189801755
Commissioning Results of the ReA RFQ at MSU*
The Facility for Rare Isotope Beams (FRIB) is currently in the preliminary design phase at Michigan State University (MSU). FRIB consists of a driver LINAC for the acceleration of heavy ion beams, followed by a fragmentation target station and a ReAccelerator facility (ReA3). ReA3 comprises gas stopper systems, an Electron Beam Ion Trap (EBIT) charge state booster, a room temperature radio frequency quadrupole (RFQ), a LINAC using superconducting quarter wave resonators and an achromatic beam transport and distribution line to the new experimental area. Beams from ReA3 will range from 3 MeV/u for heavy ions to about 6 MeV/u for light ions. The ReA3 RFQ, which is of the 4 rod type, is designed to accelerate ions with an Q/A of 0.2 to 0.5 from 12 keV/u to 600 keV/u. The RFQ operates at a frequency of 80.5 MHz and power levels up to 120 kW at 10% duty factor. In this paper we will report on commissioning results from the ReA3 RFQ using H2 and He beam from an auxiliary ion source.
45940461
STATUS OF THE FERMI @ ELETTRA PHOTOINJECTOR
The new FERMI@Elettra photoinjector is presently undergoing high-power testing and characterization at MAXlab in Lund, Sweden. This effort is a collaboration between Sincrotrone Trieste, MAX-lab and UCLA. The 1.6-cell RF gun cavity and the focusing solenoid were successfully designed and built by the Particle Beam Physics Laboratory at UCLA, delivered to Sincrotrone Trieste at the beginning of 2008, and installed in the linac tunnel at MAX-lab. Use of the MAX-lab facility will allow the FERMI project to progress significantly with the photoinjector while waiting for the completion of the new linac building extension at Sincrotrone Trieste. We report here on the high-power conditioning of the RF cavity and the first beam tests. STATUS OF THE FERMI@ELETTRA PHOTOINJECTOR∗ M. Trovò† , L. Badano, S. Biedron, D. Castronovo, F. Cianciosi, P. Craievich, M.D. Danailov, G. D’Auria, M. Ferianis, S.V. Milton, G. Penco, L. Pivetta, L. Rumiz, D. Wang, Sincrotrone Trieste, Trieste, Italy M. Eriksson, D.Kumbaro, F. Lindau, MAX-lab, Lunds Universitet, Lund, Sweden H. Badakov, A. Fukasawa, B. O’Shea, J. Rosenzweig, UCLA Department of Physics and Astronomy, Los Angeles, CA 90095
120931097
Stripline beam position monitor for the MIT-Bates South Hall Ring
The MIT-Bates South Hall Ring (SHR) is an electron storage ring currently being commissioned. It is designed to operate at an RF frequency of 2856 MHz with all of the 1812 buckets filled and a circulating current of 80 mA or greater. This leads to a small charge per bunch and the requirement for beam position monitors. Since there will be 31 such monitors in the vacuum system, it is important to suppress trapped modes which may excite coupled bunch instabilities. The stripline monitor built for the SHR is a stainless steel structure, designed to be manufactured using standard machining techniques and commercial feedthroughs. With proper 50 Ohm matching and a geometry derived from insight from MAFIA calculations, the monitor was constructed having a nearly flat RF response up through 10 GHz over the range of measurement. The stripline electronics allows the measurements with 0.1 mm resolution, maintains orbital harmonics information past the 10th harmonic, and operates over a dynamic range of 1 mA to greater than 80 mA of beam current.<<ETX>>
124623797
HESYRL 200 MeV linac single bunch energy spectrum measurement
The HESYRL 200-MeV electron linac was completed in December 1987, and has been running well. A careful study of the single-bunch energy spectrum for the linac was done. The measurement shows that the energy spread of the linac is +or-0.4%. The energy spectrum is quite stable and repeatable, and the resolution and accuracy are found to be satisfactory.<<ETX>>
55356715
PROGRESS OF THE eRHIC ELECTRON RING DESIGN
Over the past year, a baseline design of the electron ring for the eRHIC hadron-lepton collider has been developed. This site-specific design is based on the understanding of the existing RHIC machine performance and its possible upgrades. The design includes a full energy polarized electron beam injector to ensure operational reliability and to provide high integrated luminosity. The electron ring energy range is 5 to 10 GeV. The electron beam emittance, the electron beam path length, and the interaction region optics have to be adjustable over wide ranges depending on the ion species and energy for collisions. We describe the design features and expected machine performance. The results of recent beam polarization and beam-beam studies are also discussed.
55429266
STUDY OF THE ENERGY CHIRP EFFECTS ON SEEDED FEL SCHEMES AT SDUV-FEL
In this paper, theoretical and simulation study of the energy chirp effects on the HGHG and EEHG schemes are present. It is found that the central wavelength and output bandwidth of EEHG can be nearly immune to the beam energy chirp by properly setting the strengths of the chicanes. Experimental studies for both these two schemes have been carried out at the SDUV-FEL to demonstrate the theoretical predictions.
122601857
Experimental studies of longitudinal dynamics of space-charge dominated electron beams
A comprehensive experimental program was carried out at the University of Maryland Beam Transport facility to study the longitudinal beam physics of space-charge dominated bunches. This investigation included the behavior of (a) bunches with parabolic line charge profile, (b) bunches with rectangular line charge profile, and (c) local perturbations (slow and fast waves) in rectangular bunches. The major experimental results are presented in this paper.
125862664
Dynamical Breaking of Supersymmetry and Its Restoration at High Temperatures
The dynamical breaking of the supersymmetric Higgs model is discussed without adding the Fayet—Iliopoulos term to the Lagrangian. It is shown, in terms of the Nambu—Jona-Lasinio mechanism, that the supersymmetry breaking can be realized dynamically in the supersymmetric Higgs model. The supersymmetry behavior at finite temperatures is also investigated and it is shown that the supersymmetry broken dynamically at zero temperature can be restored at finite temperatures.
17396361
An analytic model of rotating hot spot and kHz QPOs in X-ray binaries
An analytic model of rotating hot spot is proposed to explain kilohertz quasiperiodic oscillations (kHz QPO) in X-ray binaries, which is based on the magnetic coupling (MC) of a rotating black hole (BH) with its surrounding accretion disc. The hot spot in the inner region of the disc is produced by energy transferred from a spinning BH with non-axisymmetric magnetic field. The frequency and energy band of the hot spot turns out to be related to six parameters, by which the strength and the azimuthal angular region of the bulging magnetic field on the BH horizon, the mass and spin of the BH, and the power-law index of the magnetic field varying with the radial coordinate on the disc are described. In addition, the correlation of the fluctuation of the bulging magnetic field with the widths of QPO frequency is discussed.
55527280
Electron beam instrumentation techniques using coherent radiation
Much progress has been made on coherent radiation research since coherent synchrotron radiation was first observed in 1989. The use of coherent radiation as a bunch length diagnostic tool has been studied by several groups. In this paper, brief introductions to coherent radiation and far-infrared measurement are given, the progress and status of their beam diagnostic application are reviewed, different techniques are described, and their advantages and limitations are discussed.
125041691
The Start-to-End Simulation of Electron Beam in the RHIC E-cooling Facility (L-band option) with PARMELA
The electron cooling facility has been proposed as a way to reduced the ion beam emittance and energy spread for the RHIC (Relativistic Heavy Ion Collider) to significantly enhance the luminosity. In a high energy electron cooling facilities like the one for RHIC, since the very higher beam quality is needed for the sufficient cooling rate, the traditional way to produce, accelerate and focus beam are hardly applicable. The new solutions include photo-injector for producing the high charge electron bunch with very low emittance, superconducting linac cavities for high current operations, strong cooler solenoid and beam transport to achieve specific beam parameters and make energyrecovery, etc. A start-to-end simulation has been performed with L-band (1.3GHz) gun and linac (TESLA cavity) to demonstrate the feasibility of such an unprecedented cooling facility from the beam production and transport point of view. The main results are, totally revised gun performance considering the crucial heating and RF power issues; workable scheme for merging high/low energy beam into linac with small bending angle dipole, septum magnet and rotation cavity; magnetized beam simulations, beam stretching and compressing, etc. It shows first time that such a design, with high charge beam, magnetized cathode, L-band super-conducting cavities and long transport lines, is feasible from the single bunch particle tracking point of view. The next step is to include real cooler solenoid sections (under design in the Magnet Division). The coherent synchrotron radiation effects is investigated in a separate study.