32 research outputs found
Analytic formulas for the rapid evaluation of the orbit response matrix and chromatic functions from lattice parameters in circular accelerators
Measurements and analysis of orbit response matrix have been providing for
decades a formidable tool in the detection of linear lattice imperfections and
their correction. Basically all storage- ring-based synchrotron light sources
across the world make routinely use of this technique in their daily operation,
reaching in some cases a correction of linear optics down to 1% beta beating
and 0.1% coupling. During the design phase of a new storage ring it is also
applied in simulations for the evaluation of magnetic and mechanical
tolerances. However, this technique is known for its intrinsic slowness
compared to other methods based on turn-by-turn beam position data, both in the
measurement and in the data analysis. In this paper analytic formulas are
derived and discussed that shall greatly speed up this second part. The
mathematical formalism based on the Lie algebra and the resonance driving terms
is extended to the off-momentum regime and explicit analytic formulas for the
evaluation of chromatic functions from lattice parameters are also derived. The
robustness of these formulas, which are linear in the magnet strengths, is
tested with different lattice configurations
Improving the precision of linear optics measurements based on turn-by-turn beam position monitor data after a pulsed excitation in lepton storage rings
Beam optics control is of critical importance for machine performance and protection. Nowadays, turn-by-turn (TbT) beam position monitor (BPM) data are increasingly exploited as they allow for fast and simultaneous measurement of various optics quantities. Nevertheless, so far the best documented uncertainty of measured ß -functions is of about 10‰ rms. In this paper we compare the ß -functions of the ESRF storage ring measured from two different TbT techniques—the N-BPM and the Amplitude methods—with the ones inferred from a measurement of the orbit response matrix (ORM). We show how to improve the precision of TbT techniques by refining the Fourier transform of TbT data with properly chosen excitation amplitude. The precision of the N-BPM method is further improved by refining the phase advance measurement. This represents a step forward compared to standard TbT measurements. First experimental results showing the precision of ß -functions pushed down to 4‰ both in TbT and ORM techniques are reported and commented.Postprint (published version
Serum miRNAs Expression and SNAP-25 Genotype in Alzheimer’s Disease
MicroRNAs (miRNAs) are small non-coding RNAs that control gene expression by binding their 3′ untranslated region (3′UTR) region; these molecules play a fundamental role in several pathologies, including Alzheimer’s disease (AD). Synaptosomal-associated protein of 25 kDa (SNAP-25) is a vesicular protein of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) involved in neural plasticity and in the exocytosis of neurotransmitters, processes that are altered in AD. Recent results showed that a reduction of SNAP-25 is associated with dementia, and that the rs363050 SNAP-25 polymorphism correlates with cognitive decline and brain atrophy, as well as with the outcome of multistructured rehabilitation in AD patients. We verified the presence of possible correlations between the serum concentration of miRNAs that bind the SNAP-25 3′UTR region and AD. Six different microRNAs (miR-181a-5p, miR-361-3p, miR-23a-3p, miR-15b-3p, 130a-3p and miR-27b-3p) that bind the SNAP-25 3′UTR region were measured by qPCR in serum of AD patients (n = 22), mild cognitive impairment (MCI) subjects (n = 22) and age- and sex-matched controls (n = 22); analysis of results was done stratified for the rs363050 SNAP-25 genotype. Results showed that miR-27b-3p, miR-23a-3p and miR181a-5p serum concentration was significantly reduced in rs363050 SNAP-25 GG homozygous AD patients. Notably, concentration of these miRNAs was comparable in rs363050 AA homozygous AD patients, MCI and healthy controls (HCs). Data herein suggest that miRNAs that bind the SNAP-25 3′UTR region interact with SNAP-25 polymorphisms to influence the neural plasticity typical of AD brains, possibly as a consequence of modulatory activity on SNAP-25 mRNA and/or protein
The resolved scaling relations in DustPedia: Zooming in on the local Universe
We perform a homogeneous analysis of an unprecedented set of spatially
resolved scaling relations (SRs) between ISM components and other properties in
the range of scales 0.3-3.4 kpc. We also study some ratios: dust-to-stellar,
dust-to-gas, and dust-to-metal. We use a sample of 18 large, spiral, face-on
DustPedia galaxies. All the SRs are moderate/strong correlations except the
dust-HI SR that does not exist or is weak for most galaxies. The SRs do not
have a universal form but each galaxy is characterized by distinct
correlations, affected by local processes and galaxy peculiarities. The SRs
hold starting from 0.3 kpc, and if a breaking down scale exists it is < 0.3
kpc. By evaluating all galaxies at 3.4 kpc, differences due to peculiarities of
individual galaxies are cancelled out and the corresponding SRs are consistent
with those of whole galaxies. By comparing subgalactic and global scales, the
most striking result emerges from the SRs involving ISM components: the
dust-total gas SR is a good correlation at all scales, while the dust-H2 and
dust-HI SRs are good correlations at subkpc/kpc and total scales, respectively.
For the other explored SRs, there is a good agreement between small and global
scales and this may support the picture where the main physical processes
regulating the properties and evolution of galaxies occur locally. Our results
are consistent with the hypothesis of self-regulation of the SF process. The
analysis of subgalactic ratios shows that they are consistent with those
derived for whole galaxies, from low to high z, supporting the idea that also
these ratios could be set by local processes. Our results highlight the
heterogeneity of galaxy properties and the importance of resolved studies on
local galaxies in the context of galaxy evolution. They also provide
observational constraints to theoretical models and updated references for
high-z studies.Comment: 42 pages, 11 figures and 5 tables in the main text, 2 figures and 1
table in Appendix. Accepted for publication in A&
Low emittance tuning for a high luminosity B-Factory (SuperB)
SuperB is an international project for an asymmetric 2 rings collider to be built in the Rome area in Italy. The two rings will have very small beam sizes at the Interaction Point and very small emittances, similar to the Linear Collider Damping Rings ones. In particular, the ultra low vertical emittances, 6 pm in the LER and 5 pm in the HER, need a careful study of the misalignment errors effects on the machine performances. Studies on the closed orbit, vertical dispersion and coupling corrections have been carried out in order to specify the maximum allowed errors and to provide a procedure for emittance tuning. A new tool which combines MADX and Matlab routines has been developed, allowing for both corrections and tuning. Results of these studies are presented
ESRF-EBS lattice model with canted beamlines
International audienceThe ESRF Extremely Brilliant Source (ESRF-EBS) lattice model is updated to include three canted beamlines. The cells are modified where necessary to include 3-Pole Wiggler (3PW), 2-Pole Wiggler (2PW) and Short Bending Magnet (SBM) sources. Several lattices are obtained for the different stages that will bring from commissioning to operation with users. A scheme for tune modification keeping key optics knobs unchanged is proposed
Study of double triple bend achromat (DTBA) lattice for a 3GeV light source
Starting from the concepts of the Hybrid Multi Bend Achromat (HMBA) lattice developed at ESRF and of the Double-Double Bend Achromat(DDBA) lattice developed at Diamond, we present a new cell tha tincludes all the advantages of the two designs. The resulting Double Triple Bend Achromat(DTBA) cel lallows for a natural horizontal emittance of less than 100pm with a large dynamic aperture and lifetime. It includes two straight sections, for insertion devices, five and three meters long. The lattice is consistent with the engineering design developed for the ESRF-EBS lattice and the layout and user requirements of Diamond. The characteristics of the cell are presented together with the results of the optimisation process
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Low Emittance Tuning Studies for SuperB
SuperB[1] is an international project for an asymmetric 2 rings collider at the B mesons cm energy to be built in the Rome area in Italy. The two rings will have very small beam sizes at the Interaction Point and very small emittances, similar to the Linear Collider Damping Rings ones. In particular, the ultra low vertical emittances, 7 pm in the LER and 4 pm in the HER, need a careful study of the misalignment errors effects on the machine performances. Studies on the closed orbit, vertical dispersion and coupling corrections have been carried out in order to specify the maximum allowed errors and to provide a procedure for emittance tuning. A new tool which combines MADX and Matlab routines has been developed, allowing for both corrections and tuning. Results of these studies are presented
New Advances in Dial-Lidar-Based Remote Sensing of the Volcanic CO2 Flux
We report here on the results of a proof-of-concept study aimed at remotely sensing the volcanic CO2 flux using a Differential Adsorption lidar (DIAL-lidar). The observations we report on were conducted in June 2014 on Stromboli volcano, where our lidar (LIght Detection And Ranging) was used to scan the volcanic plume at 3c3km distance from the summit vents. The obtained results prove that a remotely operating lidar can resolve a volcanic CO2 signal of a few tens of ppm (in excess to background air) over km-long optical paths. We combine these results with independent estimates of plume transport speed (from processing of UV Camera images) to derive volcanic CO2 flux time-series of 4816\u201333min temporal resolution. Our lidar-based CO2 fluxes range from 1.8 \ub1 0.5 to 32.1 \ub18.0kg/s, and constrain the daily averaged CO2 emissions fromStromboli at 8.3 \ub1 2.1 to 18.1 \ub1 4.5kg/s (or 718\u20131565 tons/day). These inferred fluxes fall within the range of earlier observations at Stromboli. They also agree well with contemporaneous CO2 flux determinations (8.4\u201320.1kg/s) obtained using a standard approach that combines Multi-GAS-based in-plume readings of the CO2 /SO2 ratio ( 488) with UV-camera sensed SO2 fluxes (1.5\u20133.4kg/s). We conclude that DIAL-lidars offer new prospects for safer (remote) instrumental observations of the volcanic CO2 flux
Preparation of the EBS Beam Commissioning
International audienceIn 2020 the ESRF storage ring will be upgraded to a Hybrid Multi Bend Achromat (HMBA) lattice. The commissioning of the new ring will require dedicated tools, either updated from the existing ones or newly developed. Most of the software and procedures were tested on the existing storage ring before its decommissioning. In particular we present experiments on first-turn steering and beam accumulation, check of magnet polarity and calibration, and injection tuning. The use of a control-system simulator proved to be crucial for the debugging of the software and the development of the new control system, as far as beam measurements and manipulations are concerned