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1. Sensitivity of the GAPS experiment to low-energy cosmic-ray antiprotons

Author

Rogers, F., Aramaki, T., Boezio, M., Boggs, S.E., Bonvicini, V., Bridges, G., Campana, D., Craig, W.W., von Doetinchem, P., Everson, E., Fabris, L., Feldman, S., Fuke, H., Gahbauer, F., Gerrity, C., Hailey, C.J., Hayashi, T., Kawachi, A., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mochizuki, B., Mognet, S.A.I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R.A., Osteria, G., Perez, K.M., Quinn, S., Re, V., Riceputi, E., Roach, B., Ryan, J., Saffold, N., Scotti, V., Shimizu, Y., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., Wada, T., Xiao, M., Yamatani, M., Yee, K., Yoshida, A., Yoshida, T., Zampa, G., Zeng, J., and Zweerink, J.

Published
2023
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2. Cosmic antihelium-3 nuclei sensitivity of the GAPS experiment

Author

Saffold, N., Aramaki, T., Bird, R., Boezio, M., Boggs, S.E., Bonvicini, V., Campana, D., Craig, W.W., von Doetinchem, P., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C.J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mognet, S.I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R.A., Osteria, G., Perez, K., Pope, I., Quinn, S., Re, V., Reed, M., Riceputi, E., Roach, B., Rogers, F., Ryan, J.L., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., Wada, T., Xiao, M., Yamatani, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Published
2021
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5. In Search of Cosmic-Ray Antinuclei from Dark Matter with the GAPS Experiment

Author

Xiao, M., Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, Massimo, Marcelli, N., Mochizuki, B., Mognet, S. A. I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R. A., Osteria, G., Perez, K., Quinn, S., Re, Valerio, Riceputi, Elisa, Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., von Doetinchem, P., Wada, T., Yamatami, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Subjects
Dark matter, readout electronics, Astroparticle physics, detectors, Settore ING-INF/01 - Elettronica
Published
2022

6. The GAPS Instrument: A Large Area Time of Flight and High Resolution Exotic Atom Spectrometer for Cosmic Antinuclei

Author

Quinn, S., Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, Massimo, Marcelli, N., Martucci, M., Mognet, S. I., Munakata, K., Munini, R., Nakagami, Y., Okazaki, S., Olson, J., Ong, R. A., Osteria, G., Perez, K., Re, Valerio, Riceputi, Elisa, Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Saijo, M., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tokunaga, K., Vannuccini, E., von Doetinchem, P., Wada, T., Xiao, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Subjects
Settore ING-INF/01 - Elettronica
Published
2022

7. Neural Networks approach to event reconstruction for the GAPS experiment

Author

Marcelli, N., Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, Massimo, Mochizuki, B., Mognet, S. A. I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R. A., Osteria, G., Perez, K., Quinn, S., Re, Valerio, Riceputi, Elisa, Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., von Doetinchem, P., Wada, T., Xiao, M., Yamatami, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Subjects
Settore ING-INF/01 - Elettronica
Published
2022

8. Searching for cosmic antihelium nuclei with the GAPS experiment

Author

Stoessl, A., Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, Massimo, Marcelli, N., Mognet, S. A. I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R. A., Osteria, G., Perez, K., Quinn, S., Re, Valerio, Riceputi, Elisa, Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Tiberio, A., Vannuccini, E., von Doetinchem, P., Wada, T., Xiao, M., Yamatami, M., Yoshida, A., Yoshida, T., Zampa, G., Zweerink, J., Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mochizuki, B., Mognet, S. A. I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R. A., Osteria, G., Perez, K., Quinn, S., Re, V., Riceputi, E., Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., von Doetinchem, P., Wada, T., Xiao, M., Yamatani, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Subjects
Astroparticle Physics, cosmic rays, Readout electronics, Dark matter, Detectors, GAPS, cosmic antihelium, Settore ING-INF/01 - Elettronica, cosmic ray
Abstract

At low energies, cosmic antideuterons and antihelium provide an ultra-low background signature of dark matter annihilation, decay, and other beyond the Standard Model phenomena. The General Antiparticle Spectrometer (GAPS) is an Antarctic balloon experiment designed to search for lowenergy (0.1−0.3 GeV/n) antinuclei, and is planned to launch in the austral summer of 2022. While optimized for an antideuteron search, GAPS also has unprecedented capabilites for the detection of low-energy antihelium nuclei, utilizing a novel detection technique based on the formation, decay, and annihilation of exotic atoms. The AMS-02 collaboration has recently reported several antihelium nuclei candidate events, which sets GAPS in a unique position to set constraints on the cosmic antihelium flux in an energy region which is essentially free of astrophysical background. In this contribution, we illustrate the capabilities of GAPS to search for cosmic antihelium-3 utilizing complete instrument simulations, event reconstruction, and the inclusion of atmospheric effects. We show that GAPS is capable of setting unprecedented limits on the cosmic antihelium flux, opening a new window on exotic cosmic physics.

Published
2021

9. Neural Networks approach to event reconstruction for the GAPS experiment

Author

Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mochizuki, B., Mognet, S. A. I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R. A., Osteria, G., Perez, K., Quinn, S., Re, V., Riceputi, E., Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., von Doetinchem, P., Wada, T., Xiao, M., Yamatani, M., Yoshida, A., Yoshida, T., Zampa, G., Zweerink, J., Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mochizuki, B., Mognet, S. A. I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R. A., Osteria, G., Perez, K., Quinn, S., Re, V., Riceputi, E., Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., von Doetinchem, P., Wada, T., Xiao, M., Yamatani, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Subjects
GAPS, neural networks, event reconstruction, neural network
Abstract

The General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment, scheduled for a first flight in the austral summer 2022. It is designed to measure low energy (< 0.25 GeV/n) cosmic antinuclei. A particular focus is on antideuterons, which are predicted to have an ultra-low astrophysical background as compared to signals from dark matter annihilation or decay in the Galactic halo. GAPS uses a novel technique for particle identification based on the formation and decay of exotic atoms. To achieve sufficient rejection power for particle identification, an accurate determination of several fundamental quantities is needed. The precise reconstruction of the energy deposition pattern on the primary track is a particularly intricate problem and we developed a strategy devised to solve this using modern machine learning techniques. In the future, this approach can also be used for particle identification. Here, we present preliminary results of these efforts obtained from simulations.

Published
2021

15. The flight of the GAPS prototype experiment

Author

von, Doetinchem P., Boggs, S. E., Gahbauer, F. H., Hailey, C. J., Koglin, J. E., Mognet, S. A. I., Madden, N., Ong, R. A., Perez, K. M., Zweerink, J., Aramaki, Tsuguo, Bando, Nobutaka, Fuke, Hideyuki, Okazaki, Shun, and Yoshida, Tetsuya

Subjects
Physics, COSMIC cancer database, Spectrometer, business.industry, Physics::Instrumentation and Detectors, Detector, Dark matter, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Time of flight, Optics, Indirect detection, Calibration, Antideuteron, Particle velocity, Balloon flight, Aerospace engineering, business, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

著者人数: 15名, Accepted: 2013-11-22, 資料番号: SA1004527000

Published
2013

16. The pGAPS experiment: an engineering balloon flight of prototype GAPS

Author

Ong, R. A., Boggs, S. E., Doetinchem, P. v., Gahbauer, F. H., Hailey, C. J., Koglin, J. E., Madden, N., Mognet, S. A. I., Perez, K. M., Zweerink, J., Fuke, Hideyuki, Aramaki, Tsuguo, Bando, Nobutaka, Mori, Kaya, Okazaki, Shun, and Yoshida, Tetsuya

Subjects
Physics, Atmospheric Science, Cold dark matter, Physics - Instrumentation and Detectors, Meteorology, Spectrometer, business.industry, FOS: Physical sciences, Aerospace Engineering, Astronomy and Astrophysics, Instrumentation and Detectors (physics.ins-det), Cosmic-ray antideuteron, Balloon, Prototype balloon experiment, Geophysics, Space and Planetary Science, Dark matter, General Earth and Planetary Sciences, Aerospace engineering, business, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Short duration
Abstract

The General Anti-Particle Spectrometer (GAPS) project is being carried out to search for primary cosmic-ray antiparticles especially for antideuterons produced by cold dark matter. GAPS plans to realize the science observation by Antarctic long duration balloon flights in the late 2010s. In preparation for the Antarctic science flights, an engineering balloon flight using a prototype of the GAPS instrument, "pGAPS", was successfully carried out in June 2012 in Japan to verify the basic performance of each GAPS subsystem. The outline of the pGAPS flight campaign is briefly reported., submitted to (30/Dec/2012) and accepted by (21/Jun/2013) Advances in Space Research

Published
2013

17. Cosmic ray composition at high energies: Results from the TRACER project

Author

Boyle, P. J., Ave, M., Gahbauer, F., Hoeppner, C., Hoerandel, J., Ichimura, M., Mueller, D., and Romero-Wolf, A.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics
Abstract

The TRACER instrument Transition Radiation Array for Cosmic Energetic Radiation is designed to measure the individual energy spectra of cosmic-ray nuclei in long-duration balloon flights The large geometric factor of TRACER 5 m 2 sr permits statistically significant measurements at particle energies well beyond 10 14 eV TRACER identifies individual cosmic-ray nuclei with single-element resolution and measures their energy over a very wide range from about 0 5 to 10 000 GeV nucleon This is accomplished with a gas detector system of 1600 single-wire proportional tubes and plastic fiber radiators that measure specific ionization and transition radiation signals combined with plastic scintillators and acrylic Cherenkov counters A two-week flight in Antarctica in December 2003 has led to a measurement of the nuclear species oxygen to iron O Ne Mg Si S Ar Ca and Fe up to about 3 000 GeV nucleon We shall present the energy spectra and relative abundances for these elements and discuss the implication of the results in the context of current models of acceleration and propagation of galactic cosmic rays The instrument has been refurbished for a second long-duration flight in the Northern hemisphere scheduled for summer 2006 For this flight the dynamic range of TRACER has been extended to permit inclusion of the lighter elements B C and N in the measurement., 36th COSPAR Scientific Assembly. Held 16 - 23 July 2006, in Beijing, China., p.2517

Published
2007

18. Level-crossing spectroscopy of the 7, 9, and 10D_5/2 states of 133Cs and validation of relativistic many-body calculations of the polarizabilities and hyperfine constants

Author

Auzinsh, M., Blushs, K., Ferber, R., Gahbauer, F., Jarmola, A., Safronova, M. S., Safronova, U. I., and Tamanis, M.

Subjects
Atomic Physics (physics.atom-ph), FOS: Physical sciences, Physics::Atomic Physics, Physics - Atomic Physics
Abstract

We present an experimental and theoretical investigation of the polarizabilities and hyperfine constants of D_J states in 133Cs for J=3/2 and J=5/2. New experimental values for the hyperfine constant A are obtained from level-crossing signals of the (7,9,10)D_5/2 states of 133Cs and precise calculations of the tensor polarizabilities alpha_2. The results of relativistic many-body calculations for scalar and tensor polarizabilities of the (5-10)D_3/2 and (5-10)D_5/2 states are presented and compared with measured values from the literature. Calculated values of the hyperfine constants A for these states are also presented and checked for consistency with experimental values., 12 pages, revtex4, 11 figure files

Published
2006

19. Longitudinal spin-relaxation in nitrogen-vacancy centers in electron irradiated diamond.

Author

Jarmola, A., Berzins, A., Smits, J., Smits, K., Prikulis, J., Gahbauer, F., Ferber, R., Erts, D., Auzinsh, M., and Budker, D.

Subjects
SPIN polarization, SINGLE crystals, NITROGEN spectra, DIAMONDS, GROUND state energy, TRANSMISSION electron microscopy
Abstract

We present systematic measurements of longitudinal relaxation rates (1/T1) of spin polarization in the ground state of the nitrogen-vacancy (NV-) color center in synthetic diamond as a function of NV- concentration and magnetic fieldB. NV- centers were created by irradiating a Type 1b single-crystal diamond along the [100] axis with 200 keV electrons from a transmission electron microscope with varying doses to achieve spots of different NV- center concentrations. Values of (1/T1) were measured for each spot as a function of B. [ABSTRACT FROM AUTHOR]

Published
2015
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20. Magnetic Field Gradiometer with Sub-Micron Spatial Resolution Based on Caesium Vapour in an Extremely Thin Cell.

Author

Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., Kalnins, U., Rundans, R., and Sarkisyan, D.

