@article {92, title = {Antiproton beams with low energy spread for antihydrogen production}, journal = {Journal of Instrumentation}, volume = {14}, year = {2019}, month = {05/2019}, pages = {P05009{\textendash}P05009}, abstract = {

A low energy antiproton transport from the ASACUSA{\textquoteright}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{\textpm}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.

}, doi = {10.1088/1748-0221/14/05/p05009}, url = {https://doi.org/10.1088\%2F1748-0221\%2F14\%2F05\%2Fp05009}, author = {M. Tajima and N. Kuroda and C. Amsler and H. Breuker and C. Evans and M. Fleck and A. Gligorova and H. Higaki and Y. Kanai and B. Kolbinger and A. Lanz and M. Leali and V. M{\"a}ckel and C. Malbrunot and V. Mascagna and Y. Matsuda and D. Murtagh and Y. Nagata and A. Nanda and B. Radics and M. Simon and S. Ulmer and L. Venturelli and E. Widmann and M. Wiesinger and Y. Yamazaki} } @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 {85, title = {Antihydrogen Formation and Level Population Evolution During Passage Through a Positron Plasma}, journal = {JPS Conf. Proc.}, volume = {18}, year = {2017}, pages = {011012}, doi = {10.7566/JPSCP.18.011012}, author = {B. Radics and D.J. Murtagh and Y. Yamazaki and F. Robicheaux} } @article {83, title = {Antihydrogen Synthesis in a Double-Cusp Trap}, journal = {JPS Conf. Proc.}, volume = {18}, year = {2017}, pages = {011009}, doi = {10.7566/JPSCP.18.011009}, author = {Naofumi Kuroda and Minori Tajima and Balint Radics and Pierre Dupre and Yugo Nagata and Chikato Kaga and Yasuyuki Kanai and Marco Leali and Evandro Lodi Rizzini and Valerio Mascagna and Takuya Matsudate and Horst Breuker and Hiroyuki Higaki and Yasuyuki Matsuda and Stefan Ulmer and Luca Venturelli and Yasunori 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 {73, title = {Antihydrogen level population evolution: impact of positron plasma length}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, volume = {49}, year = {2016}, pages = {064007}, abstract = {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.}, url = {http://stacks.iop.org/0953-4075/49/i=6/a=064007}, author = {B Radics and Y Yamazaki} } @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 {75, title = {The ASACUSA CUSP: an antihydrogen experiment}, journal = {Hyperfine Interactions}, volume = {235}, year = {2015}, pages = {13{\textendash}20}, abstract = {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 ({\textquoteleft}{\textquoteleft}cusp trap{\textquoteright}{\textquoteright}) 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.}, issn = {1572-9540}, doi = {10.1007/s10751-015-1205-1}, url = {http://dx.doi.org/10.1007/s10751-015-1205-1}, author = {Kuroda, N. and Ulmer, S. and Murtagh, D. J. and Gorp, S. and Nagata, Y. and Diermaier, M. and Federmann, S. and Leali, M. and Malbrunot, C. and Mascagna, V. and Massiczek, O. and Michishio, K. and Mizutani, T. and Mohri, A. and Nagahama, H. and Ohtsuka, M. and Radics, B. and Sakurai, S. and Sauerzopf, C. and Suzuki, K. and Tajima, M. and Torii, H. A. and Venturelli, L. and W{\"u}nschek, B. and Zmeskal, J. and Zurlo, N. and Higaki, H. and Kanai, Y. and Rizzini, E. Lodi and Nagashima, Y. and Matsuda, Y. 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 {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 {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 {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} } @article {32, title = {ASACUSA Gas-Jet Target: Present Status And Future Development}, journal = {AIP Conference Proceedings}, volume = {793}, year = {2005}, pages = {328-340}, keywords = {atomic beams, computer aided analysis, hadronic atoms, helium, jets, supersonic flow}, doi = {10.1063/1.2121994}, url = {http://link.aip.org/link/?APC/793/328/1}, author = {V. L. Varentsov and N. Kuroda and Y. Nagata and H. A. Torii and M. Shibata and Y. Yamazaki}, editor = {Yasunori Yamazaki and Michiharu Wada} }