<?xml version="1.0" encoding="UTF-8"?> <rss version="2.0" xmlns:media="http://search.yahoo.com/mrss/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/"> <channel> <title>CERN Document Server</title> <link>https://cds.cern.ch</link> <description>CERN Document Server latest documents</description> <language>en</language> <pubDate>Thu, 28 Nov 2024 21:52:51 GMT</pubDate> <category></category> <generator>Invenio 1.1.3.1106-62468</generator> <ttl>360</ttl> <atom:link rel="next" href="/rss?jrec=26&amp;f=author&amp;ln=ka&amp;p=Alves%2C+Diogo" /> <atom:link rel="self" href="/rss?f=author&amp;ln=ka&amp;p=Alves%2C+Diogo" /> <opensearch:totalResults>40</opensearch:totalResults> <opensearch:startIndex>1</opensearch:startIndex> <opensearch:itemsPerPage>25</opensearch:itemsPerPage> <image> <url>https://cds.cern.ch/img/site_logo_rss.png</url> <title>CERN Document Server</title> <link>https://cds.cern.ch</link> </image> <atom:link rel="search" href="https://cds.cern.ch/opensearchdescription" type="application/opensearchdescription+xml" title="Content Search" /> <textInput> <title>Search </title> <description>Search this site:</description> <name>p</name> <link>https://cds.cern.ch/search</link> </textInput> <item> <title>Impact of second-order chromaticity on the Schottky spectra of bunched beam</title> <link>https://cds.cern.ch/record/2913548</link> <description>Observation of Schottky signals provides information on important beam and machine parameters, such as transverse emittance, betatron tune, and first-order chromaticity. However, the so-far developed theory of Schottky spectra does not include the impact of the higher-order chromaticity, known to be non-negligible in the case of the Large Hadron Collider (LHC). In this contribution, we expand the theory of Schottky spectra to also take into account second-order chromaticity. Analytical results are compared with macro-particle simulations and the errors resulting from neglecting second-order chromaticity are assessed for the case of the LHC.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <pubDate>Tue, 15 Oct 2024 04:06:15 GMT</pubDate> <guid>https://cds.cern.ch/record/2913548</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2913548/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Impact of octupoles on the Schottky spectra of bunched beams</title> <link>https://cds.cern.ch/record/2912937</link> <description>Schottky monitors serve as non-invasive tools for beam diagnostics, providing insights into crucial bunch characteristics such as tune, chromaticity, bunch profile, or synchrotron frequency distribution. However, octupole magnets commonly used in circular storage rings to mitigate instabilities through the Landau damping mechanism, can significantly affect the Schottky spectrum. Due to the amplitude-dependent incoherent tune shift of individual particles, the satellites of the Schottky spectrum are smeared out as the octupolar field increases. This study investigates the impact of octupoles and their incorporation into theory, with the goal of improving beam and machine parameter evaluation from measured spectra. Theoretical findings are validated through macro-particle simulations conducted across a range of octupole strengths, encompassing typical operational conditions at the Large Hadron Collider.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pieloni, Tatiana</dc:creator> <pubDate>Wed, 09 Oct 2024 13:10:26 GMT</pubDate> <guid>https://cds.cern.ch/record/2912937</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2912937/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Improvement of the LHC orbit feedback testing framework</title> <link>https://cds.cern.ch/record/2912740</link> <description>During the Long Shutdown 2 (LS2 2019-2021) of the LHC, the orbit feedback correction software (OFB) of the LHC was redesigned to satisfy new requirements for LHC Run 3 (2022-2025) and to clean up legacy functionalities. The OFB is an essential component of LHC high intensity operation since the orbit must be stabilized to a fraction of the beam size during the entire LHC machine cycle. Redesigning such an essential and complex system during shutdowns requires thorough testing of the system functionality. The existing OFB testing system has been reviewed and improved based on the experience of LHC Run 2. An automatic, continuous integration tool has been put in place to validate future software developments before putting them in production. The solution for the OFB testing will be presented in this contribution.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Calia, Andrea</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Wenninger, Jorg</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Hostettler, Michi</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jackson, Stephen</dc:creator> <pubDate>Tue, 08 Oct 2024 05:55:17 GMT</pubDate> <guid>https://cds.cern.ch/record/2912740</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2912740/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Experimental and simulated LHC Schottky spectra</title> <link>https://cds.cern.ch/record/2912492</link> <description>Schottky monitors are valuable non-invasive tools used for beam diagnostics, providing insights into crucial bunch characteristics such as tune, chromaticity, bunch profile, or synchrotron frequency distribution. This study investigates Schottky spectra at the Large Hadron Collider (LHC) through a combination of simulations and measurements. Experimental data from lead ion bunches are compared with simulated spectra derived from time-domain, macro-particle simulations. In particular, amplitude detuning due to the octupole magnets, known to influence the Schottky spectra, is incorporated into the simulations. These simulations are performed for various octupoles currents with the goal of better understanding the interplay between octupoles and the Schottky spectrum. Finally, measured spectra are compared to simulations performed using the best available knowledge of the parameters impacting the spectra.