Subjects
MAGNETIC fields, MAGNETOMETERS, NANOSTRUCTURED materials, METAL vapors, CESIUM
Abstract

In this paper we present a device for measuring the magnetic field and its gradient with a spatial resolution of several hundred nanometres. This device is based on caesium metal vapour confined to an extremely thin cell (ETC). To measure magnetic signals, we use absorption and very low laser powers, which might be appealing for modern fabrication techniques. A portable, fully automated device was constructed. [ABSTRACT FROM AUTHOR]

Published
2015
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29. The GAPS Instrument: A Large Area Time of Flight and High Resolution Exotic Atom Spectrometer for Cosmic Antinuclei

Author

T. Aramaki, R. Bird, M. Boezio, S. E. Boggs, V. Bonvicini, D. Campana, W. W. Craig, E. Everson, L. Fabris, H. Fuke, F. Gahbauer, I. Garcia, C. Gerrity, C. J. Hailey, T. Hayashi, C. Kato, A. Kawachi, S. Kobayashi, M. Kozai, A. Lenni, A. Lowell, M. Manghisoni, N. Marcelli, B. Mochizuki, S. A. I. Mognet, K. Munakata, R. Munini, Y. Nakagami, J. Olson, R. A. Ong, G. Osteria, K. Perez, S. Quinn, V. Re, E. Riceputi, B. Roach, F. Rogers, J. A. Ryan, N. Saffold, V. Scotti, Y. Shimizu, M. Sonzogni, R. Sparvoli, A. Stoessl, A. Tiberio, E. Vannuccini, P. von Doetinchem, T. Wada, M. Xiao, M. Yamatani, A. Yoshida, T. Yoshida, G. Zampa, J. Zweerink, Aramaki, T., Bird, R., Boezio, M., Boggs, S. E., Bonvicini, V., Campana, D., Craig, W. W., Everson, E., Fabris, L., Fuke, H., Gahbauer, F., Garcia, I., Gerrity, C., Hailey, C. J., Hayashi, T., Kato, C., Kawachi, A., Kobayashi, S., Kozai, M., Lenni, A., Lowell, A., Manghisoni, M., Marcelli, N., Mochizuki, B., Mognet, S. A. I., Munakata, K., Munini, R., Nakagami, Y., Olson, J., Ong, R. A., Osteria, G., Perez, K., Quinn, S., Re, V., Riceputi, E., Roach, B., Rogers, F., Ryan, J. A., Saffold, N., Scotti, V., Shimizu, Y., Sonzogni, M., Sparvoli, R., Stoessl, A., Tiberio, A., Vannuccini, E., von Doetinchem, P., Wada, T., Xiao, M., Yamatani, M., Yoshida, A., Yoshida, T., Zampa, G., and Zweerink, J.

Subjects
Physics, Antiparticle, COSMIC cancer database, Spectrometer, Dark matter, GAPS, large-area Time-of-Flight, high-resolution exotic-atom spectrometer, cosmic-ray antinuclei, Cosmic ray, Scintillator, Nuclear physics, Antiproton, high-resolution exotic-atom spectrometer, large-area Time-of-Flight, Exotic atom
Abstract

Low-energy cosmic ray antideuterons ($

Published
2022

30. Alignment-to-orientation conversion in a magnetic field at nonlinear excitation of the D2 line of rubidium: Experiment and theory.

Author

Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., Kalvans, L., Mozers, A., and Spiss, A.

Subjects
*MAGNETIC fields, *NONLINEAR theories, *RUBIDIUM isotopes, *HYPERFINE interactions, *COHERENCE (Optics), *LASER beams
Abstract

We studied alignment-to-orientation conversion caused by excited-state level crossings in a nonzero magnetic field of both atomic rubidium isotopes. Experimental measurements were performed on the transitions of the D2 line of rubidium. These measured signals were described by a theoretical model that takes into account all neighboring hyperfine transitions, the mixing of magnetic sublevels in an external magnetic field, the coherence properties of the exciting laser radiation, and the Doppler effect. In the experiments, laser-induced fluorescence components were observed at linearly polarized excitation and their difference was taken afterwards. By observing the two oppositely circularly polarized components, we were able to see structures not visible in the difference graphs, which give deeper insight into the processes responsible for these signals. We studied how these signals are dependent on intensity and how they are affected when the exciting laser is tuned to different hyperfine transitions. The comparison between experiment and theory was carried out fulfilling the nonlinear absorption conditions. The theoretical curves described the experimental measurements satisfactorily, reproducing even small features in the shapes of the curves. [ABSTRACT FROM AUTHOR]

Published
2015
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31. Relaxation mechanisms affecting magneto-optical resonances in an extremely thin cell: Experiment and theory for the cesium D1 line.

Author

Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., Kalnins, U., Kalvans, L., Rundans, R., and Sarkisyan, D.

Subjects
*RELAXATION (Nuclear physics), *CESIUM, *MAGNETIC properties of metals, *OPTICAL properties of metals, *BLOCH equations, *MAGNETIC resonance, *HYPERFINE structure
Abstract

We have measured magneto-optical signals obtained by exciting the D1 line of cesium atoms confined to an extremely thin cell (ETC), whose walls are separated by less than 1 μm, and developed an improved theoretical model to describe these signals with experimental precision. The theoretical model was based on the optical Bloch equations and included all neighboring hyperfine transitions, the mixing of the magnetic sublevels in an external magnetic field, and the Doppler effect, as in previous studies. However, in order to model the extreme conditions in the ETC more realistically, the model was extended to include a unified treatment of transit relaxation and wall collisions with relaxation rates that were obtained directly from the thermal velocities of the atoms and the length scales involved. Furthermore, the interactions of the atoms with different regions of the laser beam were modeled separately to account for the varying laser beam intensity over the beam profile as well as saturation effects that become important near the center of the beam at the relatively high laser intensities used during the experiments in order to obtain measurable signals. The model described the experimentally measured signals for laser intensities for magnetic fields up to 55 G and laser intensities up to 1 W/cm² with excellent agreement. [ABSTRACT FROM AUTHOR]

Published
2015
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32. Current status and future plans for the general antiparticle spectrometer (GAPS)

Author

Fuke, H., Koglin, J.E., Yoshida, T., Aramaki, T., Craig, W.W., Fabris, L., Gahbauer, F., Hailey, C.J., Jou, F.J., Madden, N., Mori, K., Yu, H.T., and Ziock, K.P.

Subjects
*ASTRONOMY, *INTERSTELLAR medium, *EXOTIC atoms, *DARK matter
Abstract

Abstract: We discuss current progress and future plans for the general antiparticle spectrometer experiment (GAPS). GAPS detects antideuterons through the X-rays and pions emitted during the deexcitation of exotic atoms formed when the antideuterons are slowed down and stopped in targets. GAPS provides an exceptionally sensitive means to detect cosmic-ray antideuterons. Cosmic-ray antideuterons can provide indirect evidence for the existence of dark matter in such form as neutralinos or Kaluza–Klein particles. We describe results of accelerator testing of GAPS prototypes, tentative design concepts for a flight GAPS detector, and near-term plans for flying a GAPS prototype on a balloon. [Copyright &y& Elsevier]

Published
2008
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33. Electric field induced hyperfine level-crossings in (nD)Cs at two-step laser excitation: Experiment and theory

Author

Auzinsh, M., Blushs, K., Ferber, R., Gahbauer, F., Jarmola, A., and Tamanis, M.

Subjects
*LASER research, *ELECTRIC fields, *ZEEMAN effect, *STATISTICAL correlation
Abstract

Abstract: The pure electric field level-crossing of m F Zeeman sublevels of hyperfine F levels at two-step laser excitation is described theoretically and studied experimentally for the nD3/2 states in Cs with n =7, 9 and 10, by applying a diode laser in the first 6S1/2 →6P3/2 step and a diode or dye laser for the second 6P3/2 → nD3/2 step. Level-crossing resonance signals are observed in the nD3/2 →6P1/2 fluorescence. A theoretical model is presented to describe quantitatively the resonance signals by correlation analysis of the optical Bloch equations in the case when an atom simultaneously interacts with two laser fields in the presence of an external dc electric field. The simulations describe well the experimental signals. The tensor polarizabilities α2 (in ) are determined to be 7.45(20)×104 for the 7D3/2 state and 1.183(35)×106 for the 9D3/2 state; the electric field calibration is based on measurements of the 10D3/2 state, for which α2 is well established. The α2 value for the 7D3/2 state differs by ca. 15% from the existing experimentally measured value. [Copyright &y& Elsevier]

Published
2006
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34. Dependence of the shapes of nonzero-field level-crossing signals in rubidium atoms on the laser frequency and power density.

Author

Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., Kalvans, L., Mozers, A., and Spiss, A.

Subjects
*ZERO-point field, *RUBIDIUM, *POWER density, *OPTICAL resonance, *MAGNETOOPTICS, *PHASE transitions, *LASER beams
Abstract

We studied magneto-optical resonances caused by excited-state level crossings in a nonzero magnetic field. Experimental measurements were performed on the transitions of the D2 line of rubidium. These measured signals were described by a theoretical model that takes into account all neighboring hyperfine transitions, the mixing of magnetic sublevels in an external magnetic field, the coherence properties of the exciting laser radiation, and the Doppler effect. Good agreement between the experimental measurements and the theoretical model could be achieved over a wide range of laser power densities. We further showed that the contrasts of the level-crossing peaks can be sensitive to changes in the frequency of the exciting laser radiation as small as several tens of megahertz when the hyperfine splitting of the exciting state is larger than the Doppler broadening. [ABSTRACT FROM AUTHOR]

Published
2013
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35. Conversion of bright magneto-optical resonances into dark resonances at fixed laser frequency for D2 excitation of atomic rubidium.

Author

Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., Kalvans, L., Mozers, A., and Opalevs, D.

Subjects
*MAGNETOOPTICS, *LASER beams, *ELECTRONIC excitation, *RUBIDIUM, *DENSITY, *TEMPERATURE effect, *MAGNETIC fields, *OPTICAL polarization
Abstract

Nonlinear magneto-optical resonances on the hyperflne transitions belonging to the Z)2 line of rubidium were changed from bright to dark resonances by changing the laser power density of the single exciting laser field or by changing the vapor temperature in the cell. In one set of experiments atoms were excited by linearly polarized light from an extended cavity diode laser with polarization vector perpendicular to the light's propagation direction and magnetic field, and laser-induced fluorescence was observed along the direction of the magnetic field, which was scanned. A low-contrast bright resonance was observed at low laser power densities when the laser was tuned to the Fg =2 --· Fe = 3 transition of 87Rb and near to the Fg = 3 --> Fe = 4 transition of 85Rb. The bright resonance became dark as the laser power density was increased above 0.6 mW/cm2 or 0.8 mW/cm2, respectively. When the Fg = 2 -->· Fe = 3 transition of 87Rb was excited with circularly polarized light in a second set of experiments, a bright resonance was observed, which became dark when the temperature was increased to around 50°C. The experimental observations at room temperature could be reproduced with good agreement by calculations based on a theoretical model, although the theoretical model was not able to describe measurements at elevated temperatures, where reabsorption was thought to play a decisive role. The model was derived from the optical Bloch equations and included all nearby hyperfine components, averaging over the Doppler profile, mixing of magnetic sublevels in the external magnetic field, and a treatment of the coherence properties of the exciting radiation field. [ABSTRACT FROM AUTHOR]

Published
2012
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36. Spatial dynamics of laser-induced fluorescence in an intense laser beam: An experimental and theoretical study with alkali-metal atoms.

Author

Auzinsh, M., Berzins, A., Ferber, R., Gahbauer, F., and Kalnins, U.

Subjects
*LASER beams, *LASER-induced fluorescence, *ALKALI metals
Abstract

We show that it is possible to model accurately optical phenomena in intense laser fields by taking into account the intensity distribution over the laser beam. We present an extension of an earlier theoretical model that divides an intense laser beam into concentric regions, each with a Rabi frequency that corresponds to the intensity in that region, and solve a set of coupled optical Bloch equations for the density matrix in each region. Experimentally obtained magneto-optical resonance curves for the Fg=2 → Fe = 1 transition of the D1 line of 87Rb agree very well with the theoretical model up to a laser intensity of around 200 mW/cm² for a transition whose saturation intensity is around 4.5 mW/cm². We examine the spatial dependence of the fluorescence intensity in an intense laser beam experimentally and theoretically. We present and discuss the results of an experiment in which a broad, intense pump laser excites the Fg = 4 → Fe = 4 transition of the D2 line of cesium while a narrow probe beam scans the atoms within the pump beam and excites the D1 line of cesium, whose fluorescence is recorded as a function of probe beam position. Experimentally obtained spatial profiles of the fluorescence intensity agree qualitatively with the predictions of the model. [ABSTRACT FROM AUTHOR]

Published
2016
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37. Electric-field-induced symmetry breaking of angular momentum distribution in atoms.

Author

Auzinsh M, Blushs K, Ferber R, Gahbauer F, Jarmola A, and Tamanis M

Abstract

We report the experimental observation of alignment to orientation conversion in the 7D3/2 and 9D3/2 states of Cs in the presence of an external dc electric field and without the influence of magnetic fields or atomic collisions. Initial alignment of angular momentum states was created by two-step excitation with linearly polarized laser radiation. The appearance of transverse orientation of angular momentum was confirmed by the observation of circularly polarized light. We present experimentally measured signals and compare them with the results of a detailed theoretical model based on the optical Bloch equations. The effect is odd under time reversal and should be taken into account in ever more sensitive searches for an electron electric dipole moment.

Published
2006
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