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A significant deceleration effect on a stored coasting ion beam by a continuous-wave laser light was observed in the Schottky-noise spectrum during the laser experiments with lithium-like oxygen ion beams stored at a relativistic energy of 275.7 MeV/u at the heavy-ion storage ring CSRe in Lanzhou, China. The observed deceleration range of the laser (Δp/p≈5.7×10−6) is much broader than the expected capture range (Δp/p≈3.6×10−8), as calculated from the natural linewidth of the O5+ ion’s electronic transition (2S1/2 −2 P1/2). In order to explain this huge deviation, a phase space tracking code has been developed to investigate the interaction between the stored coasting ion beam and the laser light. Simulations reveal that the deceleration range of the typically narrow CW laser force is highly enlarged by taking into account the transverse betatron oscillation of the ions with larger emittance and the angular misalignment of the laser light direction. The experimental observation is well described by the systematic simulations. The present work is crucial for forthcoming laser cooling and precision laser spectroscopy experiments and simulations on heavy highly charged ions at the CSRe and the future facility HIAF.

The [Formula: see text] and [Formula: see text] transitions in Li-like carbon ions stored and cooled at a velocity of [Formula: see text] in the experimental storage ring (ESR) at the GSI Helmholtz Centre in Darmstadt have been investigated in a laser spectroscopy experiment. Resonance wavelengths were obtained using a new continuous-wave UV laser system and a novel extreme UV (XUV) detection system to detect forward emitted fluorescence photons. The results obtained for the two transitions are compared to existing experimental and theoretical data. A discrepancy found in an earlier laser spectroscopy measurement at the ESR with results from plasma spectroscopy and interferometry has been resolved and agreement between experiment and theory is confirmed.

We report on an experiment that was conducted in preparation of laser cooling experiments at the heavy-ion storage ring CSRe. The lifetimes of ion beams made up of 12C3+ and 16O4+ ions stored at an energy of 122 MeV/u in the CSRe were determined by two independent methods, firstly via a DC current transformer (DCCT) and secondly via a Schottky resonator. Using electron-cooling, the signals of the 12C3+ and 16O4+ ions could be separated and clearly observed in the Schottky spectrum. The obtained individual lifetimes of the 12C3+ and 16O4+ components were 23.6 s and 17.8 s, respectively. The proportion of 12C3+ ions in the stored ion beam was measured to be more than 70% at the beginning of the injection and increasing as a function of time. In addition to these measurements, the operation and remote control of a pulsed laser system placed directly next to the storage ring was tested in a setup similar to the one envisaged for future laser experiments.

© 2019 Elsevier B.V. Laser spectroscopy enables the determination of fundamental atomic and nuclear properties with high precision. In view of the low production rates of the heaviest elements, a high total efficiency is a crucial requirement for any experimental setup to be used in on-line experiments. The setup requires the use of gas stopping techniques to slow down the radionuclides of interest. In previous studies laser spectroscopy was performed inside a gas-filled stopping cell with a limited spectral resolution of a few GHz. Collisional broadening inside stopping cells ultimately limits the precision of laser spectroscopic studies and hampers in particular hyperfine spectroscopy. The spectral linewidth is reduced by an order of magnitude when the laser spectroscopy is performed in a well-collimated gas jet formed by the exit nozzle of a gas stopping cell. In addition, the exposure of the jet to high-repetition rate laser light which saturates the optical transitions allows maintaining a high total efficiency. Here, we present a new setup dedicated to laser spectroscopy of the heaviest elements with an improved resolution, which is presently under construction. This setup combines the efficient filament neutralization demonstrated for nobelium with the improved resolution of in-gas-jet spectroscopy. ispartof: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms vol:463 pages:272-276 ispartof: location:SWITZERLAND, CERN, Geneva status: published

The experimental determination of atomic levels and the first ionization potential of the heaviest elements ( Z ⩾ 100 ) is key to challenge theoretical predictions and to reveal changes in the atomic shell structure. These elements are only artificially produced in complete-fusion evaporation reactions at on-line facilities such as the GSI in Darmstadt at a rate of, at most, a few atoms per second. Hence, highly sensitive spectroscopic methods are required. Laser spectroscopy is one of the most powerful and valuable tools to investigate atomic properties. In combination with a buffer-gas filled stopping cell, the Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique provides the highest sensitivity for laser spectroscopy on the heaviest elements. The RADRIS setup, as well as the measurement procedure, have been optimized and characterized using the α -emitter 155 Yb in on-line conditions, resulting in an overall efficiency well above 1%. This paves the way for a successful search of excited atomic levels in nobelium and heavier elements.