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pieloni, Tatiana</dc:creator> <pubDate>Sun, 06 Oct 2024 04:48:16 GMT</pubDate> <guid>https://cds.cern.ch/record/2912492</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2912492/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Effect of Longitudinal Beam-Coupling Impedance on the Schottky Spectrum of Bunched Beams</title> <link>https://cds.cern.ch/record/2901255</link> <description>Schottky spectra can be strongly affected by collective effects, in particular those arising from beam-coupling impedance when a large number of bunch charges are involved. In such conditions, the direct interpretation of the measured spectra becomes difficult, which prevents the extraction of beam and machine parameters in the same way as is usually done for lower bunch charges. Since no theory is yet directly applicable to predict the impact of impedance on such spectra, we use here time-domain, macro-particle simulations and apply a semi-analytical method to compute the Schottky spectrum for various machine and beam conditions, such as the ones found at the Large Hadron Collider. A simple longitudinal resonator-like impedance model is introduced in the simulations and its effect studied in different configurations, allowing preliminary interpretations of the impact of longitudinal impedance on Schottky spectra.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pieloni, Tatiana</dc:creator> <pubDate>Tue, 18 Jun 2024 05:49:22 GMT</pubDate> <guid>https://cds.cern.ch/record/2901255</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2901255/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Studies on the Effect of Beam-Coupling Impedance on Schottky Spectra of Bunched Beams</title> <link>https://cds.cern.ch/record/2901252</link> <description>Schottky monitors can be used for non-invasive beam diagnostics to estimate various bunch characteristics, such as tune, chromaticity, bunch profile or synchrotron frequency distribution. However, collective effects, in particular beam-coupling impedance, can significantly affect Schottky spectra when large bunch charges are involved. In such conditions, the available interpretation methods are difficult to apply directly to the measured spectra, thus preventing the extraction of beam and machine parameters, which is possible for lower bunch charges. To study the impact of impedance on such spectra, we perform here time-domain, macro-particle simulations and apply a semi-analytical method to compute the Schottky signal for various machine and beam conditions, including those corresponding to typical physics operation at the Large Hadron Collider. This study provides preliminary interpretations of the impact of beam-coupling impedance on Schottky spectra by incorporating longitudinal and transverse resonator-like impedance models into the simulations.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pieloni, Tatiana</dc:creator> <pubDate>Tue, 18 Jun 2024 05:49:20 GMT</pubDate> <guid>https://cds.cern.ch/record/2901252</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2901252/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Analysis of the Transverse Schottky Signals in the LHC</title> <link>https://cds.cern.ch/record/2901244</link> <description>Schottky-based diagnostics are remarkably useful tools for the non-invasive monitoring of hadron beam and machine characteristics such as the betatron tune and the chromaticity. In this contribution recent developments in the analysis of the transverse Schottky signals measured at the Large Hadron Collider will be reported. A fitting-based technique, where the measured spectra are iteratively compared with theoretical predictions, will be presented and benchmarked with respect to the previously known methods and alternative diagnostic.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <pubDate>Tue, 18 Jun 2024 05:49:14 GMT</pubDate> <guid>https://cds.cern.ch/record/2901244</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2901244/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Statistical Properties of Schottky Spectra</title> <link>https://cds.cern.ch/record/2901223</link> <description>Schottky signals are used for non-invasive beam diagnostics as they contain information on various beam and machine parameters. The instantaneous Schottky signal is, however, only a single realisation of a random process, implicitly depending on the discrete distribution of synchrotron and betatron amplitudes and phases among the particles. To estimate the expected value of the Schottky power spectrum, and reveal the inner structure of the Bessel satellites described by the theory, the averaging of instantaneous Schottky spectra is required. This study describes this procedure quantitatively by analysing the statistical properties of the Schottky signals, including the expected value and variance of Schottky power spectra. Furthermore, we investigate how these quantities evolve with the number of particles in the bunch, the observed harmonic of the revolution frequency, the distribution of synchrotron oscillation amplitudes, and the bunch profile. The theoretical findings are compared against macro-particle simulations as well as Monte Carlo computations.