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1.
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Towards Lamb shift spectroscopy of antihydrogen atoms at the GBAR $\overline H$ beam line
/ Tanaka, T A (Tokyo U., Komaba) ; Blumer, P (Zurich, ETH) ; Janka, G (PSI, Villigen) ; Ohayon, B (Technion) ; Regenfus, C (Zurich, ETH) ; Crivelli, P (Zurich, ETH) ; Kuroda, N (Tokyo U., Komaba) ; Tsukida, R (Tokyo U., Komaba) ; Higuchi, T (Kyoto U., KURRI) ; Tanaka, K S (Waseda U., RISE)
/GBAR Collaboration
A microwave (MW) spectroscopy experiment has been proposed to directly measure the resonant frequency of $2S_{1/2}-2P_{1/2}$ Lamb shift transition in antihydrogen ($\mathrm{\bar{H}}$) atoms. The spectroscopy opens up the possibility of deriving the charge radius of antiproton ($\mathrm{\bar{p}}$) using a beam of $\mathrm{\bar{H}}$ atoms with a kinetic energy of a few keV travelling under a magnetic field-free environment.The requisite spectroscopy apparatuses have been developed and installed in the $\mathrm{\bar{H}}$ beam line at the GBAR experiment, where the production of $\mathrm{\bar{H}}$ beam at 6.1 keV was demonstrated through a charge exchange reaction of a $\mathrm{\bar{p}}$ beam passing through a positronium (Ps) cloud.The spectroscopy setup is composed of a MW spectrometer and a Lyman-$\alpha$ photon detector.The MW spectrometer consists of two consecutive MW apparatuses which have a relatively large borehole of 30 mm diameter, and each MW apparatus comprises a pair of parallel plate electrodes as its inner conductor and a rectangular box as its outer conductor.Downstream to the MW spectrometer, the Lyman-$\alpha$ detector has been installed to count the $\mathrm{\bar{H}}$ atoms remaining in the $2S$ state after interacting with the MW E-field.Towards the $\mathrm{\bar{H}}$ Lamb shift spectroscopy, we present here a characterization of the MW spectrometer, an evaluation of the detection efficiency of the Lyman-$\alpha$ detector, and a precision expected in the first line shape measurement of the $\mathrm{\bar{H}}$ Lamb shift..
2025 - 8 p.
- Published in : PoS EXA-LEAP2024 (2025) 044
Fulltext: PDF;
In : International Conference on Exotic Atoms and Related Topics and Conference on Low Energy Antiprotons (EXA/LEAP 2024), Vienna, Austria, 26 - 30 Aug 2024, pp.044
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2.
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The Ultra-Low material budget GEM based TPC for tracking with VMM3a readout
/ Garcia, F. (Helsinki U.) ; Flöthner, K.J. (CERN ; Bonn U., HISKP) ; Amato, A. (PSI, Villigen) ; Biswas, S. (PSI, Villigen) ; Brunbauer, F.M. (CERN) ; Heiss, M.W. (PSI, Villigen) ; Janka, G. (PSI, Villigen) ; Janssens, D. (CERN) ; Lisowska, M. (CERN ; U. Paris-Saclay) ; Meurer, M. (CERN ; Munich U.) et al.
The Gaseous Electron Multiplier-based Time Projection Chamber (GEM-TPC) in TWIN configuration for particle tracking has been consolidated after extensive investigations in different facilities to study its tracking performance. The most attractive feature of this detector is its ultra-low material budget, which is 0.28% X/X$_0$ and can be further reduced by decreasing the thickness of the gas traversed by the incident particles. [...]
arXiv:2501.09587.-
2025-04-01 - 7 p.
- Published in : JINST 20 (2025) C04004
Fulltext: 2501.09587 - PDF; document - PDF;
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3.
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Detector R&D Collaboration for Gaseous detectors
/ Rodas rodriguez, D et al.
Approved: 06 December 2023.-
Status: Preparation
External link: Experiment home page
Experiment: DRD1
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4.
