0000000000004498
AUTHOR
Matthias Lochmann
Laser spectroscopy of the ground-state hyperfine structure in H-like and Li-like bismuth
The LIBELLE experiment performed at the experimental storage ring (ESR) at the GSI Helmholtz Center in Darmstadt aims for the determination of the ground state hyperfine (HFS) transitions and lifetimes in hydrogen-like (209Bi82+) and lithium-like (209Bi80+) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. While the HFS transition in H-like bismuth was already observed in earlier experiments at the ESR, the LIBELLE experiment succeeded for the first time to measure the HFS transition in Li-like bismuth in a laser spectroscopy experiment.
Prognostic Factors Determining Long-Term Survival in Well-Differentiated Thyroid Cancer: An Analysis of Four Hundred Eighty-Four Patients Undergoing Therapy and Aftercare at the Same Institution
Identification of the prognostic factors relevant for long-term survival in differentiated thyroid cancer in a homogenously treated patient cohort in order to allow a better initial risk stratification.Four hundred eighty-four (358 females/126 males) patients with differentiated thyroid cancer (330 papillary [68.2%]; 154 follicular [31.8%]) were included. Inclusion criteria consisted of treatment with a uniform therapy scheme and continuous aftercare in the same institution. Initial diagnosis was between 1975-1995 (age at diagnosis, 14-84 years, median, 49.7). Tumor stage: pT1, n = 92; pT2, 211; pT3, 58; pT4, 123. Low-risk:or=pT3 NX M0, 331; high-risk pT4 and/or M1, 153. After thyroidectomy…
Lifetimes and g-factors of the HFS states in H-like and Li-like bismuth
The LIBELLE experiment performed at the experimental storage ring (ESR) at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, has successfully determined the ground state hyperfine (HFS) splittings in hydrogen-like ($^{209}\rm{Bi}^{82+}$) and lithium-like ($^{209}\rm{Bi}^{80+}$) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. Besides the transition wavelengths the time resolved detection of fluorescence photons following the excitation of the ions by a pulsed laser system also allows to extract lifetimes of the upper HFS levels and g-fac…
An improved value for the hyperfine splitting of hydrogen-like209Bi82+
We report an improved measurement of the hyperfine splitting in hydrogen-like bismuth (209Bi82+) at the experimental storage ring ESR at GSI by laser spectroscopy on a coasting beam. Accuracy was improved by about an order of magnitude compared to the first observation in 1994. The most important improvement is an in situ high voltage measurement at the electron cooler (EC) platform with an accuracy at the 10 ppm level. Furthermore, the space charge effect of the EC current on the ion velocity was determined with two independent techniques that provided consistent results. The result of nm provides an important reference value for experiments testing bound-state quantum electrodynamics in t…
Hyperfine transition in209Bi80+—one step forward
The hyperfine transitions in lithium-like and hydrogen-like bismuth were remeasured by direct laser spectroscopy at the experimental storage ring. For this we have now employed a voltage divider which enabled us to monitor the electron cooler voltage in situ. This will improve the experimental accuracy by about one order of magnitude with respect to our previous measurement using the same technique.
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…
Isotope shift measurements in the 2s1/2→ 2p3/2transition of Be+and extraction of the nuclear charge radii for7, 10, 11Be
International audience; shift measurements in the 2s 1/2 → 2p 3/2 transition of Be + and extraction of the nuclear charge radii for 7, 10, 11 Be Abstract. We have performed isotope shift measurements in the 2s 1/2 → 2p 3/2 transition of Be + ions using advanced collinear laser spectroscopy with two counterpropagating laser beams. Measurements involving a frequency comb for laser stabilization and absolute frequency determination allowed us to determine the isotope shifts with an accuracy of 2 MHz. From the isotope shifts between 9 Be and 7, 10, 11 Be, high-accuracy mass shift calculations and the charge radius of the reference isotope 9 Be we determined nuclear charge radii for the isotopes…
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.
Acute Alcohol Effects on Neuronal and Attentional Processing: Striatal Reward System and Inhibitory Sensory Interactions under Acute Ethanol Challenge
The acute influence of ethanol on cerebral activity induces complex psycho-physiological effects that are considerably more pronounced during acute ethanol influx than during maximal blood alcohol concentration (elimination phase). Despite the psychiatric and forensic relevance of these different ethanol effects, the underlying neuronal mechanisms are still unclear. In total, 20 male healthy volunteers were investigated each with three different experimental conditions in a randomized order using an intravenous ethanol challenge (40 g bolus infusion): during influx phase, elimination phase, and under placebo condition. During and after the ethanol (or placebo) infusion, neuropsychological t…
High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED
Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209Bi82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron–nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209Bi82+,80+ with a precision that is improve…
Corrigendum to “The thalamus as the generator and modulator of EEG alpha rhythm: A combined PET/EEG study with lorazepam challenge in humans” [NeuroImage 22 (2004) 637–644]
Department of Psychiatry, Johannes Gutenberg–University Mainz, 55131 Mainz, GermanyAvailable online 2 May 20061053-8119/$ - see front matter D 2006 Elsevier Inc. All rights reserved.doi:10.1016/j.neuroimage.2006.03.007DOI of original article:10.1016/j.neuroimage.2004.01.047.* Corresponding author. Department of Nuclear Medicine, Johannes Gutenberg–University Mainz, Langenbeckstr. 1, 55131 Mainz, Germany. Fax: +496131 17 2448.E-mail address: schreckenberger@nuklear.klinik.uni-mainz.de (M. Schreckenberger).Available online on ScienceDirect (www.sciencedirect.com).
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…
Metabolic changes in vestibular and visual cortices in acute vestibular neuritis
Five right-handed patients with a right-sided vestibular neuritis were examined twice with fluorodeoxyglucose positron emission tomography while lying supine with eyes closed: once during the acute stage (mean, 6.6 days) and then 3 months later when central vestibular compensation had occurred. Regional cerebral glucose metabolism (rCGM) was significantly increased (p <0.001 uncorrected) during the acute stage in multisensory vestibular cortical and subcortical areas (parietoinsular vestibular cortex in the posterior insula, posterolateral thalamus, anterior cingulate gyrus [Brodmann area 32/24], pontomesencephalic brainstem, hippocampus). Simultaneously, there was a significant rCGM decrea…