Papers by Dejan Trbojevic
arXiv (Cornell University), Sep 13, 2011
We present a new 'green energy' approach to the Energy Recovery Linac (ERL) and Recircula... more We present a new 'green energy' approach to the Energy Recovery Linac (ERL) and Recirculating Linac Accelerators (RLA) for the future Electron Ion Colliders (EIC) using single beam line made of very strong focusing combined function permanent magnets and the Fixed Field Alternating Linear Gradient (FFA-LG) principle. We are basing our design on recent very successful commissioning results of the Cornell University and Brookhaven National Laboratory ERL Test Accelerator.
We present a new approach of the Energy Recovery Linac Design for the future projects: PERLE (Pow... more We present a new approach of the Energy Recovery Linac Design for the future projects: PERLE (Powerful Energy Recovery Linac for Experiments), LHeC/FCCeH and eR- HIC. The concept uses superconducting linacs and a single xed eld beam line with multiple energy passes of electron beams. This represents an update to the existing CBETA (Cornell University Brookhaven National Laboratory ERL Test Accelerator) where the superconducting linac uses a single xed eld magnet beam line with four energy passes during acceleration and four passes during the energy recov- ery. To match the single xed eld beam line to the linac the CBETA uses the spreaders and combiners on both sides of the linac, while the new concept eliminates them. The arc cells from the single xed eld beam line are connected to the linac with adiabatic transition arcs wher cells increase in length. The orbits of di erent energies merge into a sin- gle orbit through the interleaved linac within the straight sections as in the CBE...
First Polarized Proton Collisions at RHIC
AIP Conference Proceedings, 2003
PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)
In this report we will describe the muon collider target test beam line which operates off one br... more In this report we will describe the muon collider target test beam line which operates off one branch of the AGS switchyard. The muon collider target test facility is designed to allow a prototype muon collider target system to redeveloped and studied. The bertmrequirements for the facility areambitious but feasible. Thesystem is designed to accept bunched beams of intensities up to 1.6x1013 24 GeV protons in a single bunch. The target specifications require beam spot sizes on the order of 1 mm, 1 sigma rms at the maximum intensity. We will describe the optics design, the instrumentation, and the shielding design. Results from the commissioning of the beam line will be shown.
2007 IEEE Particle Accelerator Conference (PAC), 2007
The future relativistic electron hadron collider: e-RHIC requires acceleration of electrons to 10... more The future relativistic electron hadron collider: e-RHIC requires acceleration of electrons to 10 GeV with a possible upgrade to 20 GeV. In the case that the super conducting linac is selected for acceleration, an energy recovery scheme is required. We propose to study a possibility of using the non-scaling Fixed-Field Gradient-Accelerator (NS-FFAG) for different energies. The beam will be accelerated by the superconducting linac at the top of the sine function, brought back to the front of the linac by the non-scaling FFAG and repeating this a few times until the total energy of 20 GeV is reached. After collisions the beam is brought back by the non-scaling FFAG and decelerated (on the lower RF phase) in the same sequence but in the reverse order. Conventional and non-conventional beam dynamic issues will be discussed, like the transit time matching effect and the time of flight adjustments.
PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)
In this report we will describe the muon collider target test beam line which operates off one br... more In this report we will describe the muon collider target test beam line which operates off one branch of the AGS switchyard. The muon collider target test facility is designed to allow a prototype muon collider target system to redeveloped and studied. The bertmrequirements for the facility areambitious but feasible. Thesystem is designed to accept bunched beams of intensities up to 1.6x1013 24 GeV protons in a single bunch. The target specifications require beam spot sizes on the order of 1 mm, 1 sigma rms at the maximum intensity. We will describe the optics design, the instrumentation, and the shielding design. Results from the commissioning of the beam line will be shown.
Lecture Notes in Computer Science, 2002
Bent c hanneling crystals as elements of accelerator optics with extreme, 1000-Tesla intracrystal... more Bent c hanneling crystals as elements of accelerator optics with extreme, 1000-Tesla intracrystalline Şelds can Şnd many applications in accelerator world from TeV down to MeV energies. Situated in accelerator ring, they serve for beam scraping or extraction, e.g. in RHIC and IHEP U70. Crystal itself is a miniature beamline with its own "strong focusing", beam loss mechanisms etc. We describe the algorithms implemented in the computer code CATCH used for simulation of particle channeling through crystal lattices and report the results of tracking with 100-GeVŠu Au ions in RHIC and with 70-GeV and 1-GeV protons in U70. Recent success of IHEP where a tiny, 2-mm Si crystal has channeled a 10 12 pŠs beam of 70-GeV protons out of the ring with eŞciency 85ළ followed the prediction of computer model.
The future p+p-Muon Collider should have a luminosity of the order of 10% cm-*s-l, an theenergy o... more The future p+p-Muon Collider should have a luminosity of the order of 10% cm-*s-l, an theenergy of 2 x 2TeV. Wepresent h~ademonstratioamachineatalowereaergy to test the feasibility of all components involved, whicb could be pIaced inside the existing Relativistic Heavy Ion Collides (RHIC) tunnel. Tbe maximum energy of the muonsintbeRHICcunneldependsonthemaximumattainable field in the dipoles. ' The maximum energy in the existing FUUC rings for protons is 250 GeV, where the strength of the magnetic field in the dipoles is 3. 5 T. A design of the storage ring lattice for a 50 GeV muon demonstmion machiine is also presented.
