Search results for "Accelerator"
showing 10 items of 1507 documents
Beam-based alignment of SRF cavities in an electron injector linac
2018
Proper alignment of accelerating cavities is an important issue concerning beam quality of linear rf-accelerators. In particular, SRF cavities of injector linacs using high accelerating gradients on low-velocity electron beams can deteriorate the beam quality significantly when not aligned sufficiently. On the other hand, knowing the exact position of every cavity after several cool-down cycles of a cryomodule can be difficult depending on the particular module design. We will report on operational experience on the SC injector of the Darmstadt superconducting recirculating linac and ERL (S-DALINAC) showing unwanted effects on beam dynamics and beam quality due to cavity misalignment, such…
Space charge and microbunching studies for the injection arc of MESA
2018
For intense electron bunches traversing through bends, as for example the recirculation arcs of an ERL, space charge (SC) may result in beam phase space deterioration. SC modifies the electron transverse dynamics in dispersive regions along the beam line and causes emittance growth for mismatched beams or for specific phase advances. On the other hand, longitudinal space charge together with dispersion can lead to the microbunching instability. The present study focuses on the 180° low energy (5 MeV) injection arc lattice for the multi-turn Mainz Energy-recovering Superconducting Accelerator (MESA), which should deliver a CW beam at 10⁵ MeV for physics experiments with an internal target. W…
Dark matter synchrotron emission and radio observations
2012
We compute the synchrotron emission induced by electrons produced by DM annihilations inside our galaxy. The signal is compared with observations in a large range of frequencies, from 22 MHz up to 1420 MHz. We set constraints on the DM mass and annihilation cross-section and highlight the impact of astrophysical uncertainties.
Compton transmission polarimeter for a very precise polarization measurement within a wide range of electron currents
2011
For new experiments with polarized electron and positron beams the precise and quick measurement of the beam polarization is required. The relative electron polarization has been monitored on-line using a compact transmission Compton polarimeter for a wide range of average electron currents up to 100/μA and electron beam energy of 3.5 MeV. The asymmetry induced by the beam polarization can be monitored precisely with ΔA/A < 0.2 %. Even small relative variations of the beam polarization during a beam time may be detected using this polarimeter, such as an increase ~ 1 % and subsequent decrease of the beam polarization.
The dynamics of bunched laser-cooled ion beams at relativistic energies
2007
We discuss the axial dynamics of laser-cooled relativistic C3+ ion beams at moderate bunching voltages. Schottky noise spectra measured at a beam energy of 122 MeV/u are compared to simulations of the axial beam dynamics. Ions confined in the bucket are addressed by the narrow-band force of a laser beam counter-propagating to the ion beam, while the laser frequency is detuned relatively to the cooling transition frequency in the rest frame of the bucket. At large detuning comparable to the momentum acceptance of the bucket, the axial dynamics can be well explained by the secular motion of individual non-interacting ions. At small detuning, corresponding to a small axial momentum spread Δpax…
Dealing with contaminants in Coulomb excitation of radioactive beams
2020
Abstract Data analysis of the Coulomb excitation experiment of the exotic 206Hg nucleus, recently performed at CERN’s HIE-ISOLDE facility, needs to account for the contribution to target excitation due to the strongly-present beam contaminant 130Xe. In this paper, the contamination subtraction procedure is presented.
Fast timing and trigger Cherenkov detector for collider experiments
2016
Analysis of fast timing and trigger Cherenkov detector's design for its use in collider experiments is presented. Several specific requirements are taken into account - necessity of the radiator's placement as close to the beam pipe as possible along with the requirement of gapless (solid) radiator's design. Characteristics of the Cherenkov detector's laboratory prototype obtained using a pion beam at the CERN Proton Synchrotron are also presented, showing the possibility of obtaining sufficiently high geometrical efficiency along with good enough time resolution (50 ps sigma).
HITRAP – a facility for experiments on heavy highly charged ions and on antiprotons
2009
HITRAP is a facility for very slow highly-charged heavy ions at GSI. HITRAP uses the GSI relativistic ion beams, the Experimental Storage Ring ESR for electron cooling and deceleration to 4 MeV/u, and consists of a combination of an interdigital H-mode (IH) structure with a radiofrequency quadrupole structure for further deceleration to 6 keV/u, and a Penning trap for accumulation and cooling to low temperatures. Finally, ion beams with low emittance will be delivered to a large variety of atomic and nuclear physics experiments. Presently, HITRAP is in the commissioning phase. The deceleration of heavy-ion beam from the ESR storage ring to an energy of 500 keV/u with the IH structure has be…
Simultaneous analysis of neutrinoless double beta decay and LHC pp-cross sections: limits on the left-right mixing angle
2015
The extension of the Standard Model of electroweak interactions, to accommodate massive neutrinos and/or right-handed currents, is one of the fundamental questions to answer in the cross-field of particle and nuclear physics. The consequences of such extensions would reflect upon nuclear decays, like the very exotic nuclear double-beta-decay, as well as upon high-energy proton-proton reactions of the type performed at the LHC accelerator. In this talk we shall address this question by looking at the results reported by the ATLAS and CMS collaborations, where the excitation and decay of a heavy-mass boson may be mediated by a heavy-mass neutrino in proton-proton reactions leading to two jets…
The polarized electron-nucleon collider project ENC at GSI/FAIR
2011
The ENC project attempts to realize an electron-nucleon collider at the upcoming Facility for Antiproton and Ion Research FAIR at GSI Darmstadt by utilizing the antiproton high-energy storage ring HESR for polarized proton and deuteron beams. The addition of a 3.3 GeV storage ring for polarized electrons will enable electron-nucleon collisions up to a center-of-mass energy of - s - 14 GeV. In such a configuration peak luminosities in the range of L = 10(32) to 10(33)cm(-')(2)s(-')(1) are feasible . Beam-beam effects in a space-charge dominated regimes in conjunction with high-energy electron cooling represents one of the main challenges for this project. In this paper beam- and spin dynamic…