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pieloni, Tatiana</dc:creator> <pubDate>Tue, 18 Jun 2024 05:48:55 GMT</pubDate> <guid>https://cds.cern.ch/record/2901223</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2901223/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>A Snapshot of CERN Beam Instrumentation R&amp;D; Activities</title> <link>https://cds.cern.ch/record/2901217</link> <description>The CERN accelerator complex stands out as an unique scientific tool, distinguished by its scale and remarkable diversity. Its capacity to explore a vast range of beam parameters is truly unparalleled, spanning from the minute energies of around a few keV and microampere antiproton beams, decelerated within the CERN antimatter factory, to the 6.8 TeV high-intensity proton beams that race through the Large Hadron Collider (LHC). The Super Proton Synchrotron (SPS) ring plays also a crucial role by slowly extracting protons at 400 GeV. These proton currents are then directed toward various targets, generating all sorts of secondary particle beams. These beams, in turn, become the foundation of a diverse fixed-target research program, enabling scientific exploration across a wide spectrum. Moreover, as CERN looks ahead to future studies involving electron-positron colliders, the development of cutting-edge diagnostics for low emittance, short electron pulses is also underway. This contribution serves as a snapshot, shedding light on the main R&amp;D; initiatives currently underway at CERN in the field of beam instrumentation.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lefèvre, Thibaut</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Boccardi, Andrea</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jackson, Stephen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Roncarolo, Federico</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Storey, James</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Veness, Raymond</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Zamantzas, Christos</dc:creator> <pubDate>Tue, 18 Jun 2024 05:48:52 GMT</pubDate> <guid>https://cds.cern.ch/record/2901217</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2901217/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Extraction of LHC Beam Parameters from Schottky Signals</title> <link>https://cds.cern.ch/record/2900915</link> <description>Analysis of Schottky signals provides rich insights into the dynamics of a hadron beam, with well-established methods of deriving the betatron tune and machine chromaticity. In this contribution, we will report on recent developments in the analysis and understanding of the signals measured at the Large Hadron Collider during proton and Pb⁸²⁺ fills. A fitting-based technique, where the measured spectra are iteratively compared with theoretical predictions, will be presented and compared with the previous methods. As a step beyond the classical theory of Schottky spectra, certain signal modifications due to the activity of the LHC machine systems will be discussed from the perspective of the applicability of the modified signal to the beam diagnostics.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pieloni, Tatiana</dc:creator> <pubDate>Sat, 15 Jun 2024 09:07:59 GMT</pubDate> <guid>https://cds.cern.ch/record/2900915</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2900915/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Beam Instrumentation Simulation in Python</title> <link>https://cds.cern.ch/record/2895249</link> <description>The design of acquisition electronics for particle accelerator systems relies on simulations in various domains. System level simulation frameworks can integrate the results of specific tools with analytical models and stochastic analysis. This allows the designer to estimate the performance of different architectures, compare the results, and ultimately optimize the design. These simulation frameworks are often made of custom scripts for specific designs, which are hard to share or reuse. Adopting a standard interface for modular components can address these issues. Also, providing a graphical interface where these components can be easily configured, connected and the results visualised, eases the creation of simulations. This paper identifies which characteristics ISPy (Instrumentation Simulation in Python) should fulfill as a simulation framework. It subsequently proposes a standard format for signal-processing simulation modules. Existing environments which allow script integration and an intuitive graphical interface have then been evaluated and the KNIME Analytics Platform was the proposed solution. Additionally, the need to handle parameter sweeps for any parameter of the simulation, and the need for a bespoke visualisation tool will be discussed. Python has been chosen for all of these developments due to its flexibility and its wide adoption in the scientific community. The ensuing performance of the tool will also be discussed.