54039880
Using workstation GUIs in HEP, X-Windows, Motif and the Nirvana project
We present four small, high quality, Motif based tools for high energy physicists and discuss some of the less obvious work that is necessary to fully take advantage of graphical user interfaces (GUIs). Histo-Scope and NPlot are interactive data display programs. Histo-Scope is for viewing data as it is collected in running analysis or data acquisition programs, NPlot, for plotting data from text files. Visajet is an interface for the ISAJET event simulation program. It gives users a fast way to configure ISAJET and displays ISAJET events in a three dimensional phase space display that users can rotate and manipulate with the mouse. NEdit is a GUI style plain text editor.
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.
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.
62352767
ASPECTS OF SCIENTIFIC VISUALIZATION FOR HEP ANALYSIS AT FERMILAB
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.
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.
121924363
Design and construction of a static magnetic refrigerator operatingbetween 1.8 K and 4.5 K
Abstract Following pioneer work a decade ago at CEA/CEN-Grenoble, France we have designed and constructed a static magnetic refrigerator with a capacity of about 20 W, operating on a quasi-Carnot cycle between 1.8 and 4.5 K. The active core, which contains 10.1 kg of single-crystal gadolinium-gallium garnet (GGG), is magnetized and demagnetized by a 3.5 T pulsed-field, low-loss superconducting magnet operating at 4.5 K. Thermal switching to the cold and warm sources is produced by alternatively flushing the core with liquid helium from the 1.8 and 4.5 K baths, by means of alumina-piston and -cylinder displacer pumps. Precise modelling of thermodynamic properties of GGG, as well as detailed analysis of the different sources of irreversibility, allow to estimate the available refrigeration power and optimize the operating cycle.
118096470
Helium cryogenic systems for the LEP2 and LHC projects at CERN
CERN is presently operating a large distributed 4.5 K helium cryo kW@4.5 K equivalent) for cooling the superconducting acceleration c km circumference LEP2 lepton collider. This also constitutes the fi cryogenic system (about 150 kW@4.5 K equivalent) for the future Collider (LHC), the high-field superconducting magnets of which superfluid helium. We briefly describe the main features of each sy progress of their development, construction and operation. INTRODUCTION Particle physics has volens nolens become a prime user of large cryogenics, through the generalized use of superconducting device guiding and focusing high-energy particles in recent accelerators an specific requirements, both qualitative and quantitative, set by a represented a strong driving force to stimulate technological develo push helium cryogenics out of the laboratory into industrial-scal operating with high reliability and high efficiency. At CERN, the E for Particle Physics, this evolution took place in the last d superconducting quadrupoles of the LEP high-luminosity insertions upgrade (LEP2) using superconducting acceleration cavities in larg Large Hadron Collider (LHC) project based on high-field superconduc superfluid helium cryogenics on an unprecedented scale (Figure 1).
115852928
The eight superconducting quadrupoles for the ISR high-luminosity insertion
Eight superconducting quadrupoles for a high-luminosity insertion in the ISR have been produced by industrial firms according to CERN design and manufacturing specifications, and assembled and tested at CERN. The horizontal cylindrical cryostats, which contain windings and steel yoke in a boiling helium bath, have a 173 mm warm bore. For 31 GeV beam energy, the maximum operating gradient on the quadrupole axis is 43 T m−1 and the maximum field in the windings is 5.5 T. Sextupole windings provide a linear variation of the gradient of up to 4% over the bore width and dodecapole windings trim the field pattern as a function of excitation. This paper reports about production history, acceptance tests, and performance. The results of magnetic measurements are also summarized. The insertion will be installed into the ISR as from August 1980.
32190359
Industrial Technology for Unprecented Energy and Luminosity : The Large Hadron Collider
With over 3 billion Swiss francs procurement contracts under execution in industry and the installation of major technical systems in its first 3.3 km sector, the Large Hadron Collider (LHC) construction is now in full swing at CERN, the European Organization for Nuclear Research. The LHC is not only the most challenging particle accelerator, it is also the largest global project ever for a scientific instrument based on advanced technology. Starting from accelerator performance requirements, we recall how these can be met by an appropriate combination of technologies, such as high-field superconducting magnets, superfluid helium cryogenics, power electronics, with particular emphasis on developments required to meet demanding specifications, and industrialization issues which had to be solved for achieving series production of precision components under tight quality assurance and within limited resources. This provides the opportunity for reviewing the production status of the main systems and the progress of the project.
121792953
Superfluid helium cryogenics for the large hadron collider project at CERN
Abstract The Large Hadron Collider (LHC) at CERN will be the next research instrument of high-energy physics. Colliding protons at 14 TeV center-of-mass energy and high luminosity, it will probe the structure of matter down to an unprecedentedly fine scale, thus allowing to reproduce in the laboratory phenomena which occurred in the very early universe. On the technological side, the LHC makes use of high-field superconducting magnets for guidance and focusing of the particle beams around the 26.7 km circumference of the machine, to be installed in the existing LEP tunnel. The nominal bending field of 8.65 T is produced in some 1300 twin-aperture dipoles, wound with small-filament Nb Ti conductor, and operated below 1.9 K in static baths of pressurized helium II, thus taking advantage of its specific properties as cooling fluid. We present the main technical challenges of the LHC cryogenic system, and review the actions of development and the preparatory work in progress.