0000000000073201
AUTHOR
Danyal Winters
Laser spectroscopy at the experimental storage ring - an overview
We present an overview of laser spectroscopy experiments at the experimental storage ring of GSI in Darmstadt, which have been and will be performed in the near future.
Chapter 7 HITRAP: A Facility at GSI for Highly Charged Ions
Abstract An overview and status report of the new trapping facility for highly charged ions at the Gesellschaft fur Schwerionenforschung is presented. The construction of this facility started in 2005 and is expected to be completed in 2008. Once operational, highly charged ions will be loaded from the experimental storage ring ESR into the HITRAP facility, where they are decelerated and cooled. The kinetic energy of the initially fast ions is reduced by more than fourteen orders of magnitude and their thermal energy is cooled to cryogenic temperatures. The cold ions are then delivered to a broad range of atomic physics experiments.
Laser spectroscopy of the (1s(2)2s2p) P-3(0)-P-3(1) level splitting in Be-like krypton
15th International Conference on the Physics of Highly Charged Ions, HCI2010, Fudan Univ, Shanghai, PEOPLES R CHINA, AUG 29-SEP 03, 2010; International audience; Heavy few-electron ions, such as He-, Li- and Be-like ions, are ideal atomic systems to study the effects of correlation, relativity and quantum electrodynamics. Very recently, theoretical and experimental studies of these species achieved a considerable improvement in accuracy. Be-like ions are interesting because their first excited state, i.e. (1s(2)2s2p) P-3(0), has an almost infinite lifetime (tau(0)) in the absence of nuclear spin (I), as it can only decay by a two-photon E1M1 transition to the (1s(2)2s(2)) S-1(0) ground stat…
Scintillation light produced by low-energy beams of highly-charged ions
Measurements have been performed of scintillation light intensities emitted from various inorganic scintillators irradiated with low-energy beams of highly-charged ions from an electron beam ion source (EBIS) and an electron cyclotron resonance ion source (ECRIS). Beams of xenon ions Xe$^{q+}$ with various charge states between $q$=2 and $q$=18 have been used at energies between 5 keV and 17.5 keV per charge generated by the ECRIS. The intensity of the beam was typically varied between 1 and 100 nA. Beams of highly charged residual gas ions have been produced by the EBIS at 4.5 keV per charge and with low intensities down to 100 pA. The scintillator materials used are flat screens of P46 YA…
HITRAP – a facility for experiments on heavy highly charged ions and on antiprotons
HITRAP is a facility for very slow highly-charged heavy ions at GSI. HITRAP uses the GSI relativistic ion beams, the Experimental Storage Ring ESR for electron cooling and deceleration to 4 MeV/u, and consists of a combination of an interdigital H-mode (IH) structure with a radiofrequency quadrupole structure for further deceleration to 6 keV/u, and a Penning trap for accumulation and cooling to low temperatures. Finally, ion beams with low emittance will be delivered to a large variety of atomic and nuclear physics experiments. Presently, HITRAP is in the commissioning phase. The deceleration of heavy-ion beam from the ESR storage ring to an energy of 500 keV/u with the IH structure has be…
Strong-field physics using lasers and relativistic heavy ions at the high-energy storage ring hesr at fair
The HESR high-energy ion storage ring at FAIR will provide unprecedented possibilities for strong-field physics using novel laser sources on relativistic heavy ions. An overview on the planning will be given.
