %G eng %U http://link.aip.org/link/?APC/793/307/1 %R 10.1063/1.2121992 %0 Journal Article %J AIP Conference Proceedings %D 2005 %T Production of ultra-slow antiproton beams %A Torii, Hiroyuki A. %A N. Kuroda %A M. Shibata %A Y. Nagata %A D. Barna %A M. Hori %A J. Eades %A A. Mohri %A K. Komaki %A Y. Yamazaki %E Yasunori Yamazaki %E Michiharu Wada %K atomic beams %K hadronic atoms %K plasma %B AIP Conference Proceedings %V 793 %P 293-306 %G eng %U http://link.aip.org/link/?APC/793/293/1 %R 10.1063/1.2121991 %0 Journal Article %J Physical Review EPhys. Rev. E %D 2004 %T Radial compression of protons and H_{3}^{+} ions in a multiring trap for the productionof ultralow energy antiproton beams %A Higaki, H. %A Kuroda, N. %A Yoshiki Franzen, K. %A Wang, Z. %A Hori, M. %A Mohri, A. %A Komaki, K. %A Yamazaki, Y. %B Physical Review EPhys. Rev. E %V 70 %P 026501 - %8 2004/08/24/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevE.70.026501 %0 Journal Article %J EPL (Europhysics Letters) %D 2003 %T A possible new scheme to synthesize antihydrogen and to prepare a polarised antihydrogen beam %A A. Mohri %A Y. Yamazaki %X A new scheme is proposed for synthesizing antihydrogen by trapping positrons at the centre of a field consisting of a magnetic quadrupole and an electric octupole. It is expected that the total electric field of this octupole with the space charge of the trapped positrons themselves will be strong enough to confine antiprotons inside the positron cloud, where the two particle species will combine to produce antihydrogen atoms spontaneously via radiative recombination. Furthermore, a numerical simulation has revealed that a considerable fraction of antihydrogen atoms in low-field-seeking states formed at 5 K near the centre of the trap may be transported as a 99% polarised beam and focused 1 m from the trap centre with   0.3% efficiency, corresponding to an enhancement in beam intensity by a factor 30. %B EPL (Europhysics Letters) %V 63 %P 207 %G eng %U http://stacks.iop.org/0295-5075/63/i=2/a=207 %0 Journal Article %J Review of Scientific InstrumentsRev. Sci. Instrum. %D 2003 %T Transport beam line for ultraslow monoenergetic antiprotons %A Yoshiki-Franzen, K. %A Kuroda, N. %A Torii, H. A. %A Hori, M. %A Wang, Z. %A Higaki, H. %A Yoneda, S. %A Juhasz, B. %A Horvath, D. %A Mohri, A. %A Komaki, K. %A Yamazaki, Y. %K beam handling equipment %K proton beams %B Review of Scientific InstrumentsRev. Sci. Instrum. %V 74 %P 3305 - 3311 %8 2003/07/00/ %G eng %U http://dx.doi.org/10.1063/1.1578160 %0 Journal Article %J Physical Review EPhys. Rev. E %D 2002 %T Electron cooling of high-energy protons in a multiring trap with a tank circuit monitoring the electron-plasma oscillations %A Higaki, H. %A Kuroda, N. %A Ichioka, T. %A Franzen, K. Yoshiki %A Wang, Z. %A Komaki, K. %A Yamazaki, Y. %A Hori, M. %A Oshima, N. %A Mohri, A. %B Physical Review EPhys. Rev. E %V 65 %P 046410 - %8 2002/04/02/ %G eng %U http://link.aps.org/doi/10.1103/PhysRevE.65.046410 %0 Journal Article %J AIP Conference Proceedings %D 1999 %T Multi-ring trap as a reservoir of cooled antiprotons %A T. Ichioka %A H. Higaki %A M. Hori %A N. Oshima %A K. Kuroki %A A. Mohri %A K. Komaki %A Y. Yamazaki %E John J. Bollinger %E Ronald C. Davidson %E Ross L. Spencer %K antimatter %K cooling %K electric fields %K electrodes %K magnetic fields %K particle traps %K storage rings %B AIP Conference Proceedings %V 498 %P 59-64 %G eng %U http://link.aip.org/link/?APC/498/59/1 %R 10.1063/1.1302101 %0 Journal Article %D 1999 %T Production of ultra slow antiprotons, its application to atomic collisions and atomic spectroscopy – ASACUSA project %A Yamazaki, Yasunori %K Antiprotonic atom %K Few body system %K Fundamental constants %K Ultra slow antiproton and its collision %V 154 %P 174 - 184 %8 1999/6/3/ %@ 0168-583X %G eng %U http://www.sciencedirect.com/science/article/pii/S0168583X99001913