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The Advanced Proton Driven Plasma Wakefield Experiment (AWAKE) at CERN uses 6 cm long proton bunches extracted from the Super Proton Synchrotron (SPS) at 400 GeV beam energy to drive high gradient plasma wakefields for the acceleration of electron bunches to 2 GeV within a 10 m length. Knowledge and control of the position of both copropagating beams is crucial for the operation of the experiment. Whilst the current electron beam position monitoring system at AWAKE can be used in the absence of the proton beam, the proton bunch signal dominates when both particle bunches are present simultaneously. A new technique based on the generation of Cherenkov diffraction radiation (ChDR) in a dielectric material placed in close proximity to the particle beam has been designed to exploit the large bunch length difference of the particle beams at AWAKE, 200 ps for protons versus a few ps for electrons, such that the electron signal dominates. Hence, this technique would allow for the position measurement of a short electron bunch in the presence of a more intense but longer proton bunch. The design considerations, numerical analysis and plans for tests at the CERN Linear Electron Accelerator for Research (CLEAR) facility are presented., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The Beam-Gas Curtain or BGC is the baseline instrument for monitoring the concentricity of the LHC proton beam with a hollow electron beam for the hollow e-lens (HEL) beam halo suppression device which is part of the High-Luminosity LHC upgrade. The proof-of-principles experiments of this gas-jet monitor have now been developed into a prototype instrument which has been built for integration into the LHC ring and is now under phased installation for operation in the upcoming LHC run. This paper describes the challenges overcome to produce a gas-jet fluorescence monitor for the ultra-high vacuum accelerator environment. It also presents preliminary results from the installation of the instrument at CERN., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

A gas jet beam profile monitor was designed for measuring the electron beam at the electron beam test stand (EBTS) for the Hollow electron lens (HEL) and the proton beam in the large hadron collider (LHC). It is partially installed in the LHC during the second long shutdown. The current monitor is tailored to the accelerator environment including vacuum, geometry, and magnetic field for both the EBTS and the LHC. It features a compact design, a higher gas jet density, and a wider curtain size for a better integration time and a larger detecting range. In this contribution, the commissioning of this monitor at the Cockcroft Institute will be discussed., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

For the accelerator-based future of high energy physics at the energy frontier, CERN started to investigate a 92 km circumference Future Circular Collider (FCC), as e⁺/e⁻ collider the FCC-ee will operate at beam energies up to 182.5 GeV. Beside the machine operational aspects, beam instrumentation will play a key role in verifying and optimizing the machine to achieve the ambitious beam parameters and quality. This paper gives a brief overview of the various challenges to develop the required beam instruments, with focus on beam position, beam size and bunch length measurements, and well as an outline of the planned R activities., Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, Italy

The Advanced Wakefield Experiment (AWAKE) at CERN investigates the Plasma-Wakefield acceleration of electrons driven by a relativistic proton bunch. After successfully demonstrating the acceleration process in the AWAKE Run 1, the experiment has now started the Run 2. The AWAKE Run 2 consists of several experimental periods that aim to demonstrate the feasibility of the AWAKE concept beyond the acceleration experiment, showing its feasibility as accelerator for particle physics application. As part of these developments, a dramatic effort in improving the AWAKE instrumentation is sustained. This contribution reports on the current developments of the instrumentation pool upgrade, including the digital camera system for transverse beam profile measurement, beam halo measurement and the spectrometer upgrade studies. The studies on the development of high-frequency beam position monitors are also described., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

"Fast Monte-CarlO approach to Coherence of Undulator Sources" (FOCUS) is a new GPU-based code to compute the transverse coherence of X-ray radiation from undulator sources. The code relies on scaled dimensionless quantities and analytic expressions of the electric field emitted by electrons in an undulator, obtained in the frequency domain under paraxial approximation (justified by the assumption of ultra-relativistic electrons) and free space propagation, with the addition of the resonance approximation. We describe the core structure of the code, which exploits GPUs for massively parallel computations. We validate our approach by direct comparison with SRW (Synchrotron Radiation Workshop) simulations. The benchmarks prove that FOCUS yields similar results with respect to SRW, while at the same time reducing the computation times by five orders of magnitude. Finally, we show examples of applications to beam size diagnostics. The aim of the code is to fast evaluating the transverse coherence properties of undulator X-ray radiation as a function of the electron beam parameters, and to support and help preparing more rigorous numerical simulations with traditional codes like SRW., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