The lattice design of the 50-50 Gev muon collider is presented. Due to the short lifetime of the ... more The lattice design of the 50-50 Gev muon collider is presented. Due to the short lifetime of the 50 GeV muons, the ring needs to be as small as possible. The 4 cm low betas in both planes lead to high betatron functions at the focusing quadrupoles and hence large chromaticities, which must be corrected locally. In order to maintain a low rf voltage of around 10 MV, the momentum-compaction factor must be kept to less than 10 −2 , and therefore the flexible momentum-compaction modules are used in the arcs. The dynamical aperture is larger than 6 to 7 rms beam size for ±5 rms momentum offset. Comments are given and modifications are suggested.
Working group summary: Machine design for the μ{sup +}-μ⻠collider
We summarize the discussions of the working group on Machine Design. The scope of the working gro... more We summarize the discussions of the working group on Machine Design. The scope of the working group included the entire accelerator system from beam cooling to the collider and the collider ring itself. Particular topics that were discussed in some detail included acceleration options, magnet designs (including the accelerator arcs and collider ring), instabilities, particularly in the collider ring, and
2007 IEEE Particle Accelerator Conference (PAC), 2007
Since 2001 RHIC has experienced electron cloud effects, which have limited the beam intensity. Th... more Since 2001 RHIC has experienced electron cloud effects, which have limited the beam intensity. These include dynamic pressure rises-including pressure instabilities, tune shifts, a reduction of the stability threshold for bunches crossing the transition energy, and possibly incoherent emittance growth. We summarize the main observations in operation and dedicated experiments, as well as countermeasures including baking, NEG coated warm beam pipes, solenoids, bunch patterns, anti-grazing rings, pre-pumped cold beam pipes, scrubbing, and operation with long bunches. This article is a short version of [1].
Physical Review Special Topics - Accelerators and Beams, 2008
Since 2001, the Relativistic Heavy Ion Collider has experienced electron cloud effects, some of w... more Since 2001, the Relativistic Heavy Ion Collider has experienced electron cloud effects, some of which have limited the beam intensity. These include dynamic pressure rises (including pressure instabilities), tune shifts, a reduction of the instability threshold for bunches crossing the transition energy, and possibly incoherent emittance growth. We summarize the main observations in operation and dedicated experiments as well as countermeasures including baking, nonevaporable getter coated warm beam pipes, solenoids, bunch patterns, antigrazing rings, prepumped cold beam pipes, scrubbing, and operation with long bunches.
Polarized Proton Collisions at 205 GeV at RHIC
Physical Review Letters, 2006
Design of a medium energy electron-ion collider (MeRHIC) is under development at the Collider-Acc... more Design of a medium energy electron-ion collider (MeRHIC) is under development at the Collider-Accelerator Department at BNL. The design envisions construction of a 4 GeV electron accelerator in a local area inside and near the RHIC tunnel. Electrons will be produced by a polarized electron source and accelerated in energy recovery linacs. Collisions of the electron beam with 100 GeV/u heavy ions or with 250 GeV polarized protons will be arranged in the existing IP2 interaction region of RHIC. The luminosity of electron-proton collisions at the 10³² cm²s¹ level will be achieved with 50 mA CW electron current and presently available proton beam parameters. Efficient proton beam cooling at collision energy may bring the luminosity to 10³³ cm²s¹. An important feature of MeRHIC is that it serves as a first stage of eRHIC, a future electron-ion collider at BNL with both higher luminosity and energy reach. The majority of MeRHIC accelerator components will be used in eRHIC.
Interaction Region Design for a RHIC-Based Medium-Energy Electron-Ion Collider
Review of Current FFAG Lattice Studies in North America
A resent progress report on the lattice design of the 50-50 Gev muon collider is presented. The r... more A resent progress report on the lattice design of the 50-50 Gev muon collider is presented. The ring circumference needs to be as small as possible due to the short lifetime of the 50 GeV muons. The background at the detector is affected by the continuous decay of muons into electrons which requires a dipole between the high focusing quadrupoles and the detector. To obtain a luminosity on the order of 1x10 33 cm ,2 s ,1 it is required to have beam intensities on the order of 1x10 12 particles per bunch. The rms momentum spread of the beam is equal to 0.12 क and the beta functions at the interaction point are equal to 4 cm. The maxima of the betatron functions at these quadrupoles are 1300 m, resulting in large chromaticities which must be corrected by local chromatic correction. Pairs of horizontal and vertical chromatic sextupoles are located at locations where the corresponding betatron functions are 100 m and the values of the horizontal dispersion functions are 3 and 2 m, respectively. They are carefully placed so that most of their nonlinear effects are canceled. The dynamic aperture is larger than 7 times the mean size of the beam for the momentum offsets larger than-6 and +10 sigmas.
The proton driver for the $\ mu\ mu $ collider
ABSTRACT
Feasibility Study 2 of a Muon-Based Neutrino Source
Report BNL- …, 2001
deutsch english. Publikationsansicht. 970607. Feasibility study 2 of a muon based neutrino source... more deutsch english. Publikationsansicht. 970607. Feasibility study 2 of a muon based neutrino source (2001). Ozaki, S,; Palmer, RB,; Zisman, MS,; Gallardo, JC,; Goodman, M,; Hassanein, A,; Norem, JH,; Reed, CB,; Smith, D,; Teng, LC,; Wang, Chun-xi,; Anerella, M,; ...
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Papers by Dejan Trbojevic