Search results for "Radio frequency"
showing 10 items of 118 documents
The interconversion of the radial motional modes of an ion in a Penning trap mass spectrometer by 4n-polar external radio frequency fields (n= 1,2,3,…
2013
In Penning trap mass spectrometry ion masses are determined by measuring the free cyclotron frequency via the resonant conversion of the magnetron into the cyclotron motional mode, induced by the interaction with an external radio-frequency field. With octupolar rf-fields of frequency the mass resolution has been improved by more than an order of magnitude as compared to conventional quadrupolar fields of frequency and with the same pulse duration. This result raises the question what one might expect from using 12-polar rf-fields with frequency or even 16-polar rf-fields with frequency . In this paper the theoretical model for the interconversion of the radial modes by quadrupolar and octu…
Scalar Dark Matter in the Radio-Frequency Band: Atomic-Spectroscopy Search Results
2019
Among the prominent candidates for dark matter are bosonic fields with small scalar couplings to the Standard-Model particles. Several techniques are employed to search for such couplings and the current best constraints are derived from tests of gravity or atomic probes. In experiments employing atoms, observables would arise from expected dark-matter-induced oscillations in the fundamental constants of nature. These studies are primarily sensitive to underlying particle masses below $10^{-14}$ eV. We present a method to search for fast oscillations of fundamental constants using atomic spectroscopy in cesium vapor. We demonstrate sensitivity to scalar interactions of dark matter associate…
Frequency-dependent conductivity of UPd2Al3 films
1998
The transmission of UPd2Al3 films was studied (4 K < T < 300 K) in the frequency range from 4 to 32 cm−1 by using a coherent source interferometer which allows for measuring both, amplitude and phase. In addition we report on radio frequency and optical measurements. Below 20 K the conductivity and dielectric constant show strong deviations from the behavior of a normal metal which cannot simply be explained by a single renormalized Drude model with an enhanced mass and reduced scattering rate. Instead, we find evidence for the opening of a pseudogap with a gap energy of 6 cm−1 and an extremely narrow ω = 0 mode which is responsible for the large DC conductivity.
Controlling the interactions of a few cold Rb Rydberg atoms by radiofrequency-assisted F\"orster resonances
2014
Long-range interactions between cold Rydberg atoms, which are used in many important applications, can be enhanced using F\"orster resonances between collective many-body states controlled by an external electric field. Here we report on the first experimental observation of highly-resolved radio-frequency-assisted F\"orster resonances in a few cold Rb Rydberg atoms. We also observed radio-frequency-induced F\"orster resonances which cannot be tuned by a dc electric field. They imply an efficient transition from van der Waals to resonant dipole-dipole interaction due to Floquet sidebands of Rydberg levels appearing in the rf-field. This method can be applied to enhance the interactions of a…
An all-fiber RF modulation technique: frequency response calibration of optical detectors
1995
Two all-fiber Mach-Zender interferometers have been designed to generate RF modulated light at 633 nm and 830 nm. The interferometers are scanned with a piezoelectric tube driven at its fundamental frequency of resonance. The actual experimental arrangement covers the frequency range 1 kHz to 1 GHz. The technique combines several interesting features such as the simplicity, the stability and reliability of all-fiber systems and the use of low-frequency electronics to control and generate the RF modulated light. >
Hyperfine structure andg-factor measurements in ion traps
1995
We report about measurements on ground-state hyperfine splitting constants of stable Eu+ isotopes in radio frequency ion traps and experiments on the electronicg-factor of Ba+ in a Penning trap. From the precision of both measurements, which ranges between 3·10−6 and 5·10−7, we conclude that precise determination of the differential Bohr-Weisskopf effect in chains of isotopes will be possible in the near future.
Design of a double-gap Hughes-type coupled-cavity for a Ka-band Extended Interaction Klystron
2020
In this paper, the design of a Ka-band Extended-Interaction Klystron (EIK) working at 2$\pi$ mode. The interaction structure is a three-gap Hughes-type coupled-cavity. Based on the results obtained with the 3D model developed by using CST, “cold electrical parameters” have been calculated, necessary to measure the interaction with the electron beam. The structure stability and the synchronization with the electron beam are analyzed The large-signal analysis is performed by 1D software AJDISK. Under the beam voltage and current of 19.55 kV and 0.95 A, respectively, an RF output power value of 3.86 kW and a bandwidth gain value of 37. 06 dB have been obtained
Pulsed high-energy γ-rays from the radio pulsar PSRI706–44
1992
Gamma radiation above 100 MeV in energy has been detected from the radio pulsar PSR1706-44. The gamma emission forms a single broad peak within the pulsar period of 102 ms, in contrast to the two narrow peaks seen in the other three known high-energy gamma-ray pulsars. The emission mechanism in all cases is probably the same, the differences arising from the geometry of the magnetic and rotation axes and the line of sight. Gamma-ray emission accounts for as much as 1 percent of the total neutron star spindown energy in these pulsars, much more than emerges at optical or radio frequencies. Thus, study of this emission is important in understanding pulsar emission and evolution.
Hyperfine structure andg-factor measurements in ion traps
1992
We report about measurements on ground-state hyperfine splitting constants of stable Eu+ isotopes in radio frequency ion traps and experiments on the electronicg-factor of Ba+ in a Penning trap. From the precision of both measurements, which ranges between 3·10−6 and 5·10−7, we conclude that precise determination of the differential Bohr-Weisskopf effect in chains of isotopes will be possible in the near future.
Transverse laser cooling of a radio-frequency bunched ion beam in the storage ring TSR
1996
Abstract We report on the observation of the indirect transverse laser cooling effect in a radio-frequency bunched beam of 7.3 MeV 9 Be + ions, stored in the Heidelberg Test Storage Ring and subject to direct longitudinal laser cooling. This bunched scheme offers particular advantages for producing ultracold beams with unprecedented phase-space densities.