We present a novel design for an efficient enhancement cavity for frequency doubling into the UV. Radiation of 150 mW has been generated at 257 nm and remained stable for more than 15 hours.

One of the most important atomic properties governing an element's chemical behavior is the energy required to remove its least-bound electron, referred to as the first ionization potential. For the heaviest elements, this fundamental quantity is strongly influenced by relativistic effects which lead to unique chemical properties. Laser spectroscopy on an atom-at-a-time scale was developed and applied to probe the optical spectrum of neutral nobelium near the ionization threshold. The first ionization potential of nobelium is determined here with a very high precision from the convergence of measured Rydberg series to be 6.626 21±0.000 05 eV. This work provides a stringent benchmark for state-of-the-art many-body atomic modeling that considers relativistic and quantum electrodynamic effects and paves the way for high-precision measurements of atomic properties of elements only available from heavy-ion accelerator facilities. ispartof: PHYSICAL REVIEW LETTERS vol:120 issue:26 pages:263003-263003 ispartof: location:United States status: published

Strong efforts are undertaken at GSI in Darmstadt preparing for laser spectroscopy of the synthetic element nobelium. Several excimer- and dye lasers will be used in the forthcoming search for the $^1$P$_1$ -level in 254No. Based on the highly-efficient Radiation Detected Resonance Ionization Spectroscopy (RADRIS) technique, the identification of this excited state predicted around 3.8 eV becomes possible within a relatively short period of beam-time. This will form the basis for future studies of the atomic structure of the heaviest elements.

We report on our measurements of the Lande g-factors for rovibrational states in the 10V-band of carbon disulfide. Our improved accuracy enabled us to increase the measurements precision of previous studies and additionally determine the Lande g-factors for nearly all previously assigned transitions.

We report on the cooling of neutral mercury in a magneto-optical trap utilizing the spin forbidden 1S0 → 3P1 transition at 253.7 nm. We trapped two Hg isotopes, i.e. the bosonic 202Hg and the fermionic 199Hg isotope, respectively. The temperature of the cold atom cloud was determined to be approximately 300 μK using a modified TOF-method. It is currently limited by the quality of the laser lock. Trapped neutral Hg has many interesting avenues such as a time standard and high precision measurements. Here, we discuss the possibilities of photo-association spectroscopy and the generation of ultra-cold Hg2 dimers.

An all-solid-state continuous-wave (cw) laser system for mid-infrared absorption measurements of the carbon monoxide (CO) molecule has been developed and demonstrated. The single-mode, tunable output of an external-cavity diode laser (ECDL) is difference-frequency mixed with the output of a 550-mW diode-pumped cw Nd:YAG laser in a periodically poled lithium niobate (PPLN) crystal to generate tunable cw radiation in the mid-infrared region. The wavelength of the 860-nm ECDL can be coarse tuned from 860.782 to 872.826 nm, allowing the sensor to be operated in the spectral region 4.4–4.8 μm. CO-concentration measurements were performed in CO/CO2/N2 mixtures in a room-temperature gas cell, in the exhaust stream of a well-stirred reactor (WSR) at Wright-Patterson Air Force Base and in a near-adiabatic hydrogen/air CO2-doped flame. The noise equivalent detection limits were estimated to be 1.1 and 2.5 ppm per meter for the gas cell and flame experiments, respectively. These limits were computed for combustion gas at 1000 K and atmospheric pressure assuming a signal-to-noise ratio of 1. The sensor uncertainty was estimated to be 2% for the gas-cell measurements and 10% for the flame measurements based on the repeatability of the peak absorption.

In 1933, the Prussian Academy of Sciences and Humanities was an exclusive learned society, out of touch with modern methods and funding, which had also failed to re-establish itself as a ‘centre of research’. During the Nazi regime, it was at best peripherally involved in the restructuring of German academia. While some of its members played a political role, the Academy itself retained its status as a learned society, even an academic club. This helped make possible its subsequent adaptation to the new political order in post-war Germany.

