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The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up anew energy frontier for exploration in 2010, it has gathered a global user community of about 9000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its instantaneous luminosity (rate of collisions) by a factor of five beyond the original design valueand the integrated luminosity (totalnumber of collisions) by a factor ten. The LHC is already a highly complexand exquisitely optimised machine so this upgrade must be carefully conceived and will require new infrastructures(underground and on surface)and over a decade to implement. The new configuration, known as High Luminosity LHC (HL-LHC), relies on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11–12Tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 100 metre-long high-power superconducting links with negligible energy dissipation, all of which required several years of dedicated R&D; effort on a global international level. The present document describes the technologies and components that will be used to realise the projectand is intended to serve as the basis for the detailed engineering design of the HL-LHC.

Pugnat, P. "Preliminary Study for a New Axion Dark-Matter Haloscope" in 12th "Patras" Workshop on Axions, WIMPs and WISPs, PATRAS 2016 / Kim, Younglm, Lindner, Axel, Semertzidis, Yannis K. (eds.), Verlag Deutsches Elektronen-Synchrotron : 2017 ; PATRAS 2016 : 12th "Patras" Workshop on Axions, WIMPs and WISPs, 2016-06-20 - 2016-06-24, Jeju Island 12th Patras Workshop on Axions, WIMPs and WISPs, AXION-WIMP 2016, Jeju Island, South Korea, 20 Jun 2016 - 24 Jun 2016; Hamburg : Verlag Deutsches Elektronen-Synchrotron, DESY-PROC, 129-132 (2017). doi:10.3204/DESY-PROC-2009-03/Pugnat_Pierre, A new haloscope for Axion dark-matter search is under study using in a first step the large bore superconducting magnet in construction at the LNCMI in Grenoble, which will produce 9~T in 812~mm diameter and 1400~mm height. Microwave cavities of high quality factor $Q\sim10^5-10^6$ will be developed at CAPP/IBS in Daejeon. Low-noise microwave amplification of the signal will be ensured by DC superconducting quantum interference devices (SQUID) or/and Josephson parametric amplifiers (JPA) cooled-down to 20~mK by a $^3$He/$^4$He dilution refrigerator. This new haloscope will be designed to probe QCD dark-matter Axions in the mass range of 1-100~$\mu$eV with unprecedented sensitivity., Published by Verlag Deutsches Elektronen-Synchrotron, Hamburg

Secondary electron emission processes under electron bombardment are central to many effects at surfaces and interfaces, and to many in vacuum high power RF electronic devices where multipactor can be very intense [1,2]. Ferrite materials are usually used in microwave components used in space telecommunication systems, as circulators, phase-shifters, switches, and isolators. The physics of the multipactor phenomenon existing in microwave devices based on ferrite materials is an important issue and it is urgent to be researched [3]. One difficulty in the analysis of the multipactor effect in RF components containing ferrite lies on the fact that this material is an anysotropic magnetic medium controlled by an applied permanent magnetic field, which is used to magnetize the ferrite material. SEY and other properties (structure, magnetic behaviour,...) of soft-magnetic materials were studied in this work. MnZn soft ferrites magnets are suitable in the situation of frequency < 3MHz, low loss and high μi. Compared with MnZn soft ferrite, NiZn soft ferrite are used at higher frequencies

This article describes a study performed on one of the CERN-SPS vertical rotational wire scanners in order to investigate the breakage of the wire, which occurred on several occasions during operation in 2012. The thermionic emission current of the wire was measured to evaluate temperature changes, and was observed to rise significantly as the wire approached the ultimate LHC beam in the SPS, indicating the possibility of strong coupling between the beam’s electromagnetic field and the wire. Different laboratory measurements, complemented by CST Microwave Studio simulations, have therefore been performed to try and understand the RF modes responsible for this heating. These results are presented here, along with the subsequent modifications adopted on all of the operational SPS wire scanners.

A radioactive source is proposed as a calibration device to verify the sensitivity of a microwave dark matter search experiment. The interaction of e.g., electrons travelling in an arbitrary direction and velocity through an electromagnetically “empty” microwave cavity can be calculated numerically. We give an estimation of the energy deposited by a charged particle into a particular mode. Numerical examples are given for beta emitters and two particular cases: interaction with a field free cavity and interaction with a cavity which already contains an electromagnetic field. Each particle delivers a certain amount of energy related to the modal R/Q value of the cavity. The transferred energy is a function of the particles trajectory and its velocity. It results in a resonant response of the cavity, which can be observed using a sensitive microwave receiver, provided that the deposited energy is significantly above the single photon threshold.