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Gonzalez-Berges, Manuel</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Boccardi, Andrea</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Chariton, Vasileios</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Degl'Innocenti, Irene</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jackson, Stephen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Martínez Samblas, Javier</dc:creator> <pubDate>Fri, 12 Apr 2024 04:14:19 GMT</pubDate> <guid>https://cds.cern.ch/record/2895249</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2895249/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>LHC Schottky Spectrum from Macro-Particle Simulations</title> <link>https://cds.cern.ch/record/2852557</link> <description>We introduce a method for building Schottky spectra from macro-particle simulations performed with the PyHEADTAIL code, applied to LHC beam conditions. In this case, the use of a standard Fast Fourier Transform (FFT) algorithm to recover the spectral content of the beam becomes computationally intractable memory-wise, because of the relatively short bunch length compared to the large revolution period. This would imply having to handle an extremely large amount of data for performing the FFT. To circumvent this difficulty, a semi-analytical method was developed to compute efficiently the Fourier transform. The spectral content of the beam is calculated on the fly along with the macro-particle simulation and stored in a compact manner, independently from the number of particles, thus allowing the processing of one million macro-particles in the LHC, over 10’000 revolutions, in a few hours, on a regular computer. The simulated Schottky spectrum is then compared against theoretical formulas and measurements of Schottky signals previously obtained with lead ion beams in the LHC.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lannoy, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pieloni, Tatiana</dc:creator> <pubDate>Thu, 16 Mar 2023 05:37:44 GMT</pubDate> <guid>https://cds.cern.ch/record/2852557</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2852557/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Beam Intensity Measurement in ELENA Using Ring Pick-Ups</title> <link>https://cds.cern.ch/record/2852556</link> <description>A bunched beam intensity measurement system for the CERN Extra Low ENergy Antiproton (ELENA) ring, using a cylindrical shoe-box electrostatic pick-up from the existing orbit system [1], is presented. The system has been developed to measure very challenging beam cur-rents, as low as 200nA corresponding to intensities of the order of 10$^7$ antiprotons circulating with a relativistic beta of the order of 10$^{-2}$. In this work we derive and show that the turn-by-turn beam intensity is proportional to the baseline of the sum signal and that, despite the AC-coupling of the system, the installed front-end electronics, based on a charge amplifier, not only guarantees the preservation of the bunch shape (up to a few tens of MHz), but also allows for an absolute calibration of the system. In addition, the linearity of the intensity measurements and their inde-pendence with respect to average beam position is evalu-ated using a standard electromagnetic simulation tool. Finally, experimental measurements throughout typical antiproton deceleration cycles are presented and their accuracy and precision are discussed.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Marqversen, Ole</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <pubDate>Thu, 16 Mar 2023 05:37:43 GMT</pubDate> <guid>https://cds.cern.ch/record/2852556</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2852556/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Linac3, LEIR and PS Performance with Ions in 2021 and Prospects for 2022</title> <link>https://cds.cern.ch/record/2845804</link> <description>CERN accelerators underwent a period of long shutdown from the end of 2018 to 2020. During this time frame, significant hardware and software upgrades have been put in place to increase the performance of both proton and ion accelerator chains in the High Luminosity LHC era. In the context of the CERN lead ion chain, 2021 has been mainly devoted to restore the injectors’ performance and to successfully prove the slip-stacking technique in SPS. In this paper we summarise the key milestones of the ion beam commissioning and the achieved beam performance for the Linac 3 (including the source), LEIR and PS accelerators, together with an outlook on 2022 operation.