The flow behavior of two commercial liquid crystalline polymers (LCP), Vectra B 950 and Vectra L 950 (Ticona GmbH), was investigated using a capillary rheometer with a new double slit die. The influence of pre-shearing of the melt on its viscosity and the apparent geometry dependence of its flow behavior were analyzed. The dependence of flowability on the part was determined with a modular spiral mold in which the thickness of the channel was varied. The influence of processing parameters and part geometry on the mechanical properties and morphology of molded parts was also studied.

Atlantic salmon ( Salmo salar L.), reared in sea cages for 18 months (age 36 months from hatching), were exposed to natural light (NL; control), or continuous light (LL) from January (ALJ) or March (ALM) until July. Oocyte development appeared to be arrested at the oil drop stage during winter and spring in a proportion of the females following exposure to LL. This was accompanied by a decrease in plasma oestradiol-17β and testosterone levels following the onset of LL. Somatic growth was affected by LL during winter and spring. However, the arrested sexual development in a proportion of the fish in the ALJ and ALM groups did not correlate with lower growth rate, body weight or condition factor compared with controls prior to the reduction in plasma sex steroid levels. These results suggest a photoperiodic advancement of the timing of an annual `critical period' during which sexual maturation can be arrested.

Atlantic salmon ( Salmo salar L.), reared in sea cages for 18 months (age 36 months from hatching), were exposed to natural light (NL, 61°N), or continuous additional light from January (ALJ) or March (ALM) until July. On July 13, the fish were moved to indoor raceways with brackish water (2–19‰) and ambient temperature (declining from 13.0 to 5.6°C). Fish from each treatment were subjected to either simulated natural photoperiod (SNP), continuous light (24L), or short photoperiod (8L=8 L:16D), creating a total of nine experimental groups with approx. 50 fish in each. The proportion of sexually maturing females was reduced from 91% in the NL groups, to 67% and 9% in the ALM and ALJ groups, respectively ( p ≤0.005). A similar reduction was observed among the males, from 74% in the NL groups, to 57% and 16% in the ALM and ALJ groups, respectively ( p ≤0.001). Ovulation commenced in late October in the control group (NL-SNP). Compared with control, median ovulation time was advanced by 5, 4 and 3 weeks in the ALM-8L, NL-8L and ALM-SNP groups, respectively, whereas ovulation was delayed by 1 and 6 weeks in the ALM-24L and NL-24L groups, respectively. The altered timing of ovulation among the groups was paralleled by similar shifts in the seasonal plasma oestradiol-17 β and testosterone profiles. Survival of eggs to the eyed stage was lower in the ALM-8L group (mean=64.2%) compared with the NL-SNP group (mean=92.5%), indicating a negative effect on egg quality in the most advanced group. Although abrupt changes in photoperiod can be used to control timing of ovulation in Atlantic salmon to obtain off-season eggs, the decrease in egg survival and proportion of maturing fish may set constraints on how much maturation can be advanced by use of continuous light during winter and spring. However, the effect on age at maturity may also be exploited to reduce the problem with unwanted early maturation in salmon farming.

Das von Einstein, Podolsky und Rosen 1935 ersonnene Gedankenexperiment zur Quantenmechanik beschaftigt seither die Gemuter vieler Physiker, fuhrt es doch zum Schlus, das die Beobachtung eines Teilchens instantan den Zustand eines zweiten, weit entfernten Teilchens beeinflussen kann. Klassische Alternativtheorien zur Quantenmechanik lassen sich mit Hilfe der sog. Bellschen Ungleichungen testen, die in ihrer scharfsten Version allerdings noch nicht uberpruft wurden. Dies wird mit einem neuen Experiment, das die Kernspinkomponenten zweier 199Hg-Isotope analysiert, die bei der Photodissoziation eines 199Hg-Dimeres entstehen, erstmals moglich.

