LBNL, Berkeley, California
Fermilab, Batavia, Illinois
At the LHC upgrade luminosity of 1035 cm-2 s-1, collision product power in excess of a kW is deposited in the inner triplet quadrupoles. The quadrupole field sweeps secondary particles from pp-collisions into the superconducting coils, concentrating the power deposition at the magnetic mid-planes. The local peak power density can substantially exceed the conductor quench limits and reduce component lifetime. Under these conditions, block-coil geometries may result in overall improved performance by removing the superconductor from the magnetic mid-planes and/or allowing increased shielding at such locations. First realistic energy deposition simulations are performed for an interaction region based on block-coil quadrupoles with parameters suitable for the LHC upgrade. Results are presented on 3-D distributions of power density and accumulated dose in the inner triplet components as well as on dynamic heat loads on the cryogenic system. Optimization studies are performed on configuration and parameters of the beam pipe, cold bore and cooling channels. The feasibility of the proposed design is discussed.
The EU CARE-HHH and US-LARP programmes for an LHC upgrade aim at increasing the LHC luminosity by a factor of 10 around the year 2015. The upgrade plan envisages rebuilding the interaction regions (IRs) and modifying the beam parameters. In addition to advanced low-beta quadrupoles, the future IRs may accommodate other novel elements such slim s.c. dipoles or quadrupoles embedded deep inside the detectors, global low-angle crab cavities, and wire compensators of long-range beam-beam effects. Important constraints on the upgrade path are the maximum acceptable number of detector pile-up events, favoring many closely spaced bunches, and the heat load on the cold-magnet beam screens, pointing towards fewer and more intense bunches. In addition, the upgrade of the LHC ring proper should be complemented by an upgrade of the injector complex. I will present preferred luminosity upgrade scenarios for the LHC IRs and beam parameters, sketch accompanying injector enhancements, and comment on a longer-term LHC energy upgrade.
INFN/LNF, Frascati (Roma)
SLAC, Menlo Park, California
Submitted for the High Luminosity Study Group for an Asymmetric Super-B-Factory: Parameters are being studied for a high luminosity e+e- collider operating at the Upsilon 4S that would deliver a luminosity of over 1036/cm2/s. This collider would use a novel combination of linear collider and storage ring techniques. In this scheme an electron beam and a positron beam at 4 GeV x 7 GeV are stored in low-emittance damping rings similar to those designed for a Linear Collider (LC). A LC style interaction region is included in the ring to produce sub-millimeter vertical beta functions at the collision point. A large crossing angle (±30 mrad) is used at the collision point to allow beam separation and reduce the hourglass effect. Beam currents of about 3 A x 2 A in 1700 bunches can produce a luminosity of 1036/cm2/s. Design parameters and beam dynamics effects are discussed.
INFN/LNF, Frascati (Roma)
Rome University La Sapienza, Roma
* DAPHNE Upgrade Team, "DAPHNE Upgrade for Siddharta run", DAPHNE Tech. Note G-68, Dec. 2006.
INFN/LNF, Frascati (Roma)
SLAC, Menlo Park, California
We present a preliminary design of an interaction region for a Super-B Factory with luminosity of 1x1036 cm2/s. The collision has a ± 17 mrad crossing angle and the first magnetic element starts 30 cm from the collision point. We show that synchrotron radiation backgrounds are controlled and are at least as good as the backgrounds calculated for the PEP-II accelerator. How the beams get into and out of a shared beam pipe is illustrated along with the control of relatively high synchrotron radiation power from the outgoing beams. The high luminosity makes radiative bhabha backgrounds significantly higher than that of the present B-Factories and this must be addresed in the initial design.
BNL, Upton, Long Island, New York
There are three main sources of the experimental background at RHIC. The beam-gas induced background is associated with the vacuum pressure, the beam-chamber-interaction induced background can be improved by collimations, and the beam-beam induced background is somewhat inherent, and probably harmless for the experimental data taking. The zero degree calorimeter (ZDC) is an essential luminosity detector for heavy ion operations in RHIC. It is shown that, however, the ratio of ZDC singles (background) and coincident rate is also useful in proton runs for background evaluations. In this article, the experimental background problem in RHIC polarized proton runs is reported.
CERN, Geneva
EPFL, Lausanne
It's been shown in previous conferences [*,**] that action and phase jump analysis is a promising method to measure normal quadrupole components, skew quadrupole components and even normal sextupole components. In this paper, the action and phase jump analysis is evaluated using new RHIC data.
*J. Cardona,et al, Procceedings of PAC 2005, Knoxville, Tennesse.**J. Cardona,et al, Procceedings of EPAC 2004, Lucerne, Switzerland.
The University of Texas at Austin, Austin, Texas
Until recently, values of the amplitude functions through the Interaction Regions of the Tevatron collider detectors have been inferred either by reconstructing event locations through the detector and mapping out the luminous region to deduce the beam emittance and amplitude function or by performing differential closed orbit measurements while varying steering magnets and producing detailed models of the synchrotron's optical properties which reproduce the observed orbital deviations. Both of these methods rely on often lengthy off-line analyses and sometimes many hours of experimental data to obtain a meaningful result. The new Tevatron Beam Position Monitor system, commissioned in 2005, has allowed unprecedented detail of turn-by-turn motion to be measured at the 20-micron level and for thousands of beam revolutions. Such measurements performed with a freely oscillating proton beam, excited by a kicker magnet, allow for the direct measurement of the amplitude function which is model independent. A simple measurement procedure, data analysis method, and typical results for the Tevatron experimental regions are presented.
BNL, Upton, Long Island, New York
The existence of multipolar components in the dipole and quadrupole magnets is one of the factors limiting the beam stability in the RHIC operations. So, a realistic non-linear model is crucial for understanding the beam behavior and to achieve the ultimate performance in RHIC. A procedure is developed to build a non-linear model using the available multipolar component data obtained from measurements of RHIC magnets. We first discuss the measurements performed at different stages of manufacturing of the magnets in relation to their current state in RHIC. We then describe the procedure to implement these measurement data into tracking models, including the implementation of the multipole feed down effect due to the beam orbit offset from the magnet center. Finally, the field quality analysis in the RHIC interaction regions is presented.