In recent years the potential of using Cherenkov Diffraction Radiation (ChDR) as a tool for non-invasive beam diagnostics has been thoroughly investigated. Although several theoretical models of ChDR have been developed, differences in their assumptions result in inconsistent predictions. The experimental verification is therefore needed in order to fully understand ranges of validity of available models. In this contribution we present a detailed theoretical study of the radiation yield as a function of the beam-radiator distance. Following identification of beam parameters and frequency range for which differences between the model predictions are most prominent, we compare theoretical estimates with the results of a dedicated experiment., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The Beam Rate of Neutrals (BRAN) is a monitor that provides a relative luminosity measurement for the four LHC experiments. BRANs are used during operations as a tool to find and optimise collision and to cross-check experiments luminosity monitors. While each LHC experiments is equipped with BRANs, in this contribution we will focus on the new monitors installed for ATLAS and CMS that will replace the current ageing gas chambers during LHC run 3. These will also serve as as prototypes for the future High Luminosity LHC monitors that will need to sustain an even higher collision rate. A description of the BRAN as well as the first results obtained during the LHC Run 3 start-up will be presented., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

The Beam Gas Vertex (BGV) instrument is a novel non-invasive transverse beam profile monitor under development for the High Luminosity Upgrade of the Large Hadron Collider (HL-LHC). Its principle is based on the reconstruction of the tracks and vertices issued from beam-gas inelastic hadronic interactions. The instrument is currently in the design phase, and will consist of a gas target, a forward tracking detector installed outside the beam vacuum chamber and computing resources dedicated to event reconstruction. The transverse beam profile image will then be inferred from the spatial distribution of the reconstructed vertices. With this method, the BGV should be able to provide bunch-by-bunch measurement of the beam size, together with a beam profile image throughout the whole LHC energy cycle, and independently of the beam intensity. This contribution describes the design of the gas target system and of the gas tank of the future instrument., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

An Electro-Optic Beam Position Monitor (EO-BPM) is being developed as a high-frequency (up to 10 GHz) diagnostic for crabbing and Head-Tail intra-bunch detection at the HL-LHC. Following an earlier prototype at the SPS that demonstrated single-pickup signals, an upgraded design of an interferometric EO-BPM has been beam-tested at the HiRadMat facility for validation and characterisation studies. In the new design, the fibre-coupled Mach-Zehnder interferometer arms are modulated by lithium niobate waveguides integrated in an upgraded opto-mechanical arrangement that has been developed to produce a highly magnified image field replica of the passing Coulomb field. A new detection technique that is directly sensitive to the interferometric optical difference signal from opposite EO buttons has been applied to measure single-shot bunches for the first time. A transverse resolution study over a ±20 mm range at 3 GHz bandwidth produced the first successful electro-optic bunch-by-bunch position measurement at the HiRadMat in-air extraction line. The results of this campaign show promise for an in-vacuum design that is in production for beam tests at the SPS during Run-3 of the LHC., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

In this paper, CST simulations of the coherent Cherenkov Diffraction Radiation with a range of parameters for different dielectric target materials and geometries are discussed and compared with the theoretical investigation of the Polarization Current Approach to design a prototype of a radiator for the bunch length/profile monitor for AWAKE Run 2. It was found that the result of PCA theory and CST simulation are consistent with each other regarding the shape of the emitted ChDR cone., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The Beam Gas Vertex (BGV) instrument is a non-invasive transverse beam profile monitor being designed as part of the High Luminosity Upgrade of the LHC (HL-LHC) at CERN. Its aim is to continuously measure bunch-by-bunch beam profiles, independent of beam intensity, throughout the LHC cycle. The primary components of the BGV monitor are a gas target and a forward tracking detector. Secondary particles emerging from inelastic beam-gas interactions are detected by the tracker. The beam profile is then inferred from the spatial distribution of reconstructed vertices of said interactions. Based on insights and conclusions acquired by a demonstrator device that was operated in the LHC during Run 2, a new design is being developed to fulfill the HL-LHC specifications. This contribution describes the status of the simulation studies being performed to evaluate the impact of design parameters on the instrument’s performance and identify gas target and tracker requirements., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