A beamline for x-ray laser spectroscopy at the experimental storage ring at GSI
By combining an x-ray laser (XRL) with a heavy-ion storage ring, precision laser spectroscopy of the fine-structure splitting in heavy Li-like ions will be possible. An initial study has been performed to determine the feasibility of a first experiment at the experimental storage ring at GSI in Darmstadt, which also has great potential for the experiments planned for FAIR. We plan to perform a unique, direct and precise measurement of a fine-structure transition in a heavy Li-like ion. Such a measurement will test state-of-the-art atomic structure calculations in strong fields. This endeavour will require that the existing infrastructure is complemented by a dedicated beamline for the XRL. …
Optical measurement of the longitudinal ion distribution of bunched ion beams in the ESR
Abstract An optical technique to study the longitudinal distribution of ions in a bunched ion beam circulating in a storage ring is presented. It is based on the arrival-time analysis of photons emitted after collisional excitation of residual gas molecules. The beam-induced fluorescence was investigated in the ultraviolet regime with a channeltron and in the visible region using a photomultiplier tube. Both were applied to investigate the longitudinal shape of bunched and electron-cooled 209Bi80+ ion beams at about 400 MeV/u in the experimental storage ring (ESR) at GSI Helmholtzzentrum fur Schwerionenforschung in Darmstadt, Germany. Bunch lengths were determined with an uncertainty of abo…
Absolute frequency measurements on the 2S→3S transition of lithium-6,7
The frequencies of the 2S–3S two-photon transition for the stable lithium isotopes were measured by cavity-enhanced Doppler-free laser excitation that was controlled by a femtosecond frequency comb. The resulting values of 815 618 181.57(18) and 815 606 727.59(18) MHz, respectively, for 7Li and 6Li are in agreement with previous measurements but are more accurate by an order of magnitude. There is still a discrepancy of about 11.6 and 10.6 MHz from the latest theoretical values. This is comparable to the uncertainty in the theoretical calculations, while uncertainty in our experimental values is more than a hundred-fold smaller. More accurate theoretical calculation of the transition freque…
Observation of the hyperfine transition in lithium-like bismuthBi20980+: Towards a test of QED in strong magnetic fields
We performed a laser spectroscopic determination of the $2s$ hyperfine splitting (HFS) of Li-like ${}^{209}{\text{Bi}}^{80+}$ and repeated the measurement of the $1s$ HFS of H-like ${}^{209}{\text{Bi}}^{82+}$. Both ion species were subsequently stored in the Experimental Storage Ring at the GSI Helmholtzzentrum f\"ur Schwerionenforschung Darmstadt and cooled with an electron cooler at a velocity of $\ensuremath{\approx}0.71\phantom{\rule{0.16em}{0ex}}c$. Pulsed laser excitation of the $M1$ hyperfine transition was performed in anticollinear and collinear geometry for ${\text{Bi}}^{82+}$ and ${\text{Bi}}^{80+}$, respectively, and observed by fluorescence detection. We obtain $\ensuremath{\De…
Laser spectroscopy measurement of the 2s-hyperfine splitting in lithium-like bismuth
We have recently reported on the first direct measurement of the $2s$ hyperfine transition in lithium-like bismuth (209Bi80+) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. Combined with a new measurement of the $1s$ hyperfine splitting (HFS) in hydrogen-like (209Bi82+) the so-called specific difference ${\rm{\Delta }}^{\prime} E=-61.37(36)$ meV could be determined and was found to be in good agreement with its prediction from strong-field bound-state quantum electrodynamics. Here we report on additional investigations performed to estimate systematic uncertainties of these results and on details of the experimental setup. We show that the dominating uncertainty a…
First observation of the ground-state hyperfine transition in 209Bi80+
The long sought after ground-state hyperfine transition in lithium-like bismuth 209Bi80+ was observed for the first time using laser spectroscopy on relativistic ions in the experimental storage ring at the GSI Helmholtz Centre in Darmstadt. Combined with the transition in the corresponding hydrogen-like ion 209Bi82+, it will allow extraction of the specific difference between the two transitions that is unaffected by the magnetic moment distribution in the nucleus and can therefore provide a better test of bound-state QED in extremely strong magnetic fields.
Laser cooling of stored relativistic ion beams with large momentum spreads using a laser system with a wide scanning range
New results on laser cooling of stored, bunched, relativistic ion beams are presented. For the first time it has been possible to cool an ion beam with large momentum spread without initial electron cooling or scanning of the bunching frequency by using a single cw laser system.
Laser cooling of relativistic heavy-ion beams for FAIR
Laser cooling is a powerful technique to reduce the longitudinal momentum spread of stored relativistic ion beams. Based on successful experiments at the experimental storage ring at GSI in Darmstadt, of which we show some important results in this paper, we present our plans for laser cooling of relativistic ion beams in the future heavy-ion synchrotron SIS100 at the Facility for Antiproton and Ion Research in Darmstadt.
Detection system for forward emitted photons at the Experimental Storage Ring at GSI
A single photon counting system has been developed for efficient detection of forward emitted fluorescence photons at the Experimental Storage Ring (ESR) at GSI. The system employs a movable parabolic mirror with a central slit that can be positioned around the ion beam and a selected low noise photomultiplier for detection of the collected photons. Compared to the previously used system of mirror segments installed inside the ESR the collection efficiency for forward-emitted photons is improved by more than a factor of 5. No adverse effects on the stored ion beam have been observed during operation besides a small drop in the ion current of about 5% during movement of the mirror into the b…