109697769
Report of the working group on detector simulation
An ad hoc group at Snowmass reviewed the need for detector simulation to support detectors at the SSC. This report first reviews currently available programs for detector simulation, both those written for single specific detectors and those aimed at general utility. It then considers the requirements for detector simulation for the SSC, with particular attention to enhancements that are needed relative to present programs. Finally, a list of recommendations is given.
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.
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.
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.
135785653
Very-Low-Loss Liquid Helium Transfer with Long Flexible Cryogenic Lines
The four underground areas of LEP, the large electron-positron collider now operating at CERN, are equipped with helium cryogenic plants continuously feeding superconducting magnets over distances of up to 92 m, with differences in elevation reaching 25 m. For this purpose, 500 m of vapour-shielded flexible cryogenic lines, of coaxial corrugated tube construction, have been manufactured in industry and performance tested in the laboratory prior to site installation. Several improvements in design with respect to earlier lines of similar construction, as well as systematic quality-control procedures, made it possible to achieve reproducibly linear heat inleaks of about 30 mW m−1, in self-sustained vapour shielding operation. We describe the main design principles and constructional features of the lines, and report on methods and results of their performance tests.
108030818
Helium Cryogenics at the Lep Experimental Areas
LEP, the large electron-positron collider built at CERN, is now starting to operate. Its four experimental areas, installed in large caverns down to 150 m below ground, are equipped with two types of superconducting magnet, namely large detector solenoids and “low-beta” focusing quadrupoles, operated from common ancillary cryogenic systems. The large size, geographical dispersion, underground implantation and operating environment of LEP have set unusual constraints and dictated specific choices for the four helium cryogenic plants, distribution systems, magnet cryostats, and process operation, particularly as concerns operational flexibility, reliability, safety, remote control and automation. After describing the main design features of the cryogenic systems, we report on their installation, commissioning and first experience of operation.
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.
115691553
Cryogenics in CERN accelerators
86864652
CLIC $e^+ e^-$ Linear Collider Studies - Input to the Snowmass process 2013
This paper addresses the issues in question for Energy Frontier Lepton and Gamma Colliders by the Frontier Capabilities group of the Snowmass 2013 process and is structured accordingly. It will be accompanied by a paper describing the Detector and Physics studies for the CLIC project currently in preparation for submission to the Energy Frontier group.