In recent years Cherenkov Diffraction Radiation (ChDR) has been reported as a phenomenon suitable for various types of particle accelerator diagnostics. As it would typically work best for highly relativistic beam, past studies and experiments have been mostly focusing on the lepton machines. This contribution investigates the prospects on the utilization of ChDR as a diagnostic tool for the Large Hadron Collider (LHC). Based on theoretical considerations and simulation results we estimate the properties of the expected radiation, both in the incoherent and coherent domain, and we compare them with the requirements of the existing diagnostic systems. We also address the potential problem of the use of dielectric radiators in circular machines, where secondary electrons could potentially lead to the creation of electron clouds inside the beam pipe that may affect the radiator., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

A Hollow Electron Lens (HEL) is currently under development for the High-Luminosity upgrade of the Large Hadron Collider (HL-LHC). In this device, a hollow electron beam co-propagates with a central proton beam and provides active halo control in the LHC. To ensure the concentricity of the two beams, a non-invasive diagnostic instrument is currently being commissioned. This instrument is a compact version of an existing prototype that leverages beam induced fluorescence with supersonic gas curtain technology. This contribution includes the design features of this version of the monitor, recent progress, and future plans for tests at the Cockcroft Institute and the electron lens test stand at CERN., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

A high bandwidth electro-optical beam position monitor is under development for the High Luminosity LHC. A series of measurements of the electro-optic signals were previously obtained by an EO-BPM prototype installed in the SPS. This paper focuses on an advanced design that would further improve the sensitivity of the pick-up by optimising the shape of the metallic electrode mounted onto the crystal. The proposed upgraded electro-optic pickups significantly increase the image field profile of the passing bunch inside a lithium niobate crystal embedded within the pickup. This work is based on parametric studies, performed using CST particle studio, investigating various electro-optic (electrode and crystal) configurations. We present the expected performance of the different designs, alongside with their evaluation on a test bench, highlighting the most relevant choice for a prototype pick-up to be installed on LHC, Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Since 2016 a prototype electro-optic pickup has been installed on the SPS as part of the ongoing development of a high bandwidth electro-optic beam position monitor for the High Luminosity LHC. Following the success of initial beam signal observations with the prototype, improvements of the sensitivity and stability of the pickup have become the main focus of the project. A new concept has been developed which uses an interferometric technique to measure the image field of a passing bunch. One arm of an interferometer passes through an electro-optic lithium niobate crystal, embedded in a pickup, whereas the other arm bypasses. The recombination after the pickup results in an interference pattern that changes as a bunch passes by, due to the electro-optic response of the crystal to the image field. This technique enhances the sensitivity to the field and improves control of the working point. Results from high intensity beams at the SPS are presented. These include a comparison between two different interferometric configurations that were tested on different pickups with similar beam conditions. The stability is assessed by frequency scanning interferometry during beam operation., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

When a relativistic charged particle travels at a short distance from the surface of dielectric material Cherenkov Diffraction Radiation (ChDR) is produced inside the dielectric. Recent observation of incoherent ChDR in the visible spectrum has opened the possibility of using this radiation for non-invasive beam size and position measurements. An experimental test to study this technique for highly directional beam position measurement has been initiated on the CLEAR facility at CERN, whilst another experimental investigation is underway at the Accelerator Test Facility 2 (ATF2) at KEK, Japan, to measure the resolution limit of ChDR for beam imaging diagnostics. This contribution presents the latest experimental results from both of these test facilities., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Intra-bunch transverse instabilities are routinely measured in the LHC using a "Head-Tail Monitor" based on sampling a wide-band BPM with a high-speed digitiser. However, these measurements are limited by the dynamic range and short record length possible with typical commercial oscilloscopes. This paper will present the initial results from the LHC Multi-Band Instability Monitor, a new technique developed to provide information on the beam stability with a high dynamic range using frequency domain analysis of the transverse beam spectrum., Proceedings of the 7\textsuperscript{th} Int. Beam Instrumentation Conf., IBIC2018, Shanghai, China

We present recent results on non-invasive beam profile measurement techniques based on Diffraction Radiation (DR) and Cherenkov Diffraction Radiation (ChDR). Both methods exploit the analysis of broadband electromagnetic radiation resulting from polarization currents produced in, or at the boundary of, a medium in close proximity of a charged particle beam. To increase the resolution of DR, measurements were performed in the UV range at a wavelength of 250 nm. With such configurations, sensitivity to the beam size of a 1.2 GeV electron beam below 10 um was observed at the Accelerator Test Facility (ATF) at KEK, Japan. In the case of the ChDR, a proof of principle study was carried out at the Cornell Electron Storage Ring (CESR) where beam profiles were measured in 2017 on a 5.3 GeV positron beam. At the time of writing an experiment to measure the resolution limit of ChDR has been launched at ATF where smaller beam sizes are available. We will present experimental results and discuss the application of such techniques for future accelerators., Proceedings of the 7\textsuperscript{th} Int. Beam Instrumentation Conf., IBIC2018, Shanghai, China

