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The ECN3 Beam Delivery Task Force was mandated by the PBC Study Group to assess the technical feasibility of increasing the proton beam intensity to the ECN3 hall of the North Area to satisfy the demands of a compelling set of PBC experimental physics proposals. This report summarises the findings of the Task Force that converge on a technically feasible solution with an implementation timeline that could exploit and build upon the investment already foreseen as part of Phase 1 of the NA-CONS project, and take the SPS complex into a new intensity frontier for Fixed Target physics in Run4.

The operation of wire grids and wire scanners as beam profile monitors can be heavily affected, both in terms of measurement accuracy and wire integrity, by the thermal response of the wires to the energy deposited by the charged particles. Accurate measurements of material emissivity are crucial, as Radiative Cooling represent the most relevant cooling process. In this work, we present a method for emissivity measurements of gold-coated tungsten wires based on calorimetric techniques. The dedicated electrical setup allowed allowed transient and steady state measurements for temperatures up to 2000 K. A theoretical description of the measurement technique will be followed up by the electrical set up description and a detailed discussion about the measured results and uncertainties., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

At the CERN Super Proton Synchrotron (SPS) the proton beam is supplied to the fixed target experiments in the North Area facility (NA) via a slow extraction process, taking place at 400 GeV. The monitoring of the spill quality during the extraction, lasting 4.8 seconds with the present SPS setup, is of high interest for minimising beam losses and providing the users with uniform proton-on-target rates. The monitor development challenges include the need for detecting, sampling, processing and publishing the data at rates ranging from few hundred Hz to support the present operation to several hundreds of MHz to serve future experiments proposed within the Physics Beyond Collider (PBC) programme. This paper will give an overview of the ongoing studies for optimizing the existing monitors performances and of the R dedicated to future developments. Different techniques are being explored, from Secondary Emission Monitors to Optical Transition Radiation (OTR), Gas Scintillation and Cherenkov detectors. Expected ultimate limitations from the various methods will be presented, together with 2022 experimental results, for example with a recently refurbished OTR detector., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

The CHARM High-energy Ions for Micro Electronics Reliability Assurance (CHIMERA) working group at CERN is investigating the feasibility of delivering high energy ion beams to the CHARM facility for the study of radiation effects to electronics components engineered to operate in harsh radiation environments, such as space or high-energy accelerators. The Proton Synchrotron has the potential of delivering the required high energy and high-Z (in this case, Pb) ions for radiation tests over the relevant range of Linear Energy Transfer of ~ 10 - 40 MeV cm²/mg with a > 1 mm penetration depth in silicon, specifically for single event effect tests. This contribution summarises the working group’s progress in demonstrating the feasibility of variable energy slow extraction and over a wide range of intensities. The results of a dedicated 6 GeV/u Pb ion beam test are reported to understand the performance limitations of the beam instrumentation systems needed to characterise the beam in CHARM., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

To provide HL-LHC performance, the CERN LHC injector chain underwent a major upgrade during an almost 2-year-long shutdown. In the first half of 2021 the injectors were gradually re-started with the aim to reach at least pre-shutdown parameters for LHC as well as for fixed target beams. The strategy of the commissioning across the complex, a summary of the many challenges and finally the achievements will be presented. Several lessons were learned and have been integrated to define the strategy for the performance ramp-up over the coming years. Remaining limitations and prospects for LHC beam parameters at the exit of the LHC injector chain in the years to come will be discussed. Finally, the emerging need for improved operability of the CERN complex will be addressed, with a description of the first efforts to meet the availability and flexibility requirements of the HL-LHC era while at the same time maximizing fixed target physics output., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The ability of reliably measuring the transverse beam profile in its injectors is essential for the operation of the LHC. This report aims to assess the reliability, stability, and reproducibility of the new generation of beam wire scanners developed at CERN in the framework of the LHC Injectors Upgrade (LIU). The study includes data from the over 60000 scans performed in 2021 and 2022, with a special focus on reproducibility, investigation of optimal operational settings to ensure a large dynamic range, and evaluation of absolute accuracy through comparison with other instruments present in the injectors., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

In December 2020 the newly commissioned LINAC4 started delivering beam for the CERN proton accelerator chain, replacing the old LINAC2. LINAC4 is a 352 MHz normal conducting linac, providing a beam of negative hydrogen ions at 160 MeV that are converted into protons at injection into the PS Booster synchrotron. In this paper we report on the achieved beam performance, availability, reproducibility and other operational aspects of LINAC4 during its first fully operational year. We also present the machine developments performed and the plans for future improvements., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

