CERN Accelerating science

CERN Yellow Report Articles

See also CERN Yellow Reports collection
Nyeste elementer:
2021-02-23
06:23
Status of negative momentum compaction operation at KARA / Schreiber, P (KIT, Karlsruhe) ; Boltz, T (KIT, Karlsruhe) ; Brosi, M (KIT, Karlsruhe) ; Haerer, B (KIT, Karlsruhe) ; Mochihashi, A (KIT, Karlsruhe) ; Papash, A I (KIT, Karlsruhe) ; Schuh, M (KIT, Karlsruhe) ; Müller, A -S (KIT, Karlsruhe)
For future synchrotron light sources different operation modes are of interest. Therefore various modes are currently being tested at the Karlsruhe Research Accelerator (KARA) including optics for a negative momentum compaction factor. [...]
2020 - 3 p. - Published in : 10.23732/CYRCP-2020-009.297 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.297-299 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Incoherent electron cloud effects in the Large Hadron Collider / Paraschou, K (CERN ; Aristotle U., Thessaloniki) ; Iadarola, G (CERN)
During the operation of the Large Hadron Collider in 2018, the majority of physics data was collected with a beam energy of 6.5 TeV, a bunch spacing of 25 ns and with β-functions in the high luminosity interaction points equal to 30 cm. In this configuration, it was found through several experimental measurements that electron cloud induces a significant degradation of the beam lifetime. [...]
2020 - 7 p. - Published in : 10.23732/CYRCP-2020-009.249 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.249-255 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Mitigation of the impedance-related collective effects in FCC-ee / Zobov, Mikhail (Frascati) ; Belli, E (CERN) ; Kersevan, Roberto (CERN) ; Novokhatski, A (SLAC) ; Zadeh, S G (Rostock U.) ; Migliorati, Mauro (Rome U.)
In order to achieve a high luminosity in the electron-positron Future Circular Collider (FCC-ee), very intense multi-bunch beams with low emittances are accumulated in two separate rings and collide in two interaction regions exploiting the crab waist collision scheme. In order to preserve beam quality and to avoid collider performance degradation a careful study of beam collective effects is required. [...]
2020 - 7 p. - Published in : 10.23732/CYRCP-2020-009.279 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.279-285 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Implementation of transverse dampers in beam stability analyses / Li, K (CERN) ; Komppula, J (CERN)
Collective effects in high intensity, high energy particle accelerators and colliders are becoming increasingly important as performance is continuously pushed to the limits. The mitigation of collective effects, in particular coherent beam instabilities, relies heavily on transverse feedback systems. [...]
2020 - 5 p. - Published in : 10.23732/CYRCP-2020-009.211 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.211-215 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Feedback design for control of the micro-bunching instability based on reinforcement learning / Boltz, T (KIT, Karlsruhe) ; Brosi, M (KIT, Karlsruhe) ; Bründermann, E (KIT, Karlsruhe) ; Haerer, B (KIT, Karlsruhe) ; Kaiser, P (KIT, Karlsruhe) ; Pohl, C (KIT, Karlsruhe) ; Schreiber, P (KIT, Karlsruhe) ; Yan, M (KIT, Karlsruhe) ; Asfour, T (KIT, Karlsruhe) ; Müller, A -S (KIT, Karlsruhe)
The operation of ring-based synchrotron light sources with short electron bunches increases the emission of coherent synchrotron radiation in the THz frequency range. However, the micro-bunching instability resulting from self-interaction of the bunch with its own radiation field limits stable operation with constant intensity of CSR emission to a particular threshold current. [...]
2020 - 3 p. - Published in : 10.23732/CYRCP-2020-009.227 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.227-229 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Space charge effects on Landau damping from octupoles / Kornilov, V (Darmstadt, GSI) ; Boine-Frankenheim, O (Darmstadt, GSI)
Octupole magnets are the cornerstone of the collective instability mitigation in many hadron synchrotrons, including the future SIS100 synchrotron of the FAIR project. The betatron tune shifts, and the tune spread, linearly increase with the octupole magnet current, and enhance Landau damping. [...]
2020 - 5 p. - Published in : 10.23732/CYRCP-2020-009.237 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.237-241 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Destabilising effect of resistive transverse dampers / Métral, E (CERN)
A resistive transverse damper is needed for multi-bunch operation in a machine like the CERN LHC and it is very efficient as it considerably reduces the necessary amount of nonlinearities (from octupoles) needed to reach beam stability through Landau damping. However, a resistive transverse damper also destabilizes the single-bunch motion below the transverse mode coupling instability (TMCI) intensity threshold (for zero chromaticity), introducing a new kind of instability, which has been called “ISR instability” (for Imaginary tune Split and Repulsion). [...]
2020 - 6 p. - Published in : 10.23732/CYRCP-2020-009.221 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.221-226 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Coherent and incoherent space charge resonance effects / Hofmann, Ingo (Darmstadt, GSI ; Darmstadt, Tech. U.)
The question of interplay of coherent and incoherent space charge driven resonances and of their Landau damping has found some interest in beam dynamics of modern high-intensity synchrotrons. We revisit the theoretical and simulation models describing coherent half-integer parametric resonances, analyze their Landau damping in 2D beams on the basis of simulated tune spectra and conclude that above second order (envelope modes) they play no role in realistic, Gaussian-like beam models. [...]
2020 - 7 p. - Published in : 10.23732/CYRCP-2020-009.230 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.230-236 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Interplay of transverse damper and head-tail instability / Smaluk, V (Brookhaven Natl. Lab.) ; Bassi, G (Brookhaven Natl. Lab.) ; Blednykh, A (Brookhaven Natl. Lab.)
Transverse head-tail instability is a major limitation for the single-bunch beam current in circular accelerators. Beam-based feedback is one of the potential tools to suppress this type of instability. [...]
2020 - 5 p. - Published in : 10.23732/CYRCP-2020-009.216 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.216-220 (CERN-2020-009)

Detaljert visning - Lignende elementer
2021-02-20
06:37
Electron cloud effects in positron storage rings / Ohmi, Kazuhito (KEK, Tsukuba)
This is a review of electron cloud effects/instabilities observed in positron storage rings. Coupled bunch and fast head-tail instabilities caused by an electron cloud have been studied for a long time, and the agreement of experiments and simulations/theory is almost perfect in positron storage rings. [...]
2020 - 7 p. - Published in : 10.23732/CYRCP-2020-009.242 Fulltext: PDF;
In : ICFA mini-Workshop on Mitigation of Coherent Beam Instabilities in Particle Accelerators (MCBI 2019), Zermatt, Switzerland, 23 - 27 Sep 2019, pp.242-248 (CERN-2020-009)

Detaljert visning - Lignende elementer