The feasibility of cleanly separating the main 10.128MHz bunches from the 101.28MHz satellite bunches with a travelling-wave type chopper at HIE-ISOLDE was investigated using a simple model comprising a chain of synchronised capacitors pulsed at high-voltage. Even with a relatively large transverse aperture of 30mm it appears feasible to remove the satellite bunches spaced at 75mm without significantly perturbing the main bunch. We estimate that for a chopping voltage of 1.2 kV a string of 20 capacitors is required to impart the required deflection of 4 mrad to beams with A=q = 4:5 and the mechanical length of the system can be kept under 0.5 m. The deflection imparted on the main pulse is . 1% of that received by the discarded satellite bunches and the transverse emittance growth of the beam is small if the rise/fall times are kept below 5 ns. The HIE-ISOLDE specification is similar to the specification of the meander strip-line chopper developed at CERN for Linac4 and the application of this technology at HIE-ISOLDE could be of interest.

For the characterization of components, systems and signals in the radiofrequency (RF) and microwave ranges, several dedicated instruments are in use. In this article the fundamentals of the RF signal techniques are discussed. The key element in these front ends is the Schottky diode which can be used either as a RF mixer or as a single sampler. The spectrum analyser has become an absolutely indispensable tool for RF signal analysis. Here the front end is the RF mixer as the RF section of modern spectrum analyses has a ra ther complex architecture. The reasons for this complexity and certain working principles as well as limitations are discussed. In addition, an overview of the development of scalar and vector signal analysers is given. For the determination of the noise temperature of a one-port and the noise figure of a two-port, basic concepts and relations are shown as well as a brief discussion of commonly used noise-measurement techniques. In a further part of this article the operating principles of network analysers are shown. A distinction can be made between scalar and vector network analysers and their methods of measuring the transmission or reflection coefficients are explained. As digital signal processing has become cheap and easily available over the last 30 years, these instruments have become extremely versatile and powerful. Fourier transformation permits time-domain measurements and allows the removal of undesired parts of the signal trace in the time domain by gating. Network analysers require sophisticated calibration procedures, which are now indispensable for many measurement applications. Non-linear network analysis completes tests of most characteristic amplifier features. The Smith chart is a very valuable and important tool that facilitates interpretation of S-parameter measurements. The last part of this article gives a brief overview of how to use the chart. Its definition as well as an introduction on how to navigate inside the chart are illustrated. Useful examples show the broad possibilities for use of the chart in a variety of applications. This article is a compilation of previous CAS proceedings where information being in the scope of the intermediate-level RF course was extracted.

During the development of ferrite-loaded accelerating cavities, the electromagnetic properties of the dispersive ferrite material need to be known. We describe a coaxial short-circuit measurement technique to measure the complex permeability of toroidal-shaped samples (127mm outer and 70mm inner diameter) that are exposed to an external magnetic bias field. The external magnetic bias field is applied perpendicular to the RF magnetic field. With this method it is possible to characterize the frequency dependence of the permeability for a frequency range of 1- 100MHz. The dependence of the permeability on the external magnetic bias is presented for the ferrite G-510 from Trans-Tech Inc. and the material characterization is shown in the same frequency range. The measurement results are verified by simulations of the measurement set-up.

For the special requirements related to particle accelerators, knowledge of the different material parameters of dielectrics and other materials are needed in order to carry out simulations during the design process of accelerator components. This includes also properties of magnetically biased ferrites of which usually little information is available about material characteristics, especially in magnetic bias fields. Several methods of measurement are discussed and compared of which some require delicate sample preparation whereas others can work with unmodified material shapes that makes those methods also suited for acceptance checks on incoming materials delivered by industry. Applications include characterization of different materials, as absorbers in which dielectric losses play an increasing role, as well as low frequency measurements on ferrites that are used for tunable cavities. We present results obtained from both broadband and resonant measurements on different materials determined in the same sample holder. Where possible, the results were confirmed with alternative methods.

Paper presented at the 8th International Workshop on Multipactor, Corona and Passive Intermodulation in Space RF Hardware (MULTICOPIM'14) held in Valencia (Spain) on 17-19 September 2014. The presentation took place in the Session 12: SEY Mitigation Techniques.

To mitigate electron cloud in particle accelerators a carbon coating with low SEY (Secondary Electron Yield) has been developed. In the case of the SPS (Super Proton Synchrotron), which belongs to the LHC injector chain, testing of the performance of coated beam pipes directly in the accelerator must cope with the schedule of the regular machine operation. For this reason an alternative tool based on RF induced multipacting in a coaxial configuration has been designed for ex-situ characterization of the main bending dipoles of the SPS. In this contribution we report the results obtained before and after coating for two 6.4 meter dipoles with different cross sections of the vacuum chambers. The multipacting is monitored by measuring the pressure rise and the RF reflected power. After coating, the power threshold to induce multipacting is strongly reduced indicating a lower propensity for electron cloud. The impact of the RF coupling on the sensitivity of the technique is discussed.

