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P. Geltenbort - One of the best experts on this subject based on the ideXlab platform.

  • Neutron lifetime measurement with the UCN trap-in-trap MAMBO
    2020
    Co-Authors: A Pichlmaier, K Schreckenbach, V Varlamov, P. Geltenbort
    Abstract:

    We have measured the free neutron lifetime τ n by storage of ultra-Cold Neutrons (UCN) in a Fomblin coated UCN trap of in situ variable size. The method was initially developed by W

  • Measurement of the neutron lifetime with ultra-Cold Neutrons stored in a magneto-gravitational trap
    arXiv: Nuclear Experiment, 2014
    Co-Authors: V. F. Ezhov, P. Geltenbort, A. Z. Andreev, B. A. Bazarov, A. G. Glushkov, V. A. Knyaz'kov, N. A. Kovrizhnykh, G. B. Krygin, Oscar Naviliat-cuncic
    Abstract:

    We report a new measurement of the neutron lifetime using ultra-Cold Neutrons stored in a magneto-gravitational trap made of permanent magnets. Neutrons surviving in the trap after fixed storage times have been counted and the trap losses have continuously been monitored during storage by detecting Neutrons leaking from the trap. The value of the neutron lifetime resulting from this measurement is $\tau_n=(878.3\pm1.9)$s. It is the most precise measurement of the neutron lifetime obtained with magnetically stored Neutrons.

  • neutron lifetime measurement with the ucn trap in trap mambo ii
    Physics Letters B, 2010
    Co-Authors: A Pichlmaier, V E Varlamov, K Schreckenbach, P. Geltenbort
    Abstract:

    Abstract We have measured the free neutron lifetime τ n by storage of ultra-Cold Neutrons (UCN) in a Fomblin coated UCN trap of in situ variable size. The method was initially developed by W. Mampe et al. (1989) [10] with MAMBO I and improved by the addition of a prestorage volume yielding a well defined UCN spectrum for storage in the main trap. By extrapolation to infinite trap size using the time scaling method we obtain for the free neutron lifetime τ n = ( 880.7 ± 1.3 ± 1.2 ) s . Data from different UCN spectra, trap temperatures and storage times were used for the evaluation. The present result is compared with other experimental neutron lifetime data.

  • qubounce the dynamics of ultra Cold Neutrons falling in the gravity potential of the earth
    Nuclear Physics, 2009
    Co-Authors: H Abele, Tobias Jenke, David Stadler, P. Geltenbort
    Abstract:

    Abstract The dynamics of a quantum mechanical wave packet bouncing off a hard surface in the gravitational field of the earth combines quantum theory with aspects of Newtonian mechanics at short distances. We realize such a quantum bouncing ball with ultraCold Neutrons. By quantum interference, this experiment is sensitive to gravity-like forces at a length scale below 10 μm and can test speculations on large extra dimensions of submillimeter size of space-time or the origin of the cosmological constant in the universe.

  • Position-sensitive spectroscopy of ultra-Cold Neutrons with Timepix pixel detector
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2009
    Co-Authors: Jan Jakubek, M. Platkevic, Philipp Schmidt-wellenburg, P. Geltenbort, C. Plonka-spehr, Manfred Daum
    Abstract:

    Abstract We present an implementation of the silicon pixel device Timepix for position and energy-sensitive detection of ultra-Cold Neutrons (UCN) with an efficiency of 70% and a spatial resolution of 5.3 μm. A layer of 400 μg/cm2 of 6LiF deposited onto the Timepix sensor surface was used as a neutron converter. The energy of each detected neutron is measured using standard time-of-flight (TOF) technique. Thus, for each detected neutron the position and energy is determined. We demonstrate this technique on the real-time measurement of energy- and position-dependent reflection of UCNs from a bent foil of stainless steel making direct visualization of total reflection angle for different neutron energies.

M Fally - One of the best experts on this subject based on the ideXlab platform.