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Positron accumulation in the GBAR experiment
/ GBAR Collaboration
We present a description of the GBAR positron (e+) trapping apparatus, which consists of a three stage Buffer Gas Trap (BGT) followed by a High Field Penning Trap (HFT), and discuss its performance. The overall goal of the GBAR experiment is to measure the acceleration of the neutral antihydrogen (H) atom in the terrestrial gravitational field by neutralising a positive antihydrogen ion (H+), which has been cooled to a low temperature, and observing the subsequent H annihilation following free fall. [...]
arXiv:2205.04530.-
2022-07-25 - 28 p.
- Published in : Nucl. Instrum. Methods Phys. Res., A 1040 (2022) 167263
Fulltext: PDF;
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5.
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A pulsed high-voltage decelerator system to deliver low-energy antiprotons
/ Husson, A (IJCLab, Orsay) ; Kim, B H (Seoul Natl. U., Dept. Phys. Astron.) ; Welker, A (CERN) ; Charlton, M (Swansea U.) ; Choi, J J (Seoul Natl. U., Dept. Phys. Astron.) ; Chung, M (UNIST, Ulsan) ; Cladé, P (Paris, Lab. Kastler Brossel) ; Comini, P (IRFU, Saclay) ; Crépin, P -P (Paris, Lab. Kastler Brossel) ; Crivelli, P (Zurich, ETH-CSCS/SCSC) et al.
The GBAR (Gravitational Behavior of Antihydrogen at Rest) experiment at CERN requires efficient deceleration of 100 keV antiprotons provided by the new ELENA synchrotron ring to synthesize antihydrogen. This is accomplished using electrostatic deceleration optics and a drift tube that is designed to switch from -99 kV to ground when the antiproton bunch is inside – essentially a charged particle “elevator” – producing a 1 keV pulse. [...]
2021 - 7 p.
- Published in : Nucl. Instrum. Methods Phys. Res., A 1002 (2021) 165245
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7.
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Development of a PbWO$_4$ Detector for Single-Shot Positron Annihilation Lifetime Spectroscopy at the GBAR Experiment
/ Kim, B H (Seoul Natl. U.) ; Choi, J J (Seoul Natl. U.) ; Chung, M (UNIST, Ulsan) ; Cladé, P (Paris, Lab. Kastler Brossel) ; Comini, P (IRFU, Saclay) ; Crivelli, P (Zurich, ETH) ; Crépin, P-P (Paris, Lab. Kastler Brossel) ; Dalkarov, O (Lebedev Inst.) ; Debu, P (IRFU, Saclay) ; Dodd, L (Swansea U.) et al.
We have developed a PbWO$_{4}$ (PWO) detector with a large dynamic range to measure the intensity of a positron beam and the absolute density of the ortho-positronium ($\mathrm{o-Ps}$) cloud it creates. A simulation study shows that a setup based on such detectors may be used to determine the angular distribution of the emission and reflection of $\mathrm{o-Ps}$ to reduce part of the uncertainties of the measurement. [...]
2020 - 4 p.
- Published in : Acta Phys. Pol. A 137 (2020) 122-125
In : 15th International Workshop on Slow Positron Beam Techniques and Applications, Prague, Czechia, 2-6 Sep 2019, pp.122-125
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8.
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Positron production using a 9 MeV electron linac for the GBAR experiment
/ Charlton, M. (Swansea U.) ; Choi, J.J. (Seoul Natl. U., Dept. Phys. Astron.) ; Chung, M. (UNIST, Ulsan) ; Cladé, P. (Paris, Lab. Kastler Brossel) ; Comini, P. (IRFU, Saclay) ; Crépin, P.P. (Paris, Lab. Kastler Brossel) ; Crivelli, P. (Zurich, ETH) ; Dalkarov, O. (Lebedev Inst.) ; Debu, P. (IRFU, Saclay) ; Dodd, L. (Swansea U.) et al.
For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN's Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. [...]
arXiv:2006.05966.-
2021-01-01 - 33 p.
- Published in : Nucl. Instrum. Methods Phys. Res., A 985 (2021) 164657
Fulltext: PDF;
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