Tuning the high-order harmonic lines of a Nd:Glass laser for soft x-ray laser seeding

Taking advantage of the non-adiabatic blue-shift of high-order harmonics generated by a fixed frequency Nd:Glass laser system, we are able to report more than 50 % coverage of the XUV spectral range between 18 nm and 35 nm. The generated harmonic lines are capable of seeding Ni-like Y, Zr and Mo soft x-ray lasers and others.

Laser spectroscopy of radioactive lead and thallium isotopes

By collincar fast beam laser spectroscopy hyperfine structure and isotope shift have been measured of neutron deficient radioactive isotopes of lead (190Pb,191Pb,192Pb,193Pb,194Pb,195Pb,196Pb,197Pb) and thallium (188Tl190Tl,191Tl,192Tl,194Tl,196Tl). Therefrom nuclear magnetic dipole moments, electric quadrupole moments, changes of the mean square charge radii and deformation parameters are deduced and compared with predictions from theory.

Towards laser cooling of fast Be+ ions in the storage ring TSR

Publisher Summary This chapter presents a clear understanding of laser-ion interactions under storage ring conditions to prepare the basis of laser cooling of fast-stored ion beams. In addition, the method of laser-induced fluorescence provides precise data for beam properties such as absolute velocity, momentum spread, and lifetime. 9Be+ ions stored in a heavy-ion storage ring are a promising species for laser cooling down to temperatures several orders of magnitude less than those reached for protons by electron cooling at the Novosibirsk ring. Short cooling times and microkelvin temperatures can be envisaged, where the structure of the ion beam is dominated by Coulomb repulsion. The chap…

Collinear two-photon excitation of indium rydberg states in a fast atomic beam

The 29p-Rydberg state of neutral indium was produced by double resonant two-photon excitation in a fast atomic beam and detected via field ionization in a longitudinal electric field.

Nuclear moments and change in the charge-radii of neutron deficient lead isotopes

The nuclear moments of195Pb and the change in the charge radii of192,194,195,196Pb have been determined from the isotope shift and hyperfine structure of the 723 nm line of neutral lead by collinear laser spectroscopy.

A test of special relativity with stored lithium ions

Laser spectroscopy at the heavy ion storage ring TSR in Heidelberg allows for precision experiments testing the limits of the special theory of relativity. With an opticalΛ-type three-level system of7Li+ the Doppler shift has been measured by saturation spectroscopy as a test of the time dilatation factor γ = (1 −β2)−1/2 at an ion velocity ofυ = 6.4% c. A precision ofΔν/ν < 9 × 10−9 has been obtained, which sets a second-order limit of 1.1 × 10−6 for any deviation from the time dilatation factor. The fourth-order limit of this deviation is set below 2.7 × 10−4 by the present experiment. These limits are given at a 1 σ confidence level.

Testing Time Dilation on Fast Ion Beams

We report the status of an experimental test of time dilation in Special Relativity. This is accomplished by simultaneously measuring the forward and backward Doppler shifts of an electronic transition of fast moving ions, using high-precision laser spectroscopy. From these two Doppler shifts both the ion velocity ? = v/c and the time dilation factor can be derived. From measurements based on saturation spectroscopy on lithium ions stored at ? = 0.03 and ? = 0.06 in the TSR heavy-ion storage ring, we achieved an upper limit for a [?2] deviation from Special Relativity of . In recent measurements on a ? = 0.34 Li+ beam in the ESR storage ring we used optical-optical double-resonance spectros…

The dynamics of bunched laser-cooled ion beams at relativistic energies

We discuss the axial dynamics of laser-cooled relativistic C3+ ion beams at moderate bunching voltages. Schottky noise spectra measured at a beam energy of 122 MeV/u are compared to simulations of the axial beam dynamics. Ions confined in the bucket are addressed by the narrow-band force of a laser beam counter-propagating to the ion beam, while the laser frequency is detuned relatively to the cooling transition frequency in the rest frame of the bucket. At large detuning comparable to the momentum acceptance of the bucket, the axial dynamics can be well explained by the secular motion of individual non-interacting ions. At small detuning, corresponding to a small axial momentum spread Δpax…

Laser spectroscopy and laser cooling of relativistic stored ion beams

Abstract Experiments with relativistic ions at the test storage ring TSR [P. Baumann et al., Nucl. Instr. and Meth. A268 (1988) 531] demonstrate the potential of the interaction of laser light with energetic stored ions for spectroscopic purposes as well as for manipulation of the ion velocity. Latest results for Li+ ions are reported. At the ion energies available at ESR [B. Franzke, Nucl. Instr. and Meth. B24 B25 (1987) 19] it will become possible to prepare and store bare ions up to U92+. Experiments using these exotic beams are discussed and an outlook to the situation at even higher energies is given.

Nuclear spins, moments and charge radii of108?111Sn

The hyperfine structure splittings (hfs) and isotope shifts (IS) in the atomic transitions 5s2 5p21S0 → 5s2 5p6s1,3P1 have been measured for the radioactive isotopes108−111Sn and all stable ones. The tin isotopes were prepared as fast atomic beams for collinear laser spectroscopy at the GSI online mass separator following a fusion reaction. Nuclear spins, magnetic dipole, electric quadrupole moments and changes in mean square charge radii have been determined. In109Sn the spinI=5/2 was measured for the nuclear ground state (T1/2=18 min) in contradiction to the literature value. The mean square charge radii show a parabolic behaviour with a maximum at N=66. This is interpreted by collective …

Demonstration of an efficient pumping scheme for a 7.36-nm Ni-like samarium soft x-ray laser

The demonstration of a 7.36 nm Ni-like Sm soft x-ray laser pumped by 36 J of a Nd:glass chirped pulse amplification laser is presented. Double-pulse single-beam non-normal incidence pumping was applied for the efficient soft x-ray laser generation. Here the applied technique included a new single optic focusing geometry for large beam diameters, a single-pass grating compressor traveling-wave tuning capability and an optimized high energy laser double-pulse. This scheme has the potential for even shorter wavelength soft x-ray laser pumping.

Test of Special Relativity in a Heavy Ion Storage Ring

Determination of nuclear spins of short-lived isotopes by laser induced fluorescence

Abstract The spins of several nuclear ground and isomeric states have been measured for a number of mercury isotopes. The fluorescent light from the 6s6p3P1 state is observed at 2537 A after excitation with the frequency doubled output of a pulse dye laser. Four different laser induced fluorescence techniques were tested for their applicability: double resonance, Hanle effect, time delayed integral Hanle beats, and time resolved quantum beats. The sensitivity and selectivity of these models are compared with emphasis on the determination of spins of nuclei far from beta-stability, where short half lives and low production yields restrict the number of available atoms. The experiments were c…

Nuclear Shape Staggering in Very Neutron-Deficient Hg Isotopes Detected by Laser Spectroscopy

The isotope shifts of $^{188}\mathrm{Hg}$, $^{186}\mathrm{Hg}$, and $^{184}\mathrm{Hg}$ in the 2537-\AA{} line have been measured by use of tunable dye laser at the on-line mass separator ISOLDE at CERN. The results are $\ensuremath{\delta}\ensuremath{\nu}(^{188}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=35.8(2)$ GHz; $\ensuremath{\delta}\ensuremath{\nu}(^{186}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=39.4(2)$ GHz; and $\ensuremath{\delta}\ensuremath{\nu}(^{184}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=43.1(2)$ GHz. These data combined with those obtained by $\ensuremath{\beta}$-radiation-detected optical pumping ($\ensuremath{\beta}$-RADOP) on the odd Hg isotopes yield a huge odd-even…

Laser spectroscopy of neutron deficient lead and thallium isotopes: Systematics of nuclear radii in the Z = 82 region

Publisher Summary The high sensitivity achievable in laser spectroscopic methods allows the extraction of nuclear quantities even of artificially produced short-lived nuclides far off from nuclear stability. By analyzing the hyperfine structure and the isotope shift magnetic dipole moments, the electric quadrupole moments and the change of the nuclear charge radius can be studied. This chapter describes an experiment that was carried out at the GSI on-line mass separator using collinear fast atomic-beam laser spectroscopy. Radioactive lead and thallium isotopes were produced by bombarding natural tungsten targets with oxygen beams. For the lighter thallium isotopes, a tantalum target was us…

Test of special relativity in an ion storage ring

An accurate measurement of the Doppler effect in collinear laser spectroscopy has been performed at the TSR storage ring with electron cooled7Li+ ions atΒ=0.064. This experiment is a sensitive test of theγ=(1−Β2)−1/2 factor(Β=v/c) in the special theory of relativity. The Doppler shifted frequencies of the moving7Li+ ions are compared with calibrated molecular lines at rest. The frequencies at rest for the7Li+ ions are known from independent measurements. The Doppler shifted frequencies in the collinear experiment have been measured with a precision ofδv/v=6×10−9, mainly limited by the signal width of the resonance. A corresponding upper limit of 8×10−7 is deduced for any deviation of the ti…

Enhancement of the laser-driven proton source at PHELIX

High power laser science and engineering 8, e24 (2020). doi:10.1017/hpl.2020.23

Laser cooling of stored high-velocity ions by means of the spontaneous force

A longitudinal laser cooling of ion beams at about 5% of the velocity of light has been performed at the Heidelberg Test Storage Ring with various cooling schemes employing the spontaneous force. For a 7.29-MeV $^{9}\mathrm{Be}^{+}$ beam with an initial longitudinal temperature of 2700 K, the main characteristics of laser cooling in a storage ring are discussed. When undamped, the transverse betatron oscillations of the coasting ions limit the longitudinal temperature after laser cooling to typically 1 K. After damping the transverse motion by precooling the ions with an electron cooler, longitudinal temperatures of below 30 mK have been obtained in the subsequent laser cooling. In this cas…

First laser cooling of relativistic ions in a storage ring

The first successful laser cooling of ions at relativistic energies was observed at the Heidelberg TSR storage ring. A $^{7}\mathrm{Li}^{+}$-ion beam of 13.3 MeV was oberlapped with resonant copropagating and counterpropagating laser beams. The metastable ions were cooled from 260 K to a longitudinal temperature of below 3 K and decelerated by several keV. The longitudinal velocity distribution was determined by a fluorescence method. After laser cooling a strongly enhanced narrow peak appeared in the Schottky noise spectrum in addition to the uncooled ion distribution.

Modern Ives-Stilwell Experiments At Storage Rings: Large Boosts Meet High Precision

We give a brief overview of time dilation tests using high-resolution laser spectroscopy at heavy-ion storage rings. We reflect on the various methods used to eliminate the first-order Doppler effect and on the pitfalls encountered, and comment on possible extensions at future facilities providing relativistic heavy ion beams at $\gamma \gg 1$.

First experiments with the heidelberg test storage ring TSR

Abstract The Heidelberg heavy ion test storage ring TSR started operation in May 1988. The lifetimes of the ion beams observed in the first experiments can be explained by interactions with the residual gas. Multiple Coulomb scattering, single Coulomb scattering, electron capture and electron stripping are the relevant processes. Electron cooling of ions as heavy as O 8+ has been observed for the first time. With increasing particle number, the longitudinal Schottky noise spectrum becomes dominated by collective waves for cooled beams, allowing a determination of velocities of sound. After correcting for these coherent distortions fo the Schottky spectrum, the longitudinal beam temperature …