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Biancacci, Nicolo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Albright, Simon</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alemany-Fernández, Reyes</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Angoletta, Maria Elena</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Barrientos, Diego</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bartosik, Hannes</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bellodi, Giulia</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bertolo, Sebastien</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bodart, Dominique</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bozzolan, Michele</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Damerau, Heiko</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Di Lorenzo, Francesco</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Frassier, Alexandre</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Gamba, Davide</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Huschauer, Alexander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jensen, Steen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Kain, Verena</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Koevener, Toke</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Kotzian, Gerd</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Küchler, Detlef</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lasheen, Alexandre</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Le Godec, Gilles</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Levens, Thomas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Madysa, Nico</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mahner, Edgar</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Marqversen, Ole</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mastrostefano, Cristiano</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Meruga, Phani Deep</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mutin, Christophe</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">O'Neil, Michael</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Piccinini, Giampaolo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Scrivens, Richard</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Solvang, Preben</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Valuch, Daniel</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Velotti, Francesco</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Wegner, Rolf</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Wetton, Chris</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Zampetakis, Michail</dc:creator> <pubDate>Wed, 11 Jan 2023 05:08:46 GMT</pubDate> <guid>https://cds.cern.ch/record/2845804</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2845804/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Application of reinforcement learning in the LHC tune feedback</title> <link>https://cds.cern.ch/record/2836033</link> <description>The Beam-Based Feedback System (BBFS) was primarily responsible for correcting the beam energy, orbit and tune in the CERN Large Hadron Collider (LHC). A major code renovation of the BBFS was planned and carried out during the LHC Long Shutdown 2 (LS2). This work consists of an explorative study to solve a beam-based control problem, the tune feedback (QFB), utilising state-of-the-art Reinforcement Learning (RL). A simulation environment was created to mimic the operation of the QFB. A series of RL agents were trained, and the best-performing agents were 9 then subjected to a set of well-designed tests. The original feedback controller used in the QFB was reimplemented to compare the performance of the classical approach to the performance of selected RL agents in the test scenarios. Results from the simulated environment show that the RL agent performance can exceed the controller-based paradigm.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Grech, Leander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Valentino, Gianluca</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Hirlaender, Simon</dc:creator> <pubDate>Fri, 07 Oct 2022 04:02:18 GMT</pubDate> <guid>https://cds.cern.ch/record/2836033</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2836033/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Estimation of transverse bunch characteristics in the LHC using Schottky-based diagnostics</title> <link>https://cds.cern.ch/record/2812541</link> <description>In this paper, we discuss different approaches for the estimation of transverse bunch characteristics, namely, tune and chromaticity, using Schottky-based diagnostics. In particular, we show how, depending on the signal quality and the availability of other instruments or information sources, we can choose appropriate strategies combining both spectrum fitting procedures and explicit parameter calculations. In addition, we revisit and formally derive the expression that relates the chromaticity with the width of the Schottky spectral sidebands, discussing the rigorous meaning of this width and in which conditions it can be applied. Results obtained using the proposed approaches are compared with the standard techniques for different fills in the LHC.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <pubDate>Fri, 17 Jun 2022 06:03:44 GMT</pubDate> <guid>https://cds.cern.ch/record/2812541</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2812541/files/PhysRevAccelBeams.25.062801.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Renovation of the Beam-Based Feedback Controller in the LHC</title> <link>https://cds.cern.ch/record/2809486</link> <description>This work presents an extensive overview of the design choices and implementation of the Beam-Based Feedback System (BBFS) used in operation until the LHC Run 2. The main limitations of the BBFS are listed and a new design called BFCLHC, which uses the CERN Front-End Software Architecture (FESA), framework is proposed. The main implementation details and new features which improve upon the usability of the new design are then emphasised. Finally, a hardware agnostic testing framework developed by the LHC operations section is introduced.