The feasibility of determining nuclear quadrupole hyperfine splittings in the ground electronic state of a polyatomic molecule using a double resonance quantum beat method has been demonstrated. Pyrimidine molecules were coherently excited into single rotational states of the S0 201 (13a1) vibrational level. The resulting hyperfine level coherences were then probed, after a variable time delay, by excitation to the S1 O0 level with subsequent fluorescence detection. Analysis showed that the quadrupole structure in the 201 (13a1) level is similar to that previously measured in the vibrational ground state. Applications of this method and possible experimental extensions are discussed.

article i nfo It is urgently aimed in prenatal medicine to identify pregnancies, which develop life-threatening preeclamp- sia prior to the manifestation of the disease. Here, we use recurrence-based methods to distinguish such pregnancies already in the second trimester, using the following cardiovascular time series: the variability of heart rate and systolic and diastolic blood pressures. We perform recurrence quantification analysis (RQA), in addition to a novel approach, e-recurrence networks, applied to a phase space constructed by means of these time series. We examine all possible coupling structures in a phase space constructed with the above-mentioned biosignals. Several measures including recurrence rate, determinism, laminarity, trap- ping time, and longest diagonal and vertical lines for the recurrence quantification analysis and average path length, mean coreness, global clustering coefficient, assortativity, and scale local transitivity dimension for the network measures are considered as parameters for our analysis. With these quantities, we perform a quadratic discriminant analysis that allows us to classify healthy pregnancies and upcoming preeclamptic patients with a sensitivity of 91.7% and a specificity of 45.8% in the case of RQA and 91.7% and 68% when using e-recurrence networks, respectively.

Pulsed UV-IR double-resonance spectroscopy was implemented to demonstrate IR absorption spectroscopy in electronically excited polyatomic molecules by fluorescence dip detection, using jet-cooled propynal (HCCCHO) excited to the first excited singlet state S1 as an example. This method opens the possibility to study the spectroscopy and dynamics of rovibronic states which are not accessible in one-photon transitions or are non-fluorescing

Eggshell zona radiata proteins (zr-proteins) were found to occur normally in plasma of sexually mature female (but not male) Atlantic salmon (Salmon salar). In order to ascertain the physiological relevance of these findings, we developed a specific enzyme-linked immunoassay for zr-proteins and screened plasma from sexually maturing Atlantic salmon females throughout an annual reproductive cycle. While zr-proteins were detectable at low levels in female adult salmon plasma prior to sexual maturation, zr-protein levels increased dramatically as sexual maturation proceeded. The strong correlation between gonado-somatic index (GSI) and plasma zr-proteins indicates a reproductive role for blood borne zr-proteins. During the vitellogenic phase, levels of plasma zr-proteins were positively correlated with GSI and with plasma levels of gonadotropin I (GtH I) and estradiol-17β, as determined by radioimmuno-assays. However, during final sexual maturation, only the plasma level of gonadotropin II (GtH II) was positively correlated to GSI. In contrast, zr-proteins and estradiol-17β were both negatively correlated to plasma level of GtH II during this period. In view of estradiol-17β-induced hepatic synthesis and secretion of zr-proteins (Oppen-Berntsen et al.: Journal of Endocrinology 135:293–302, 1992a) and the established role of gonadotropins in regulating ovarian estradiol synthesis, we interpret the observed correlations among plasma levels of GtH I, estradiol-17β and zr-proteins in Atlantic salmon to signify that GtH I regulates ovarian estradiol-17β synthesis, which in turn regulates hepatic synthesis and secretion of both vitellogenin and zr-proteins during oogenesis. © 1994 Wiley-Liss, Inc.

We implement spontaneous parametric down‐conversion in temperature‐stabilized PP‐KTP with detection rates up to 103 photon pairs per second and μW pump power at 404 nm as a source for single photons. In this contribution we describe two applications: While in a first experiment the photon pairs will be used to implement a free‐space QKD‐setup based on the BB84 protocol without the need of active polarization switching, the second setup focusses on a two‐photon setup based on feedback.

By introducing the IR—UV pump—probe technique to detect molecular quantum beats, this phenomenon is utilized as a Doppler-free time domain spectroscopy for the electronic ground state. The technique is demonstrated with Stark quantum beats of vibrationally excited S0 levels to determine the electric dipole moment, but it can be equally well applied to study structure and dynamics of ground state molecules and radicals. Exciting the aldehydic CH stretching mode ν2 of propynal, HCCCHO, a dipole moment was found which is, within experimental error, identical to that previously measured for the vibrational ground state by microwave spectroscopy.

The hatching process of eggs from Atlantic salmon was investigated. Salmon eggs were subjected to hypoxia under different alkaline conditions in the laboratory using different buffers in the test systems. Hypoxia was a highly effective inducer of hatching in mature salmon eggs (2 days before natural hatching at 5–7°C), causing 100% hatching within 2 h of application at physiological pH. Salmon eggs were also induced to hatch by hypoxia 2–3 weeks ahead of normal hatching, but hatching occurred more slowly and asynchronously than in mature eggs and was not complete (86%). However, in this situation the induction of salmon egg hatching by hypoxia was greatly facilitated at alkaline pH. Hypoxia induced hatching only when applied less than 1 month prior to normal hatching, i.e. after ca. 300 day degrees (dC) of development. Under normoxic and physiological pH conditions hatching of mature salmon eggs was induced by dopaminergic antagonists and delayed by dopaminergic agonists. Noradrenergic and serotonergic agents also induced hatching, but they apparently act through a terminal dopaminergic mechanism. The data suggest that hypoxia is involved in the natural hatching process, and that physiological signals for hatching in mature salmon eggs may involve specific neural monitors of oxygen tension.

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.

We have performed a test run for laser cooling experiments with 12C3+ ion beams at an energy of 122 MeV/u at the CSRe with a pulsed laser. During this beamtime a lot of progress have been made. This was the first time we could successfully separate the 12C3+ ions and 16O4+ ions in the Schottky spectrum with the help of electron cooling. And our newly installed CPM detector worked well during the experiment. We tried to see effects from the interaction of the pulsed laser light with the stored 12C3+ ion beams, but no cooling effects could yet be observed.

Summary from only given. We report on the current status of our work concerning the development of new optical sensors for the measurement of hydroxyl (OH) and nitric oxide (NO). Laser based sensors potentially fulfill all requirements to implement pollutant detection generated in combustion processes.

In the present study, yeast colony development serves as a model system to study growth of fungal populations with negligible nutrient and signal transport within the mycelium. Mathematical simulations address the question whether colony development is governed by diffusional limitation of nutrients. A hybrid one-dimensional cellular automaton model was developed that describes growth of discrete cells based upon microscopic interaction rules in a continuous field of nutrient and messenger. The model is scaled for the geometry of the experimental setup, cell size, growth- and substrate uptake rates. Therefore, calculated cell density profiles and nutrient distributions can be compared to experimental results and the model assumptions can be verified. In the physiologically relevant parameter range, simulations show an exponentially declining cell density along the median axis of the colonies in case of a diffusion limited growth scenario. These results are in good agreement with cell density profiles obtained in cultivations of the yeast Candida boidinii with glucose as the limiting carbon source but stand in contrast to the constant cell density profile estimated for Yarrowia lipolytica grown under the same conditions. While from the comparison of experimental results and simulations a diffusion limited growth mechanism is proposed for glucose limited C. boidinii colonies, this hypothesis is rejected for the growth of Y. lipolytica. As an alternative, a quorum sensing model was developed that can explain the evolution of constant cell density profiles based on the effect of a not further characterized unstable or volatile messenger. r 2004 Elsevier Ltd. All rights reserved.

The recent progress in the areas of external cavity diode lasers, nonlinear optics and fiber amplification enable new optical sensors based on absorption spectroscopy in the UV range. Since transitions between electronic excited states are utilized, these sensors potentially offer higher sensitivity than comparable infra-red absorption sensors. Our work on OH and NO sensors is discussed.

The sexual theory of cell evolution has clear corollaries. All higher life would be initially sexual, and of two types (A- or Eu-karyotes). Relations would be dynamic with alternative unions and dissolution of the union of the two constituent moneric species, even as their viability as free-living species tended to decline in subsequent evolution. Superior bioenergetics meant eukaryotes were retained in multicellular species. However, some a-karyotes would be phylogenetically older than eukaryotes, a point which if verified, would render such biota of fundamental significance.

Three level systems driven by two coherent fields result in dark state (coherent population trapped) resonances. Such states are in many instances the basis for electromagnetically induced transparency (EIT) and lasing without inversion (LWI). Inhomogeneous broadening due to atomic motion in gases, or different effective masses for various levels in quantum wells presents a minor problem for Eit, but is more serious in the case of LWI. However, recent work involving four level systems driven by three coherent fields results in certain sharp features (interference between double-dark resonances) in the optical response. We here show that such double-dark states are interesting and potentially useful in mitigating the effects of inhomogeneous broadening in atomic and semiconductor quantum well systems.

One of the most challenging problems in physics is the detection and identification of the matter that appears to account for as much as 90% of the matter in the universe. A proposed new technique to search for this matter is discussed. The technique uses laser induced fluorescence to detect the ions produced in a gaseous detector.