In the framework of the LHC Injectors Upgrade project, the Beam Gas Ionisation (BGI) profile monitors installed in the Proton Synchrotron (PS) were fitted with a gas injection system capable of boosting the signal rate high enough to capture single turn acquisitions immediately after injection. This contribution reports on the studies carried out during the beam commissioning of the BGI system in a turn-by-turn matching monitor mode for its eventual implementation in an optimisation framework to preserve emittance during transfer between the PS Booster and PS. The BGI commissioning included a benchmarking with data from a wire-grid secondary emission monitor inserted into the circulating beam., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The CERN fixed target experimental areas have recently acquired new importance thanks to newly proposed experiments, such as those linked to Physics Beyond Colliders (PBC) activities. Secondary Emission Monitors (SEMs) are the instruments currently used for measuring beam current, position and size in these areas. Guaranteeing their reliability, resistance to radiation and measurement precision is challenging. This paper presents the studies being conducted to understand ageing effects on SEM devices, to calibrate and optimise the SEM design for future use in these beamlines. These include feasibility studies for the application of machine learning techniques, with the objective of expanding the range of tools available for data analysis., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

The LINAC4 is now equipped with two laser profile and emittance meters, basically non destructive and not limited by beam power density. A pulsed laser is transported through fibres and focused into the 160 MeV H⁻ beam. Its interaction with the H⁻ ions detaches electrons that are collected by an electron-multiplier, while the resultingH⁰ particles, after being separated from the main H⁻ beam by a dipole magnet, are recorded by a diamond strip detector, few meters away from the interaction point. The emittance and profile are reconstructed from the laser step by step scan of the beam. After several years of feasibility tests and prototyping, this paper will present all details about the final HW and SW implementation and the 2022 experimental results., Proceedings of the 11th International Beam Instrumentation Conference, IBIC2022, Kraków, Poland

As part of the LHC injector Upgrade (LIU), the CERN SPS is now equipped with a new Beam Dumping System (SBDS) designed to cope with the high power beams foreseen for the High Luminosity LHC (HL-LHC) era. Before reaching the dump, the proton beam (from 26 to 450 GeV) is vertically kicked and then diluted passing through a series of horizontal and vertical bumps. This prevents the dump damage, by reducing the power density per surface unit. The quality of each dump event must be recorded and verified and all parameters of the SBDS are logged and analysed from the so-called Post-Mortem dataset. An essential part of the verification is performed by a beam imaging system based on a Chromox screen imaged on a digital camera. The desired availability level (100%, to protect the dump) and the harsh radiation environment made the design extremely challenging. For example, it implied the need for a 17 m long optical line made of high-quality optical elements, a special camera shielding (to minimise single event upsets) and a generally careful design accounting for maintenance aspects, mainly related to expected high activation levels. After giving an overview of the whole imaging system design with details on the chosen layout and hardware, this paper will discuss the DAQ and SW architecture, including the automatic, on-line, image selection for validating every dump event. This will be complemented with experimental results demonstrating the performance and reliability achieved so far., Proceedings of the 10th International Beam Instrumentation Conference, IBIC2021, Pohang, Rep. of Korea

A novel generation of fast Beam Wire Scanners (BWS), developed in the framework of the LHC Injectors Upgrade (LIU), has been recently deployed in the 3 LHC injector synchrotrons, accelerating protons from 160 MeV to 450 GeV, during the 2019-2020 LHC long shutdown. The monitors feature high precision motor controller, high resolution wire position monitoring and wide dynamic range secondary particles detectors. This contribution will document the commissioning of the 17 new systems during the accelerator complex restart in 2021, which is an exciting and challenging phase in the life cycle of an instrument. A summary of the so far achieved levels of reliability, reproducibility, detectors/DAQ bandwidth and overall accuracy, will be used to revisit the options for further improving the systems��� performance in the future., Proceedings of the 10th International Beam Instrumentation Conference, IBIC2021, Pohang, Rep. of Korea

