CLIC Beam Position Monitor Tests

Prototype CLIC beam position monitors (BPMs) have been tested in the CLIC test facility (CTF) using a 50 MeV, 1 nC single bunch beam. The test set-up consisted of two BPMs and a charge normalization/phase reference cavity. The detection electronics consisted of a 5 channel super-heterodyne receiver to give charge independent horizontal and vertical positions in each BPM. Data were taken and processed at the full 10 Hz CTF repetition rate using a PC running LabVIEW. Both BPMs were mounted on 0.1 µm resolution micro-movers for displacement calibration. Separate tests in the lab of both cavities and electronics have shown that the potential resolution of the BPM system is less than one micron. An upper limit on resolution of ±4 µm has been demonstrated directly with the CTF beam. The measurement was almost certainly limited by the shot to shot angular jitter of the CTF beam

Ultra-fast sampling of terahertz pulses from a quantum cascade laser using superconducting antenna-coupled NbN and YBCO detectors

We demonstrate the ultra-fast detection of terahertz pulses from a quantum cascade laser (QCL) using superconducting NbN and YBCO detectors. This has enabled both the intrapulse and interpulse dynamics of a THz QCL to be measured directly, including interpulse heating effects on sub-μs timescales

Three-Dimensional Analysis of Wakefields Generated by Flat Electron Beams in Planar Dielectric-Loaded Structures

An electron bunch passing through dielectric-lined waveguide generates $\check{C}$erenkov radiation that can result in high-peak axial electric field suitable for acceleration of a subsequent bunch. Axial field beyond Gigavolt-per-meter are attainable in structures with sub-mm sizes depending on the achievement of suitable electron bunch parameters. A promising configuration consists of using planar dielectric structure driven by flat electron bunches. In this paper we present a three-dimensional analysis of wakefields produced by flat beams in planar dielectric structures thereby extending the work of Reference [A. Tremaine, J. Rosenzweig, and P. Schoessow, Phys. Rev. E 56, No. 6, 7204 (1997)] on the topic. We especially provide closed-form expressions for the normal frequencies and field amplitudes of the excited modes and benchmark these analytical results with finite-difference time-domain particle-in-cell numerical simulations. Finally, we implement a semi-analytical algorithm into a popular particle tracking program thereby enabling start-to-end high-fidelity modeling of linear accelerators based on dielectric-lined planar waveguides.Comment: 12 pages, 2 tables, 10 figure

30 GHz RF Pulse Stretcher for CTF2

A 30 GHz pulse stretcher was designed, manufactured, tuned, and installed within a period of about two months and was successfully used in CTF2 to investigate the pulse length dependence of maximum achievable surface gradient in one of the copper 30 GHz accelerating structures

The Compact Linear e+^+e−^- Collider (CLIC): Accelerator and Detector

The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear e$^+$e$^-$ collider under development by international collaborations hosted by CERN. This document provides an overview of the design, technology, and implementation aspects of the CLIC accelerator and the detector. For an optimal exploitation of its physics potential, CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, for a site length ranging between 11 km and 50 km. CLIC uses a two-beam acceleration scheme, in which normal-conducting high-gradient 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments, and system tests have resulted in significant progress in recent years. Moreover, this has led to an increased energy efficiency and reduced power consumption of around 170 MW for the 380 GeV stage, together with a reduced cost estimate of approximately 6 billion CHF. The detector concept, which matches the physics performance requirements and the CLIC experimental conditions, has been refined using improved software tools for simulation and reconstruction. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. The construction of the first CLIC energy stage could start as early as 2026 and first beams would be available by 2035, marking the beginning of a physics programme spanning 25-30 years and providing excellent sensitivity to Beyond Standard Model physics, through direct searches and via a broad set of precision measurements of Standard Model processes, particularly in the Higgs and top-quark sectors.Comment: Input to the European Particle Physics Strategy Update on behalf of the CLIC and CLICdp Collaboration

Energy dependence of processing and breakdown properties of Cu and Mo

Peer reviewe

The Rydberg-Atom-Cavity Axion Search

We report on the present progress in development of the dark matter axion search experiment with Rydberg-atom-cavity detectors in Kyoto, CARRACK I and CARRACK II. The axion search has been performed with CARRACK I in the 8 % mass range around $10 \mu {\rm eV}$, and CARRACK II is now ready for the search in the wide range $2 \mu {\rm eV} - 50 \mu {\rm eV}$. We have also developed quantum theoretical calculations on the axion-photon-atom system in the resonant cavity in order to estimate precisely the detection sensitivity for the axion signal. Some essential features on the axion-photon-atom interaction are clarified, which provide the optimum experimental setup for the axion search.Comment: 8 pages, 2 figures, Invited talk presented at the Dark2000, Heidelberg, Germany,10-15 July, 200