The two LHC injection kicker systems produce an integrated field strength of 1.3 T·m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen is placed in the aperture of each magnet, which consists of a ceramic tube with conductors in the inner wall. The conductors provide a path for the beam image current and screen the ferrite yoke against wakefields. Recent LHC operation, with high intensity beam stable for many hours, resulted in significant heating of both the ferrite yoke and beam impedance reduction ferrites. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the ferrite yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. Thermal measurement data has been analysed, a thermal model developed and emissivity measurements carried out. Various measures to improve the ferrite cooling have been simulated, including an improved emissivity of the vacuum tank and active cooling on the outside of the tank.

High secondary electron yield of metallic surfaces used in accelerator and also in space applications is of general concern. In addition to several well-known coating preparation techniques and microscopic or macroscopic mechanical roughness (grooves) which may significantly increase microwave losses the concept of magnetic surface roughness has been proposed recently to lower the effective secondary electron yield (SEY). In this concept a smooth and very good conducting surface with low microwave losses is maintained, but underneath this surface a large number of tiny permanent magnets are located to build a rough magnetic equipotential structure. In this paper we present and discuss measurement of the SEY and the improvement in terms of SEY for different parameter ranges.

In this work we describe the latest results for the measurements of the hyperfine structure of antiprotonic $^3$He. Two out of four measurable super-super-hyperfine {SSHF} transition lines of the $(n,L)=(36,34)$ state of antiprotonic $^3$He were observed. The measured frequencies of the individual transitions are $11.12548(08)$ GHz and $11.15793(13)$ GHz, with an increased precision of about 43% and 25% respectively compared to our first measurements with antiprotonic $^3$He [S. Friedreich {\it et al.}, Phys. Lett. B 700 (2011) 1--6]. They are less than $0.5$~MHz higher with respect to the most recent theoretical values, still within their estimated errors. Although the experimental uncertainty for the difference of $0.03245(15)$~GHz between these frequencies is large as compared to that of theory, its measured value also agrees with theoretical calculations. The rates for collisions between antiprotonic helium and helium atoms have been assessed through comparison with simulations, resulting in an elastic collision rate of $\gamma_e = 3.41 \pm 0.62$~MHz and an inelastic collision rate of $\gamma_i = 0.51 \pm 0.07$~MHz.

A novel type of 2.76 m long slotted, or perforated, strip-line pick-up, or kicker electrode structure, for CSRe stochastic cooling of non-relativistic particle beams with β~ 0.7 is presented. It is installed inside a bending vacuum chamber with the output signal taken from the downstream end. This slotted structure features a sufficiently broad bandwidth, good beam coupling impedance, low losses and a comparatively easy mechanical construction and installation into the CSRe dipole chamber. In this paper the electrode structure and pickup tank, as well as the beam test results will be presented.

CERN, the European Organization for Nuclear Research, is actively engaged in identifying technologies developed for its accelerator complex that could be profitably used by partner research organizations or commercial companies in applications with potentially high socio-economic impact beyond pure fundamental physics research. \nIn the first part of the paper, an overview of CERN current strategy in the field of Technology Transfer and Intellectual Property Management will be presented, with details on the most effective models, implementation tools and processes developed to achieve satisfactory dissemination and valorisation of the knowledge generated within the Organization. \nIn the second part, CERN currently available technology portfolio will be described with focus on cases originated from the Accelerator and Technology Sector. A selection of promising on-going projects embracing a variety of technology fields and application areas will be detailed to showcase technical challenges and possible benefits of initiatives driven by (but not limited to) the needs of CERN scientific programme.

As the ELENA project is now well underway, focus is turned to the Antiproton Decelerator (AD) itself. Most of the machine’s key components are in operation since more than 25 years and a substantial consolidation program is now being launched in view of continued operation beyond 2025. \nOver the course of the next few years a progressive consolidation of the AD Target area, the AD ring and all associated systems will take place. Several investigations have recently been performed in the target area with the objective of establishing the radiation environment and the sensitivity of the antiproton production to potential misalignment of the production elements. Identification of reliability and serviceability issues of the AD ring components and associated systems has been done and will continue during the 2013 shut-down. Planned and on-going consolidation activities are also discussed with emphasis on stochastic and electron beam cooling, instrumentation, RF systems, vacuum, magnets, power converters and beam transfer equipment.