@article {71,
	title = {Towards a precise measurement of the antihydrogen ground state hyperfine splitting in a beam: the case of in-flight radiative decays},
	journal = {Journal of Physics B: Atomic, Molecular and Optical Physics},
	volume = {48},
	year = {2015},
	month = {29/07/2015},
	pages = {184001},
	abstract = {<p>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{\textendash}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.</p>
},
	keywords = {Antihydrogen, ground state hyperfine splitting measurement, radiative decay},
	url = {http://stacks.iop.org/0953-4075/48/i=18/a=184001},
	author = {R Lundmark and C Malbrunot and Y Nagata and B Radics and C Sauerzopf and E Widmann}
}
@article {28,
	title = {Positron accumulation and manipulation for antihydrogen synthesis},
	journal = {Journal of Physics: Conference Series},
	volume = {225},
	year = {2010},
	pages = {012018},
	abstract = {<p>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.</p>
},
	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}
}