  • Three-port beam splitter for slow Neutrons using holographic nanoparticle-polymer composite diffraction gratings
    Applied Physics Letters, 2012
    Co-Authors: J Klepp, Yasuo Tomita, Christian Pruner, J Kohlbrecher, M Fally
    Abstract:

    Diffraction of slow Neutrons by nanoparticle-polymer composite gratings has been observed. By carefully choosing grating parameters such as grating thickness and spacing, a three-port beam splitter operation for Cold Neutrons - splitting the incident neutron intensity equally into the plus-minus first and zeroth diffraction orders - was realized. As a possible application, a Zernike three-path interferometer is briefly discussed.

  • neutron optical beam splitter from holographically structured nanoparticle polymer composites
    Physical Review Letters, 2010
    Co-Authors: M Fally, J Klepp, Yasuo Tomita, Toshihiro Nakamura, Christian Pruner, M A Ellabban, R A Rupp, Max Bichler, Drevensek I Olenik, J Kohlbrecher
    Abstract:

    We report a breakthrough in the search for versatile diffractive elements for Cold Neutrons. Nanoparticles are spatially arranged by holographical means in a photopolymer. These grating structures show remarkably efficient diffraction of Cold Neutrons up to about 50% for effective thicknesses of only 200 micron. They open up a profound perspective for next generation neutron-optical devices with the capability to tune or modulate the neutron diffraction efficiency. Neutron-optical phenomena arise from coherent elastic scattering. They are described by the wave equation for Neutrons. The essential material property is the neutronoptical potential or, equivalently, the neutron refractive index at wavelength � [1]. The basic diffractive element is a (one-dimensional) sinusoidal grating characterized by a refractive index n(x) = n0 + n1 cos(Kx) which is periodically modulated with the spatial frequency K and amplitude n1. Depending on its diffraction efficiency, it can be used as beam splitter, mirror or monochromator, and it can be altered and arranged to form more complex devices for imaging, spectroscopy, and in particular, Cold neutron interferometry [2–4]. Efficient neutron optical devices are vital for any neutron experiment, either as part of the instrumentation (e.g. monochromators, guides, calibration standards) or as a tool to investigate fundamental physical questions (e.g. interferometers). Neutron optics - and in particular interferometry with thermal Neutrons using perfect crystals as diffractive elements - has reached a satisfying level giving rise to an appealing insight on quantum mechanical problems [5]. As the difference of the refractive index for Neutrons from unity depends quadratically on the wavelength the latter should be further increased to maximize the neutron-optical potential. On the other hand the neutron flux decreases dramatically at low energies. On top of that interferometry experiments with very Cold Neutrons, so far, employed ruled or blazed gratings as thin diffraction elements. Consequently various diffraction orders are excited at the same time resulting

  • colossal light induced refractive index modulation for Neutrons in holographic polymer dispersed liquid crystals
    Physical Review Letters, 2006
    Co-Authors: M Fally, M A Ellabban, Irena Drevensekolenik, Klaus P Pranzas, J Vollbrandt
    Abstract:

    We report strong diffraction of Cold Neutrons from an only 30 {mu}m thick holographic polymer-dispersed liquid crystal (H-PDLC) transmission grating. The light-induced refractive-index modulation for Neutrons is about 10{sup -6}, i.e., nearly 2 orders of magnitude larger than in the best photo-neutron-refractive materials probed up to now. This makes H-PDLCs a promising candidate for fabricating neutron-optical devices.

H Abele - One of the best experts on this subject based on the ideXlab platform.

  • anni a pulsed Cold neutron beam facility for particle physics at the ess
    European Physical Journal Web of Conferences, 2019
    Co-Authors: T Soldner, Bastian Markisch, H Abele, G Konrad, F M Piegsa, U Schmidt, Camille Theroine, Pablo Torres Sanchez
    Abstract:

    Pulsed beams have tremendous advantages for precision experiments with Cold Neutrons. In order to minimise and measure systematic effects, they are used at continuous sources in spite of the related substantial decrease in intensity. At the European Spallation Source ESS these experiments will profit from the pulse structure of the source and its 50 times higher peak brightness compared to the most intense reactor facilities, making novel concepts feasible. Therefore, the Cold neutron beam facility for particle physics ANNI was proposed as part of the ESS instrument suite. The proposed design has been re-optimised to take into account the present ESS Cold moderator layout. We present design considerations, the optimised instrument parameters and performance, and expected gain factors for several reference experiments.