During the LHC Long Shutdown 2 (LS2), the H��� LINAC4 replaced the proton LINAC2 as Proton Synchrotron Booster (PSB) injector. In each of the four PSB rings, the injection region was upgraded to accommodate the necessary elements for a proper H��� charge exchange injection systems. Four internal beam dumps (one per ring), installed downstream the stripping foil, block the unstripped H��� particles not injected in the ring. The H0-H��� monitors consists in 4 titanium plates placed few centimetres upstream of the dump, intercepting partially stripped H��� or not stripped H��� ions. They allow a continuous monitoring of the stripping efficiency and, connected to an interlock system, block the injection process in case of heavy degradation or breakage of the foil, which would heavily damage the dumps. The contribution will focus on the commissioning and operation these new systems. This will include the calibration campaigns, performed by comparison to beam current transformers during special periods with low intensity beams and no stripping foils. During normal operation it was already possible to monitor stripping inefficiencies below 1% and compare different beams and stripping foil types., Proceedings of the 10th International Beam Instrumentation Conference, IBIC2021, Pohang, Rep. of Korea

The LHC injectors Upgrade (LIU) program has been fully implemented during the second long shutdown (LS2), which took place in 2019-20. In this context, new or upgraded beam instrumentation was developed to cope with H⁻ beam in LINAC4 and the new Proton Synchrotron Booster (PSB) injection systems which would provide high brightness proton beams in the rest of the injector complex. After a short overview of the newly installed diagnostics, the main focus of this paper will move to the instruments already commissioned with the beam. This will include LINAC4 diagnostics, the PSB H⁰/H⁻ monitor, the PSB Trajectory Measurement System, and the PS beam gas ionization monitor. In addition, particular emphasis will be given to the first operational experience with the new generation of fast wire scanners installed in all injector synchronous., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

The operation of wire grids as beam profile monitors, both in terms of measurement accuracy and wire integrity, can be heavily affected by the thermal response of the wires to the energy deposited by the charged particles. A comprehensive model to describe such interaction has been implemented including beam induced heating, all relevant cooling processes and the various phenomena contributing to the wire signal such as secondary emission and H⁻ electron scattering. The output from this model gives a prediction of the wire signal and temperature evolution under different beam conditions. The model has been applied to the wire grids of the CERN LINAC4 160 MeV H-beam and compared to experimental measurements. This successful benchmarking allowed the model to be used to review the beam power limits for operating wire grids in LINAC4., Proceedings of the 9th International Beam Instrumentation Conference, IBIC2020, Santos, Brazil

Understanding the different sources of emittance dilution along the LHC injector chain is an import-ant part of providing the high brightness proton beams demanded by the LHC Injectors Upgrade (LIU) project. In this context, the first beam-based measurements of the magnetic waveforms of the Proton Synchrotron Booster’s (PSB) extraction kickers were carried out and used to quantifythe transverse emittance blow-up during extraction and transfer to the Proton Synchrotron (PS).In this report, the waveform measurement technique will be briefly outlined before the results andtheir implications for the LIU project and beam performance reach are discussed.

Understanding the different sources of emittance dilution along the LHC injector chain is an important part of providing the high brightness proton beams demanded by the LHC Injectors Upgrade (LIU) project. In this context, the first beam-based measurements of the magnetic waveforms of the Proton Synchrotron Booster’s (PSB) extraction kickers were carried out and used to quantify the transverse emittance blow-up during extraction and transfer to the Proton Synchrotron (PS). In this contribution, the waveform measurement technique will be briefly outlined before the results and their implications for the LIU project and beam performance reach are discussed., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Many of the beam image systems at CERN are located in high radiation environments. In order to cope with this issue, VIDICON cameras are presently used but their production has been nowadays discontinued worldwide. The development of an alternative beam imaging system is described here, based on radiation tolerant optical fibre bundles. Such an optical line relays the image of a scintillating screen to a standard CMOS camera, located away from the high radiation zone. A prototype system based on a 10m long bundle with 10⁴ fibres has been tested in the TT2 transfer line at CERN. The light transmission is rather low, but is compensated by the sensitivity of the CMOS camera. The system had a field of view of 60 mm and a spatial resolution of ~1 mm. The radiation hardness of such a fiber bundle was tested at the IRMA-CEA facility in Saclay, France. The bundle was irradiated at a rate of 3.6 kGy/h for 8 consecutive day. The total integrated dose achieved was ~700 kGy, which corresponds to about ten years of operation at the beam imaging station with the highest radiation dose at CERN. While the light transmission was reduced by 50%, this is still adequate to provide acceptable images., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

