Protection and Diagnostic Systems for High Intensity Beams

This paper presents a summary of the facilities for beam interlocks and diagnostics to protect the CERN SPS machine. An overview of the existing systems is given, which are based on beam loss and beam current monitors and large beam position excursion in the horizontal plane. The later system mainly protects the system against a failure of the transverse damping system. The design for a new large excursion interlock for both transverse planes is also presented in some detail. For this system a digital approach is being taken to allow post-mortem analysis of the behaviour of the beam prior to the activation of the interlock

Application of different analytical methods for the determination of phenolics and antioxidant activity in hawthorn (Crataegus spp.) bud and sprout herbal extracts

Hawthorn (Crataegus spp., family: Rosaceae) extracts have been used as pharmaceutical preparations owing to positive effects on cardiovascular system. The AlCl3-based official method employed for the determination of pharmacologically active compounds was compared with other techniques such as Folin-Ciocalteau method and HPLC-DAD. Antioxidant activity was determined by ABTS radical cation assay. Methods were applied on extracts from buds and sprouts collected from common hawthorn (C. monogyna Jacq., C. laevigata (Poir.) DC.) located in Northeastern Italy. Phenolic content determined by AlCl3-based method, Folin-Ciocalteau method, and HPLC-DAD was in the range 23,534-27,728, 75,284-100,616 and 57,317-58,639 mg kg-1 of dry matter (DM), respectively, in buds, and 17,280-19,330, 27,653-38,590, and 30,635-32,185 mg kg-1 DM, respectively, in sprouts. Antioxidant activity ranged from 119,864 to 174,640 and 31,484 to 52,584 mg Trolox eq. kg-1 DM in buds and sprouts, respectively. Phenolic amount and profile were significantly affected by phenological stage and sampling location. Antioxidant activity was related to flavan-3-ol and hydroxycinnamic acid amount, and to non-phenolic substances. AlCl3-based method underestimated total phenolic content owing to lack of selectivity to important phenolic classes whereas Folin-Ciocalteau method was affected by non-phenolic interfering substances. HPLC-DAD proved to be more effective in determining hawthorn phenolics

Transverse Instabilities of the LHC Proton Beam in the SPS

The availability from the injectors of the proton beam required for the LHC era has allowed studying its transverse behaviour in the SPS. Profile and beam oscillation measurements evidenced the existence of strong transverse instabilities developing along the batch and inducing an emittance blow-up of increasing importance from the head to the tail of the batch. An intensity threshold, comparable to that observed for the development of the beam induced electron cloud, has been found for the onset of the above phenomena. The results of the measurements and their possible interpretation are presented

Crossing Over from Attractive to Repulsive Interactions in a Tunneling Bosonic Josephson Junction

We explore the interplay between tunneling and interatomic interactions in the dynamics of a bosonic Josephson junction. We tune the scattering length of an atomic $^{39}$K Bose-Einstein condensate confined in a double-well trap to investigate regimes inaccessible to other superconducting or superfluid systems. In the limit of small-amplitude oscillations, we study the transition from Rabi to plasma oscillations by crossing over from attractive to repulsive interatomic interactions. We observe a critical slowing down in the oscillation frequency by increasing the strength of an attractive interaction up to the point of a quantum phase transition. With sufficiently large initial oscillation amplitude and repulsive interactions the system enters the macroscopic quantum self-trapping regime, where we observe coherent undamped oscillations with a self-sustained average imbalance of the relative well population. The exquisite agreement between theory and experiments enables the observation of a broad range of many body coherent dynamical regimes driven by tunable tunneling energy, interactions and external forces, with applications spanning from atomtronics to quantum metrology.Comment: 10 pages, 8 figures, supplemental materials are include

Dynamical formation of quantum droplets in a K39 mixture

We report on the dynamical formation of self-bound quantum droplets in attractive mixtures of $^{39}$K atoms. Considering the experimental observations of Semeghini et al., Phys. Rev. Lett. 120, 235301 (2018), we perform numerical simulations to understand the relevant processes involved in the formation of a metastable droplet from an out-of-equilibrium mixture. We first analyze the so-called self-evaporation mechanism, where the droplet dissipates energy by releasing atoms, and then we consider the effects of losses due to three-body recombinations and to the balancing of populations in the mixture. We discuss the importance of these three mechanisms in the observed droplet dynamics and their implications for future experiments

Spatial Bloch oscillations of a quantum gas in a "beat-note" superlattice

We report the experimental realization of a new kind of optical lattice for ultra-cold atoms where arbitrarily large separation between the sites can be achieved without renouncing to the stability of ordinary lattices. Two collinear lasers, with slightly different commensurate wavelengths and retroreflected on a mirror, generate a superlattice potential with a periodic "beat-note" profile where the regions with large amplitude modulation provide the effective potential minima for the atoms. To prove the analogy with a standard large spacing optical lattice we study Bloch oscillations of a Bose Einstein condensate with negligible interactions in the presence of a small force. The observed dynamics between sites separated by ten microns for times exceeding one second proves the high stability of the potential. This novel lattice is the ideal candidate for the coherent manipulation of atomic samples at large spatial separations and might find direct application in atom-based technologies like trapped atom interferometers and quantum simulators.Comment: 5 pages, 4 figure

Practice patterns for acute ischemic stroke workup: A longitudinal population‐based study

Background We examined practice patterns of inpatient testing to identify stroke etiologies and treatable risk factors for acute ischemic stroke recurrence. Methods and Results We identified stroke cases and related diagnostic testing from four 1‐year study periods (July 1993 to June 1994, 1999, 2005, and 2010) of the Greater Cincinnati/Northern Kentucky Stroke Study. Patients aged ≥18 years were included. We focused on evaluation of extracranial arteries for carotid stenosis and assessment of atrial fibrillation because randomized controlled trials supported treatment of these conditions for stroke prevention across all 4 study periods. In each study period, we also recorded stroke etiology, as determined by diagnostic testing and physician adjudication. An increasing proportion of stroke patients received assessment of both extracranial arteries and the heart over time (50%, 58%, 74%, and 78% in the 1993–1994, 1999, 2005, and 2010 periods, respectively; P &lt;0.0001 for trend), with the most dramatic individual increases in echocardiography (57%, 63%, 77%, and 83%, respectively). Concurrently, we observed a decrease in strokes of unknown etiology (47%, 48%, 41%, and 38%, respectively; P &lt;0.0001 for trend). We also found a significant increase in strokes of other known causes (32%, 25%, 45% and 59%, respectively; P &lt;0.0001 for trend). Conclusions Stroke workup for treatable causes of stroke are being used more frequently over time, and this is associated with a decrease in cryptogenic strokes. Future study of whether better determination of treatable stroke etiologies translates to a decrease in stroke recurrence at the population level will be essential. </jats:sec