@article {78, title = {Antihydrogen synthesis in a double-CUSP trap towards test of the CPT-symmetry}, journal = {Hyperfine Interactions}, volume = {237}, year = {2016}, pages = {156}, abstract = {

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.

}, issn = {1572-9540}, doi = {10.1007/s10751-016-1368-4}, url = {http://dx.doi.org/10.1007/s10751-016-1368-4}, author = {Radics, B. and Ishikawa, S. and Kuroda, N. and Murtagh, D. J. and Nagata, Y. and Tajima, M. and Van Gorp, S. and Abo, Y. and Dupre, P. and Higashi, Y. and Kaga, C. and Leali, M. and Mascagna, V. and Venturelli, L. and Zurlo, N. and Breuker, H. and Higaki, H. and Kanai, Y. and Rizzini, E. Lodi and Matsuda, Y. and Ulmer, S. 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 {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 {23, title = {Development of a monoenergetic ultraslow antiproton beam source for high-precision investigation}, journal = {Physical Review Special Topics - Accelerators and BeamsPhys. Rev. ST Accel. Beams}, volume = {15}, year = {2012}, month = {2012/02/17/}, pages = {024702 -}, url = {http://link.aps.org/doi/10.1103/PhysRevSTAB.15.024702}, author = {Kuroda, N. and Torii, H. A. and Nagata, Y. and Shibata, M. and Enomoto, Y. and Imao, H. and Kanai, Y. and Hori, M. and Saitoh, H. and Higaki, H. and Mohri, A. and Fujii, K. and Kim, C. H. and Matsuda, Y. and Michishio, K. and Nagashima, Y. and Ohtsuka, M. and Tanaka, K. 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 {28, title = {Positron accumulation and manipulation for antihydrogen synthesis}, journal = {Journal of Physics: Conference Series}, volume = {225}, year = {2010}, pages = {012018}, abstract = {

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.

}, url = {http://stacks.iop.org/1742-6596/225/i=1/a=012018}, author = {H Imao and K Michishio and Y Kanai and N Kuroda and Y Enomoto and H Higaki and K Kira and A Mohri and H A Torii and Y Nagata and C Kim and Y Matsuda and Y Nagashima and Y Yamazaki} } @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 {29, title = {ASACUSA MUSASHI: New progress with intense ultra slow antiproton beam}, journal = {Hyperfine Interactions}, volume = {194}, year = {2009}, pages = {71-76}, keywords = {Antihydrogen, Antiproton, Positron}, issn = {0304-3843}, doi = {10.1007/s10751-009-0032-7}, url = {http://dx.doi.org/10.1007/s10751-009-0032-7}, author = {Imao, H. and Tarek, M. and Michishio, K. and Enomoto, Y. and Shimoyama, T. and Kanai, Y. and Kuroda, N. and Mohri, A. and Higaki, H. and Saitoh, H. and Torii, H.A. and Nagata, Y. and Toyoda, H. and Matsuda, Y. and Nagashima, Y. 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 {30, title = {Cross-beam atomic collision experiment between ultra-low-energy antiprotons and a supersonic gas jet}, journal = {Hyperfine Interactions}, volume = {194}, year = {2009}, pages = {37-43}, keywords = {Cross-beam atomic collision, Supersonic~gas~jet, Ultra-low-energy antiprotons}, issn = {0304-3843}, doi = {10.1007/s10751-009-0027-4}, url = {http://dx.doi.org/10.1007/s10751-009-0027-4}, author = {Torii, H.A. and Nagata, Y. and Toyoda, H. and Imao, H. and Kuroda, N. and Varentsov, V.L. and Yamazaki, Y.} } @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 {24, title = {Radial compression of antiproton cloud for production of ultraslow antiproton beams}, journal = {AIP Conference Proceedings}, volume = {1114}, year = {2009}, pages = {157-162}, keywords = {particle traps, plasma, plasma simulation}, doi = {10.1063/1.3122278}, url = {http://link.aip.org/link/?APC/1114/157/1}, author = {N. Kuroda and Y. Nagata and H. A. Torii and D. Barna and J. Eades and D. Horv{\'a}th and M. Hori and H. Imao and K. Komaki and A. Mohri and M. Shibata and Y. Yamazaki}, editor = {James R. Danielson and Thomas Sunn Pedersen} } @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 {34, title = {Observation of Ultra-Slow Antiprotons using Micro-channel Plate}, journal = {AIP Conference Proceedings}, volume = {1037}, year = {2008}, pages = {311-317}, keywords = {elementary particles, nuclear fragmentation, protons}, doi = {10.1063/1.2977850}, url = {http://link.aip.org/link/?APC/1037/311/1}, author = {H. Imao and H. A. Torii and Y. Nagata and H. Toyoda and T. Shimoyama and Y. Enomoto and H. Higaki and Y. Kanai and A. Mohri and Y. Yamazaki}, editor = {Yasuyuki Kanai and Yasunori Yamazaki} } @article {14, title = {Confinement of a Large Number of Antiprotons and Production of an Ultraslow Antiproton Beam}, journal = {Physical Review Letters}, volume = {94}, year = {2005}, month = {2005/01/18/}, pages = {023401 -}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.94.023401}, author = {Kuroda, N. and Torii, H. A. and Franzen, K. Yoshiki and Wang, Z. and Yoneda, S. and Inoue, M. and Hori, M. and Juhasz, B. and Horvath, D. and Higaki, H. and Mohri, A. and Eades, J. and Komaki, K. and Yamazaki, Y.} } @article {11, title = {Electron cooling of high-energy protons in a multiring trap with a tank circuit monitoring the electron-plasma oscillations}, journal = {Physical Review EPhys. Rev. E}, volume = {65}, year = {2002}, month = {2002/04/02/}, pages = {046410 -}, url = {http://link.aps.org/doi/10.1103/PhysRevE.65.046410}, author = {Higaki, H. and Kuroda, N. and Ichioka, T. and Franzen, K. Yoshiki and Wang, Z. and Komaki, K. and Yamazaki, Y. and Hori, M. and Oshima, N. and Mohri, A.} } @article {33, title = {Multi-ring trap as a reservoir of cooled antiprotons}, journal = {AIP Conference Proceedings}, volume = {498}, year = {1999}, pages = {59-64}, keywords = {antimatter, cooling, electric fields, electrodes, magnetic fields, particle traps, storage rings}, doi = {10.1063/1.1302101}, url = {http://link.aip.org/link/?APC/498/59/1}, author = {T. Ichioka and H. Higaki and M. Hori and N. Oshima and K. Kuroki and A. Mohri and K. Komaki and Y. Yamazaki}, editor = {John J. Bollinger and Ronald C. Davidson and Ross L. Spencer} }