R. Corsini

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^-

One of the major objectives of CTF3 (CLIC Test Facility) is the production of 30 GHz power for the high-gradient testing of CLIC accelerating structures. To this end a dedicated beam line, power generating structure and power transfer line have been designed, installed and commissioned. 52 MW of 30 GHz power with a pulse length of 74 ns and a repetition rate of 16 Hz were delivered to the high-gradient test area. This will allow operation of test accelerating structures in the first CTF3 run of 2005 up to the nominal CLIC accelerating gradient of 150 MV/m and beyond the nominal pulse length. The system is described and the performances of the CTF3 linac, beam line and the rf components are reviewed.

Linear Collider Based on CLIC Technology

The proposed Compact Linear Collider (CLIC) is a multi-TeV electron-positron collider for particle physics based on an innovative two-beam acceleration concept. A high-intensity drive beam powers the main beam of a high-frequency (30 GHz) linac with a gradient of 150 MV/m, by means of transfer structure sections. The aim of the CLIC Test Facility (CTF3) is to make exhaustive tests of the main CLIC parameters and to prove the technical feasibility. One of the points of particular interest is the demonstration of bunch train compression and combination in the Delay Loop and in the Combiner Ring. Thus, detailed knowledge about the longitudinal beam structure is of utmost importance and puts high demands on the diagnostic equipment. Among others, measurements with a streak camera have been performed on the linac part of the CTF3 as well as on the newly installed Delay Loop. This allowed e.g. monitoring of the longitudinal structure of individual bunches, the RF combination of the beam, the behavior during phase shifts and the influence of the installed wiggler. This article first gives an overview of the CTF3 facility, then describes in detail the layout of the long optical lines required for observation of either optical transition radiation or synchrotron radiation, and finally shows first results obtained during the last machine run this year.

30 GHz Power Production in CTF3

The CLIC study is high power testing accelerating structures in a number of different materials and accelerating structure designs to understand the physics of breakdown, determine the appropriate scaling of performance and in particular to find ways to increase achievable accelerating gradient. The most recent 30 GHz structures which have been tested include damped structures in copper, molybdenum, titanium and aluminum. The results from these new structures are presented in this paper.

Longitudinal beam profile measurements at CTF3 using a streak camera

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 ...

30 GHz high-gradient accelerating structure test results

We discuss the RF system, the drive linac, drive beam generation, the isochronous ring drive beam scheme, the main linac injector system, machine parameters, beam dynamics and final focus studies and the alignment test facility and beam monitor test results.

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

The CLIC Test Facility CTF3, built at CERN by an international collaboration, aims at demonstrating the feasibility of the CLIC scheme of multi-TeV electron- positron collider by 2010. CTF3 consists of a 150 MeV drive beam linac followed by a 42 m long delay loop and an 84 m combiner ring. The installation will include in its final configuration a two-beam test stand and a test decelerator. The linac and delay loop have been already commissioned, while the combiner ring has been completed by the first half of 2007. High gradient testing of accelerating structures is also under way. The status of the facility, the experimental results obtained and the future plans will be presented.

CLIC-a compact and efficient high energy linear collider

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.

Results on CLIC proof of principle from CTF3

Abstract Discharge capillary-based active plasma lenses are a promising new technology for strongly focusing charged particle beams, especially when combined with novel high gradient acceleration methods. Still, many questions remain concerning such lenses, including their transverse field uniformity, limitations due to plasma wakefields and whether they can be combined in multi-lens lattices in a way to cancel chromaticity. These questions will be addressed in a new plasma lens experiment at the CLEAR User Facility at CERN. All the subsystems have been constructed, tested and integrated into the CLEAR beam line, and are ready for experiments starting late 2017.

Bunch frequency multiplication in the CLIC Test Facility CTF3

We present experimental evidence of electron induced upsets in a reference ESA SEU monitor, the SEU based particle detector, induced by 200 MeV electron beam at the VESPER facility at CERN. Comparison of experimental cross sections and simulated cross sections are shown and the differences are analyzed. Possible secondary contributions to the upset rate by neutrons and cumulative dose effects are discussed, showing that electronuclear reactions are the expected SEU mechanism. Insight is given as to possible overall electron contribution to the upset rates in the Jovian radiation environment inside a typical spacecraft shielding are evaluated.