During the last three years, the emission of Cherenkov Diffraction Radiation (ChDR), appearing when a relativistic charged particle moves in the vicinity of a dielectric medium, has been investigated with the aim of providing non-invasive beam diagnostics. ChDR has very interesting properties, with a large number of photons emitted in a narrow and well-defined solid angle, providing excellent conditions for detection with very little background. This contribution will present a collection of recent beam measurements performed at several facilities such as the Cornell Electron Storage Ring, the Advanced Test Facility 2 at KEK, the Diamond light source in the UK and the CLEAR test facility at CERN. Those results, complemented with simulations, suggest that the use of both incoherent and coherent emission of Cherenkov diffraction radiation could open up new beam instrumentation possibilities for relativistic charged particle beams., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

The CERN Linear Electron Accelerator for Research (CLEAR) has now finished its second year of operation, providing a testbed for new accelerator technologies and a versatile radiation source. Hosting a varied experimental program, this beamline provides a flexible test facility for users both internal and external to CERN, as well as being an excellent accelerator physics training ground. The energy can be varied between 60 and 220 MeV, bunch length between 1 and 4 ps, bunch charge in the range 10 pC to 2 nC, and number of bunches in the range 1 to 200, at a repetition rate of 0.8 to 10 Hz. The status of the facility with an overview of the recent experimental results is presented., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Due to limitations with non-invasive beam size diagnostics in the LHC, particularly during the energy ramp, there has been an interest to explore quadrupolar-based measurements for estimating the transverse beam size, and hence determining the transverse emittance. This technique is especially attractive as it is completely passive and can use the existing beam position instrumentation. In this work, we perform an analysis of this method and present recent measurements taken during energy ramps. Quadrupolar-based measurements are compared with wire-scanner measurements and a calibration strategy is proposed to overcome present limitations., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

Background Aspecific scoring systems are used to predict the risk of death postsurgery in patients with infective endocarditis ( IE ). The purpose of the present study was both to analyze the risk factors for in‐hospital death, which complicates surgery for IE , and to create a mortality risk score based on the results of this analysis. Methods and Results Outcomes of 361 consecutive patients (mean age, 59.1±15.4 years) who had undergone surgery for IE in 8 European centers of cardiac surgery were recorded prospectively, and a risk factor analysis (multivariable logistic regression) for in‐hospital death was performed. The discriminatory power of a new predictive scoring system was assessed with the receiver operating characteristic curve analysis. Score validation procedures were carried out. Fifty‐six (15.5%) patients died postsurgery. BMI >27 kg/m 2 (odds ratio [ OR ], 1.79; P =0.049), estimated glomerular filtration rate OR , 3.52; P IV ( OR , 2.11; P =0.024), systolic pulmonary artery pressure >55 mm Hg ( OR , 1.78; P =0.032), and critical state ( OR , 2.37; P =0.017) were independent predictors of in‐hospital death. A scoring system was devised to predict in‐hospital death postsurgery for IE (area under the receiver operating characteristic curve, 0.780; 95% CI, 0.734–0.822). The score performed better than 5 of 6 scoring systems for in‐hospital death after cardiac surgery that were considered. Conclusions A simple scoring system based on risk factors for in‐hospital death was specifically created to predict mortality risk postsurgery in patients with IE .

Quadrupolar moment measurements based on electromagnetic pick-ups (PU), like BPMs, have attracted particular interest as non-intercepting diagnostics to determine the transverse beam size. Here, the second-order moment, which contains information about the beam size, is extracted from the BPM electrode signals. Despite the simplicity of the concept, quadrupololar measurements have always been challenging in practice. This is related to the fact that the quadrupolar moment constitutes only a very small part of the total PU signal, which is dominated by the contributions of beam intensity and position. In this study we discuss the limitations of absolute quadrupolar measurements if applying traditional BPM technologies, and we propose a new approach to efficiently overcome them via movable PUs. Moreover, we highlight the potential use of BPMs as an emittance measurement system during the energy ramp at synchrotrons by performing differential quadrupolar measurements, which show a remarkably higher accuracy than absolute measurements. Dedicated studies using different types of BPMs in the Large Hadron Collider (LHC) at CERN demonstrated promising results., Proceedings of the 61\textsuperscript{st} ICFA ABDW on High-Intensity and High-Brightness Hadron Beams, HB2018, Daejeon, Korea