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Grech, Leander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Calia, Andrea</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Hostettler, Michael</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jackson, Stephen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Valentino, Gianluca</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Wenninger, Jorg</dc:creator> <pubDate>Fri, 13 May 2022 23:01:16 GMT</pubDate> <guid>https://cds.cern.ch/record/2809486</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2809486/files/document.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>An Off-Momentum Beam Loss Feedback Controller and Graphical User Interface for the LHC</title> <link>https://cds.cern.ch/record/2778517</link> <description>During LHC operation, a campaign to validate the configuration of the LHC collimation system is conducted every few months. This is performed by means of loss maps, where specific beam losses are deliberately generated with the resulting loss patterns compared to expectations. The LHC collimators have to protect the machine from both betatron and off-momentum losses. In order to validate the off-momentum protection, beam losses are generated by shifting the RF frequency using a low intensity beam. This is a delicate process that, in the past, often led to the beam being dumped due to excessive losses. To avoid this, a feedback system based on the 100 Hz data stream from the LHC Beam Loss system has been implemented. When given a target RF frequency, the feedback system approaches this frequency in steps while monitoring the losses until the selected loss pattern conditions are reached, so avoiding the excessive losses that lead to a beam dump. This paper will describe the LHC off-momentum beam loss feedback system and the results achieved.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Salvachua, Belen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Azzopardi, Gabriella</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jackson, Stephen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mirarchi, Daniele</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Pojer, Mirko</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Valentino, Gianluca</dc:creator> <pubDate>Sat, 14 Aug 2021 04:58:17 GMT</pubDate> <guid>https://cds.cern.ch/record/2778517</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2778517/files/10.18429_JACoW-ICALEPCS2019-MOPHA064.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Kalman filter-based longitudinal phase-space reconstruction method for hadron machines</title> <link>https://cds.cern.ch/record/2776597</link> <description>This work proposes a novel longitudinal phase-space reconstruction method for hadron machines. The proposed method is based on a Kalman filter and can therefore provide real-time estimates of the phase-space reconstruction. The main input for the method is real-time measurements of the longitudinal bunch profile. Beam conditions in the LHC are used throughout this work as examples of the applicability and practical implementation of such a method. Longitudinal phase-space reconstructions obtained with the proposed method are compared with a tomographic-based technique using experimentally logged data from the LHC wall current monitors.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lasocha, Kacper</dc:creator> <pubDate>Thu, 22 Jul 2021 15:44:31 GMT</pubDate> <guid>https://cds.cern.ch/record/2776597</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2776597/files/PhysRevAccelBeams.24.072801.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>An Alternative Processing Algorithm for the Tune Measurement System in the LHC</title> <link>https://cds.cern.ch/record/2772585</link> <description>The betatron tune in the Large Hadron Collider (LHC) is measured using a Base-Band-Tune (BBQ) system. Processing of these BBQ signals is often perturbed by 50Hz noise harmonics present in the beam. This causes the tune measurement algorithm, currently based on peak detection, to provide incorrect tune estimates during the acceleration cycle with values that clearly oscillate between neighbouring harmonics. The LHC tune feedback cannot be used to its full extent in these conditions as it relies on stable and reliable tune estimates. In this work we present two alternative tune measurement algorithms, designed to mitigate this problem by ignoring small frequency bands around the 50Hz harmonics and estimating the tune from spectra with gaps. One is based on Gaussian Processes and the other is based on a weighted moving average. We compare the tune estimates of the new and present algorithms and put forward a proposal that can be implemented during the renovation of the BBQ system for the next physics run of the LHC.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Grech, Leander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Gąsior, Marek</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jackson, Stephen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jones, Owain Rhodri</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Levens, Thomas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Valentino, Gianluca</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Wenninger, Jorg</dc:creator> <pubDate>Sat, 12 Jun 2021 04:33:15 GMT</pubDate> <guid>https://cds.cern.ch/record/2772585</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2772585/files/10.18429_JACoW-IBIC2020-WEPP27.