M.E. Biagini

Proposal of an Experiment on Bunch Length Modulation in DAφNe

Obtaining very short bunches is an issue especially for colliders but also for CSR sources. The modulation of the bunch length in a strong rf focusing regime had been proposed, corresponding to a high value of the synchrotron tune. A ring structure where the function R56 along the ring oscillates between large positive and negative values will produce bunch length modulation. The synchrotron frequency can be tuned both by the rf power and by the integral of the function R56, up to the limit of zero value corresponding to the isochronicity condition. The proposal of a bunch length modulation along the ring in DAΦNE is here described. DAΦNE lattice can be tuned to positive or negative momentum compaction values, or to structures in which the two arcs are respectively set to positive/negative integrals of the R56 function. With the installation of an extra rf system at 1.3 GHz, experiments on bunch length modulation both in the regime of high and low synchrotron tune can be realized.

Studies of a scheme for low emittance muon beam production from positrons on target

A new scheme to produce muon beams characterised by very low emittance, in such a way to avoid the need for cooling, using a positron beam of about 45 GeV interacting on electrons on target is being studied by our group. This scheme is challenging and innovative, and needs a full design study to be developed. In particular, one of the novel topics to be investigated is the interaction between the positron beam stored in a low emittance ring with a thin target, to be inserted directly in the ring chamber to produce muons. nProduced muons will then be immediately collected at the exit of the target and transported to two

Low Emittance Muon Beams from Positrons

mu^+

SuperB Progress Report for Accelerator

and

PEP-II Status and Outlook

mu^-

Crabbed Waist Collisions in DAFNE and Super-B Design

accumulator rings. In this paper, after having highlighted the rational in designing a muon collider, we descrive in detail this new muon production scheme, discussing the simulation of the e+ beam interacting with the target, its degradation in the 6-D phase space and the optimisation of the e+ ring design mainly to maximise the energy acceptance.

DAFNE Setup And Operation With the Crab-Waist Collision Scheme

We are studying a novel scheme to produce muon beams characterised by very low emittance, thus allowing to avoid the need for cooling, using a positron beam of about 45 GeV interacting on electrons on a fixed target. This is a challenging scheme, and a full design study has to be developed. One of the key innovative topics to be investigated regards the interaction between the positron beam stored in a low emittance ring with a thin target inserted directly in the ring cham- ber. Produced muons will then be immediately collected at the exit of the target and transported to two μ+ and μ− accumulator rings. In this paper, after an introduction highlighting the rational in designing a muon collider, we discuss in detail this new muon production scheme, covering the simulation of the e+ beam interacting with the target, its degradation in the 6-D phase space and the optimisation of the e+ ring design mainly to maximise the energy acceptance.

DAΦNE OPERATION WITH THE UPGRADED KLOE-2 DETECTOR

This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name SuperB. This project builds on a long history of successful e+e- colliders built around the world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called crab waist. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and national laboratories. In Italy these may include INFN Frascati and the University of Pisa, in the United States SLAC, LBNL, BNL and several universities, in France IN2P3, LAPP, and Grenoble, in Russia BINP, in Poland Krakow University, and in the UK the Cockcroft Institute. The construction time for this collider is a total of about four years. The new tunnel can be bored in about a year. The new accelerator components can be built and installed in about 4 years. The shipping of components from PEP-II at SLAC to Italy will take about a year. A new linac and damping ring complex for the injector for the rings can be built in about three years. The commissioning of this new accelerator will take about a year including the new electron and positron sources, new linac, new damping ring, new beam transport lines, two new collider rings and the Interaction Region. The new particle physics detector can be commissioned simultaneously with the accelerator. Once beam collisions start for particle physics, the luminosity will increase with time, likely reaching full design specifications after about two to three years of operation. After construction, the operation of the collider will be the responsibility of the Italian INFN governmental agency. The intent is to run this accelerator about ten months each year with about one month for accelerator turn-on and nine months for colliding beams. The collider will need to operate for about 10 years to provide the required 50 ab{sup -1} requested by the detector collaboration. Both beams as anticipated in this collider will have properties that are excellent for use as sources for synchrotron radiation (SR). The expected photon properties are comparable to those of PETRA-3 or NSLS-II. The beam lines and user facilities needed to carry out this SR program are being investigated.

Status of SuperB Project

PEP-II/BABAR are presently in their second physics run. With machine and detector performance and reliability at an all-time high, almost 51 fb{sup -1} have been integrated by BABAR up to mid-October 2001. PEP-II luminosity has reached 4.4 x 10{sup 33} cm{sup -2} s{sup -1} and our highest monthly delivered luminosity has been above 6 pb{sup -1}, exceeding the performance parameters given in the PEP-II CDR by almost 50%. The increase compared to the first run in 2000 has been achieved by a combination of beam-current increase and beam-size decrease. In this paper we will summarize the PEP-II performance and the present limitations as well as our plans to further increase machine performance.