The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE), based at CERN, explores the use of a proton driven plasma wake-field to accelerate electrons at high energies over short distances. This paper introduces the Beam Position Measurement (BPM) system of the proton beamline and its performance. This BPM system is composed of 21 dual plane button pickups distributed along the 700m long transfer line from the CERN Super Proton Synchrotron (SPS) extraction point to beyond the plasma cell. The electrical pulses from the pickups are converted into analogue signals proportional to the intensity and displacement of the beam using logarithmic amplifiers, giving the system a high dynamic range (>50dB). These signals are digitized and processed by an FPGA-based front-end card featuring an ADC sampling at 40Msps. Each time a bunch is detected, the intensity and position data is sent over 1km of copper cable to surface electronics through a serial link at 10 Mbps. There, the data is further processed and stored. The dynamic range, resolution, noise and linearity of the system as evaluated from the laboratory and 2016 beam commissioning data will be discussed in detail., Proceedings of the 6th Int. Beam Instrumentation Conf., IBIC2017, Grand Rapids, MI, USA

The new "CERN Linear Electron Accelerator for Research" (CLEAR) facility at CERN started its operation in fall 2017. CLEAR results from the conversion of the CALIFES beam line of the former CLIC Test Facility (CTF3) into a new testbed for general accelerator R&D and component studies for existing and possible future accelerator applications. CLEAR can provide a stable and reliable electron beam from 60 to 220 MeV in single or multi bunch configuration at 1.5 GHz. The experimental program includes studies for high gradient acceleration methods, e.g. for CLIC X-band and plasma technology, prototyping and validation of accelerator components, e.g. for the HL-LHC upgrade, and irradiation test capabilities for characterization of electronic components and for medical applications. An overview of the facility capabilities and a summary of the latest results will be presented., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Nominal operating conditions for the Compact Linear Collider (CLIC) 380 GeV requires 72 MV/m loaded accelerating gradients for a 180 ns flat-top pulse. Achieving this requires extensive RF conditioning which past tests have demonstrated can take several months per structure, when conditioned at the nominal repetition rate of 50 Hz. At CERN there are three individual X-band test stands currently operational, testing up to 6 structures concurrently. For CLIC's 380 GeV design, 28,000 accelerating structures will make up the main linac. For a large scale conditioning programme, it is important to understand the RF conditioning process and to optimise the time taken for conditioning. In this paper, we review recent X-band testing results from CERN's test stands. With these results we investigate how to optimise the conditioning process and demonstrate the feasibility of pre-conditioning the structures at a higher repetition rate before installation into the main linac., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Based on recent measurements of incoherent Cherenkov Diffraction Radiation (ChDR) performed on the Cornell Electron Storage Ring, we present here a concept for the centering of charged particle beams when passing close to dielectric material. This would find applications as beam instrumentation in dielectric capillary tubes, typically used in novel accelerating technologies, as well as in collimators using bent crystals for high-energy, high-intensity hadron beams, such as the Large Hadron Collid-er or Future Circular Collider. As a charged particle beam travels at a distance of a few mm or less from the surface of a dielectric material, incoherent ChDR is produced inside the dielectric. The photons are emitted at a large and well-defined angle that allows their detection with a limited contribution of background light. A set of ChDR detectors distributed around a dielectric would enable both the beam position and tilt angle to be measured with a good resolution., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Measurements with quadrupolar pick-ups (PU) have attracted particular interest as non-intercepting diagnostics for determining the transverse beam size. They are based on processing the signals of an electromagnetic PU for the extraction of the second-order moment, which contains information about the beam size. Despite the simplicity of the concept, quadrupololar measurements have always been highly challenging in reality. This comes from the fact that the quadrupolar moment constitutes only a very small part of the total PU signal dominated by the intensity and the position signals. Therefore, the beam size information can easily be lost due to small imperfections in the signal processing chain, such as asymmetries in the electronics and cables. In this paper, we present a new method for quadrupolar measurements using movable PUs. Through position and aperture scans, our technique minimizes the parasitic beam position signal and takes into account imperfections of the PU, cables and electronics, thus enabling an efficient auto-calibration of the measurement system. Preliminary studies, using collimators with embedded electrostatic PUs in the LHC at CERN, have shown very promising results., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