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

We present the recent developments of a study aiming at measuring the transverse beam profile using the Heterodyne Near Field Speckles (HNFS) method. The HNFS technique consists of a suspension of nanoparticles suspended in a liquid and illuminated by synchrotron radiation (either in the visible or in X-ray wavelength range). The transverse coherence of the source, and therefore, under the conditions of validity of the Van Cittert and Zernike theorem, the transverse electron beam size is retrieved from the interference between the transmitted beam and the spherical waves scattered by each nanoparticle. We here describe the fundamentals of this technique, as well as the recent experimental results obtained with 12 keV radiation at the NCD beamline at ALBA. The applicability of such technique for future accelerators (e.g. CLIC or FCC) is also discussed., Proceedings of the 7\textsuperscript{th} Int. Beam Instrumentation Conf., IBIC2018, Shanghai, China

In the framework of the LHC Injectors Upgrade (LIU) project, the investigation and quantification of the optics mismatch between the CERN Proton Synchrotron Booster (PSB) and PS is a crucial step in understanding the source of horizontal emittance growth between the two machines. Extensive studies were carried out to estimate the mismatch from single-pass measurements in the transfer line and to rematch the transfer line to reduce the dispersive mismatch at PS injection while keeping the betatron matching unaltered. This paper presents the results of the data analysis of more recent multi-turn measurements, which profited from a new turn-by-turn beam profile monitor in the PS ring, to assess the achieved level of matching and corresponding emittance growth. The results confirm the improved matching and demonstrate the feasibility of the multi-turn technique as a fundamental tool that will be important for the recommissioning of the renovated transfer line after Long Shutdown 2., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

Annual high intensity requests of over 10¹⁹ protons on target (POT) from the CERN Super Proton Synchrotron (SPS) Fixed Target (FT) physics program continue, with the prospect of requests for even higher, unprecedented levels in the coming decade. A concerted and multifaceted R effort has been launched to understand and reduce the slow extraction induced radioactivation of the SPS and to anticipate future experimental proposals, such as SHiP* at the SPS Beam Dump Facility (BDF)**, which will request an additional 4·10¹⁹ POT per year. In this contribution, we report on operational improvements and recent advances that have been made to significantly reduce the slow extraction losses, by up to a factor of 3, with the deployment of new extraction concepts, including passive and active (thin, bent crystal) diffusers and extraction on the third-integer resonance with octupoles. In light of the successful tests of the prototype extraction loss reduction schemes, an outlook and implications for future SPS FT operation will be presented., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

At CERN, fast beam wire scanners serve as reference transverse profile monitors in all synchrotrons. As part of the LHC Injector Upgrade project, a new generation of scanners has been designed to improve system reliability, precision and accuracy in view of higher brightness beams. This paper will discuss the performance achieved during both laboratory calibration and prototype testing with beam. The beam measurements performed in 2018 demonstrated excellent system reliability and reproducibility, while calibration in the laboratory showed that an accuracy below 10 um can be achieved on the wire position determination., Proceedings of the 8th International Beam Instrumentation Conference, IBIC2019, Malmö, Sweden

Transverse emittance measurements with wire scanners have been extensively studied across the accelerator complex at CERN due to their important role in characterizing the beam and their complicated modeling. In recent years, this topic has been of particular interest for the LHC Injectors Upgrade (LIU) project, where a tight transverse emittance blow-up budget between the Proton Synchrotron Booster (PSB) and the Proton Synchrotron (PS) is imposed to assure the required beam brightness for the High Luminosity LHC (HL-LHC). In order to maintain a high brightness beam, any source of emittance blow-up along the PSB cycle needs to be identified and mitigated. While wire scanners have been mostly used at extraction energy in the PSB, they can also operate along the energy cycle. The scattering of the protons with the wire increases considerably at lower energies, leading to an overestimation of the beam emittance. In this contribution we present the most recent studies, focusing on precisely quantifying the blow-up created by the flying wire with measurements in an optimized set-up and compared to FLUKA simulations., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

The high efficiency of most slow extraction systems makes quantifying the exact amount of beam lost in the process extremely challenging. This is compounded by the lack of time structure in the extracted beam, as is typically required by the high-energy physics experiments, and the difficulty in accurately calibrating D.C. intensity monitors in the extraction line at count rates of ~ 10¹³ Hz. As a result, it is common for the extraction inefficiency to be measured by calibrating the beam loss signal induced by the slow extraction process itself. In this paper, measurements of the extraction efficiency performed at the CERN Super Proton Synchrotron for the third-integer resonant slow extraction of 400 GeV protons over recent years will be presented and compared to expectation from simulation. The technique employed will be discussed along with its limitations and an outlook towards a future online extraction efficiency monitoring system will be given., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada