# CERN Published Articles

2019-09-19
06:28
 Modern BigData technologies to store and access metadata for the ATLAS experiment / Barberis, D (Genua U. ; INFN, Genua) /ATLAS Structured data storage technologies evolve very rapidly in the IT world, driven by BigData projects. LHC experiments, and ATLAS in particular, select and use these technologies to store a wealth of metadata, balancing the performance for a given set of use cases with the availability, ease of use and of getting support, and stability of the product. [...] 2018 - 6 p. - Published in : Afr. Rev. Phys.: 13 (2018) , pp. 0009 External links: Fulltext; Fulltext In : The First Biennial African Conference on Fundamental Physics and Applications, Windhoek, Namibia, 28 Jun - 4 Jul 2018, pp.0009

2019-09-18
06:48
 Producing multi-coloured bunches through beam-induced ionization injection in plasma wakefield accelerator / Vafaei-Najafabadi, N (Stony Brook U.) ; Amorim, L D (Stony Brook U.) ; Adli, E (Oslo U.) ; An, W (UCLA) ; Clarke, C I (SLAC) ; Clayton, C E (UCLA) ; Corde, S (Palaiseau, Lab. Opt. Appl.) ; Gessner, S (CERN) ; Green, S Z (SLAC) ; Hogan, M J (SLAC) et al. This paper discusses the properties of electron beams formed in plasma wakefield accelerators through ionization injection. In particular, the potential for generating a beam composed of co-located multi-colour beamlets is demonstrated in the case where the ionization is initiated by the evolving charge field of the drive beam itself. [...] 2019 - Published in : Philos. Trans. R. Soc. Lond. A 377 (2019) 20180184 In : Directions in particle beam-driven plasma wakefield acceleration : Theo Murphy meeting, Newport Pagnell, Buckinghamshire, UK, 4 - 5 Jun 2019, pp.20180184

2019-09-18
06:48
 Betatron radiation and emittance growth in plasma wakefield accelerators / San Miguel Claveria, P (Palaiseau, Lab. Opt. Appl.) ; Adli, E (Oslo U.) ; Amorim, L D (Stony Brook U.) ; An, W (UCLA) ; Clayton, C E (UCLA) ; Corde, S (Palaiseau, Lab. Opt. Appl.) ; Gessner, S (CERN) ; Hogan, M J (SLAC) ; Joshi, C (UCLA) ; Kononenko, O (Palaiseau, Lab. Opt. Appl.) et al. Beam-driven plasma wakefield acceleration (PWFA) has demonstrated significant progress during the past two decades of research. The new Facility for Advanced Accelerator Experimental Tests (FACET) II, currently under construction, will provide 10 GeV electron beams with unprecedented parameters for the next generation of PWFA experiments. [...] 2019 - 9 p. - Published in : Philos. Trans. R. Soc. Lond. A 377 (2019) 20180173 Fulltext from publisher: PDF; In : Directions in particle beam-driven plasma wakefield acceleration : Theo Murphy meeting, Newport Pagnell, Buckinghamshire, UK, 4 - 5 Jun 2019, pp.20180173

2019-09-18
06:48
 Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section / COMPASS Collaboration We report on the first measurement of exclusive single-photon muoproduction on the proton by COMPASS using 160 GeV/$c$ polarised $\mu^+$ and $\mu^−$ beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average of the measured $\mu^+$ and $\mu^−$ cross sections for deeply virtual Compton scattering on the squared four-momentum transfer $t$ from the initial to the final proton. [...] 2019 - 7 p. - Published in : Phys. Lett. B 793 (2019) 188-194 Article from SCOAP3: PDF;

2019-09-18
06:48
 Experimental ion mobility measurements in Ne-CF$_4$ / Marques, D J G (LIP, Coimbra ; Coimbra U.) ; Cortez, A F V (LIP, Coimbra ; Coimbra U.) ; Escada, J (LIP, Coimbra ; Coimbra U.) ; Veenhof, R (CERN ; Moscow Phys. Eng. Inst. ; Uludag U.) ; Neves, P N B (Closer, Lisbon) ; Conde, C A N (LIP, Coimbra ; Coimbra U.) ; Santos, F P (LIP, Coimbra ; Coimbra U.) ; Borges, F I G M (Coimbra U. ; LIP, Coimbra) In this paper we present the results of the ion mobility measurements made in gaseous mixtures of neon with carbon tetrafluoride (Ne-CF$_4$) at a total pressure 8 Torr (10.6 mbar) and for low reduced electric fields in the 10 to 25 Td range (2.4–6.1 kV$\cdot$ cm$^{−1}\cdot$bar$^{−1}$), at room temperature. The time-of-arrival spectra revealed only one peak, which was attributed to CF$_3^+$. [...] 2019 - 9 p. - Published in : JINST 14 (2019) P04015 Fulltext from Publisher: PDF;

2019-09-18
06:48
 Experimental ion mobility measurements in pure iC$_4$H$_{10}$10 and Ar-iC$_4$H$_{10}$ mixtures / Cortez, A F V (Coimbra U. ; LIP, Coimbra) ; Santos, M A G (Coimbra U. ; LIP, Coimbra) ; Veenhof, R (CERN ; Moscow Phys. Eng. Inst. ; Uludag U.) ; Escada, J (LIP, Coimbra) ; Neves, P N B (Closer, Lisbon) ; Santos, F P (LIP, Coimbra ; Coimbra U.) ; Conde, C A N (LIP, Coimbra ; Coimbra U.) ; Borges, F I G M (LIP, Coimbra ; Coimbra U.) In this paper we present the results of the ion mobility measurements made in pure isobutane (iC$_4$H$_{10}$) and in mixtures with argon (Ar-iC$_4$H$_{10}$) for a total pressure of 8 Torr (10.6 mbar) and for low reduced electric fields in the 10 Td to 45 Td range (2.4–10.8 kV$\cdot$cm$^{−1}\cdot$bar$^{−1}$), at room temperature. The reduced mobilities, obtained from the peak centroid of the time-of-arrival spectra, are presented for Ar concentrations in the 5%–95% range.. 2019 - 13 p. - Published in : JINST 14 (2019) P04010 Fulltext from publisher: PDF;

2019-09-18
05:20
 Parametrized black hole quasinormal ringdown. II. Coupled equations and quadratic corrections for nonrotating black holes / McManus, Ryan (Johns Hopkins U.) ; Berti, Emanuele (Johns Hopkins U.) ; Macedo, Caio F.B. (Para U.) ; Kimura, Masashi (Rikkyo U.) ; Maselli, Andrea (Rome U. ; INFN, Rome) ; Cardoso, Vitor (Lisbon, CENTRA ; CERN) Linear perturbations of spherically symmetric spacetimes in general relativity are described by radial wave equations, with potentials that depend on the spin of the perturbing field. In previous work we studied the quasinormal mode spectrum of spacetimes for which the radial potentials are slightly modified from their general relativistic form, writing generic small modifications as a power-series expansion in the radial coordinate. [...] arXiv:1906.05155.- 2019-08-30 - 16 p. - Published in : Phys. Rev. D 100 (2019) 044061 Article from SCOAP3: PDF; Preprint: PDF;

2019-09-17
07:01
 Dynamic Response of Advanced Materials Impacted by Particle Beams: The MultiMat Experiment / Pasquali, M (CERN) ; Bertarelli, A (CERN) ; Accettura, C (CERN ; Milan Polytechnic) ; Berthome, E (CERN) ; Bianchi, L (CERN) ; Bolz, P (Darmstadt, GSI) ; Carra, F (CERN) ; Fichera, C (BIAM, St Paul lez Durance) ; Frankl, M I (CERN) ; Furness, T (Huddersfield U.) et al. The introduction at CERN of new extremely energetic particle accelerators, such as the high-luminosity large hadron collider (HL-LHC) or the proposed future circular collider (FCC), will increase the energy stored in the circulating particle beams by almost a factor of two (from 360 to 680 MJ) and of more than 20 (up to 8500 MJ), respectively. In this scenario, it is paramount to assess the dynamic thermomechanical response of materials presently used, or being developed for future use, in beam intercepting devices (such as collimators, targets, dumps, absorbers, spoilers, windows, etc.) exposed to potentially destructive events caused by the impact of energetic particle beams. [...] publ - 30 p. - Published in : Journal of Dynamic Behavior of Materials 5 (2019) 266-295 External link: Fulltext from publisher

2019-09-17
07:01
 Commissioning of a beam screen test bench experiment with a future circular hadron collider type synchrotron radiation beam / Gonzalez, L A (CERN ; Frascati) ; Gil-Costa, M (Madrid, CIEMAT ; CERN) ; Baglin, V (CERN) ; Chiggiato, P (CERN) ; Garion, C (CERN) ; Kersevan, R (CERN) ; Casalbuoni, S (KIT, Karlsruhe) ; Huttel, E (KIT, Karlsruhe) ; Bellafont, I (CELLS - ALBA, LLS) ; Perez, F (CELLS - ALBA, LLS) Coping with synchrotron radiation (SR) that originated at superconducting bending magnets is one of the major challenges in the design of the vacuum beam pipes of hadron colliders. In the case of the Future Circular hadron Collider (FCC-hh), similarly as for the LHC, a beam screen, operating at higher temperatures than the cold mass, has been designed in order to preserve the superconducting magnet cold bores from direct synchrotron irradiation. [...] 2019 - 12 p. - Published in : Phys. Rev. Accel. Beams 22 (2019) 083201 Fulltext from publisher: PDF;

2019-09-17
07:00
 Activation experiment at the CERN-EU high-energy Reference Field (CERF) facility to benchmark ActiWiz and FLUKA predictions: A comparison after 30 days of cooling time / Duchemin, Charlotte (CERN) ; Theis, Chris (CERN) ; Vincke, Helmut (CERN) An experiment was carried out in June 2018 at CERN in order to benchmark FLUKA and ActiWiz activation calculations with experimental data. A first set of samples made of Copper, Aluminium, Stainless Steel and Kovar with a well-known elemental composition was irradiated by the direct impact of a mixed hadron beam of the CERF facility with a momentum 120 GeV/c. [...] 2019 - 15 p. - Published in : Nucl. Instrum. Methods Phys. Res., A 937 (2019) 72-86