An Electro-Optic Beam Position Monitor is being developed for the HL-LHC, aimed at the detection of high order proton bunch instabilities and as a diagnostic for crabbed bunch rotation. A prototype EO-BPM was installed in the CERN SPS during 2016 and recent first beam tests of the EO pick-up are presented. The tested system comprises two opposing pick-ups, each equipped with 5mm cubic LiNbO3 crystals in vacuum, illuminated by polarized light from a fibre-coupled CW 780 nm laser. The 1 ns proton bunch induces a temporal modulation in the polarization state of light emerging from each birefringent crystal, by the Pockels effect. The modulation is analyzed, then recorded by a fibre-coupled fast photodetector in the counting room. The very first experimental signals obtained by the EO-pickups of a passing proton bunch are reported as a proof of concept of the idea. Moreover, the expected response of the beam signal is measured with respect to remotely controlled changes in the polarizer and analyzer orientations. The data are compared with analytical and electromagnetic simulations. Following the first detection, we report the latest status of the prototype design and future prospects., Proceedings of the 6th Int. Beam Instrumentation Conf., IBIC2017, Grand Rapids, MI, USA

The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) at CERN aims to develop a proof-of-principle electron accelerator based on proton driven plasma wake-field acceleration. The core of AWAKE is a 10 metre long plasma cell filled with Rubidium vapour in which single, 400 GeV, proton bunches extracted from the CERN Super Proton Synchrotron (SPS) generate a strong plasma wakefield. The plasma is seeded using a femtosecond pulsed Ti:Sapphire laser. The aim of the experiment is to inject low energy electrons onto the plasma wake and accelerate them over this short distance to an energy of several GeV. To achieve its commissioning goals, AWAKE requires the precise measurement of the position and transverse profile of the laser, proton and electron beams as well as their temporal synchronisation. This contribution will present the beam instrumentation systems designed for AWAKE and their performance during the 2016 proton beam commissioning period., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

This paper presents the design on the Cornell Electron Storage Ring (CESR) of an experimental set-up to meas-ure incoherent Diffraction Cherenkov Radiation (DChR) produced in a 2 cm long SiO2 radiator by a 2.1 GeV elec-tron beam. The electron beam is circulating at a distance of few mm from the edge of the radiator and the DChR photon output power is expected to be significantly higher than the diffraction radiation power emitted from a metal-lic slit of similar aperture. The radiator design and the detection set-up are presented in detail together with sim-ulations describing the expected properties of the emitted DChR in terms of light intensity and spectral bandwidth. Finally, potential applications of DChR are discussed., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The LHC Schottky monitors have the potential to measure and monitor some important beam parameters, tune, momentum spread, chromaticity and emittance, in a non-invasive way. We present recent upgrade and improvement efforts of the transverse LHC Schottky systems operating at 4.8 GHz. This includes optimization of the slotted waveguide pickups and a re-design of the RF front-end electronics to detect the weak, incoherent Schottky signals in presence of large, coherent beam harmonics., Proceedings of the 5th Int. Beam Instrumentation Conf., IBIC2016, Barcelona, Spain

AWAKE will be the first proton driven plasma wakefield acceleration experiment worldwide. The facility is located in the former CNGS area at CERN and will include a proton, laser and electron beam line merging in a 10 m long plasma cell, which is followed by the experimental diagnostics. In the first phase of the AWAKE physics program, which started at the end of 2016, the effect of the plasma on a high energy proton beam will be studied. A proton bunch is expected to experience the so called self-modulation instability, which leads to the creation of micro-bunches within the long proton bunch. The plasma channel is created in a rubidium vapor via field ionization by a TW laser pulse. This laser beam has to overlap with the proton beam over the full length of the plasma cell, resulting in tight requirements for the stability of the proton beam at the plasma cell in the order of ~ 0.1 mm. In this paper the beam commissioning results of the ~810 m long transfer line for proton bunches with 3·10¹¹ protons/bunch and a momentum of 400 GeV/c will be presented with a focus on the challenges of the parallel operation of the laser and proton beam., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