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Feasibility of Hardware Acceleration in the LHC Orbit Feedback Controller</title> <link>https://cds.cern.ch/record/2772240</link> <description>Orbit correction in accelerators typically make use of a linear model of the machine, called the Response Matrix (RM), that relates local beam deflections to position changes. The RM is used to obtain a Pseudo-Inverse (PI), which is used in a feedback configuration, where positional errors from the reference orbit as measured by Beam Position Monitors (BPMs) are used to calculate the required change in the current flowing through the Closed Orbit Dipoles (CODs). The calculation of the PIs from the RMs is a crucial part in the LHC’s Orbit Feedback Controller (OFC), however in the present implementation of the OFC this calculation is omitted as it takes too much time to calculate and thus is unsuitable in a real-time system. As a temporary solution the LHC operators pre-calculate the new PIs outside the OFC, and then manually upload them to the OFC in advance. In this paper we aim to find a solution to this computational bottleneck through hardware acceleration in order to act automatically and as quickly as possible to COD and/or BPM failures by re-calculating the PIs within the OFC. These results will eventually be used in the renovation of the OFC for the LHC’s Run 3.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Grech, Leander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jackson, Stephen</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Valentino, Gianluca</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Wenninger, Jorg</dc:creator> <pubDate>Thu, 10 Jun 2021 04:08:55 GMT</pubDate> <guid>https://cds.cern.ch/record/2772240</guid> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>A Machine Learning Approach for the Tune Estimation in the LHC</title> <link>https://cds.cern.ch/record/2767777</link> <description>The betatron tune in the Large Hadron Collider (LHC) is measured using a Base-Band Tune (BBQ) system. The processing of these BBQ signals is often perturbed by 50 Hz noise harmonics present in the beam. This causes the tune measurement algorithm, currently based on peak detection, to provide incorrect tune estimates during the acceleration cycle with values that oscillate between neighbouring harmonics. The LHC tune feedback (QFB) cannot be used to its full extent in these conditions as it relies on stable and reliable tune estimates. In this work, we propose new tune estimation algorithms, designed to mitigate this problem through different techniques. As ground-truth of the real tune measurement does not exist, we developed a surrogate model, which allowed us to perform a comparative analysis of a simple weighted moving average, Gaussian Processes and different deep learning techniques. The simulated dataset used to train the deep models was also improved using a variant of Generative Adversarial Networks (GANs) called SimGAN. In addition, we demonstrate how these methods perform with respect to the present tune estimation algorithm.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Grech, Leander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Valentino, Gianluca</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <pubDate>Thu, 27 May 2021 04:27:09 GMT</pubDate> <guid>https://cds.cern.ch/record/2767777</guid> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2767777/files/10.3390_info12050197.pdf"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Analysis of Quadrupolar Measurements for Beam Size Determination in the LHC</title> <link>https://cds.cern.ch/record/2750970</link> <description>Due to limitations with non-invasive beam size diagnostics in the LHC, particularly during the energy ramp, there has been an interest to explore quadrupolar-based measurements for estimating the transverse beam size, and hence determining the transverse emittance. This technique is especially attractive as it is completely passive and can use the existing beam position instrumentation. In this work, we perform an analysis of this method and present recent measurements taken during energy ramps. Quadrupolar-based measurements are compared with wire-scanner measurements and a calibration strategy is proposed to overcome present limitations.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Gąsior, Marek</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lefèvre, Thibaut</dc:creator> <pubDate>Wed, 03 Feb 2021 05:03:47 GMT</pubDate> <guid>https://cds.cern.ch/record/2750970</guid> <media:thumbnail xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750970/files/Fulltext.gif?subformat=icon"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750970/files/Fulltext.pdf"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750970/files/Fulltext.jpg?subformat=icon-700"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750970/files/Fulltext.jpg?subformat=icon-180"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Cherenkov Diffraction Radiation as a tool for beam diagnostics</title> <link>https://cds.cern.ch/record/2750968</link> <description>During the last three years, the emission of Cherenkov Diffraction Radiation (ChDR), appearing when a relativistic charged particle moves in the vicinity of a dielectric medium, has been investigated with the aim of providing non-invasive beam diagnostics. ChDR has very interesting properties, with a large number of photons emitted in a narrow and well-defined solid angle, providing excellent conditions for detection with very little background. This contribution will present a collection of recent beam measurements performed at several facilities such as the Cornell Electron Storage Ring, the Advanced Test Facility 2 at KEK, the Diamond light source in the UK and the CLEAR test facility at CERN. Those results, complemented with simulations, suggest that the use of both incoherent and coherent emission of Cherenkov diffraction radiation could open up new beam instrumentation possibilities for relativistic charged particle beams.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lefèvre, Thibaut</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Apollonio, Marco</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Aryshev, Alexander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bergamaschi, Michele</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Billing, Michael</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bleko, Vitol'd</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bobb, Lorraine</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Bordlemay Padilla, Yadira</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Conway, Joseph</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Curcio, Alessandro</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Fedorov, Kirill</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Gardelle, Jacques</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Gogolev, Sergey</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Harryman, Daniel</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Jones, Owain Rhodri</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Karataev, Pavel</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Kieffer, Robert</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Konkov, Anatoly</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Lekomtsev, Konstantin</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Markova, Julia</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mazzoni, Stefano</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Mounet, Nicolas</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Potylitsyn, Alexander</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Schlogelhofer, Anders</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Senes, Eugenio</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Shanks, James</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Shkitov, Dmitry</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Terunuma, Nobuhiro</dc:creator> <pubDate>Wed, 03 Feb 2021 05:03:47 GMT</pubDate> <guid>https://cds.cern.ch/record/2750968</guid> <media:thumbnail xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750968/files/Fulltext.gif?subformat=icon"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750968/files/Fulltext.pdf"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750968/files/Fulltext.jpg?subformat=icon-700"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750968/files/Fulltext.jpg?subformat=icon-180"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> <item> <title>Estimation of Longitudinal Profiles of Ion Bunches in the LHC Using Schottky-Based Diagnostics</title> <link>https://cds.cern.ch/record/2750958</link> <description>The Large Hadron Collider (LHC) Schottky monitors have been designed to measure various parameters of relevance to beam quality, namely tune, momentum spread and chromaticity. We present another application of this instrument - the evaluation of longitudinal bunch profiles. The relation between the distribution of synchrotron amplitudes within the bunch population and the longitudinal bunch profile is derived from probabilistic principles. Our approach, limited to bunched beams with no intra-bunch coherent motion, initially fits the cumulative power spectral density of acquired Schottky spectra with the underlying distribution of synchrotron amplitudes. The result of this fit is then used to reconstruct the bunch profile using the derived model. The results obtained are verified by a comparison with measurements from the LHC Wall Current Monitors.</description> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Łasocha, Kacper</dc:creator> <dc:creator xmlns:dc="http://purl.org/dc/elements/1.1/">Alves, Diogo</dc:creator> <pubDate>Wed, 03 Feb 2021 05:03:46 GMT</pubDate> <guid>https://cds.cern.ch/record/2750958</guid> <media:thumbnail xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750958/files/Fulltext.gif?subformat=icon"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750958/files/Fulltext.pdf"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750958/files/Fulltext.jpg?subformat=icon-700"/> <media:content xmlns:media="http://search.yahoo.com/mrss/" url="https://cds.cern.ch/record/2750958/files/Fulltext.jpg?subformat=icon-180"/> <dc:title xmlns:dc="http://purl.org/dc/elements/1.1/" xml:lang="fr"/> <dc:hasPart xmlns:dc="http://purl.org/dc/elements/1.1/">['']</dc:hasPart> <dc:hasVersion xmlns:dc="http://purl.org/dc/elements/1.1/"/> </item> </channel> </rss>