  • exotic decay channels are not the cause of the neutron lifetime anomaly
    Physics Letters B, 2019
    Co-Authors: D Dubbers, Bastian Markisch, T Soldner, Heiko Saul, H Abele
    Abstract:

    Abstract Since long neutron lifetimes measured with a beam of Cold Neutrons are significantly different from lifetimes measured with ultraCold Neutrons bottled in a trap. It is often speculated that this “neutron anomaly” is due to an exotic dark neutron decay channel of unknown origin. We show that this explanation of the neutron anomaly can be excluded with a high level of confidence when use is made of our new result for the neutron decay β asymmetry. Furthermore, data from neutron decay now compare well with Ft-data derived from nuclear β decays.

  • Exotic decay channels are not the cause of the neutron lifetime anomaly
    'Elsevier BV', 2019
    Co-Authors: D Dubbers, Bastian Markisch, T Soldner, Heiko Saul, H Abele
    Abstract:

    Since long neutron lifetimes measured with a beam of Cold Neutrons are significantly different from lifetimes measured with ultraCold Neutrons bottled in a trap. It is often speculated that this “neutron anomaly” is due to an exotic dark neutron decay channel of unknown origin. We show that this explanation of the neutron anomaly can be excluded with a high level of confidence when use is made of our new result for the neutron decay β asymmetry. Furthermore, data from neutron decay now compare well with Ft-data derived from nuclear β decays. Keywords: Neutron, Beta decay, Lifetime, Beta asymmetry, Dark neutron deca

  • qubounce the dynamics of ultra Cold Neutrons falling in the gravity potential of the earth
    Nuclear Physics, 2009
    Co-Authors: H Abele, Tobias Jenke, David Stadler, P. Geltenbort
    Abstract:

    Abstract The dynamics of a quantum mechanical wave packet bouncing off a hard surface in the gravitational field of the earth combines quantum theory with aspects of Newtonian mechanics at short distances. We realize such a quantum bouncing ball with ultraCold Neutrons. By quantum interference, this experiment is sensitive to gravity-like forces at a length scale below 10 μm and can test speculations on large extra dimensions of submillimeter size of space-time or the origin of the cosmological constant in the universe.

  • quantum states of Neutrons in the gravitational field and limits for non newtonian interaction in the range between 1 μm and 10 μm
    LNP, 2003
    Co-Authors: H Abele, S Baesler, Alexander Westphal
    Abstract:

    Quantum states in the Earth’s gravitational field can be observed, when ultra-Cold Neutrons fall under gravity. In an experiment at the Institut Laue-Langevin in Grenoble, Neutrons are reflected and trapped in a gravitational cavity above a horizontal mirror. The population of the ground state and the lowest states follows, step by step, the quantum mechanical prediction. An efficient neutron absorber removes the higher, unwanted states. The quantum states probe Newtonian gravity on the micrometer scale and we place limits for gravity-like forces in the range between 1 μm and 10 μm.

S Baesler - One of the best experts on this subject based on the ideXlab platform.

  • a new cryogenic apparatus to search for the neutron electric dipole moment
    Journal of Instrumentation, 2019
    Co-Authors: S Baesler, Lm Bartoszek, Mohammad Ahmed, Ricardo Alarcon, A Aleksandrova, L Barronpalos, D Beck
    Abstract:

    A cryogenic apparatus is described that enables a new experiment, nEDM@SNS, with a major improvement in sensitivity compared to the existing limit in the search for a neutron Electric Dipole Moment (EDM). This apparatus uses superfluid ⁴He to produce a high density of Ultra-Cold Neutrons (UCN) which are contained in a suitably coated pair of measurement cells. The experiment, to be operated at the Spallation Neutron Source at Oak Ridge National Laboratory, uses polarized ³He from an Atomic Beam Source injected into the superfluid 4He and transported to the measurement cells where it serves as a co-magnetometer. The superfluid ⁴He is also used as an insulating medium allowing significantly higher electric fields, compared to previous experiments, to be maintained across the measurement cells. These features provide an ultimate statistical uncertainty for the EDM of 2−3× 10⁻²⁸ e-cm, with anticipated systematic uncertainties below this level.

  • new precision measurements of free neutron beta decay with Cold Neutrons
    arXiv: Nuclear Experiment, 2014
    Co-Authors: S Baesler, J D Bowman, S I Penttila, D Pocanic
    Abstract:

    Precision measurements in free neutron beta decay serve to determine the coupling constants of beta decay, and offer several stringent tests of the Standard Model. This paper describes the free neutron beta decay program planned for the Fundamental Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and puts it into the context of other recent and planned measurements of neutron beta decay observables.

  • new precision measurements of free neutron beta decay with Cold Neutrons
    Journal of Physics G, 2014
    Co-Authors: S Baesler, J D Bowman, S I Penttila, D Pocanic
    Abstract:

    Precision measurements in free neutron beta decay serve to determine the coupling constants of beta decay, and offer several stringent tests of the standard model. This study describes the free neutron beta decay program planned for the Fundamental Physics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and finally puts it into the context of other recent and planned measurements of neutron beta decay observables.

  • quantum states of Neutrons in the gravitational field and limits for non newtonian interaction in the range between 1 μm and 10 μm
    LNP, 2003
    Co-Authors: H Abele, S Baesler, Alexander Westphal
    Abstract:

    Quantum states in the Earth’s gravitational field can be observed, when ultra-Cold Neutrons fall under gravity. In an experiment at the Institut Laue-Langevin in Grenoble, Neutrons are reflected and trapped in a gravitational cavity above a horizontal mirror. The population of the ground state and the lowest states follows, step by step, the quantum mechanical prediction. An efficient neutron absorber removes the higher, unwanted states. The quantum states probe Newtonian gravity on the micrometer scale and we place limits for gravity-like forces in the range between 1 μm and 10 μm.

V K Ignatovich - One of the best experts on this subject based on the ideXlab platform.

  • limits on a nucleon nucleon monopole dipole coupling from spin relaxation of polarized ultra Cold Neutrons in traps
    European Physical Journal C, 2009
    Co-Authors: V K Ignatovich, Y N Pokotilovski
    Abstract:

    A new limit is presented on the axion-like monopole–dipole P, T-non-invariant interaction in a range (10−4–1) cm. The spin-dependent nucleon–nucleon potential between Neutrons and nucleons of the walls of the cavity containing ultra-Cold Neutrons should affect the neutron depolarization probability at their reflection from the walls. The limit is obtained from existing data on the ultra-Cold neutron depolarization probability per one collision with the walls.

  • reflection of the de broglie wave packet from thin films
    Proceedings of SPIE the International Society for Optical Engineering, 2000
    Co-Authors: V K Ignatovich, Filipp V Ignatovitch
    Abstract:

    Reflection of Cold Neutrons from thin films, when the free neutron wave function is supposed to be the de Broglie singular wave-packet, is considered. Small corrections to interference pattern for the reflection dependence on the packet width is found. This correction for the case, when the width of the packet extracted from ultra Cold Neutrons anomaly, is calculated. The correction is shown can also be represented as a small contribution of incoherent reflection from interfaces of the film. The magnitude of this contribution is computed.

  • quantum mechanics of the de broglie wave packet and a review of inelastic losses of ucn in bottles
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2000
    Co-Authors: V K Ignatovich, Masahiko Utsuro
    Abstract:

    Abstract Different inelastic processes of ultra-Cold Neutrons (UCN) loss in traps are considered. A hypothesis of the de Broglie singular wave-packet description of the neutron wave function to explain anomalous losses of UCN is proposed. An experiment to check the hypothesis, and its results are discussed.

  • neutron time interferometry
    Foundations of Physics, 1999
    Co-Authors: J Felber, V K Ignatovich, R Gahler, R Golub, P Hank, T Keller, U Rauch
    Abstract:

    We compare a “Mach-Zehnder interferometer in time” for Cold Neutrons with its well-known spatial counterpart and demonstrate the intimate connection between space and time for both setups. Further, we outline a combined space-time interferometer, which coherently splits a wavepacket in longitudinal and lateral direction. On the way towards time interferometry “neutron computer holography” seems to be an attractive application. It allows the three-dimensional reconstruction of an object from the scattered intensity, but in contrast to holography with light, there is no need for a reference wave. On the other hand, the possible resolution is worse than in the light case.