The majority of optical diagnostics currently used will not stand up to the requirements of the next generation of particle accelerators. Current methodologies need innovation to be able to reach the sub-micrometre resolution and sensitivity that will be required. One technique that has the potential to meet these requirements is optical transition radiation (OTR) imaging. A new algorithm is proposed which incorporates OTR theory, optical effects and beam distribution. This algorithm takes an existing method used for beam imaging and pushes the limits resolution beyond that normally attainable. In doing so, it can provide a reliable and economical diagnostic for future accelerators. A discussion on further applications of the algorithm is also presented., Proceedings of the 8th Int. Particle Accelerator Conf., IPAC2017, Copenhagen, Denmark

Electro-Optic Transposition (EOT) is the basis for an improved longitudinal bunch profile diagnostic we are developing in ASTeC as part of the CLIC UK research program. The scheme consists of transposing the Cou-lomb field profile of an electron bunch into the intensity envelope of an optical pulse via the mixing processes that occur between a CW laser probe and Coulomb field in an electro-optic material. This transposed optical pulse can then be amplified and characterised using robust laser techniques ' in this case chirped pulse optical parametric amplification and frequency resolved optical gating, allowing the Coulomb field to be recovered. EOT is an improvement over existing techniques in terms of the achievable resolution which is limited by the EO material response itself, reduced complexity of the laser system required since nanosecond rather than femtosecond lasers are used, and insensitivity of the system to bunch-laser arrival time jitter due to using a nanosecond long probe. We present results showing the retrieval of a THz pulse (Coulomb field stand-in) which confirms the principle behind the EOT system., Proceedings of the 5th Int. Beam Instrumentation Conf., IBIC2016, Barcelona, Spain

Optical systems are used to transfer light in beam diagnostics for a variety of imaging applications. The effect of the point spread function (PSF) of these optical systems on the resulting measurements is often approximated or misunderstood. It is imperative that the optical PSF is independently characterised, as this can severely impede the attainable resolution of a diagnostic measurement. A high quality laser and specially chosen optics have been used to generate an intense optical point source in order to accomplish such a characterisation. The point source was used to measure the PSFs of various electron-beam imaging systems. These systems incorporate a digital micro-mirror array, which was used to produce very high (>105) dynamic range images. The PSF was measured at each intermediary image plane of the optical system; enabling the origin of any perturbations to the PSF to be isolated and potentially mitigated. One of the characterised systems has been used for optical transition radiation (OTR) measurements of an electron beam at KEK-ATF2 (Tsukuba, Japan)., Proceedings of the 5th Int. Beam Instrumentation Conf., IBIC2016, Barcelona, Spain

A limiting factor on the maximum beam intensity that can be stored in the Large Hadron Collider (LHC) is the growth of transverse beam instabilities. Understanding and mitigating these effects requires a good knowledge of the beam parameters during the instability in order to identify the cause and provide the necessary corrections. This paper presents the suite of beam diagnostics that have been put into operation to monitor these beam instabilities and the development of a trigger system to allow measurements to be made synchronously with multiple instruments as soon as any instability is detected., Proceedings of the 5th Int. Beam Instrumentation Conf., IBIC2016, Barcelona, Spain

In order to study the feasibility of Optical Transition (OTR) and Diffraction (ODR) Radiation based profile measurement for the future electron-positron linear colliders (ILC, CLIC) a new dedicated instrument is under development at CERN to be installed in KEK-ATF2 beam line in fall 2015. To optimize sensitivity to micron and sub-micron beam sizes, we plan to observe ODR/OTR in the visible-UV wavelength range, down to approximately 150 nm. ODR light will be produced by narrow (25-500 μm) slits with non-uniform reflectivity. To improve our knowledge on the complex pattern produced by ODR, a preparatory experiment is being conducted on the CTF3 CALIFES beam line (CERN). This device produces interferences between two OTR screens in the visible optical range with the possibility to control the distance between them, i.e. to probe the shadowing region. The new results of this OTR interference measurement will be presented, together with the latest results from the ODR run in CesrTA (Wilson lab-Cornell)., Proceedings of the 4th International Beam Instrumentation Conference, IBIC2015, Melbourne, Australia

