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Spectrometry of Captured Highly Charged Ions Produced Following Antiproton Annihilations
Authors:
F. P. Gustafsson,
M. Volponi,
J. Zielinski,
A. Asare,
I. Hwang,
S. Alfaro Campos,
M. Auzins,
D. Bhanushali,
A. Bhartia,
M. Berghold,
R. S. Brusa,
K. Calik,
A. Camper,
R. Caravita,
F. Castelli,
G. Cerchiari,
S. Chandran,
A. Chehaimi,
S. Choudapurkar,
R. Ciuryło,
P. Conte,
G. Consolati,
M. Doser,
R. Ferguson,
M. Germann
, et al. (39 additional authors not shown)
Abstract:
We report a proof-of-principle study demonstrating the first capture and time-of-flight spectrometry of highly charged ions (HCIs) produced following antiproton annihilations in a Penning-Malmberg trap. A multi-step nested-trap technique was developed using the \aegis\ experiment to identify annihilation-linked captured ions. The trapping and spectrometry of helium and argon ions demonstrates the…
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We report a proof-of-principle study demonstrating the first capture and time-of-flight spectrometry of highly charged ions (HCIs) produced following antiproton annihilations in a Penning-Malmberg trap. A multi-step nested-trap technique was developed using the \aegis\ experiment to identify annihilation-linked captured ions. The trapping and spectrometry of helium and argon ions demonstrates the approach. This work establishes a foundation for the in-trap synthesis of radioactive HCIs and the study of cold nuclear annihilation fragments, with the long-term goal of enabling a sensitive tool for probing the outer nuclear periphery.
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Submitted 18 December, 2025; v1 submitted 9 October, 2025;
originally announced October 2025.
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TALOS (Total Automation of LabVIEW Operations for Science): A framework for autonomous control systems for complex experiments
Authors:
M. Volponi,
J. Zieliński,
T. Rauschendorfer,
S. Huck,
R. Caravita,
M. Auzins,
B. Bergmann,
P. Burian,
R. S. Brusa,
A. Camper,
F. Castelli,
G. Cerchiari,
R. Ciuryło,
G. Consolati,
M. Doser,
K. Eliaszuk,
A. Giszczak,
L. T. Glöggler,
Ł. Graczykowski,
M. Grosbart,
F. Guatieri,
N. Gusakova,
F. Gustafsson,
S. Haider,
M. A. Janik
, et al. (30 additional authors not shown)
Abstract:
Modern physics experiments are frequently very complex, relying on multiple simultaneous events to happen in order to obtain the desired result. The experiment control system plays a central role in orchestrating the measurement setup: However, its development is often treated as secondary with respect to the hardware, its importance becoming evident only during the operational phase. Therefore, t…
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Modern physics experiments are frequently very complex, relying on multiple simultaneous events to happen in order to obtain the desired result. The experiment control system plays a central role in orchestrating the measurement setup: However, its development is often treated as secondary with respect to the hardware, its importance becoming evident only during the operational phase. Therefore, the AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) collaboration has created a framework for easily coding control systems, specifically targeting atomic, quantum, and antimatter experiments. This framework, called Total Automation of LabVIEW Operations for Science (TALOS), unifies all the machines of the experiment in a single entity, thus enabling complex high-level decisions to be taken, and it is constituted by separate modules, called MicroServices, that run concurrently and asynchronously. This enhances the stability and reproducibility of the system while allowing for continuous integration and testing while the control system is running. The system demonstrated high stability and reproducibility, running completely unsupervised during the night and weekends of the data-taking campaigns. The results demonstrate the suitability of TALOS to manage an entire physics experiment in full autonomy: being open-source, experiments other than the AEgIS experiment can benefit from it.
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Submitted 2 September, 2024;
originally announced September 2024.
