Louis Rinolfi

A 3 TeV

A possible design of a multi-TeV e+e- linear collider is presented. The design is based on the CLIC (Compact Linear Collider) two-beam technology proposed and developed at CERN. Though the study has shown that this technology is applicable to a linear collider with centre-of-mass energies from 500 GeV or less up to 5 TeV, the present report focuses on the nominal energy of 3 Te V. First, a short overview is given of the physics that could possibly be done with such a collider. Then, the description of the main-beam complex covers the injection system, the 30 GHz main linac, and the beam delivery system. The presentation of the RF power source includes the beam-generation scheme, the drive-beam decelerator, which consists of several 625 m long units running parallel to the main linac, and the power-extraction system. Finally, brief outlines are given of all the CLIC test facilities. They cover in particular the new CLIC test facility CTF3 which will demonstrate the feasibility of the power production technique, albeit on a reduced scale, and a first full-scale single-drive-beam unit, CLICI, to establish the overall feasibility of the scheme.

e^+ e^-

In this paper we discuss a new approach to two-beam acceleration. The energy for RF production is initially stored in a long-pulse electron beam which is efficiently accelerated to about 1.2 GeV by a fully loaded, conventional, low frequency (∼1 GHz) linac. The beam pulse length is twice the length of the high-gradient linac. Segments of this long pulse beam are compressed using combiner rings to create a sequence of higher peak power drive beams with gaps in between. This train of drive beams is distributed from the end of the linac against the main beam direction down a common transport line so that each drive beam can power a section of the main linac. After a 180-degree turn, each high-current, low-energy drive beam is decelerated in low-impedance decelerator structures, and the resulting power is used to accelerate the low-current, high-energy beam in the main linac. The method discussed here seems relatively inexpensive, is very flexible and can be used to accelerate beams for linear colliders over ...

Linear Collider Based on CLIC Technology

The Two-Beam Accelerator concept is one of the most promising methods for producing RF power for future linear colliders. In particular it allows upgrades to multiTeV energies. One of its challenges is the production of the high current drive beam, which as it passes through decelerating structures, produces RF power for acceleration of the main beam. These challenges must be studied at a smaller scale test facility.

A new method for RF power generation for two-beam linear colliders

For improved reliability, the front-end of the LEP (Large Electron Positron colliding beam accelerator) Injector Linac (LIL) has been replaced. The new system has been used for LEP runs since March of 1991. The experimental results presented show a significant improvement of beam characteristics. These results also agree well with those of the simulation programs.<<ETX>>

CTF3 Drive-Beam Injector Design

The aim of the CLIC Test Facility CTF3 at CERN is to prove the feasibility of key issues of the two-beam based Compact Linear Collider (CLIC) study. In particular, it addresses the generation of a drive beam with the appropriate time structure to produce high power RF pulses at a frequency of 30 GHz. The first major goal of CTF3 was to demonstrate, at low charge, the combination of successive bunch trains by RF deflectors in an isochronous ring. This bunch frequency multiplication has been successfully performed for various combination factors up to five and will be presented.

A new front-end for the LEP Injector Linac

The objectives of the CLIC Test Facility (CTF) are to study the generation of short intense electron bunches using a laser driven photocathode in an RF gun, to generate 30 GHz RF power for high gradient tests of prototype CLIC components, and to test beam position monitors. The performance of the CTF has improved dramatically in the course of the past year and highlights are presented.

Bunch frequency multiplication in the CLIC Test Facility CTF3

At the request of the L3 collaboration (one of the LEP (Linear Electron-Positron collider) experiments) a new facility was built to close to the Electron Positron Accumulator (EPA) to provide a single electron per beam pulse at an energy which can be selected between 180 MeV and 500 MeV. The intensity of the ejected electron beam is reduced by changing the gun parameters and by adjusting the aperture of the slits in the linac. The energy is defined by letting the beam do 1/sup 1/4/ turn in the EPA. The energy spread is limited to +or-0.5*10/sup -3/ by reducing the slits aperture in the LIL/EPA transfer line. A new transfer line was built to transport the beam from the EPA ejection septum to the detector test stand. The facility was then used to test the response of the L3 electromagnetic calorimeter composed of bismuth-germanium-oxide crystals in the 100-MeV range.<<ETX>>

CLIC Test Facility developments and results

Abstract The longitudinal and lateral shower profiles for 500 MeV electrons in iron are studied using dosimetry and activation techniques. The results are compared with Monte Carlo simulations and other previously published data. The agreement between the data and the EGS4 simulation results is good; a simple shower profile parametrization of type kz α−1 exp (−βz) does not represent the experimental data well at and around the shower maximum. The differences observed in the activation and dose profiles clearly show the role of photons in electromagnetic showers. The photon fraction increases as the shower develops deeper and they carry a larger energy fraction farther into the absorber. Photodisintegration reactions are responsible for the activation of the iron and we identified Mn 54 , Fe 53 and Mn 56 as more active isotopes among several others. These studies were performed for estimating the dose and its profile for the CMS quartz fiber calorimeter radiation damage work performed at LIL (CERN).

Single electron beams from the LEP pre-injector

This report sums up in two volumes the first 50 years of operation of the CERN Proton Synchrotron. After an introduction on the genesis of the machine, and a description of its magnet and powering systems, the first volume focuses on some of the many innovations in accelerator physics and instrumentation that it has pioneered, such as transition crossing, RF gymnastics, extractions, phase space tomography, or transverse emittance measurement by wire scanners. The second volume describes the other machines in the PS complex: the proton linear accelerators, the PS Booster, the LEP pre-injector, the heavy-ion linac and accumulator, and the antiproton rings.

Electromagnetic shower profile measurements in iron with electrons

The CLIC polarized electron source is based on a DC gun where the photocathode is illuminated by a laser beam. Each micro-bunch has a charge of 6x10 9 e