Any imaging system requires the use of various optical components to transfer the light from the source, e.g. optical radiation generated by a charged particle beam, to the sensor. The impact of the transfer optics on the image resolution is often not well known. To improve this situation, the point spread function (PSF) of the optical system must be measured, preferably, with high dynamic range. For this purpose we have created an intense, small (~ 1 μm) point source using a high quality laser and special focusing optics; and introduced a digital micro-mirror array in the optical system to substantially increase its dynamic range. The PSFs of optical systems that are currently being developed for high resolution, high dynamic range beam imaging using optical transition and diffraction radiation are measured and compared to Zemax simulations. The goal of these studies is to systematically understand and mitigate any ill effects on the PSF due to aberrations, diffraction and misalignment of the components of the imaging system. We present the results of our measurements and simulations., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The Diode ORbit and OScillation System (DOROS) system is designed to provide accurate measurements of the beam position in the LHC. The oscillation part of the system, which is able to provide turn-by-turn data, is used to measure the transverse coupling. Since the system provides high resolution measurements for many turns only small excitations are needed to accurately measure the transverse coupling. In this article we present the performance the system to measure coupling and compare it to the BPMs not equipped with this system., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The main beam of the Compact LInear Collider (CLIC) requires the beam trajectory to be measured with 50 nm spatial resolution. It also requires a time resolution capable of making position measurements of the head and tail of the 156 ns long CLIC bunch train, for use in dispersion free steering based on an energy chirp applied along the train. For this purpose, a stainless steel 15 GHz cavity BPM prototype has been manufactured, installed at the CLIC Test Facility (CTF3) and tested with beam. An improved design has been fabricated from copper. We discuss results from the two types of the prototype pickups, both from laboratory tests and from beam tests. We also cover the development of the new downconverter electronics., Proceedings of the 4th International Beam Instrumentation Conference, IBIC2015, Melbourne, Australia

During the Run I in 2012, several instabilities have been observed at the Large Hadron Collider (LHC) during the Betatron squeeze. The predictions of instability thresholds are based on the computation of the beam Landau damping by calculating the Stability Diagrams (SD). These instabilities could be explained by a deterioration of the SD due to beam-beam resonance excitation which could change the particle distributions. Beam Transfer Functions (BTF) provide a measurement of the Stability Diagram. The BTFs are sensitive to the particle detuning with amplitude as well as to the particle distributions therefore they represent a powerful tool to understand experimentally the stability of beams during the LHC operational cycle. First BTF measurements at the LHC are presented for different machine configurations and settings and compared to predictions., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

Les filtres plantés de roseaux sont de plus en plus utilisés dans le traitement des eaux de ruissellement urbain. L’étude réalisée met en avant le traitement des surverses d’un déversoir d’orage par un filtre planté de macrophytes dans des conditions topographiques désavantageuses. L’absence de dénivelé concilié à une nappe phréatique affleurante a conduit à la création d’un ouvrage atypique qui fonctionne selon deux flux : horizontal et vertical. Les analyses réalisées sur ce site pilote mettent en avant la capacité épuratoire de la filière. Des points d’amélioration ont été définis afin de créer un dernier ouvrage similaire sur la commune.

The LHC Schottky system allows the measurement of beam parameters such as tune and chromaticity in an entirely non-invasive way by extracting information from the statistical fluctuations in the incoherent motion of particles. The system was commissioned in 2011 and provided satisfactory beam-parameter measurements during LHC run 1 for lead-ions. However, for protons its usability was substantially limited due to strong interfering signals originating from the coherent motion of the particle bunch. The system has recently been upgraded with optimized travelling-wave pick-ups and an improved 4.8~GHz microwave signal path, with the front-end and the triple down-mixing chain optimized to reduce coherent signals. Design and operational aspects for the complete system are shown and the results from measurements with LHC beams in Run II are presented and discussed., Proceedings of the 7th Int. Particle Accelerator Conf., IPAC2016, Busan, Korea

The extensive array of beam instrumentation with which the LHC is equipped, has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. High Luminosity LHC (HL-LHC) brings with it a number of new challenges in terms of instrumentation that will be discussed in this contribution. The beam loss system will need significant upgrades in order to be able to cope with the demands of HL-LHC, with cryogenic beam loss monitors under investigation for deployment in the new inner triplet magnets to distinguish between primary beam losses and collision debris. Radiation tolerant integrated circuits are also being developed to allow the front-end electronics to sit much closer to the detector. Upgrades to other existing systems are also envisaged; including the beam position measurement system in the interaction regions and the addition of a halo measurement capability to synchrotron light diagnostics. Additionally, several new diagnostic systems are under investigation, such as very high bandwidth pick-ups and a streak camera installation, both able to perform intra-bunch measurements of transverse position on a turn by turn basis., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA