121120449
Design and simulation of muon ionization cooling channels for the Fermilab Neutrino Factory feasibility study
In the past few years, the concept of a high intensity muon storage ring has been pursued as an option for the next generation neutrino source. To produce the high intensity muon beam needed for the successful operation of a neutrino source, on the order of 1020 muon decays per year, the phase space occupied by the muon beam must be significantly reduced before the beam is accelerated. The initial transverse emittance of the muon beam before acceleration is assumed to be 9p mm rad. Because of the time limitation imposed by the muon lifetime, the technique employed to accomplish the desired emittance reduction is ionization cooling. In this paper we present two ionization cooling lattice designs, which use solenoidal focusing elements and liquid hydrogen absorbers to reduce the muon beam phase space. We discuss the design concepts and engineering constraints for these lattices and present simulation results obtained using a detailed tracing code with a complete model of muon-matter interactions. The reduction in transverse emittance is approximately a factor of 5. This result is within a factor of 2 of the total cooling requirements for a successful neutrino factory design and within a factor of 1.4 of the requirements for the main cooling section specified in the conceptual design of this machine.
16599712
Comparison of tracking codes for the International Linear Collider
In an effort to compare beam dynamics and create a "benchmark" for Dispersion Free Steering (DFS) a comparison was made between different International Linear Collider (ILC) simulation programs while performing DFS. This study consisted of three parts. Firstly, a simple betatron oscillation was tracked through each code. Secondly, a set of component misalignments and corrector settings generated from one program was read into the others to confirm similar emittance dilution. Thirdly, given the same set of component misalignments, DFS was performed independently in each program and the resulting emittance dilution was compared. Performance was found to agree exceptionally well in all three studies.
1161525
Recent studies of dispersion matched steering for the ILC bunch compressor and main linac
The dispersion matched steering (DMS) method is studied in detail in the context of a curved main linac. In the absence of cavity tilts (rotations in the YZ plane), DMS provides a unique and stable solution with negligible emittance growth. If cavity tilts are about 300 murad, the algorithm is not very robust. The emittance growth through the entire linac for positrons is about 5 nm, if the system is strictly static and statistical averaging can be used to improve beam position measurements. This growth is mostly eliminated if the dispersion and its derivative at injection can be adjusted. If anticipated ground motion, beam and klystron jitter, beam position measurement resolution are introduced (i.e. dynamical case), the emittance preservation goal is currently not achieved by DMS alone. Mitigation strategies are outlined.
62352767
ASPECTS OF SCIENTIFIC VISUALIZATION FOR HEP ANALYSIS AT FERMILAB
33125511
Beam-Beam Effects in the Tevatron Run II
Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams are significant sources of beam loss and lifetime limitations in the Tevatron Collider Run II (2001-present). We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in high energy physics (HEP) operation, predict the performance for planned luminosity upgrades and discuss ways to improve it.
116622236
Beam simulation tools for GEANT4 (and neutrino source applications)
Geant4 is a tool kit developed by a collaboration of physicists and computer professionals in the High Energy Physics field for simulation of the passage of particles through matter. The motivation for the development of the Beam Tools is to extend the Geant4 applications to accelerator physics. Although there are many computer programs for beam physics simulations, Geant4 is ideal to model a beam going through material or a system with a beam line integrated to a complex detector. There are many examples in the current international High Energy Physics programs, such as studies related to a future Neutrino Factory, a Linear Collider, and a very Large Hadron Collider.
115884934
Operational experience with the LEP low-beta superconducting quadrupoles
37953593
A Superconducting High-Luminosity Insertion in the Intersecting Storage Rings (ISR)
A focusing insertion will be constructed at an intersection of the ISR, to achieve a reduction of the effective beam height by about a factor 6 in the interaction diamond and a corresponding increase of the luminosity. It will contain eight superconducting quadrupole magnets, capable of producing gradients of 43 Tm-1 in a warm bore of 173 mm diameter: four of them have a magnetic length of 1.15 m and four of 0.65 m. The magnets are also equipped with sextupole windings, to match the gradients to particle momenta over the beam width, and with dodecapole correction windings. After construction and successful operation of a prototype magnet in the laboratory, competitive tenders were obtained from industry on the basis of technical specifications and manufacturing drawings. The magnets proper and the cryostats are being manufactured under two separate contracts. The insertion will be installed within 1980 at intersection I8, for use in physics experiments with a large magnetic spectrometer.
135424099
High performance flexible cryogenic helium transfer lines
CERN has installed and is operating in its Intersecting Storage Rings a superconducting high-luminosity insertion, the main elements of which are eight superconducting quadrupole magnets, housed in liquid helium bath cryostats. The design and construction of the transfer lines are discussed with photos. The site erection is described and operational experience presented with typical pumping curve of transfer line insulation space charted. Insulation vacuum and thermal performance are shown with the two-phase flow in transfer line diagramed. The economics of the flexible lines are itemized.
117713839
CONCEPTUAL STUDY OF THE SUPERFLUID HELIUM CRYOGENIC SYSTEM FOR THE CERN LARGE HADRON COLLIDER (LHC)
Studies are presently being made on the possibility of installing a Large Hadron Collider (LHC) in the existing underground tunnel of the LEP accelerator at CERN. The main element of the LHC would be a ring of 10 T superconducting magnets, distributed over the 26.7 km circumference of the machine. One of the current ideas is to use Nb-Ti magnets operated in superfluid helium. This paper presents possible solutions for a long distributed superfluid helium system within the constraints of an accelerator environment.
59027060
ASSESSING RISK IN COSTING HIGH-ENERGY ACCELERATORS:FROM EXISTING PROJECTS TO THE FUTURE LINEAR COLLIDER
High-energy accelerators are large projects funded by public money, developed over the years and constructed via major industrial contracts both in advanced technology and in more conventional domains such as civil engineering and infrastructure, for which they often constitute one-off markets. Assessing their cost, as well as the risk and uncertainty associated with this assessment is therefore an essential part of project preparation and a justified requirement by the funding agencies. Stemming from the experience with large circular colliders at CERN, LEP and LHC, as well as with the Main Injector, the Tevatron Collider Experiments and Accelerator Upgrades, and the NOvA Experiment at Fermilab, we discuss sources of cost variance and derive cost risk assessment methods applicable to the future linear collider, through its two technical approaches for ILC and CLIC. We also address disparities in cost risk assessment imposed by regional differences in regulations, procedures and practices.