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Real-time antiproton annihilation vertexing with sub-micron resolution
Authors:
M. Berghold,
D. Orsucci,
F. Guatieri,
S. Alfaro,
M. Auzins,
B. Bergmann,
P. Burian,
R. S. Brusa,
A. Camper,
R. Caravita,
F. Castelli,
G. Cerchiari,
R. Ciuryło,
A. Chehaimi,
G. Consolati,
M. Doser,
K. Eliaszuk,
R. Ferguson,
M. Germann,
A. Giszczak,
L. T. Glöggler,
Ł. Graczykowski,
M. Grosbart,
F. Guatieri,
N. Gusakova
, et al. (42 additional authors not shown)
Abstract:
The primary goal of the AEgIS experiment is to precisely measure the free fall of antihydrogen within Earth's gravitational field. To this end, a cold ~50K antihydrogen beam has to pass through two grids forming a moiré deflectometer before annihilating onto a position-sensitive detector, which shall determine the vertical position of the annihilation vertex relative to the grids with micrometric…
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The primary goal of the AEgIS experiment is to precisely measure the free fall of antihydrogen within Earth's gravitational field. To this end, a cold ~50K antihydrogen beam has to pass through two grids forming a moiré deflectometer before annihilating onto a position-sensitive detector, which shall determine the vertical position of the annihilation vertex relative to the grids with micrometric accuracy. Here we introduce a vertexing detector based on a modified mobile camera sensor and experimentally demonstrate that it can measure the position of antiproton annihilations with an accuracy of $0.62^{+0.40}_{-0.22}μm$, which represents a 35-fold improvement over the previous state-of-the-art for real-time antiproton vertexing. Importantly, these antiproton detection methods are directly applicable to antihydrogen. Moreover, the sensitivity to light of the sensor enables the in-situ calibration of the moiré deflectometer, significantly reducing systematic errors. This sensor emerges as a breakthrough technology for achieving the \aegis scientific goals and has been selected as the basis for the development of a large-area detector for conducting antihydrogen gravity measurements.
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Submitted 23 June, 2024;
originally announced June 2024.
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CIRCUS: an autonomous control system for antimatter, atomic and quantum physics experiments
Authors:
Marco Volponi,
Saiva Huck,
Ruggero Caravita,
Jakub Zielinski,
Georgy Kornakov,
Grzegorz Kasprowicz,
Dorota Nowicka,
Tassilo Rauschendorfer,
Benjamin Rienäcker,
Francesco Prelz,
Marcis Auzins,
Benedikt Bergmann,
Petr Burian,
Roberto Sennen Brusa,
Antoine Camper,
Fabrizio Castelli,
Roman Ciuryło,
Giovanni Consolati,
Michael Doser,
Lisa Glöggler,
Łukasz Graczykowski,
Malgorzata Grosbart,
Francesco Guatieri,
Nataly Gusakova,
Fredrik Gustafsson
, et al. (27 additional authors not shown)
Abstract:
A powerful and robust control system is a crucial, often neglected, pillar of any modern, complex physics experiment that requires the management of a multitude of different devices and their precise time synchronisation. The AEgIS collaboration presents CIRCUS, a novel, autonomous control system optimised for time-critical experiments such as those at CERN's Antiproton Decelerator and, more broad…
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A powerful and robust control system is a crucial, often neglected, pillar of any modern, complex physics experiment that requires the management of a multitude of different devices and their precise time synchronisation. The AEgIS collaboration presents CIRCUS, a novel, autonomous control system optimised for time-critical experiments such as those at CERN's Antiproton Decelerator and, more broadly, in atomic and quantum physics research. Its setup is based on Sinara/ARTIQ and TALOS, integrating the ALPACA analysis pipeline, the last two developed entirely in AEgIS. It is suitable for strict synchronicity requirements and repeatable, automated operation of experiments, culminating in autonomous parameter optimisation via feedback from real-time data analysis. CIRCUS has been successfully deployed and tested in AEgIS; being experiment-agnostic and released open-source, other experiments can leverage its capabilities.
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Submitted 7 February, 2024;
originally announced February 2024.
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Positronium laser cooling via the $1^3S$-$2^3P$ transition with a broadband laser pulse
Authors:
L. T. Glöggler,
N. Gusakova,
B. Rienäcker,
A. Camper,
R. Caravita,
S. Huck,
M. Volponi,
T. Wolz,
L. Penasa,
V. Krumins,
F. Gustafsson,
M. Auzins,
B. Bergmann,
P. Burian,
R. S. Brusa,
F. Castelli,
R. Ciuryło,
D. Comparat,
G. Consolati,
M. Doser,
Ł. Graczykowski,
M. Grosbart,
F. Guatieri,
S. Haider,
M. A. Janik
, et al. (27 additional authors not shown)
Abstract:
We report on laser cooling of a large fraction of positronium (Ps) in free-flight by strongly saturating the $1^3S$-$2^3P$ transition with a broadband, long-pulsed 243 nm alexandrite laser. The ground state Ps cloud is produced in a magnetic and electric field-free environment. We observe two different laser-induced effects. The first effect is an increase in the number of atoms in the ground stat…
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We report on laser cooling of a large fraction of positronium (Ps) in free-flight by strongly saturating the $1^3S$-$2^3P$ transition with a broadband, long-pulsed 243 nm alexandrite laser. The ground state Ps cloud is produced in a magnetic and electric field-free environment. We observe two different laser-induced effects. The first effect is an increase in the number of atoms in the ground state after the time Ps has spent in the long-lived $3^3P$ states. The second effect is the one-dimensional Doppler cooling of Ps, reducing the cloud's temperature from 380(20) K to 170(20) K. We demonstrate a 58(9) % increase in the coldest fraction of the Ps ensemble.
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Submitted 12 October, 2023;
originally announced October 2023.
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A large-momentum-transfer matter-wave interferometer to measure the effect of gravity on positronium
Authors:
G. Vinelli,
F. Castelli,
R. Ferragut,
M. Romé,
M. Sacerdoti,
L. Salvi,
V. Toso,
M. Giammarchi,
G. Rosi,
G. M. Tino
Abstract:
This paper reports the study of a new interferometric configuration to measure the effect of gravity on positronium. A Mach-Zehnder matter-wave interferometer has been designed to operate with single-photon transitions and to transfer high momentum to a 200 eV positronium beam. The work shows the results and methods used to simulate the interferometer and estimate the operating parameters and the…
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This paper reports the study of a new interferometric configuration to measure the effect of gravity on positronium. A Mach-Zehnder matter-wave interferometer has been designed to operate with single-photon transitions and to transfer high momentum to a 200 eV positronium beam. The work shows the results and methods used to simulate the interferometer and estimate the operating parameters and the time needed to perform the experiment. It has been estimated that within less than one year, the acquisition time is sufficient to achieve a 10\% accuracy level in measuring positronium gravitational acceleration, even with a poorly collimated beam, which is significant for theoretical models describing matter-antimatter symmetry. These results pave the way for single photon transition large momentum transfer interferometry with fast atomic beams, which is particularly useful for studies with antimatter and unstable atoms.
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Submitted 30 September, 2023; v1 submitted 21 March, 2023;
originally announced March 2023.
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A cryogenic tracking detector for antihydrogen detection in the AEgIS experiment
Authors:
C. Amsler,
M. Antonello,
A. Belov,
G. Bonomi,
R. S. Brusa,
M. Caccia,
A. Camper,
R. Caravita,
F. Castelli,
D. Comparat,
G. Consolati,
A. Demetrio,
L. Di Noto,
M. Doser,
P. A. Ekman,
M. Fani,
R. Ferragut,
S. Gerber,
M. Giammarchi,
A. Gligorova,
F. Guatieri,
P. Hackstock,
D. Haider,
S. Haider,
A. Hinterberger
, et al. (33 additional authors not shown)
Abstract:
We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1 T superconducting magnet of the AEgIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4 K and are read out by silicon photomultipliers (MPPCs) at near room tempe…
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We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1 T superconducting magnet of the AEgIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4 K and are read out by silicon photomultipliers (MPPCs) at near room temperature. FACT provides the antiproton/antihydrogen annihilation position information with a few ns timing resolution. We present the hardware and software developments which led to the successful operation of the detector for antihydrogen detection and the results of an antiproton-loss based efficiency assessment. The main background to the antihydrogen signal is that of the positrons impinging onto the positronium conversion target and creating a large amount of gamma rays which produce a sizeable signal in the MPPCs shortly before the antihydrogen signal is expected. We detail the characterization of this background signal and its impact on the antihydrogen detection efficiency.
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Submitted 6 March, 2022;
originally announced March 2022.
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Rydberg-positronium velocity and self-ionization studies in 1T magnetic field and cryogenic environment
Authors:
M. Antonello,
A. Belov,
G. Bonomi R. S. Brusa,
M. Caccia,
A. Camper,
R. Caravita,
F. Castelli,
D. Comparat,
G. Consolati,
L. Di Noto,
M. Doser,
M. Fani,
R. Ferragut,
J. Fesel,
S. Gerber,
A. Gligorova,
L. T. Glöggler,
F. Guatieri,
S. Haider,
A. Hinterberger,
O. Khalidova,
D. Krasnicky,
V. Lagomarsino,
C. Malbrunot,
S. Mariazzi
, et al. (21 additional authors not shown)
Abstract:
We characterized the pulsed Rydberg-positronium production inside the AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) apparatus in view of antihydrogen formation by means of a charge exchange reaction between cold antiprotons and slow Rydberg-positronium atoms. Velocity measurements on positronium along two axes in a cryogenic environment (10K) and in 1T magnetic field were pe…
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We characterized the pulsed Rydberg-positronium production inside the AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) apparatus in view of antihydrogen formation by means of a charge exchange reaction between cold antiprotons and slow Rydberg-positronium atoms. Velocity measurements on positronium along two axes in a cryogenic environment (10K) and in 1T magnetic field were performed. The velocimetry was done by MCP-imaging of photoionized positronium previously excited to the $n=3$ state. One direction of velocity was measured via Doppler-scan of this $n=3$-line, another direction perpendicular to the former by delaying the exciting laser pulses in a time-of-flight measurement. Self-ionization in the magnetic field due to motional Stark effect was also quantified by using the same MCP-imaging technique for Rydberg positronium with an effective principal quantum number $n_{eff}$ ranging between 14 and 22. We conclude with a discussion about the optimization of our experimental parameters for creating Rydberg-positronium in preparation for an efficient pulsed production of antihydrogen.
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Submitted 22 February, 2022; v1 submitted 11 November, 2019;
originally announced November 2019.
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Efficient $2^3S$ positronium production by stimulated decay from the $3^3P$ level
Authors:
M. Antonello,
A. Belov,
G. Bonomi,
R. S. Brusa,
M. Caccia,
A. Camper,
R. Caravita,
F. Castelli,
G. Cerchiari,
D. Comparat,
G. Consolati,
A. Demetrio,
L. Di Noto,
M. Doser,
M. Fanì,
S. Gerber,
A. Gligorova,
F. Guatieri,
P. Hackstock,
S. Haider,
A. Hinterberger,
A. Kellerbauer,
O. Khalidova,
D. Krasnicky,
V. Lagomarsino
, et al. (26 additional authors not shown)
Abstract:
We investigate experimentally the possibility of enhancing the production of $2^3S$ positronium atoms by driving the $1^3S$-$3^3P$ and $3^3P$-$2^3S$ transitions, overcoming the natural branching ratio limitation of spontaneous decay from $3^3P$ to $2^3S$. The decay of $3^3P$ positronium atoms towards the $2^3S$ level has been effciently stimulated by a 1312.2nm broadband IR laser pulse. The depend…
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We investigate experimentally the possibility of enhancing the production of $2^3S$ positronium atoms by driving the $1^3S$-$3^3P$ and $3^3P$-$2^3S$ transitions, overcoming the natural branching ratio limitation of spontaneous decay from $3^3P$ to $2^3S$. The decay of $3^3P$ positronium atoms towards the $2^3S$ level has been effciently stimulated by a 1312.2nm broadband IR laser pulse. The dependence of the stimulating transition efficiency on the intensity of the IR pulse has been measured to find the optimal enhancement conditions. A maximum relative increase of $ \times (3.1 \pm 1.0) $ in the $2^3S$ production efficiency, with respect to the case where only spontaneous decay is present, was obtained.
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Submitted 18 April, 2019;
originally announced April 2019.
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Gamma Factory at CERN -- novel research tools made of light
Authors:
W. Placzek,
A. Abramov,
S. E. Alden,
R. Alemany Fernandez,
P. S. Antsiferov,
A. Apyan,
H. Bartosik,
E. G. Bessonov,
N. Biancacci,
J. Bieron,
A. Bogacz,
A. Bosco,
R. Bruce,
D. Budker,
K. Cassou,
F. Castelli,
I. Chaikovska,
C. Curatolo,
P. Czodrowski,
A. Derevianko,
K. Dupraz,
Y. Dutheil,
K. Dzierzega,
V. Fedosseev,
N. Fuster Martinez
, et al. (37 additional authors not shown)
Abstract:
We discuss the possibility of creating novel research tools by producing and storing highly relativistic beams of highly ionised atoms in the CERN accelerator complex, and by exciting their atomic degrees of freedom with lasers to produce high-energy photon beams. Intensity of such photon beams would be by several orders of magnitude higher than offered by the presently operating light sources, in…
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We discuss the possibility of creating novel research tools by producing and storing highly relativistic beams of highly ionised atoms in the CERN accelerator complex, and by exciting their atomic degrees of freedom with lasers to produce high-energy photon beams. Intensity of such photon beams would be by several orders of magnitude higher than offered by the presently operating light sources, in the particularly interesting gamma-ray energy domain of 0.1-400 MeV. In this energy range, the high-intensity photon beams can be used to produce secondary beams of polarised electrons, polarised positrons, polarised muons, neutrinos, neutrons and radioactive ions. New research opportunities in a wide domain of fundamental and applied physics can be opened by the Gamma Factory scientific programme based on the above primary and secondary beams.
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Submitted 14 June, 2019; v1 submitted 21 March, 2019;
originally announced March 2019.
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Velocity selected production of $2^3S$ metastable positronium
Authors:
C. Amsler,
M. Antonello,
A. Belov,
G. Bonomi,
R. S. Brusa,
M. Caccia,
A. Camper,
R. Caravita,
F. Castelli,
G. Cerchiari,
D. Comparat,
G. Consolati,
A. Demetrio,
L. Di Noto,
M. Doser,
M. Fanì,
S. Gerber,
A. Gligorova,
F. Guatieri,
P. Hackstock,
S. Haider,
A. Hinterberger,
H. Holmestad,
A. Kellerbauer,
O. Khalidova
, et al. (30 additional authors not shown)
Abstract:
Positronium in the $2^3S$ metastable state exhibits a low electrical polarizability and a long lifetime (1140 ns) making it a promising candidate for interferometry experiments with a neutral matter-antimatter system. In the present work, $2^3S$ positronium is produced - in absence of electric field - via spontaneous radiative decay from the $3^3P$ level populated with a 205nm UV laser pulse. Than…
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Positronium in the $2^3S$ metastable state exhibits a low electrical polarizability and a long lifetime (1140 ns) making it a promising candidate for interferometry experiments with a neutral matter-antimatter system. In the present work, $2^3S$ positronium is produced - in absence of electric field - via spontaneous radiative decay from the $3^3P$ level populated with a 205nm UV laser pulse. Thanks to the short temporal length of the pulse, 1.5 ns full-width at half maximum, different velocity populations of a positronium cloud emitted from a nanochannelled positron/positronium converter were selected by delaying the excitation pulse with respect to the production instant. $ 2^3S $ positronium atoms with velocity tuned between $ 7 \cdot 10^4 $ m/s and $ 10 \cdot 10^4 $ m/s were thus produced. Depending on the selected velocity, a $2^3S$ production effciency ranging from $\sim 0.8 \%$ to $\sim 1.7%$, with respect to the total amount of emitted positronium, was obtained. The observed results give a branching ratio for the $3^3P$-$2^3S$ spontaneous decay of $(9.7 \pm 2.7) \% $. The present velocity selection technique could allow to produce an almost monochromatic beam of $\sim 1 \cdot 10^3 $ $2^3S$ atoms with a velocity spread $ < 10^4 $ m/s and an angular divergence of $\sim$ 50 mrad.
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Submitted 18 April, 2019; v1 submitted 6 August, 2018;
originally announced August 2018.
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Producing long-lived $2^3\text{S}$ Ps via $3^3\text{P}$ laser excitation in magnetic and electric fields
Authors:
S. Aghion,
C. Amsler,
M. Antonello,
A. Belov,
G. Bonomi,
R. S. Brusa,
M. Caccia,
A. Camper,
R. Caravita,
F. Castelli,
G. Cerchiari,
D. Comparat,
G. Consolati,
A. Demetrio,
L. Di Noto,
M. Doser,
C. Evans,
M. Fani,
R. Ferragut,
J. Fesel,
A. Fontana,
S. Gerber,
M. Giammarchi,
A. Gligorova,
F. Guatieri
, et al. (40 additional authors not shown)
Abstract:
Producing positronium (Ps) in the metastable $2^3\text{S}$ state is of interest for various applications in fundamental physics. We report here about an experiment in which Ps atoms are produced in this long-lived state by spontaneous radiative decay of Ps excited to the $3^3\text{P}$ level manifold. The Ps cloud excitation is obtained with a UV laser pulse in an experimental vacuum chamber in pre…
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Producing positronium (Ps) in the metastable $2^3\text{S}$ state is of interest for various applications in fundamental physics. We report here about an experiment in which Ps atoms are produced in this long-lived state by spontaneous radiative decay of Ps excited to the $3^3\text{P}$ level manifold. The Ps cloud excitation is obtained with a UV laser pulse in an experimental vacuum chamber in presence of guiding magnetic field of 25 mT and an average electric field of 300 V/cm. The indication of the $2^3\text{S}$ state production is obtained from a novel analysis technique of single-shot positronium annihilation lifetime spectra. Its production efficiency relative to the total amount of formed Ps is evaluated by fitting a simple rate equations model to the experimental data and found to be $ (2.1 \pm 1.3) \, \% $.
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Submitted 20 February, 2018;
originally announced February 2018.
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Measurement of antiproton annihilation on Cu, Ag and Au with emulsion films
Authors:
S. Aghion,
C. Amsler,
A. Ariga,
T. Ariga,
G. Bonomi,
P. Braunig,
R. S. Brusa,
L. Cabaret,
M. Caccia,
R. Caravita,
F. Castelli,
G. Cerchiari,
D. Comparat,
G. Consolati,
A. Demetrio,
L. Di Noto,
M. Doser,
A. Ereditato,
C. Evans,
R. Ferragut,
J. Fesel,
A. Fontana,
S. Gerber,
M. Giammarchi,
A. Gligorova
, et al. (47 additional authors not shown)
Abstract:
The characteristics of low energy antiproton annihilations on nuclei (e.g. hadronization and product multiplicities) are not well known, and Monte Carlo simulation packages that use different models provide different descriptions of the annihilation events. In this study, we measured the particle multiplicities resulting from antiproton annihilations on nuclei. The results were compared with predi…
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The characteristics of low energy antiproton annihilations on nuclei (e.g. hadronization and product multiplicities) are not well known, and Monte Carlo simulation packages that use different models provide different descriptions of the annihilation events. In this study, we measured the particle multiplicities resulting from antiproton annihilations on nuclei. The results were compared with predictions obtained using different models in the simulation tools GEANT4 and FLUKA. For this study, we exposed thin targets (Cu, Ag and Au) to a very low energy antiproton beam from CERN's Antiproton Decelerator, exploiting the secondary beamline available in the AEgIS experimental zone. The antiproton annihilation products were detected using emulsion films developed at the Laboratory of High Energy Physics in Bern, where they were analysed at the automatic microscope facility. The fragment multiplicity measured in this study is in good agreement with results obtained with FLUKA simulations for both minimally and heavily ionizing particles.
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Submitted 23 April, 2017; v1 submitted 23 January, 2017;
originally announced January 2017.
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The parametric spring-mass system, its connection with non-linear optics, and an approach for undergraduate students
Authors:
Ilario Boscolo,
Fabrizio Castelli,
Marco Stellato,
Stefano Vercellati
Abstract:
The spring-mass system studied in undergraduate physics laboratories may exhibit complex dynamics due to the simultaneous action of gravitational and elastic forces in addition to air friction. In the first part of this paper, we describe a laboratory experiment aimed at beginner students which also gives those with a more advanced background an opportunity to explore more complex aspects of the m…
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The spring-mass system studied in undergraduate physics laboratories may exhibit complex dynamics due to the simultaneous action of gravitational and elastic forces in addition to air friction. In the first part of this paper, we describe a laboratory experiment aimed at beginner students which also gives those with a more advanced background an opportunity to explore more complex aspects of the motions involved. If students are not given predefined apparatus but are allowed instead to design their own set-up for the experiment, they may also learn something about the thought processes and experimental procedures used in physics. In the second part of this paper, we present a systematic study of the parametric behavior of the system because teachers have to master its dynamics. The non-linear interaction between the vertical and the pendular oscillations in a vertical spring-mass system depends on the ratio between the frequencies of the two motions and on the motion's excitation. Systematic experimental investigations, coupled with relevant simulations, highlight the many aspects of physics involved in the partition of energy transfer between the two modes. The different motion waveforms obtained by sweeping through the resonance curve and by applying small and strong excitations are presented and analyzed. The influence of the unavoidable spurious motions is investigated. An analogy between the parametric interaction in a spring--mass system and that found during frequency conversion in non-linear optical crystals is discussed.
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Submitted 21 February, 2014;
originally announced February 2014.
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Annihilation of low energy antiprotons in silicon
Authors:
S. Aghion,
O. Ahlén,
A. S. Belov,
G. Bonomi,
P. Bräunig,
J. Bremer,
R. S. Brusa,
G. Burghart,
L. Cabaret,
M. Caccia,
C. Canali,
R. Caravita,
F. Castelli,
G. Cerchiari,
S. Cialdi,
D. Comparat,
G. Consolati,
J. H. Derking,
S. Di Domizio,
L. Di Noto,
M. Doser,
A. Dudarev,
R. Ferragut,
A. Fontana,
P. Genova
, et al. (34 additional authors not shown)
Abstract:
The goal of the AE$\mathrm{\bar{g}}$IS experiment at the Antiproton Decelerator (AD) at CERN, is to measure directly the Earth's gravitational acceleration on antimatter. To achieve this goal, the AE$\mathrm{\bar{g}}$IS collaboration will produce a pulsed, cold (100 mK) antihydrogen beam with a velocity of a few 100 m/s and measure the magnitude of the vertical deflection of the beam from a straig…
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The goal of the AE$\mathrm{\bar{g}}$IS experiment at the Antiproton Decelerator (AD) at CERN, is to measure directly the Earth's gravitational acceleration on antimatter. To achieve this goal, the AE$\mathrm{\bar{g}}$IS collaboration will produce a pulsed, cold (100 mK) antihydrogen beam with a velocity of a few 100 m/s and measure the magnitude of the vertical deflection of the beam from a straight path. The final position of the falling antihydrogen will be detected by a position sensitive detector. This detector will consist of an active silicon part, where the annihilations take place, followed by an emulsion part. Together, they allow to achieve 1$%$ precision on the measurement of $\bar{g}$ with about 600 reconstructed and time tagged annihilations.
We present here, to the best of our knowledge, the first direct measurement of antiproton annihilation in a segmented silicon sensor, the first step towards designing a position sensitive silicon detector for the AE$\mathrm{\bar{g}}$IS experiment. We also present a first comparison with Monte Carlo simulations (GEANT4) for antiproton energies below 5 MeV
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Submitted 11 March, 2014; v1 submitted 20 November, 2013;
originally announced November 2013.
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Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors
Authors:
AEgIS Collaboration,
S. Aghion,
O. Ahlén,
C. Amsler,
A. Ariga,
T. Ariga,
A. S. Belov,
G. Bonomi,
P. Bräunig,
J. Bremer,
R. S. Brusa,
L. Cabaret,
C. Canali,
R. Caravita,
F. Castelli,
G. Cerchiari,
S. Cialdi,
D. Comparat,
G. Consolati,
J. H. Derking,
S. Di Domizio,
L. Di Noto,
M. Doser,
A. Dudarev,
A. Ereditato
, et al. (46 additional authors not shown)
Abstract:
The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moiré deflectometer. The goal is to determine the gravitational acceleration g for antihydrogen with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon micro-strip detector to measure the…
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The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moiré deflectometer. The goal is to determine the gravitational acceleration g for antihydrogen with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon micro-strip detector to measure the time of flight. Nuclear emulsions can measure the annihilation vertex of antihydrogen atoms with a precision of about 1 - 2 microns r.m.s. We present here results for emulsion detectors operated in vacuum using low energy antiprotons from the CERN antiproton decelerator. We compare with Monte Carlo simulations, and discuss the impact on the AEgIS project.
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Submitted 24 June, 2013;
originally announced June 2013.
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An undergraduate study of harmonic and parametric motion of a simple spring-mass system from motion waveforms
Authors:
Ilario Boscolo,
Fabrizio Castelli,
Marco Stellato
Abstract:
The spring-mass system studied in undergraduate physics laboratories may show complex dynamics due to the simultaneous action of gravitational, elastic, and torsional forces, in addition to air friction. In this paper, we describe a laboratory exercise that caters to beginning students while giving those with more background an opportunity to explore more complex aspects of the motion. If students…
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The spring-mass system studied in undergraduate physics laboratories may show complex dynamics due to the simultaneous action of gravitational, elastic, and torsional forces, in addition to air friction. In this paper, we describe a laboratory exercise that caters to beginning students while giving those with more background an opportunity to explore more complex aspects of the motion. If students are not given predefined apparatus but are allowed to design the experiment setup, they may also learn something about physics thinking and experimental procedure. Using results thus produced, we describe a variety of spring-mass oscillation patterns, discussing the physics of the significant deviations from simple harmonic motion. The parametric oscillation behavior we have observed is reported and investigated. This study is based on analysis of motion waveforms.
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Submitted 3 June, 2013; v1 submitted 6 August, 2012;
originally announced August 2012.
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Formation Of A Cold Antihydrogen Beam in AEGIS For Gravity Measurements
Authors:
G. Testera,
A. S. Belov,
G. Bonomi,
I. Boscolo,
N. Brambilla,
R. S. Brusa,
V. M. Byakov,
L. Cabaret,
C. Canali,
C. Carraro,
F. Castelli,
S. Cialdi,
M. de Combarieu,
D. Comparat,
G. Consolati,
N. Djourelov,
M. Doser,
G. Drobychev,
A. Dupasquier,
D. Fabris,
R. Ferragut,
G. Ferrari,
A. Fischer,
A. Fontana,
P. Forget
, et al. (40 additional authors not shown)
Abstract:
The formation of the antihydrogen beam in the AEGIS experiment through the use of inhomogeneous electric fields is discussed and simulation results including the geometry of the apparatus and realistic hypothesis about the antihydrogen initial conditions are shown. The resulting velocity distribution matches the requirements of the gravity experiment. In particular it is shown that the inhomogen…
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The formation of the antihydrogen beam in the AEGIS experiment through the use of inhomogeneous electric fields is discussed and simulation results including the geometry of the apparatus and realistic hypothesis about the antihydrogen initial conditions are shown. The resulting velocity distribution matches the requirements of the gravity experiment. In particular it is shown that the inhomogeneous electric fields provide radial cooling of the beam during the acceleration.
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Submitted 30 May, 2008;
originally announced May 2008.
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Apparent superluminal advancement of a single photon far beyond its coherence length
Authors:
S. Cialdi,
I. Boscolo,
F. Castelli,
V. Petrillo
Abstract:
We present experimental results relative to superluminal propagation based on a single photon traversing an optical system, called 4f-system, which acts singularly on the photon's spectral component phases. A single photon is created by a CW laser light down{conversion process. The introduction of a linear spectral phase function will lead to the shift of the photon peak far beyond the coherence…
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We present experimental results relative to superluminal propagation based on a single photon traversing an optical system, called 4f-system, which acts singularly on the photon's spectral component phases. A single photon is created by a CW laser light down{conversion process. The introduction of a linear spectral phase function will lead to the shift of the photon peak far beyond the coherence length of the photon itself (an apparent superluminal propagation of the photon). Superluminal group velocity detection is done by interferometric measurement of the temporal shifted photon with its correlated untouched reference. The observed superluminal photon propagation complies with causality. The operation of the optical system allows to enlighten the origin of the apparent superluminal photon velocity. The experiment foresees a superluminal effect with single photon wavepackets.
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Submitted 16 April, 2009; v1 submitted 9 May, 2008;
originally announced May 2008.